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Table of Content

    10 May 2009, Volume 42 Issue 5
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Fundamental Roles of Cornerstone Breeding Lines in Wheat Reflected by SSR Random Scanning
    Scientia Agricultura Sinica. 2009, 42(5):  1503-1511 .  doi:10.3864/j.issn.0578-1752.2009.05.001
    Abstract ( 1018 )   PDF (444KB) ( 1805 )   Save
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    【Objective】 The purpose of this study was to reveal genetic relationship between the large-scale cultivated wheat varieties and the founder genotypes (cornerstone breeding parents) and illuminate the role of the founder genotypes in breeding at genomic level. 【Method】 Sixty-six large-scale planted varieties and 13 founder genotypes were genotyped at 481 SSR loci by the ABI 3730. 【Result】 Analyses of principal coordinate (PCO) and neighbor-joining cluster based on the genotyping data showed that the 66 large-scale planted varieties were clustered into six major groups. In each group, there is at least one founder. Within each group, most of the large-scale planted varieties are the descendents of the founder. Varieties from the same province usually jointed into one group. Two founders, Bima 4 and St2422-464 convey more alleles favored in breeding than their sister lines, Bima 1 and St1472-506, respectively. Usually, the older cornerstone breeding parents are the founders for the new ones. Among sister lines, the new founder has more difference than large-scale cultivated varieties to their founder genotype. 【Conclusion】 Therefore, innovation and enhancement of germplasm is the base for breeding large-scale planted varieties. It should occupy proper portion in national breeding program.

    Cloning of BnWRI1 Gene and the Effect of RNA Interference on Seed Oil Content in Oilseed Rape
    Scientia Agricultura Sinica. 2009, 42(5):  1512-1518 .  doi:10.3864/j.issn.0578-1752.2009.05.002
    Abstract ( 913 )   PDF (437KB) ( 976 )   Save
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    【Objective】 The study was to determine the effect of BnWRI1 gene on oil content of oilseed rape seed. 【Method】RT-PCR was employed to isolate a 384 bp fragment from the coding region of BnWRI1, which was then inserted into the RNAi vector of pGΩ4ARi in both forward and reverse directions to form a plant expression vector pGΩ4ARi-WRI1. The vector was introduced into oilseed rape cv. Zhongshuang 9 via pollen-tube pathway method. 【Result】 Three transgenic plants were confirmed by PCR and Southern Blot analysis that the foreign fragment integrated into the plant genomes. BnWRI1 transcript levels and seed oil contents were detected by semi-quantitative RT-PCR and improved Soxhlet extraction, respectively. The results showed that BnWRI1 expression was inhibited and seed oil content drastically decreased in each transgenic plant compared with non-transgenic plants. 【Conclusion】 Silencing endogenous BnWRI1 by RNAi can decrease seed oil content, which suggested BnWRI1 could effectively regulate seed oil content in oilseed rape.

    Advances in Research on Genetic Resources, Breeding and Genetics of Mungbean (Vigna radiata L.)
    Scientia Agricultura Sinica. 2009, 42(5):  1519-1527 .  doi:10.3864/j.issn.0578-1752.2009.05.003
    Abstract ( 1077 )   PDF (330KB) ( 1481 )   Save
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    As a traditional crop, mungbean (Vigna radiata L.) is widely cultivated in China. It is also important in modern planting systems because it can improve the environments of soils by nitrogen fixation. However, comparing to the major crops, the genetic study of mungbean is lagged, which has limited the intensive development of this crop. In the paper, studies on breeding and genetics of mungbean both in China and the world were reviwed, the main aim is to supply useful information so as to improve the genetic study and accelerate the development of mungbean in China.

    A Review of Utilization of Heterosis in Three Legume Crops of Pigeonpea, Alfalfa and Soybean
    Scientia Agricultura Sinica. 2009, 42(5):  1528-1539 .  doi:10.3864/j.issn.0578-1752.2009.05.004
    Abstract ( 1007 )   PDF (324KB) ( 1075 )   Save
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    The legume used to be believed a species that its heterosis is difficult to be utilized in crop production. The release of commercial hybrids in pigeonpea, alfalfa and soybean in recent years has paved the way for the exploitation of heterosis in legume crops. The advances in the discovery of male sterility, the development of hybrid cultivars and in the technology improvement of hybrid seed production in these three crops are reviewed in details with the emphasis on the applied technology development. Studies show that heterosis commonly exists in legumes. The keys leading to the use of heterosis are to find cytoplasmic male-sterile system and genotypes with high cross-pollination rate. Enough quantity of pollination insects and favorable environment for hybrid seed production are also important.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

    Effect of Ecological Environments on Panicle Traits and Its Relationship with Subspecies Characteristics in Filial Generations of Cross Between Indica and Japonica

    Scientia Agricultura Sinica. 2009, 42(5):  1540-1549 .  doi:10.3864/j.issn.0578-1752.2009.05.005
    Abstract ( 1119 )   PDF (446KB) ( 709 )   Save
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    【Objective】 The purpose of this study was to investigate the effect of ecological environments on panicle traits and its relationship with subspecies characteristics in filial generations of cross between indica and japonica. 【Method】Two RILs populations, one derived from the cross between Zhongyouzhao8 (indica) and Toyonihiki (japonica) named as RIL1, the other derived from the cross between Qishanzhan (indica) and Akihikari (japonica) named as RIL2, were grown in Liaoning and Sichuan to study the effect of ecological environments on panicle traits and its relationship with subspecies characteristics. 【Result】The panicle morphological traits, anatomic traits and subspecies characteristics changed significantly. From Liaoning to Sichuan, panicle neck width and the number of large vascular bundles in panicle neck decreased, the number of small vascular bundles in the second top stem and the ratio of large vascular bundles between the second top stem and panicle neck increased, the seed setting rate and seed setting rate on secondary branch decreased significantly. Cheng’s index was more japonicalinous in Sichuan than in Liaoning. The number of large vascular bundles in panicle neck, the ratio of large to small vascular bundles in panicle neck, the ratio of large vascular bundles between the second top stem and panicle neck, seed setting rate and 1000-grain weight showed a significant difference in different subspecies types. The number of vascular bundles showed a significantly positive correlation with the panicle sink structure traits. But there was no significant correlation with the grain plumpness traits. Contrarily, subspecies characteristics showed a positive correlation with the grain plumpness traits and no significant correlation with panicle sink structure traits. 【Conclusion】The effects of ecological environments on panicle traits were significant. It is a feasible method to select and improve the vascular bundles traits based on panicle neck width. Because the mutual restraint relationship is found among the number of large vascular bundles in panicle neck, the grain plumpness traits and Cheng’s index, the breeders have to take all factors into consideration in northern China.

    Effects of Water Stress on Grain Filling and Activities of Enzymes Involved in Starch Synthesis in Rice
    Scientia Agricultura Sinica. 2009, 42(5):  1550-1558 .  doi:10.3864/j.issn.0578-1752.2009.05.006
    Abstract ( 1287 )   PDF (276KB) ( 994 )   Save
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    【Objective】 The aim of the experiment is to ascertain grain filling and activities of enzymes involved in starch synthesis in rice with different drought resistant abilities under water stress. 【Method】 The experiment was carried out to study dry matter translocation of stem and sheath, grain filling and activities of enzymes involved in starch synthesis in three rice hybrids with different drought resistant abilities under both normal and drought conditions. 【Result】 The results indicated that water stress decreased dry matter weight of stem and sheath at heading and harvest stage and export amount of stems and sheath, export and transform percentage of the matter after heading, reduced grain growth potentiality, the maximum rate of grain filling and mean rate of grain filling, shortened active grain-filling period and time to reach the maximum grain-filling rate, and decreased activity of key enzymes in rice grain including soluble starch synthase (SSS), ADP glucose pyrophosphorylase (ADPGPPase) and soluble starch branch enzyme during grain filling, which was obvious less in better drought resistant cultivars than those in weaker ones. Dry matter weight of stem and sheath at heading, export amount of stems and sheath, export and transform percentage of the matter after heading were positively significant or very significant correlation with grain yield. 【Conclusion】 Under water stress, higher export and transform percentage of stem and sheath, rate of grain filling, activity of key enzymes in rice grain were the physiological basis for smaller yield reduction of better drought resistant cultivars.

    The Genetic Differences in Phosphorus Distribution and Translocation in Waxy Corn
    Scientia Agricultura Sinica. 2009, 42(5):  1559-1567 .  doi:10.3864/j.issn.0578-1752.2009.05.007
    Abstract ( 1197 )   PDF (237KB) ( 612 )   Save
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    【Objective】 The objective of this study is understand the regularity of phosphorus (P) distribution and translocation and their effects on P absorption and utilization, and explain the genotype differences of P distribution and translocation and their effects on the yield formation. 【Method】 The 31 waxy corn (Zea mays L. ceratina Kulesh) varieties released in recent years in China were planted to analyze the genotype differences of P distribution and translocation in the same fertilization condition. 【Result】 The results showed that the P distribution centre changed with the change of the growth centre in the process of growth of waxy corn. And the P mainly distributed in leaf blade and stem before silking stage, then the P distribution centre begin changed to ear after silking stage, and it changed to kernel formation gradually. Moreover, there were significant differences in the P translocation rate and the rate of P translocation in the produce of different organ among different varieties, respectively. Through correlation analysis, it was found that the P translocation rate had a dominant effect on yield, P utilization efficiency and P harvest index , but it had minor effect on total P. Through path analysis, it was found that the P translocation rate of the leaf blade was high for the varieties of high-fresh ear yield and high-fresh kernel yield, and the P translocation rate of stem and bracteal leaf was high for the varieties of high-maturity kernel yield. In addition, it was beneficial for high P utilization efficiency as for fresh ear, fresh kernel or maturity kernel of the produce that there are high P translocatrion rate of leaf sheath. 【Conclusion】 There were significant genotype differences of P distribution and translocation in Waxy Corn. And the P translocation rate had a dominant effect on yield, P utilization efficiency and P harvest index, but it had minor effect on total P. Moreover, the P utilization efficiency can be improved through improve the P translocation rate, especially the P translocation rate of leaf sheath.

    Genetic Diversity and Phylogeny of Siderophore Producing Bacteria Isolated from Cotton Rhizosphere in China’s Xinjiang

    Scientia Agricultura Sinica. 2009, 42(5):  1568-1574 .  doi:10.3864/j.issn.0578-1752.2009.05.008
    Abstract ( 1084 )   PDF (363KB) ( 788 )   Save
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    【Objecive】 The aim of this paper is to reveal the genetic diversity of siderophore producing bacteria in Xinjiang provincial cotton rhizospheric soils, and to screen some effective siderophore strains. 【Method】 The genetic diversity of 68 siderophore strains isolated from cotton rhizospheric soil was analyzed by BOXAIR-PCR and 16S rRNA PCR-RFLP. Furthermore, the phylogeny of the representative strains was determined by 16S rRNA sequences analysis. 【Result】 Analysis of BOXAIR-PCR showed that all the strains were divided into 11 BOXAIR-PCR groups. The results of 16S rRNA PCR-RFLP analysis suggested that the genetic diversity was also existed and 10 genotypes were formed. The 16S rDNA sequence of representative strains was analyzed and the phylogenic tree was constructed, and the results revealed that these siderophores belonged to seven different genera, ie. Pseudomonas, Enterobacter, Acinetobacter, Bacillus, Alcaligenes, Brachybacterium and Pantoea, and strains belonged to genus of Pseudomonas was the predominant one among them. 【Conclusion】 The genetic diversity of the siderophore strains isolated from cotton rhizospheric soils in Xinjiang province is high.

    Effects of Nitrogen on Cotton Senescence and the Corresponding Physiological Mechanisms
    Scientia Agricultura Sinica. 2009, 42(5):  1575-1581 .  doi:10.3864/j.issn.0578-1752.2009.05.009
    Abstract ( 1140 )   PDF (272KB) ( 1024 )   Save
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    【Objective】 The effects of N content in soil on the physiological and biochemical indexes, amount of dry-matter accumula, tissue water content, boll load per unit leaf in cotton were studied in the field. 【Method】 The physiological characters of the leaves on stem , amount of dry-matter accumulation and tissue water content of the above-ground cotton plants, boll load per unit leaf was studied under different N levels (low level, 0 kg?hm-2, middle level, 189.50 kg?hm-2, high level, 395.0 kg?hm-2). 【Result】 The turning point from bloom to senescence is at the later full boll stage. The results showed that there was a negative correlation between nitrogen and the cotton premature senescence. Compared to mid-nitrogen and high-nitrogen treatments, under the condition of low nitrogen, the content of Chl. and dissolvable protein, photosynthetic rate, the amount of dry-matter accumulation and the activities of SOD and POD all decreased. But the content of MDA and boll load per unit leaf increased. It was concluded that cotton had a faster senescence under low nitrogen treatment. However, the efficiency of nitrogen decreased with the increase of nitrogen (from middle N level to high N level). 【Conclusion】N content in soil affects the cotton senescence remarkably. Low-nitrogen decreased the physiological characteristics of leaves, and protmoted the senescence; mid-nitrogen and high-nitrogen delay aging.

    The Role of D1 Protein Turnover and Xanthophylls Cycle in Protecting Photosynthetic Apparatus of Broccoli Leaves Against Photodamage

    Scientia Agricultura Sinica. 2009, 42(5):  1582-1589 .  doi:10.3864/j.issn.0578-1752.2009.05.010
    Abstract ( 1398 )   PDF (333KB) ( 774 )   Save
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    【Objective】 The objective of this study is to understand the characteristics of photoinhibition and mechanisms of photoprotection in broccoli leaves. 【Method】 The roles of D1 protein turnover and xanthophylls cycle in protecting photosynthetic apparatus of broccoli leaves against photodamage were studied by using their inhibitors and chlorophyll fluorescence parameters.【Result】 Significant decreases in Fv/Fm and increases in Fo were observed in broccoli leaves exposed to strong light stress (light intensity 1 800 μmol?m-2?s-1) for 1-4 h or a natural high temperature and strong light condition at noon in summer, the changes of Fv/Fm or Fo showed recovery in darkness for 5h or when sunlight intensity decreased after 14:00. SM and DTT resulted in stronger degree of reducement in Fv/Fm, qP, F’v/F’m and ΦPSⅡwhen broccoli leaves were treated with strong light. Compared to the control, ΦPSⅡ and F’v/F’m after chlorophyll fluorescence induction with light intensity 1 000 μmol?m-2?s-1 for 660 seconds in SM-treated leaves decreased by about 85.71%, 80.31% in broccoli leaves treated under 1 800 μmol?m-2?s-1 for 4h and then recovered in the dark for 12h, and in DTT-treated leaves reduced by about 22.45% and 11.48%, respectively. 【Conclusion】 These results suggested that there were perfect mechanisms of photoprotection in broccoli leaves, and that photosynthetic apparatus in SM- or DTT-treated leaves were photodamaged under strong light. More severe photodamage occurred in SM-treated leaves than that in DTT-treated ones, indicating that D1 protein turnover might play more important role in protecting photosynthetic apparatus of broccoli leaves against photodamage than xanthophylls cycle.

    Effects of Arbuscular Mycorrhizal Fungi and Salicylic Acid on Salt Tolerance of Strawberry (Fragaria×ananassa Duch) Plants
    Scientia Agricultura Sinica. 2009, 42(5):  1590-1594 .  doi:10.3864/j.issn.0578-1752.2009.05.011
    Abstract ( 1004 )   PDF (281KB) ( 1031 )   Save
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    【Objective】 The synergic effect of arbuscular mycorrhizal (AM) fungi and exogenous salicylic acid (SA) on increase of salt-tolerance of strawberry plants was explored. 【Method】 Pot experiments in greenhouse were carried out with strawberry (Fragaria×ananassa Duch cv. Hanie) plants inoculated with AM fungus (Glomus mosseae) and treated with exogenous SA. 【Result】 The leaf chlorophyll and K contents in leaves and roots were significantly increased, but the content of malondialdehyde was reduced in strawberry plants treated with G. mosseae, exogenous SA, or G. mosseae+exogenous SA, while the latter showed the best beneficial effects. Under the stress with NaCl 6 g?L-1, G. mosseae and exogenous SA could significantly enhance SOD, POD and CAT activities in strawberry leaves and plant growth. The treatment with G. mosseae and exogenous SA showed the best benefits in increasing salt tolerance of strawberry plants. 【Conclusion】 It is concluded that AM fungal inoculation with SA application could synergically enhance salt-tolerance of plants.

    The Micro-Distribution of Elements in Distichlis spicata and Festuca arundinacea Under Salt Stress
    Scientia Agricultura Sinica. 2009, 42(5):  1595-1600 .  doi:10.3864/j.issn.0578-1752.2009.05.012
    Abstract ( 957 )   PDF (408KB) ( 695 )   Save
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    【Objective】 The objective of this paper is to investigate the relationship between the salt-tolerance and the microdistribution of mineral ions in roots, stems and leaves of Distichlis spicata and Festuca arundinacea under salt stress. 【Method】 Distichlis spicata (halophyte) and Festuca arundinacea (glycophyte) were grown hydroponically with 250mM NaCl. Root tips, stems, and leaves were harvested for microanalysis 20 days after transplanting. Using an energy dispersive X-ray microanalyzer (EDX), the X-ray percentage of atom content and the peak of X-ray energy spectra intensity were measured. 【Result】It was shown that high Cl- and Na+ X-ray peaks were recorded in root tissues regardless of D. spicatar and F. arundinacea, but X-ray percentages of Na+ and Cl- content in root stelar cells of F. arundinacea were higher than in D. spicata. While comparable, the higher percentage of Na+ content existed in the stem xylem, and higher percentage of Cl- content distributed in the stem phloem in D. spicata than in F. arundinacea. The concentration of Na+ in leaves of F. arundinacea was 2 times more than in leaves of D. spicata【Conclusion】 Distichlis spicata regulated toxic ion absorption by the mechanism of selective absorption in roots, and recirculated Na+ back to roots by phloem or retrieval Na+ from xylem. Thus less toxic ion was transported to leaf tissue. Therefore the microdistribution of mineral ions in plants was involved in salt tolerance.
    PLANT PROTECTION
    Recent Progress on Molecular Mapping and Cloning of Blast Resistance Genes in Rice (Oryza sativa L.)
    Scientia Agricultura Sinica. 2009, 42(5):  1601-1615 .  doi:10.3864/j.issn.0578-1752.2009.05.013
    Abstract ( 1022 )   PDF (457KB) ( 2017 )   Save
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    Rice blast, caused by Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. Development and use of resistant cultivars is considered as the most economical, effective and environment-friendly method to control this disease. With the availability of genomic sequences of both Oryza sativa and M. oryzae, the rice pathosystem has become the model system for dissection of interactions of plant-pathogen. Over the past 50 years, eighty-four blast resistance genes and large amount of quantitative trait locus for resistance to the pathogen have been identified through genetic analysis. Of them, eight major blast resistance genes and one recessive gene controlling partial resistance in rice have been cloned. In this review, the recent progress on molecular mapping and cloning of blast resistance genes was summarized. All the resistance genes mentioned were integrated into a genetic linkage map by compiling the information of DNA markers linked to individual resistance gene. The possible allelism relationship between resistance genes in a cluster was further discussed. In addition, the strategy for resistance gene cloning in the post-genome era was also discussed.

    Proteomic Analysis of Stripe Rust Resistance Wheat Line Taichung29*6/Yr5 Inoculated with Stripe Rust Race CY32

    Scientia Agricultura Sinica. 2009, 42(5):  1616-1623 .  doi:10.3864/j.issn.0578-1752.2009.05.014
    Abstract ( 1277 )   PDF (671KB) ( 1215 )   Save
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    【Objective】 To investigate the biochemical changes of wheat resistance to stripe rust after infected with the stripe rust, a resistive line of wheat (Taichung29*6/Yr5) infected with stripe rust CY32 was compared to mock-inoculated wheat by comparative proteomics technology. 【Method】 Proteins were extracted from leaves infected with a virulent race of stripe rust CY32 and control group after 48 hours of inoculation, and then separated by using two-dimensional electrophoresis (2-DE). The differential protein spots were selected for MALDI-TOF MS analysis and database searching. 【Result】 By using 2-DE,2 uniquely expressed spots, 5 up-regulated spots and 6 down-regulated spots were observed in Taichung29*6/Yr5 leaves inoculated with stripe rust CY32. Total of 11 proteins, including pathogenesis-related homeodomain protein, beta-glucosidase, glutathione transferase etc, were identified. 【Conclusion】 Through analysis of protein function , it is presumed that these differential proteins are correlated with the infextation of stripe rust race CY32.

    Rapid Detection of Phytophthora sojae Using SSR Marker and Nested PCR

    Scientia Agricultura Sinica. 2009, 42(5):  1624-1630 .  doi:10.3864/j.issn.0578-1752.2009.05.015
    Abstract ( 1192 )   PDF (635KB) ( 833 )   Save
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    【Objective】 This study was aimed at developing a rapid and accurate molecular technique for detection of Phytophthora sojae and diagnosis of soybean Phytophthora root rot at early stage. 【Method】 Based on the SSR marker Psc239 of P. sojae, two primer pairs, Psc239EF/Psc239ER and Psc239F/Psc239R, were designed specifically to amplify DNA from P. sojae by nested PCR. 【Result】 The primer pairs and nested PCR assay were assessed for specificity using DNA from 36 isolates of P. sojae and 25 isolates of other oomycetes and fungi, Psc239EF/Psc239ER, Psc239F/Psc239R and nested PCR could amplify 519 bp, 242 bp and 242 bp fragments only from P. sojae, respectively, no amplification product was observed from other oomycetes and fungi. In conventional PCR, the sensitivity of detection was of 50 pg?μl-1 P. sojae DNA for both primer pairs, in the nested PCR the detection limit was 50 f g?μl-1. The detection limit for oospores of P. sojae in soil was of 0.4 oospores in 1g soils by the nested PCR. The nested PCR assay was also used to detect DNA extracted from infected soybean tissues and soil samples. 【Conclusion】 The nested PCR assay based on SSR marker Psc239 could be used to rapidly detect P. sojae in soil and diagnose Phytophthora root rot on soybean.

    Isolation, Identification and Interaction of Rhizosphere Microorganisms Involved in Peach Replant Diseases
    Scientia Agricultura Sinica. 2009, 42(5):  1631-1638 .  doi:10.3864/j.issn.0578-1752.2009.05.016
    Abstract ( 956 )   PDF (409KB) ( 740 )   Save
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    【Objective】 The objective of this study is to explain the relation of peach replant diseases and rhizosphere microorganisms. 【Method】Peach rhizosphere microorganisms were isolated with Mфller Potassium Cyanide Medium. The isolated strains were identified by 16S rDNA sequences and biological characterization. Biocontrol effect were observed in pot trials initially.【Result】 Three bacteria strains (CN-X4, CN-X9, CN-X17) which could utilize amygdalin as carbon source and produce hydrocyanic acid were separated from peach rhizophere soil, and three rhizosphere actinomyces strains(CN-G2, CN-G3, CN-G5)were also isolated, and show different antagonistic effect on the three bacterial strains by plate bacteriostasis assays. Strain CN-X4 and strain CN-X17 were identified as Agrobacterium tumefaciens, but they were different subspecies. Strains CN-X9, CN-G2 and CN-G5 were proved to belong to Pseudomonas sp, Streptomyces microflavus, Streptomyces lavendulae, respectively. Strain CN-G3 may be close or similar to a species of Streptomyces griseus. Biocontrol effect was significant in pot trials. 【Conclusion】 There were not only bacteria which could utilize amygdalin as carbon source and produce hydrocyanic acid but also actinomyces which had antagonistic effect on the bacteria in peach rhizosphere. The unbalance of the rhizosphere microorganisms is considered as a crucial factor for peach replant diseases occurrence.

    Gene Cloning and Tissue-Specific Expression of an Olfactory Receptor in Microplitis Mediator (Hymenoptera: Braconidae)

    Scientia Agricultura Sinica. 2009, 42(5):  1639-1645 .  doi:10.3864/j.issn.0578-1752.2009.05.017
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    【Objective】 The expression of an olfactory receptor of Microplitis mediator was studied. 【Method】 The olfactory receptor gene of Microplitis mediator was cloned using RT-PCR. And its tissue-specific expression and quantitative changes at different developmental stages were detected using real-time PCR. 【Result】 A gene encoding a novel olfactory receptor, which is antenna- specific, was isolated from Microplitis mediator (Hymenoptera: Braconidae). Its expression levels reached the maximum amount on the emergence day of female and reached the maximum amount at the d stage before emergence of male. 【Conclusion】This receptor is antenna- specific in Microplitis mediator.

    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Effects of Long-Term Fertilization on Change of Labile Organic Carbon in Three Typical Upland Soils of China

    Scientia Agricultura Sinica. 2009, 42(5):  1646-1655 .  doi:10.3864/j.issn.0578-1752.2009.05.018
    Abstract ( 919 )   PDF (438KB) ( 1142 )   Save
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    【Objective】 Based on 3 long-term experiments, temporal and spatial responses of total soil organic carbon (TOC) and labile organic carbon (LOC) in red soil, black soil and grey-desert soil to various long-term fertilizations were discussed.【Method】 Fractionation method of soil organic carbon was applied to determine the contents of LOC and the percentage of LOC to TOC in black soil, grey-desert soil and red soil. 【Result】 Results showed that the content of TOC and LOC and the percentage of LOC to TOC under 16 years of non-fertilization (CK) in grey-desert soil decreased significantly by 11.7%, 34.9% and 5.4 percentage points, respectively. After long-term application of chemical nitrogen fertilizer (N), the content of TOC of the 3 soils kept no significant change throughout the studied period. However, the percentage of LOC to TOC for the 3 soils all decreased significantly. It decreased by 9.5 percentage points in black soil, which was the most of the 3 studied soils. After 16 years application of NP and NPK, the percentage of LOC to TOC in black soil and grey-desert soil decreased significantly. While there was increasing trend for red soil. There was significant increase in the contents of TOC and LOC and the percentage of LOC to TOC under long-term application of chemical fertilizers combinated with manure (NPKM、1.5 NPKM). After long-term application of NPKM, the contents of TOC, LOC and the percentage of LOC to TOC in red soil increased by 80.6%, 146.2% and 7.5 percentage points, respectively, which was the most. For grey-desert soil it was 64.4%, 138.0% and 5.0 percentage points, respectively. For long-term application of NPK with straw return (NPKS), the contents of TOC, LOC and the percentage of LOC to TOC in red soil increased by 21.6%, 59.0% and 7.5 percentage points. However, it was stable in black soil and grey-desert soil. 【Conclusion】 The percentage of LOC to TOC response sensitively to long-term fertilization and could be one of the indicators for the quality of soil organic carbon. Long-term non-fertilization and only chemical nitrogen fertilizers lead to decrease in the contents of total soil organic carbon and the percentage of LOC to TOC in most cases. Long-term application of NPKM could maintain and improve quality and quantity of soil organic carbon. The effect of long-term application of NPKM was better than that of NPKS, and they were both better than that of long-term application of NPK.

    Study on the Method of Soil Productivity Assessment in Northeast Black Soil Regions of China

    Scientia Agricultura Sinica. 2009, 42(5):  1656-1664 .  doi:10.3864/j.issn.0578-1752.2009.05.019
    Abstract ( 1369 )   PDF (434KB) ( 831 )   Save
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    【Objective】 Investigate a simple and practical method for soil productivity assessment in Northeast black soil regions of china. 【Method】 The research based on soil Productivity Index model(PI for short). Firstly, 8 kinds of physico-chemical properties had been chosen base on the Characteristics of research area, cluster and correlation analysis had been done to 8 kinds of physico-chemical properties of 120 soil samples from 25 black soil local type. Subsequently, parameter index were calculated with existing findings. Modify Productivity Index (MPI) which suitable to apply in research regions was gained finally. And simulated results were compared with crop yield of these soil profiles. 【Result】 The results showed that the suitable parameters for soil productivity assessment in Northeast black soil regions were soil available water, soil pH, clay content and Organic Matter content,compared with original PI,MPI expanded clay content and Organic Matter content parameters, condensed bulk density parameter ; The verification result indicated that the validation of MPI was better than PI’s, there were high significant correlation between MPI index and unit yield of maize, the equation was: Y = 3.1275 ln (MPI) + 10.052, with R2=0.7564.【Conclusion】 The analysis results show that PI is a good model for such study as soil productivity assessment in the research area.

    Effects of Phosphorus Fertilizer on the Utilization Ratio of Nitrate Accumulated in Deep Soil Profile by Wheat
    Scientia Agricultura Sinica. 2009, 42(5):  1665-1671 .  doi:10.3864/j.issn.0578-1752.2009.05.020
    Abstract ( 946 )   PDF (330KB) ( 762 )   Save
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    【Objective】 The purpose of this study was to indicate the effects of phosphorus application on utilization ratio of nitrate accumulated in deep soil profile by wheat in north China. 【Method】 Field micro-plot experiments and the injection technique of labeled NO3--N were adopted. 【Result】The results showed that, 15N which was injected in 100-120 cm soil profile and diffused in the near layers could be absorbed by wheat with the utilization ratio of nitrate 6.8%, 16.4%, 11.2% in three P levels of P0, P60, P120. The phosphorus applied in the topsoil made the roots grow better with more root length density and dry root weight in it than without phosphorus, by which more deep soil nitrate could be assimilated by wheat and then improved the utilization ratio of nitrate by wheat. 【Conclusion】 Phosphorus application promoted the growth of roots in the deep layers which accelerated the absorption of nitrate accumulated in deep soil profile by wheat, while too much phosphorus fertilizer inhibited the growth of roots of wheat.

    Coupling Effect of Water and Nitrogen on Cotton Under Different Drip Irrigation Lateral Placements
    Scientia Agricultura Sinica. 2009, 42(5):  1672-1681 .  doi:10.3864/j.issn.0578-1752.2009.05.021
    Abstract ( 1450 )   PDF (427KB) ( 606 )   Save
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    【Objective】 The objective of the paper was to study the coupling effect on cotton yield, nitrogen use efficiency (NUE) and water use efficiency (WUE) at different levels of water and nitrogen under different lateral placements. 【Method】 By using the factor of water and nitrogen in different drip irrigation lateral placements that including 1 lateral 4 rows, 2 laterals 4 rows and 2 laterals 6 rows, which using universal design of the second rotation, field experiments were conducted. 【Result】 The result showed that as for the coupling effect of water and nitrogen on cotton yield, that of water was more significant than nitrogen under 1 lateral 4 rows, nitrogen was more significant than water under 2 laterals 4 rows and 2 laterals 6 rows. Cotton yield of three drip irrigation patterns were positive correlated when irrigation water at 65.1-284.9 mm. At a certain level of nitrogen, in 1 lateral 4 rows, a positive correlation between nitrogen and cotton yield when nitrogen was 16.2-94.2 kg?hm-2, in 2 laterals 4, a rows negative correlation when nitrogen was 16.2-69 kg?hm-2and a positive correlation when nitrogen was 69-94.2 kg?hm-2, in 2 laterals 6, a rows positive correlation in 16.2-55.2 kg?hm-2and a negative correlation in 55.2-94.2 kg?hm-2. As for the coupling effect of water and nitrogen on nitrogen use efficiency (NUE), nitrogen was more significant than water under the three drip irrigation patterns. In 1 lateral 4 rows, a negative correlation between NUE when nitrogen was 16.2-82.2 kg?hm-2 and a positive correlation when N was 82.2-94.2 kg?hm-2. In 2 laterals 4 rows, a negative correlation between NUE when nitrogen was 16.2-69.0 kg?hm-2 and a positive correlation whan N was 69.0-94.2kg?hm-2. In 2 laterals 6 rows, a negative correlation between NUE and when applied nitrogen within 16.2-94.2 kg?hm-2. As for the three drip irrigation patterns, a positive correlation between water and NUE when irrigation water was in 65.1-284.9 mm. As for the coupling effect of water and nitrogen on water use efficiency (WUE), water was more significant than nitrogen under 1 lateral 4 rows and 2 laterals 4 rows, nitrogen was more significant than water under 2 laterals 6 rows. In 1 lateral 4 rows, a positive correlation between nitrogen and WUE was found. In 2 laterals 4 rows, a negative correlation in the applied nitrogen of 16.2-41.4 kg?hm-2 and a positive correlation in the applied nitrogen of 44.2-94.2 kg?hm-2 was found, in 2 laterals-6 rows, a positive correlation in the applied nitrogen of 16.2-55.2 kg?hm-2 and a negative correlation in 55.2-94.2 kg?hm-2was found. In three drip irrigation patterns, a negative correlation between water and WUE under the condition of water in 65.1-284.9 mm was found. 【Conclusion】 According to different patterns of drip irrigation water and nitrogen coupling effect, different modes of drip irrigation water and nitrogen management strategy were established with cotton yield, NUE, WUE for the objectives the result showed that 2 laterals 4 rows are most effective in promotion of the coupling effect of water and nitrogen and is conducive to the drip irrigation of cotton fields of water and nitrogen management.

    Effects of Soil Water Content on Cotton Root Growth and Distribution Under Mulched Drip Irrigation

    Scientia Agricultura Sinica. 2009, 42(5):  1682-1689 .  doi:10.3864/j.issn.0578-1752.2009.05.022
    Abstract ( 1059 )   PDF (422KB) ( 964 )   Save
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    【Objective】 The relation between soil water content and the growth of cotton root was studied for the scheme of field water and cotton yield under mulched drip irrigation. 【Method】 Based on the field experiments, three treatments of soil water content were conducted with 90%θf, 75%θf, 60%θf (θf is field water capacity). Cotton roots and root-shoot ratio were studied with digging method, and the soil moisture was observed with TDR, and cotton yield was measured. 【Result】 The results indicated that the growth of cotton root accorded with Logistic growth curve in corresponding three treatments of soil water content, the cotton root grew quickly and its weight was very high under the soil water treatment of 75%θf because of the suitable soil water condition, grew slowly and its weight was lower in the soil of the treatment of 90%θf beyond the suitable soil water condition, and the root weight was mediate under the soil water treatment of 60%θf. For the three water treatments, the cotton root weight decreased with soil depth, and decreased extensively in deeper soil layer with the soil moisture increment. Compared with other treatments, the ratio of cotton root weight in 0-30 cm soil layer to the total root weight was the highest under the soil water treatment of 75%θf. The cotton root system was distributed mainly in the soil narrow row and wide row mulched with plastic film, and the distribution of root was small in the soil outside plastic film. Compared with other treatments, the weight of cotton root was the highest in the soil narrow row or wide row mulched with plastic film under the soil water treatment of 75%θf. Root-shoot ratio decreased with the soil moisture increment. The soil water content affected cotton yields, and cotton yield was the highest under the soil water treatment of 75%θf. 【Conclusion】The sustained higher soil moisture level is unfavorable to the growth of cotton root system and yield of cotton under mulched drip irrigation.

    The Transformation and Transport of Main Degradation Products of Atrazine in Soils - A Review

    Scientia Agricultura Sinica. 2009, 42(5):  1690-1697 .  doi:10.3864/j.issn.0578-1752.2009.05.023
    Abstract ( 1141 )   PDF (232KB) ( 649 )   Save
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    Atrazine is an herbicide commonly used on summer maize in North and Northeast China, and deethylatrazine (DEA) and deisopropylatrazine (DIA), its two main metabolisms in soils, have similar toxicity with the parent compound, and have high polarity and mobility. In this review, the research progresses of the adsorption, degradation and leaching behaviors of the main metabolisms of atrazine in soils were summarized and analyzed in detail. It is shown that more recently, attention has been focused on the study of the transformation and transport of the two metabolisms of atrazine in soils, however, a systematic and quantitative study of the environmental fate of DEA and DIA in soils have not been carried out. This review will provide some references to the researchers on their studies.

    HORTICULTURE
    Identification of Chinese Cabbage-Cabbage Double Alien Monosomic Addition Line by SSR and Studies on Its Characters
    Scientia Agricultura Sinica. 2009, 42(5):  1698-1704 .  doi:10.3864/j.issn.0578-1752.2009.05.024
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    【Objective】 Chinese cabbage-cabbage alien addition line was screened, alien chromosomes introduced into Chinese cabbage were identified by SSR, and the characters of the alien addition line were further analyzed. 【Method】 The BC1F2 progenies derived from allotriploid hybrid (AAC) and diploid Chinese cabbage (AA) were used as materials, by using analysis of the root tip cell chromosome number and linkage group-specific SSR markers from linkage groups of cabbage, the Chinese cabbage-cabbage alien addition line was selected and identified. 【Result】 A plant (2n=22) was obtained. Amplification results of 3 pairs of primers assigned linkage group 01 and 2 pairs of primers assigned 08 linkage group on this plant were the same as allotriploid hybrid, however, the amplification results of 20 pairs of primers assigned other 7 linkage groups were the same as Chinese cabbage. Therefore, the introduced cabbage chromosomes in this plant were grouped into linkage groups 01 and 08 of cabbage, which was double alien monosomic addition line. Ten bivalents and two univalents were observed at the stage of diakinesis in most of double alien monosomic addition line’s PMCs, 11-11 and 10-12 distributions were observed at anaphaseⅠ in most of PMCs, and the gametes with n=11 were observed at anaphaseⅡ. 【Conclusion】 Chinese cabbage-cabbage addition alien line could be exactly identified by specific SSR markers for cabbage compared with Chinese cabbage. And Chinese cabbage-cabbage double alien monosomic addition line added linkage groups 01 and 08 of cabbage was obtained, which laid a foundation for further obtaining the Chinese cabbage-cabbage monosomic alien addition lines and disomic alien addition lines added linkage group 01 or 08 of cabbage.

    In Silico Cloning and Sequence Analysis of Phospholipase Dα Gene from Peach Fruit

    Scientia Agricultura Sinica. 2009, 42(5):  1705-1712 .  doi:10.3864/j.issn.0578-1752.2009.05.025
    Abstract ( 1146 )   PDF (919KB) ( 1174 )   Save
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    【Objective】 The aim of this study was to isolate and clone new gene coding for phospholipase Dα from Prunus persica. 【Method】 In silico cloning was used to isolate cDNA sequence of PLDα, RT-PCR and Northern blot analysis were used to test the sequence and to analyze its expression during storage at 4℃. 【Result】 The obtained sequence contained a complete ORF, from 172 bp to 2 604 bp, encoded 810 amino acids. Compared with other plants, such as tomato, strawberry and grape etc., it was found that the amino acids sequence encoded by phospholipase Dα gene was almost conserved. Semi-quantitative RT-PCR and Northern blot analysis indicated that PLDα could be induced by low temperature. 【Conclusion】 Full length PLDα gene was first isolated and characterized from peach fruit, suggesting it is an efficient technique for cloning novel genes by searching EST database with homologous gene of relative species. Transcription profile of PLDα mRNA has provided a scientific basis for further research on the relationship between PLDα and low temperature.

    Analysis on the Genetic Relationships of Chinese Ziziphus with SRAP Markers

    Scientia Agricultura Sinica. 2009, 42(5):  1713-1719 .  doi:10.3864/j.issn.0578-1752.2009.05.026
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    【Objective】 The phylogeny and genetic relationships of Chinese Ziziphus’s germplasm resources were studied at molecular levels for providing new molecular evidences of classification, protection and utilization of germplasm resources of Ziziphus. 【Method】 The sequence-related amplified polymorphism (SRAP) was assessed to analyze the genetic relationships among 14 species of Ziziphus, 11 cultivars of Z. jujuba Mill. and one outgroup. 【Result】 A total of 580 DNA bands were amplified by 19 selective primers, 570 of which (98.28%) were polymorphic. The average number of polymorphic DNA bands amplified by each primer was 30. The genetic similarities of 26 materials ranged at 0.22 to 0.99. UPGMA method cluster analysis showed that 26 materials were classified into six cluster groups with the genetic similarity of 0.38. 【Conclusion】 The results showed that SRAP technique is efficient in studying genetic relationships among Ziziphus. Z. jujuba Mill. and Z. acidojujuba C. Y. Cheng et M. J. Liu should be treated as a species, and further infraspecific classification of Z. jujuba Mill. should be classified into two subspecies. The scientific names of new taxa (Chinese jujube and wild jujube) were Ziziphus jujuba Mill. subsp. jujuba and Ziziphus jujuba Mill. subsp. spinosa (Bunge) J.Y. Peng, X.Y. Li et L.Li respectively. Z. xiangchengensis Y. L.Chen et P. K.Chou, Z. montana W.W. Smith and Z. mairei Dode may originate from same ancestry Z. xiangchengensis Y. L. Chen et P. K. Chou and Z. montana W.W. Smith should be treated as a species. The infraspecific taxon of Z. jujuba Mill. is not suitable to set up varieties.

    Analysis of Genetic Diversity and Relationship of Tea Germplasms Originated from Fujian Province Based on EST-SSR Markers

    Scientia Agricultura Sinica. 2009, 42(5):  1720-1727 .  doi:10.3864/j.issn.0578-1752.2009.05.027
    Abstract ( 1238 )   PDF (487KB) ( 859 )   Save
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    【Objective】 Genetic polymorphism of tea germplasms from Fujian, China and their relationships were analyzed so as to offer some information to be used in genetic improvement and parental selection in tea breeding programs. 【Method】 The 26 pairs of EST-SSR primers, including 23 newly derived by the authors and 3 from previous references, were used to analyze the 42 tea accessions from Fujian, China. Based on EST-SSR data, a dendrogram was constructed using UPGMA method. 【Result】 Totally 86 alleles were amplified using the 26 EST-SSR primers, the number of alleles per primer ranged from 2 to 5, with an average of 3.31. The polymorphism information content (PIC) varied from 0.05 to 0.75, with an average of 0.56. The expected heterozygosity (He) varied from 0.02 to 0.81 and the observed heterozygosity (Ho) ranged from 0.02 to 0.97, with an average of 0.60 and 0.55, respectively. The Shannon index of the Fujian tea population was 1.16. The 42 accessions were classified into 2 groups based on the similarity coefficient at 0.40. 【Conclusion】 The results show that the genetic polymorphism of tea germplasms in Fujian is relatively abundant, and the relationships among the 42 accessions are clearly defined.

    STORAGE·FRESH-KEEPING·PROCESSING
    Isolation and Purification of Anthocyanins from Blood Oranges by Column Chromatography
    Scientia Agricultura Sinica. 2009, 42(5):  1728-1736 .  doi:10.3864/j.issn.0578-1752.2009.05.028
    Abstract ( 1199 )   PDF (461KB) ( 1181 )   Save
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    【Objective】 Isolation and purification of anthocyanins from blood oranges by column chromatography were made, and then the anthocyanins of blood orange were identified. 【Method】 The behavior of static adsorption and desorption, dynamic adsorption and desorption of twelve kinds of resins was compared. Toyopearl TSK HW-40S column was employed to separate and purify the anthocyanin extracts from blood orange. Then, the anthocyanins of blood orange were identified by HPLC-ESI/MS analysis. 【Result】 The results indicated that NKA-9 macroporous resin was the optimum for the anthocyanins of blood orange purification, and the optimum elution reagent was 50% ethanol with citric acid (pH 2.5). The best separation of Toyopearl TSK HW-40S column was obtained using a mobile phase of 35% methanol with 2% formic acid at a flow-rate of 0.6 ml?min-1. Three major anthocyanins of blood orange were isolated. HPLC-ESI/MS analysis results show that the anthocyanins of blood orange are mainly cyanidin-3-glucoside (35.2%) and cyaniding-3-(6″-malonyl) glucoside (42.9%). Furthermore, cyanidin-3-(3″-malonyl) glucoside, cyanidin 3-(6″-dioxalyl) glucoside and cyanidin-3-glucoside adduct: 4- vinylcatechol were identified in blood orange. 【Conclusion】 The combination of NKA-9 macroporous resin and Toyopearl TSK HW-40S column chromatography for separation and purification of blood orange anthocyanins is an effective method, and HPLC-ESI/MS analysis is a convenient, rapid and effective method for identification of anthocyanins from blood orange.

    Relationship Between Granulation and Active Oxygen Metabolism of Juice Sac in Pummelo Fruit During Maturation

    Scientia Agricultura Sinica. 2009, 42(5):  1737-1743 .  doi:10.3864/j.issn.0578-1752.2009.05.029
    Abstract ( 1147 )   PDF (326KB) ( 996 )   Save
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    【Objective】 The relationship between granulation and active oxygen metabolism of juice sac in pummelo [Citrus grandis (L.) Osbeck cv. Guanximiyou] fruit during maturation was investigated. 【Method】 Fruits of pummelo from old trees with higher ratio of juice sac granulation fruits, that with normal fruits, and optimum-aged trees with lower ratio of granulation fruits and that with normal fruits were used to study the changes in contents of MDA, H2O2, and lignin, activities of reactive-oxygen-scavenging enzymes (POD, SOD, CAT), and contents of endogenous antioxidants (AsA, GSH) in process of juice sac granulation. 【Result】 The index of juice sac granulation and contents of H2O2 and MDA increased while contents of ASA and GSH decreased, whereas SOD activity first declined and then increased and CAT activity increased, but POD activity rose more significantly in the fruits from the old trees in contrast to optimum-aged trees.【Conclusion】The results suggest that the disorder of active oxygen metabolism of juice sac of pummelo fruit during maturation may result in the accumulation of active oxygen (H2O2) and the increase of POD activity, which promote the synthesis of lignin, and finally cause juice sac granulation.

    Study on Optimal Hydrolysis Process for Preparing Rice Bran Short Peptides with Two Enzymes
    Scientia Agricultura Sinica. 2009, 42(5):  1744-1750 .  doi:10.3864/j.issn.0578-1752.2009.05.030
    Abstract ( 1151 )   PDF (366KB) ( 831 )   Save
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    【Objective】 To establish an optimal enzymatic hydrolysis process for short peptides directly from rice bran under low and medium temperature. 【Method】 Quadratic regression orthogonal rotational combing design was used to determine the optimal enzymatic hydrolysis process. Anthrone colorimetry’s method was used to measure the carbohydrates content, pH-stat method to measure the degree of hydrolysis and Kjeldahl’s method to measure the recovery of protein. 【Result】 The optimum enzymatic hydrolysis conditions for short peptides were: reaction time of viscozyme for removing carbohydrate was 2 hours firstly, then protease hydrolysis with alcalase and trypsin was carried out at pH 8.2, temperature 45℃, the activity ratio between alcalase and trypsin was 59﹕41, the total enzyme activity was 5 750 U/g substrate, and 3 hours. Under such conditions the DH was 23.04%, the recovery of protein could reach up to 84.33%, TCA-SN was 68.40%, and the molecular weight of peptides was mainly concentrated at below 1 000 D. 【Conclusion】 It is a better approach with convenient operation and high recovery of protein for preparing rice bran short peptides compared to traditional ways of extracting protein first and then preparing short peptides with enzymatic hydrolysis.

    ANIMAL SCIENCE·RESOURCE INSECT
    Study on Genetic Regulation of Microsatellite Loci Gene of Three Inbred Families of Wuzhishan Miniature Pig

    Scientia Agricultura Sinica. 2009, 42(5):  1751-1760 .  doi:10.3864/j.issn.0578-1752.2009.05.031
    Abstract ( 937 )   PDF (409KB) ( 621 )   Save
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    【Objective】 To investigate the pattern of genetic variation of three inbred families of Wuzhishan Miniature pig (WZSP) from the 13th to the 18th generations. 【Method】 Fourteen autosome microsatellite DNA markers were used to estimate their genetic heterozygosity (H), polymorphic information content (PIC) and number of alleles (N). 【Result】 The results showed that the average N , H, PIC in the pooled samples of familiesⅠ F14-16, ⅡF15-18, Ⅲ F14-17 were 2 , 0.40, 0.26; 1.92, 0.32, 0.26, 2.17, 0.44 and 0.32, respectively. The 7 of 14 microsatellites had reached the homozygosis completely in families Ⅱat 18th. 【Conclusion】 The results suggested that the average N is decreasing and the genetic homozygosity is increasing with the improving inbred generation of WZSP. The differentiation coefficient is 0.07 between three inbreed families respectively. The highest level of genetic homozygosity is in families Ⅱat 18th, but genetic variation is a little difference between inbreeding pig and mice. However, this study revealed the pattern of genetic variation at microsatellite loci in the 3 inbred families of WZSP with one of the most important findings to be the high level of unexpected heterozygosity at some loci, e.g. Sw874 and Sw936 that could be part of the unique genetics of three families. A hypothesis is that certain functional genes linked with such microsatellite loci may be involved in the maintenance of viability of these inbred families of WZSP remains for further investigation.

    The Genetic Diversity and Phylogenetic Relationship Among Pig Breeds of Shandong Province Based on mtDNA CytB Gene
    Scientia Agricultura Sinica. 2009, 42(5):  1761-1767 .  doi:10.3864/j.issn.0578-1752.2009.05.032
    Abstract ( 972 )   PDF (300KB) ( 812 )   Save
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    【Objective】 In order to provide data and scientific basis for reasonable utilization and protection of biodiversity, the genetic diversity and phylogenetic relationships of 12 pig breeds (8 pig breeds from Shandong Province, 3 introduced pig breeds and Meishan pigs) were studied. 【Method】 In the study, the PCR amplification, sequencing and data analyzing ways of biologic informatics were used. 【Result】 All the 8 pig breeds from Shandong Province shared common haplotype, had rather small genetic diversity within breeds and small mean genetic distances between breed too. The pig breeds from Shandong Province had rather small mean genetic distances with Meishan and Yorkshire too, but had big distances with Duroc and Landrance. Both the NJ phylogenetic tree and the classified measure based on four SNPs of CytB, which classify the pigs into European and Asian haplotypes, classified the above samples into 2 clades. One included all sample of pig breeds from Shandong Province excepted one haplotype of Luyan White pigs, Meishan pigs and two haplotypes of Yorkshire, and the other included Duroc, Landrace, part haplotype of Yokshire and one haplotype of Luyan White pigs. 【Conclusion】 Firstly, the pig breeds from Shandong Province had the common maternal ancestor, the genetic diversity were rather small within every breeds. Secondly, the introduced pigs were used as sire, not dam, to improve the growth performance and lean meat percentage of the pig breeds from Shandong Province. Thirdly, it was a convenient measure to use the 4 SNPs of CytB to detect the maternal blood of the new pig breeds (or synthetic lines) bred by Chinese and European pig breeds.

    Polymorphism of Progesterone Receptor Gene and Its Relationship with Litter Size of Jining Grey Goats

    Scientia Agricultura Sinica. 2009, 42(5):  1768-1775 .  doi:10.3864/j.issn.0578-1752.2009.05.033
    Abstract ( 963 )   PDF (529KB) ( 674 )   Save
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    【Objective】 The objectives of the present study were to search for genetic markers associated with high litter size and to provide a scientific basis for marker-assisted selection for high proliferation in goats. 【Method】 Fifteen pairs of primers were designed to detect single nucleotide polymorphisms of exon 1 to exon 9 of progesterone receptor (PGR) gene in Jining Grey, Boer, Liaoning Cashmere and Angora goats by PCR-SSCP. 【Result】 Only the products amplified by primers P1, P8 and P9 displayed polymorphisms. For primer P1, three genotypes (AA, AB and BB) were detected in Jining Grey goats, two genotypes (AA and AB) in other goat breeds. Sequencing revealed one mutation (31G→A) of PGR gene in the genotype BB in comparison to the genotype AA, and this mutation resulted in an amino acid change of Ala→Thr. The does with genotype BB had 0.52 (P<0.05) or 0.98 (P<0.001) kids more than those with genotype AB or AA, and the does with genotype AB had 0.46 (P<0.05) kids more than those with genotype AA in Jining Grey goats. For primer P8, only one genotype (CC) was detected in Jining Grey goats, two genotypes (CC and CD) were detected in Boer goats, and three genotypes (CC, CD and DD) were detected in other goat breeds. Sequencing revealed one mutation (2810C→G) of PGR gene in the genotype DD in comparison to the genotype CC, and this mutation did not cause any amino acid change. For primer P9, two genotypes (FF and FG) were detected in Jining Grey and Boer goats, and three genotypes (FF, FG and GG) were detected in other goat breeds. Sequencing revealed one mutation (60128T→A) of PGR gene in the genotype GG in comparison to the genotype FF, and this mutation did not cause any amino acid change. The does with genotype FF had 0.32 (P>0.05) kids more than those with genotype FG in Jining Grey goats. 【Conclusion】 These results preliminarily indicated that the PGR gene is either a major gene that influences the prolificacy in Jining Grey goats or a molecular marker in close linkage with such a gene.

    Development of Oocytes and Follicles in Grafted Ovaries in Male Recipient Mice Stimulation by Gonadotrophins

    Scientia Agricultura Sinica. 2009, 42(5):  1776-1782 .  doi:10.3864/j.issn.0578-1752.2009.05.034
    Abstract ( 909 )   PDF (391KB) ( 830 )   Save
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    【Objective】 This experiment was made to investigate the effect of gonadotrophin on follicle development and oocyte maturation and development in grafted ovaries in male recipient mice. 【Method】 Ovaries from 1-day-old mice were xenografted underneath the kidney capsule of 7-12-week old male recipient mice. Graft recipients were treated with or without xogenous gonadotrophin prior to graft collection. The 7-12-week old female mice were treated with gonadotrophin and used as controls. Twenty-one days after grafted, the ovarian grafts were recovered for examination of their size, recoverable proportion and follicular growth. The oocyte maturation and fertilization were conducted in in vitro. The 2-cell cleavage rate and Blastocyst rate were determined. 【Result】 The ovary recovery rate was 85.4% in recipients without treatment, insignificantly differed from the treated group (90.7%) (P>0.05). The follicles of grafts could develop to maturation stage and GV oocytes of (41.4±25.8) per ovarian graft were retrieved. The in vitro matured GV oocytes could develop to two-cell embryos in the rate of 17.5%, but not to blastocyst in the non-treated group. The follicles could develop to the antral stage and undergo periovulatory changes following xenografting and exposure to a luteinizing stimulus, with expanded cumulus-oocyte complex, mucified cumulus cell and corpus luteum. MII oocytes as well as GV oocytes were retrieved from the treated group, the yield of MII and GV oocytes per ovarian graft was (8.5±7.1) and (33.4±20.1), the two-cell cleavage rate was 44.3% and 33.9%, and the blastocyst rate was 6.3% and 0.48%, respectively. There was a significant difference in the two-cell cleavage rate and blastocyst rate between groups treated with or without xogenous gonadotrophin (P<0.01), but not in the yield of oocytes (P>0.05). The two-cell cleavage rate of oocytes collected from 21 d grafts was lower than that of the control group (P<0.01), and without significant difference in the blastocyst rate between MII oocytes from the grafts and the control (P>0.05). 【Conclusion】Stimulation with exogenous gonadotrophins did not significantly increase oocyte yield of grafted ovaries in male recipients but did enhance the competence of follicular growth, oocyte maturation and embryo development.

    The Estrus Cycle, Diestrus and the Related Influencing Factors in Female Alpine Musk Deer (Moschus sifanicus) in Captivity
    Scientia Agricultura Sinica. 2009, 42(5):  1783-1788 .  doi:10.3864/j.issn.0578-1752.2009.05.035
    Abstract ( 1106 )   PDF (243KB) ( 581 )   Save
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    【Objective】 For exploring and determining the number of estrus, duration of diestrus and the potential influencing factors in captive Alpine musk deer (Moschus sifanicus). 【Method】 From Oct. 2000 to Jan. 2001, the random sampling and all-occurrence recording methods were used to record the number of estrus and duration of diestrus in 22 captive female Alpine musk deers at Xinglongshan musk deer farm in Xinglongshan National Nature Reserve of Gansu Province. The sampling population was divided into classes by such variables as sexual experience, age, age class, origin, the reproduction cost in previous year and next year, and the potential impacts of the above variables on the estrus and duration of diestrus were explored. 【Result】 The results showed that captive female musk deers entered into estrus seasonally with (1.88±0.13) cycles, and the average duration of diestrus is (12.23±0.52) d (n=22). The duration of diestrus of females at different ages and age-classes was not significantly different (P>0.05), however, the factor of age influenced the estrus significantly (P<0.05), and the estrus of sexual-inexperienced females [(3.00±0.32) cycles, n=9] was longer than that of sexual-experienced [(1.55±0.11) times, n=13]. The origin of female deer had no significant impact on the estrus cycles and duration of diestrus. The reproductive cost last year did not affect the estrous and mating parameters such as estrus cycle and the duration of diestrus, but those females fawning next year had more estrus [(1.71±0.16), n=7] and shorter diestrus [(10.13±2.24), n=3] than those barren next year [(2.20±0.18) cycles, n=7; (13.00±2.00) days, n=7].【Conclusion】The temporal estrus pattern of captive female alpine musk deer is influenced by factors such as social interaction among captive individuals, enclosure environments, age and the sexual experience, the origin of females, but is not related to its estrus pattern. Furthermore, the reproduction cost last year of female musk deer do not influence the estrus, those females fawning next year, however, have more estrus and shorter diestrus than those barren next year.

    VETERINARY SCIENCE
    Construction and Identification of Streptococcus suis Type 2 Deficient in IMPDH Expression

    Scientia Agricultura Sinica. 2009, 42(5):  1789-1796 .  doi:10.3864/j.issn.0578-1752.2009.05.036
    Abstract ( 1098 )   PDF (638KB) ( 659 )   Save
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    【Objective】 Streptococcus suis type 2 (SS2) is an important zoonotic pathogen. The inosine 5-monophosphate dehydrogenase is a newly found protein of SS2, therefore, the objective of this study is to construct the impdh-knockout strain for further research on the correlation impdh with virulence. 【Method】 The suicide vector pSET4s and chloromycetin (cat) were used to construct the mutant of IMPDH gene by homologous recombination. 【Result】 The results from PCR and Western-blot methods showed that IMPDH gene was successfully replaced. Also, the SS2-H (△IMPDH) was found to be less competent for six carbohydrates metabolism, slower growth curve, far less acidic substances and be less virulent in mouse, rabbit and porcine models of infection than parent SS2. For Balb/c mice, the LD50 of SS2-H (△IMPDH) was 8.3×108 CFU, whereas the LD50 of SS2-H was 3.36×108 CFU. All rabbits infected with SS2-H (△IMPDH) of equal to or above 1.0×109 CFU presented only hyperthermy (i.e. at least 1℃ over the normal body temperature).All pigs infected with SS2-H (△IMPDH) presented only clinical syndromes and could not cause death. 【Conclusion】 The impdh-knockout SS2 was successfully constructed and named SS2-H (△IMPDH). The experiments pathogenicity to swine, Balb/c mice and rabbits indicate that SS2-H (△IMPDH) weakens virulence to sensitive animals.

    Establishment of Reverse Genetics of H1N1 Subtype Swine Influenza Virus and Generation of Cell Culture High-Yield Recombinant Vaccine Candidate

    Scientia Agricultura Sinica. 2009, 42(5):  1797-1804 .  doi:10.3864/j.issn.0578-1752.2009.05.037
    Abstract ( 1251 )   PDF (409KB) ( 860 )   Save
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    【Objective】 To establish a reverse genetics system of H1N1subtype swine influenza virus and to construct high-yield H1N1 subtype swine influenza virus candidate vaccine strain propagating in MDCK cells. 【Method】 A/Swine/ Guangdong/LM/2004 (H1N1) was chosen to generate new recombinant virus by reverse genetics. 【Result】 rH1N1 was rescued, and all the genes of which derived from the parental strain. After several rounds passages of the rH1N1 in MDCK cells, maximum HA titer of 1﹕64 was achieved. Meanwhile, re-LM was obtained which contained hemagglutinin (HA) and neuraminidase (NA) genes derived from LM, and the other six internal genes from A/Goose/Dalian/3/01(H9N2). Both rH1N1 and re-LM showed a perfect stability. The maximum HA titer of re-LM was 1﹕1 024 was observed, after consecutive passages in MDCK cells, moreover, the HA titer was steady, which showed that re-LM had the characteristics of high-yield. A formalin- inactivated oil-emulsion vaccine was prepared with re-LM. Inoculation of piglets with the inactivated vaccine, the HI antibodied were detectable at two weeks post-vaccination. The average HI titers were above 1﹕32 after two weeks of the first vaccination, and which could reach 1﹕512 after the third times vaccination, demonstrating it′s optimal immunogenicity. 【Conclusion】 This is the first report of successful in establishment of the reverse genetics system of H1N1 subtype swine influenza virus in the world. It settles the foundation for further research on pathogenicity mechanism and the production of cell grown influenza vaccine of H1N1 swine influenza in the future.

    Genetic Variations of ORF5 Gene and Nsp2 Gene of Porcine Reproductive and Respiratory Syndrome Virus Isolates from China in 2005-2007

    Scientia Agricultura Sinica. 2009, 42(5):  1805-1812 .  doi:10.3864/j.issn.0578-1752.2009.05.038
    Abstract ( 934 )   PDF (647KB) ( 714 )   Save
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    【Objective】 PRRSV were isolated from China in 2005-2007 to recognize the molecular biology character, phylogenetic relationship and the state quo of PRRSV prevalent isolates. 【Method】36 PRRSV isolates were isolated from 81 suspected clinical samples in 4 provinces which suffered PRRS in China in 2005-2007, ORF5 and Nsp2 genes of these isolates were sequenced and analyzed. 【Result】 36 isolates are North America PRRSV, which of ORF5 genes were composed of 603 nucleotides, encoded polypeptides of 200 amino acid residues, no gene deletion or inseration. Variations of the deduced amino acids of ORF5 gene mainly occurred at positions of 9 to 39. Nsp2 genes of PRRSV isolates were composed of 2940 or 2850 nucleotides. Compared with 15 PRRSV isolates, Nsp2 genes deletions of 21 PRRSV isolates were occured at positions of 481 and 532-596 amino acid. Compared with 14 PRRSV ORF5 and Nsp2 genes recorded by GenBank, most isolates show a close distance evolutionary relationship with Ch-1a, except for B02-2005, which may respect with PRRS vaccine virus. PRRSV isolates from different times show descendant homology compared with earlier isolates. 【Conclusion】 Based on amino acid sequence phylogenetic tree of ORF5 gene and Nsp2 gene, the 36 PRRSV isolates partly belong to subgroup Ⅳ represented by VR-2332, partly to subgroup Ⅰ represented by BJ-4, and partly to subgroup Ⅱ represented by Ch-1a. PRRSV ORF5, Nsp2 nucleotides and amino acids have taken place a larger variation, the genetic relationship of PRRSV isolates from different regions exist cross-cutting phenomenon, no obvious geographical characteristics.

    Establishment and Application of Detecting the Residues of Florfenicol in Chicken Muscle by Indirect Competitive Enzyme-Linked Immunosorbent Assay
    Scientia Agricultura Sinica. 2009, 42(5):  1813-1819 .  doi:10.3864/j.issn.0578-1752.2009.05.039
    Abstract ( 930 )   PDF (298KB) ( 1147 )   Save
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    【Objective】 The purpose of the study is to obtain special antibody and develop competitive indirect enzyme-linked immunosorbent assay (ciELISA) for florfenicol 【Method】 Florfenicol hapten was conjugated with the carrier proteins bovine serum albumin (BSA) as immunogen and with human serum albumin (HSA) as coating antigen, respectively, and the coupling ratio of FFC-HS-BSA was 14.4 and the coupling ratio of FFC-HS-HSA was 14.7. Polyclonal antibody against florfenicol was generated by immunizing rabbits with FFC-HS-BSA. 【Result】 The antiserum with high titer was 1﹕102 400. The indirect competitive ELISA revealed that the optimal concentration of rabbit serum was 1﹕6 400, the optimal concentration of coated antigen was 0.5 μg?ml-1, and the optimal concentration of sheep anti-rabbit IgG was 1﹕20 000. The regression equation was Y=-0.1516X + 0.788 (R2=0.9859), the lowest detection limit was 0.18 ng?ml-1, the linear range was from 0.18 ng?ml-1 to 500 ng?ml-1, and the coefficients of variation of intra-assay and inter-assay were respectively 4.86% and 7.77%. The antiserum had cross reactivity of 0.094% and 0.098% with chloramphenicol and thiamphenicol, respectively, but had cross reactivity of less than 0.01% with others. The recoveries in chicken ranged from 84.14% to 106.1%. 【Conclusion】 The antibodies with high titer and specificity were produced successfully and a competitive indirect enzyme-linked immunosorbent assay (ciELISA) was developed for the detection of florfenicol residue in chicken. The results showed that the method is sensitive, accurate, convenient, and quick.

    Effects of the Compound Traditional Medicine Weeping Forsythia on Expression of Th Differentiation Signaling Transduction Protein Calcineurin
    Scientia Agricultura Sinica. 2009, 42(5):  1820-1826 .  doi:10.3864/j.issn.0578-1752.2009.05.040
    Abstract ( 1006 )   PDF (425KB) ( 578 )   Save
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    【Objective】 The objective of this experiment is to explore the mechanism of the compound traditional medicine weeping forsythia regulating immunity by testing the expression of the differentiation signaling transduction protein, calcineurin. 【Method】 To prepare the compound weeping forsythia prescription serum, the Ova and ConA were used as antigen in induction and T cell as presenting cell, the T cells were inlervening cultured for 24 hours, and then the expression of calcineurin was examined by RT- PCR and Western blot. 【Result】 The expression of CaN mRNA was elevated in the 0.1% Ova groups comparing with normal serum and serum-free group. The 0.1% Ova groups were significally different with the 10% Ova groups (P<0.01). The protein expression of CaN was significantly down regulated in compound weeping forsythia serum groups with Western blot detecting, but there was no significant difference between the two groups at concentration of 0.1% Ova. The CaN expression of the compound weeping forsythia serum group was elevated obviously compared with the group without serum (P<0.05). 【Conclusion】The compound weeping forsythia has provided an immunomodulation by transduction of regulatory signal, and by realizing many aspects and double direction regulation. The results showed that the compound weeping forsythia has more referential values of the selection medication on deficiency syndrome and excess syndrome.

    RESEARCH NOTES
    Expression Analysis and Establishment of Regeneration System of Oleate Desaturase Gene in Peanut

    Scientia Agricultura Sinica. 2009, 42(5):  1827-1832 .  doi:10.3864/j.issn.0578-1752.2009.05.041
    Abstract ( 1012 )   PDF (430KB) ( 663 )   Save
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    【Objective】 This article aims at breeding of new materials with high oleate in peanut. (Method) Plant dual expression vector pFGC/2nd, containing oleic desaturase gene, was transferred into full bud explants of peanut via Agrobacterium tumefaciens, and trsnsgenic plants were got by screening with kanamycin. 【Result】 It was better-performing that the bud explants were dipped into Agrobacterium suspension (OD600=0.6) for 8 - 10 min and then cultured on MS medium in the dark for three days. After induction screening for three months or so, a total of 16 conversion plants were produced, of which 11 transgenic plants were positive by PCR analysis. It stated that the foreign gene had been integrated into the receptor plant. The further Real Time PCR indicated that the expression level of four transgenic plants was significantly reduced. 【Conclusion】 It is speculated that target genes maybe suppressed by dsRNA interference, and the high oleate material could be selected.

    Effects of Different Water and Nitrogen Forms on Starch Yields and Starch Pasting Properties of Weak Gluten Wheat Variety Yumai 50

    Scientia Agricultura Sinica. 2009, 42(5):  1833-1840 .  doi:10.3864/j.issn.0578-1752.2009.05.042
    Abstract ( 1144 )   PDF (225KB) ( 622 )   Save
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    【Objective】 In order to reveal the regulating effects of water and nitrogen forms on paste traits of starch of weak gluten wheat variety Yumai50 and filtrate the feasible treatment which the starch quality of weak gluten wheat could be better advanced. 【Method】 A field experiment was conducted from 2004 to 2005, two elements including water (three levels) and nitrogen (three forms) were conducted to study the effects of water and nitrogen forms on starch yield and starch paste traits of weak gluten wheat variety Yumai50. 【Result】 The improving effects of raised irrigation and applied NH4+-N on starch yields were effective, the main viscosity parameters with W1 treatment were better than that with W2 and W3 treatment, the value of PT and BD was N3>N1>N2, and the value of PV, TV, SB and FV was N2>N1>N3. In view of the interaction of water and nitrogen forms, the values of PV, TV, SB and FV were the highest and the value of PT and BD was the lowest in jointing stage irrigation and NO3--N application treatment among all the water and nitrogen forms treatments, and there was only a certain viscosity index needs to be improved in other treatments. 【Conclusion】 The regulating and controling effects of different water and nitrogen forms treatments on starch yield and starch paste traits in weak gluten wheat variety Yumai50 were effective. Starch yield was highest with irrigation at jointing stage, booting stage, filling stage and NH4+-N application treatment, but the starch paste traits were most excellent in irrigation at jointing stage and NO3--N application treatment.

    Studies on Gene Lr24 Conferring Resistance to Wheat Leaf Rust by TRAP Analysis
    Scientia Agricultura Sinica. 2009, 42(5):  1841-1848 .  doi:10.3864/j.issn.0578-1752.2009.05.043
    Abstract ( 883 )   PDF (586KB) ( 686 )   Save
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    【Objective】 This research aims to develop a TRAP marker that is closely linked to or co-segregated with Lr24, and could be employed as a probe for library screening. 【Method】 TRAP analysis was employed and ninety TRAP primer pairs were used to test the resistant and susceptible parents, as well as the resistant bulk (Br) and the susceptible bulk (Bs) in this study. The TRAP primers displaying polymorphism between tested lines were employed to map the linkage in the F2 population derived from TcLr24×Thatcher subsequently, and to detect the specificity of the primer with 45 NILs of wheat leaf rust resistance and 30 diploid materials of wheat further. 【Result】 Ten of 90 TRAP primer pairs displayed polymorphism among TcLr24, Br and Thatcher, Bs, accounting for 11.11%. And a further study found that one stable primer, ARBI1/ RGA-2F, generating a 161 bp fragment was presented only in F2 resistance population, and absent in susceptible population. Forty-five wheat leaf rust resistance NILs or single gene lines and 30 diploid materials of wheat were also tested with this primer pair. This specific band was also present in TcLr19, TcLr29, TcLr38, Lr42 and TcLr44, but absent in all the 30 diploid materials. 【Conclusion】 It is concluded that the marker ARBI1/ RGA-2F is closely linked to Lr24, and can be used for MAS to detect Lr24 in Lr24 resistance breeding, further can be used as a probe for screening cDNA and BAC library of TcLr24.

    Natural Infection of Bidens pilosa L. by Bidens mottle virus in Yunnan

    Scientia Agricultura Sinica. 2009, 42(5):  1849-1853 .  doi:10.3864/j.issn.0578-1752.2009.05.044
    Abstract ( 929 )   PDF (369KB) ( 983 )   Save
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    【Objective】 This study was carried out to determine the pathogen causing the mosaic and mottle symptom on Bidens pilosa L.. 【Method】 Viral particles in the infected leaves were detected by electron microscopy. Serological relation between the pathogenic virus and genus Potyvirus was examined by indirect ELISA. Moreover, the sequence of the 3′-part genome of the virus was cloned by RT-PCR and sequenced by common molecular biological methods. For bioinformational analysis, programs of BLAST at NCBI, Clustal_X, BioEdit and MEGA 4.0 were used for alignment and phylogenetic tree construction. 【Result】 Electron microscopy of leaf dips from infected plants revealed flexuous particles 650-700 nm in length and 13 nm in width. Cytoplasmic laminar aggregates and pinwheel inclusions were observed in ultrathin sections. Serological reaction between the virus and the antibody of potyvirus was positive. A DNA fragment of 1.8 kb with high identity to the sequence of Bidens mottle virus (BiMoV) could be amplified through the universal primers of family Potyviridae virus. Analysis of the sequence revealed that the amino acid identity of CP and nucleotide identity of 3′UTR to corresponding sequences of BiMoV were both more than 96%. 【Conclusion】 The evidences suggests that the pathogen causing mosaic and mottle symptom on Bidens pilosa L. is BiMoV, which is the first report of BiMoV infecting a member of the Bidens L. in China.

    Physiological Mechanism of Putrescine Enhancement of Root-Zone Hypoxia Tolerance in Cucumber Plants
    Scientia Agricultura Sinica. 2009, 42(5):  1854-1858 .  doi:10.3864/j.issn.0578-1752.2009.05.045
    Abstract ( 1183 )   PDF (275KB) ( 709 )   Save
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    【Objective】 The purpose of this study is to investigate the physiological mechanism involved in the enhancement effects of putrescine (Put) on hypoxic stress tolerance. 【Method】 Cucumber (Cucumis sativus L.) seedlings were grown hydroponically and subjected to Put and root-zone hypoxia treatment with or without inhibition the internal nitrate reduction reaction. 【Result】 The actual (NRact) and maximal (NRmax) nitrate reductase activities were greatly enhanced by Put application, particularly in roots exposed to hypoxia. The reduction of leaf net CO2 assimilation rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) together with the root mitochondrial respiration rate of total (Vt), cytochrome pathway (Vcyt), and alternative pathway respiration (Valt) were all greatly alleviated by the exogenous Put application. However, when nitrate reduction was inhibited by tungstate in the nutrient solution, Put not only failed to alleviate the hypoxia injury of leaf photosynthesis and root mitochondrial respiration, but also exacerbated the decrease of the activities of the two basic metabolic processes. 【Conclusion】 These results indicate that nitrate reduction process is involved in the enhancement effects of Put on root-zone hypoxia tolerance in cucumber plants.

    Effects of Water Stress on Photosynthesis and Associated Physiological Characters of Capsicum annuum L.
    FU Qiu-shi,Jian Cui,Bing Zhao,Yang-dong Guo
    Scientia Agricultura Sinica. 2009, 42(5):  1859-1866 .  doi:10.3864/j.issn.0578-1752.2009.05.046
    Abstract ( 1121 )   PDF (930KB) ( 1328 )   Save
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    【Objective】 The effects of water stress on photosynthesis and associated physiological characters of capsicum were studied, the aims were to reveal the relationship between photosynthetic traits and drought tolerance of two cultivars. 【Method】 The experiment was conducted under two water levels: no stress (75%-80% of field capacity) and stress (30%-40% of field capacity). The responses of plants growth, physiological changes, photosynthetic parameters, chlorophyll fluorescence, stomatal characters, ultrastructure of chloroplast were investigated. 【Result】 The results showed that, under the water stress condition, the growth of the plants was inhibited, the total plant dry weight declined significantly, and root/ shoot increased. Leaf water potential, leaf relative water content and leaf pigment decreased, the contents of malondialdehyde, the proline as well as the activities of superoxide dismutase and peroxidase increased. The Pn, Gs, Tr, Ci, ΦPSII, ETR and qP decreased, but the NPQ and WUE increased. The stomata became smaller and the density decreased, and most of them closed. The chloroplasts became round in shape, the lamellae arranged disorderly and the number of starch grain decreased or disappeared. 【Conclusion】 The decrease of net photosynthetic rate was considered as a result of stomatal restriction. The changes of photosynthetic parameters, chlorophyll fluorescence, stomata characters and the ultrastructure of chloroplast correlated significantly to drought resistance.

    Classification of Rosa hybrida var. minima Cultivars by Pollen Morphology
    Scientia Agricultura Sinica. 2009, 42(5):  1867-1874 .  doi:10.3864/j.issn.0578-1752.2009.05.047
    Abstract ( 1414 )   PDF (755KB) ( 715 )   Save
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    【Objective】 Pollen-morphological characteristics and relationship between pollen morphological characteristics and classification of Rosa hybrida var. minima cultivars were examined. 【Method】 Pollens of 10 miniature rose cultivars were examined by LM (Light Microscopy ) and SEM (Scanning Electron Microscopy). The cluster analysis was carried out based on the observation results. 【Result】 The pollen grains were tricalporate and 3-lobed circular in polar view. Different cultivars showed different exine sculpture and fringes,luminas and verrucate. The pollen shapes were spheroidal or super-spheroidal by P/E (Polar axis length / Equatorial axis length) criteria. The result of cluster analysis indicated that the cultivars could be classified into three groups when similarity coefficient was 0.37. The first group included White Koster, Pink Koster, Purple Ministar, Romantic and their pollen exine sculpture was of dense fringes and dense luminas. The second group included Gold Sun, Maddy, Dwarf Fairy, Hula Girl, Winter Plum and their pollen exine showed dense fringes, rare or bare luminas and verrucate sculpture. The third group included Red Cloud and its pollen exine showed rare and fringes rare luminas sculpture. Compared the palynological classification result with morphological classification result, it was found that they were similar and with little differences. 【Conclusion】 Different Rosa hybrida var. minima cultivars show a different exine sculpture. Palynological analysis could be used in the classification of Rosa hybrida var. minima cultivars and the result is supportive to the result of morphological classification.
    Optimization of Freezing and Thawing Protocol of Rapid Freezing Techniques of Boar Semen in 0.5 ml Straws
    Scientia Agricultura Sinica. 2009, 42(5):  1875-1880 .  doi:10.3864/j.issn.0578-1752.2009.05.048
    Abstract ( 1321 )   PDF (217KB) ( 741 )   Save
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    【Objective】 This study was performed to optimize freezing and thawing protocol of rapid boar seminal cryopreservation in 0.5 ml straws. 【Method】 0.5 ml straws were placed at the height of 3, 5, 7, 9 and 11 cm above liquid nitrogen (LN) for 3, 5, 10, 15 and 20 min in polyethylene box, respectively. And the optimal freezing protocol was determined after straws were frozen in LN and thawed in water bath at 37℃ for 30 s. The optimal thawing protocol was determined from six basal protocols, including 37℃ for 30 s, 42℃ for 25 s, 47℃ for 20 s, 52℃ for 15 s, 57℃ for 10 s and 62℃ for 5 s. 【Result】 In twenty-five freezing protocol, both at post-thawed 0 h and 8 h, the percentages of TMS, PMI and NAR of spermatozoa were highest in semen frozen at 3 cm for 10 min. In six thawing protocols, the percentages of TMS, PMI, NAR and Mt-MP of spermatozoa were higher, and the concentration of MDA was lower in semen thawed at higher temperature. Moreover, compared with the control, the percentages of TMS, PMI, NAR and Mt-MP were increased (P<0.05) and the concentration of MDA was decreased significantly (P<0.05) in semen thawed at 57℃ for 10 s and 62℃ for 5 s, and there was no difference between thawed at 57℃ for 10s and 62℃ for 5s (P>0.05). 【Conclusion】 For the rapid freeze-thawing method of this experiment, adopting optimized freezing and thawing protocol increased the quality of thawed semen, meanwhile, freezing 0.5 ml straws at 3 cm for 10 min and thawing at 57℃ for 10 s or 62℃ for 5 s were the optimal protocol.