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Table of Content

    10 March 2005, Volume 38 Issue 03
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES
    Genetic Diversity of Allozyme of Cultivated Rice in
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    Scientia Agricultura Sinica. 2005, 38(03):  433-438 . 
    Abstract ( 1354 )   PDF (293KB) ( 826 )   Save
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    Allozyme variation of cultivated rice (Oryza sativa L.) in China's Taiwan Province was investigated using 1 591 cultivars based on 14 allozyme loci Pgi1, Pgi2, Amp1, Amp2, Amp3, Amp4, Sdh1, Adh1, Cat1, Icd1, Est1, Est2, Est5 and Est9. The analysis showed that there existed 47 alleles in the tested materials, which covered 78.3% of total 60 alleles found in Oryza sativa L. in the world by the method of gel electrophoresis with system I. In the tested cultivars, the allele frequencies ranged from 0.001 to 0.997 and the gene diversity indexes (Ha) from 0.006 to 0.585. The average gene diversity index (Ht) and the degree of polymorphism (DP) were 0.239 and 18.3, respectively. Of 47 alleles observed, 24 ones (51%) had gene frequencies less than 0.05, and 5 ones (Amp1-1, Adh1-1, Icd1-1, Est1-1, Est5-1) higher than that of 0.95. It was found that there were 182 genotypes based on tested alleles, and allele Est9-null was only identified from 3 rice cultivars in Taiwan Province. The results of genetic differentiation index (Gst) and cluster analysis indicated that the difference of indica and japonica cultivars was significant in cultivars in Taiwan Province, especially in the loci of Amp2, Cat1, Pgi1, Est2 and Pgi2. The result reveals that cultivated rice in Taiwan Province is richer in genetic diversity in term of allozyme alleles, and is an important part of genetic diversity of Chinese rice germplasm.
    Characterization of RAPD Markers and RFLP Marker Linked to Powdery Mildew Resistant Gene Derived from Different H. villosa
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    Scientia Agricultura Sinica. 2005, 38(03):  439-445 . 
    Abstract ( 898 )   PDF (523KB) ( 680 )   Save
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    The analysis was carried out on performance of the resistant gene from H. villosa accession of the former Soviet Union to different isolates of Bluemerie graminis. Polymorphisms were revealed between 6D/6V substitution line Pm930640 and its pedigree parents using five RAPD markers of OPAN031700, OPAI01700, OPAL03750, OPAD07480 and OPAG15580 screened out from 120 random 10-mers primers. Three RAPD markers of OPAN03, OPAI01 and OPAL03 were linked with the resistant gene by analysis of F2 population of Chancellon×Pm930640. Analysis of RAPD markers of 29 wheat lines, including lines conferring one of the most genes from Pm1 to Pm20 respectively, lines conferring resistant gene from two H. villosa accessions and the related wheat parents, showed that these markers not only linked to the gene resistant to powdery mildew from H. villosa, but also detected different genetic backgrounds. OPAL03750 can be used as the marker to distinguish the different resistant lines from two H. villosa accessions because it was only observed in the materials from H. villosa of the former Soviet Union. RFLP analysis also showed the polymorphisms between two H. villosa accessions and their derived resistant lines.
    Phenotypic Recurrent Selection and MAS for Pooling High Yield Genes Related with Heterosis in Upland Cotton
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    Scientia Agricultura Sinica. 2005, 38(03):  446-453 . 
    Abstract ( 1228 )   PDF (287KB) ( 619 )   Save
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    In order for development of new parents for development of new hybrids,the parental materials of popularized hybrids including Xiangzamian 2, Wanza 40 and Zhongmiansuo28 were used to construct recurrent populations for Pooling High Yield Genes in Upland cotton, and two cycles of selection were completed. The objective of this experiment was to investigate the results of phenotypic recurrent selection and MAS. The phenotypic recurrent selection was effective at both individual and cross level, and in different environments for the same trait. The tendency of mean variation in initial population and all populations of two cycles showed no difference, and the means of the most traits including lint yield, seed cotton yield and boll numbers per plant of populations in the second cycle were significantly higher than that of populations in the initial cycle while the genetic variances had no significant difference among them. The effects of MAS using S1495210, S167280 and S3994100, which identified by interval mapping in our institute were closely related to the QTLs for lint yield, lint percent and seed size respectively, were significant. MAS were also efficient using the marker S3452180, identified by individual maker mapping, related to lint yield and lint percent. The results of MAS for lint percent with two markers were more efficient than those with one of two markers.
    Isolation and Structural Analysis of the Seed-Specific Promoter from Soybean
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    Scientia Agricultura Sinica. 2005, 38(03):  454-461 . 
    Abstract ( 1035 )   PDF (349KB) ( 799 )   Save
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    The promoter region(BCSP666) of β-conglycinin α-subunit gene from the genomic DNA of soybean Jilin 43 was isolated by PCR method. Sequencing analysis showed that the cloned fragment BCSP666 had the similar structure of the soybean seed-specific promoter β-conglycinin α′-subunit gene promoter and β-conglycinin β-subunit gene promoter, and it also contains many of the motifs that contribute to the seed-specific promoter activity. Based on this sequencing analysis, it was deduced that promoter fragment BCSP666 had the seed-sepecific promoter activity. And then we constracted the seed-specific expression vector pBMI666 with the promoter fragment BCSP666 and Δ6-fatty acid desaturase gene from Mortierella isabellina. The Δ6- fatty acid desaturase is the rate-limiting enzyme of the desaturation of linoleic acid in production of an essential fatty acid, γ- linolenic acid (GLA). The production of γ-linolenic acid (GLA) was observed in soybean callus cells, which were transformed with this vector. This confirmed the promoter activity of the promoter fragment BCSP666.
    Variation in Root Starch Gelatinization Characteristics During the Growth and Development of Sweetpotato
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    Scientia Agricultura Sinica. 2005, 38(03):  462-467 . 
    Abstract ( 939 )   PDF (426KB) ( 911 )   Save
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    The Differential Scanning Calorimetry (DSC) and Rapid Visco-Analyzer (RVA) were used to determine the starch gelatinization characteristics during the growth of three sweetpotato cultivars. The results showed that the starch contents of three sweetpotato cultivars all decreased as growth progressed. Changes of the amylose content at different harvesting periods could be discriminated according to the cultivars. At the early harvests amylose contents of Xushu18 and Zheda9201 were relatively high, but those of Zhe3449 were low. As the growth duration prolonged, the peaks of DSC thermograms tended to occur at a low temperature and not to be so obtrusive with the increased width of the peak. Obvious decreases in values of onset, peak and conclusion temperatures, as well as enthalpy of phase transitions, were observed as growth time lengthened. The peak viscosities, as determined through RVA, showed a rising tendency as growth progressed. In addition, statistical analysis revealed that there were correlations between the amylose content and gelatinization characteristics to some extent, which were affected by genotypes evidently.
    Genetic Diversity of Agropyron mongolicum Keng Populations
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    Scientia Agricultura Sinica. 2005, 38(03):  468-473 . 
    Abstract ( 943 )   PDF (315KB) ( 827 )   Save
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    According to the population biology theories, genetic diversity of 35 populations of Agropyron mongoliucm Keng distributed over various regions in China was studied. The results showed that there was an abundant genetic diversity (H'=1.7779) among these populations in morphological characters. As for the distribution pattern of genetic diversity, the genetic variation among populations (90.85 %) was greater than that within populations (9.15%). Genetic diversity of this species distributed over every region was different, whose turn was Shaanxi region (H'=1.8627) > Ningxia region (H'=1.1.8332) > Inner Mongolia (H'=1.7232) > Xinjiang region (H'=1.6453) > Gansu region (H'=1.6436). But those of Shaanxi and Ningxia regions were collected from the southern brink of the Maowusu desert where there have abundant populations, which is about 68.6 % of the total analyzed. So high emphasis should be put on the Agropyron mongoliucm populations distributed over the southern brink of the Maowusu desert whether for the purpose of scientific research or productive application. Additionally, the significance of the population for species' definition and the effective conservation strategy to this plant were discussed.
    TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY
    Growth Phenomenon of Adventitious Root Penetrating Through the Base of Sheath and Its Effects on Leaf Senescence in Rice
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    Scientia Agricultura Sinica. 2005, 38(03):  474-479 . 
    Abstract ( 933 )   PDF (308KB) ( 808 )   Save
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    An interesting phenomenon of root growth in rice has been observed. The phenomenon is that the roots emerged from the nodes consequentially penetrate the base of leaf sheath grown from the nodes where roots grow and below it as well. The results from experiments with 300 diverse cultivars showed that the number of non-rooting nodes and the number of green leaves in full-heading stage presented the positive correlation (r=0.8457), and the linear regression equation was y=0.0045+0.9756x. The results indicated that wounding made by root penetrating growth and contesting nutrition likely cause and accelerate leaf senescence, rooting at higher nodes and overmuch root numbers are an important reasons of leaf premature senescence in hybrid rice. It was supposed that proper root number, much branches and deep-root is a development direction of breeding for ideal type root system in rice.
    Physiological Mechanism of Seed Germination ( Oryza sativa L.) Under Low Temperature
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    Scientia Agricultura Sinica. 2005, 38(03):  480-485 . 
    Abstract ( 1232 )   PDF (465KB) ( 1092 )   Save
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    High germination rate at low temperature (low temperature germinability, LTG) is an essential characteristic of rice varieties adapted to direct seeding culture. To determine the difference of LTG among the varieties and its physiological mechanism of seed germination under low temperature, Japonica cultivars USSR5, Hatanishiki and Indica cultivars Miyang23 and N22 were used to study the mechanism of seed germination. The results showed that USSR5 came from the former Soviet Union and Hatanishiki came from Japan had higher seed germinability under low temperature, while Miyang23 and N22 with weakly low temperature germinability. The main reasons were that Miyang23 and N22 were more sensitive to GA3, ABA, and low temperature. Furthermore, it was revealed that low temperature and exogenous hormone might affect the seed germination through regulating the activity of amylase type 3 by electrophoresis. During the seed germinating, the USSR5 seed with high LTG contained higher level of endogenous ABA under low temperature than normal, and the ratio of GA1/ABA was lower than that of N22 under low temperature, this may be one of the main reasons of USSR5 with high LTG.
    Effect of Calcium on Growth of Coleoptile and Root in Wheat Under Osmotic Stress
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    Scientia Agricultura Sinica. 2005, 38(03):  486-491 . 
    Abstract ( 930 )   PDF (517KB) ( 818 )   Save
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    Under osmotic stress induced by PEG-6000 (20%), when the roots of wheat(Triticum aestivum L. cv 4185)were treated with low concentration of exogenous Ca2+ at 10-6-10-3 mol·L-1, there were no significant difference in growth of coleoptiles and roots, but the growth was inhibited by exogenous Ca2+ at 10-2 mol·L-1. The treatments for roots with EGTA (1, 5,10 mmol·L-1), LaCl3 (0.5, 1 mmol·L-1) and Verapamil (250, 500 μmol·L-1) inhibited the growth of coleoptiles and roots, which were closely related to the increase of peroxidase (POD) activity. These results showed that under osmotic stress, the wheat was more sensitive to deficiency of Ca2+. The higher exogenous Ca2+ concentration, lower extracellular Ca2+ concentration and blocking Ca2+ transfer would suppress the growth of wheat coleoptiles and roots.
    Effects of Different Nitrogen Application Strategies on Yield and Forage Nutritive Quality of Zea mexicana
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    Scientia Agricultura Sinica. 2005, 38(03):  492-497 . 
    Abstract ( 1093 )   PDF (355KB) ( 956 )   Save
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    The effects of different nitrogen application strategies (nitrogen rates and nitrogen application stage) on yield and forage nutritive quality of summer Zea mexicana were studied in an experiment of pool culture. When the natural plant height was 110 cm the plant should be clipped. In the whole growth period, it could be clipped 3 times (H1,H2 and H3 means the first, second and third harvest stage, respectively).To evaluate the forage nutritive value, six items including crude protein (CP), ether extract (EE), nitrogen free extract (NFE), acid detergent fiber (ADF), crude ash (CA), and gross energy (GE) were used. The results showed that the content of CP and EE increased and the content of CA and ADF dereased by two nitrogen rates (High-rate N, 600 kg·ha-1;Mid-rate N, 300 kg·ha-1),which also improved the fresh and dry harvest biomass of the whole plants at H1 and the leaves at H2. But the stalks at H2 and the whole plants at H3 were affected by additional application of nitrogen fertilizer. The yield of CP, EE, CA, NFE, and GE was affected by nitrogen rates, the ADF yield increased with the increase of fresh and dry harvest biomass. It is concluded that all nitrogen applied as base fertilizer can harvest the higher biomass and improve the forage nutritive quality of summer Zea mexicana.
    Quantitative Improvement of Beer-Lambert Law with Spectral Remote Sensing Technology and Its Application
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    Scientia Agricultura Sinica. 2005, 38(03):  498-503 . 
    Abstract ( 1109 )   PDF (364KB) ( 1034 )   Save
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    In this paper, a simple, quick, non-destructive approach, using remotely sensed normalized difference vegetation index (NDVI), was proposed to rebuild quantitatively Beer-Lambert law, thereafter, by means of statistical analysis, the rebuilt Beer-Lambert law was verified with various years' independent data set. The results indicated that NDVI could give expression to the dynamic variation of plant canopy structural parameters. NDVI increased gradually after sowing of maize, up to 55 days, thereafter, declined sharply towards physiological maturity. At the time of 55 days, the difference in NDVI, LAI and K among the three plant types was the largest, respectively. Additionally, NDVI, LAI and K were different from various LOV (leaf orientation value), respectively. NDVI of flat-type cultivars (LOV≤30°) in reaching saturation point was earlier than the others. It was feasible to rebuild Beer-Lambert law through NDVI, and most suitable for erectophile-type cultivars. Recently, due to more and more erectophile-type cultivars bred by researchers, the rebuilt Beer-Lambert law related to NDVI played a more and more important role in practical application.
    PLANT PROTECTION
    Cloning and Sequence Analysis of Coat Protein Genes of Turnip Mosaic Virus Isolates Obtained from Shandong
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    Scientia Agricultura Sinica. 2005, 38(03):  504-510 . 
    Abstract ( 931 )   PDF (360KB) ( 699 )   Save
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    Six isolates of turnip mosaic virus named TuMV-SD1, TuMV-SD2, TuMV-SD3, TuMV-SD4, TuMV-SD5, and TuMV-SD6 were isolated from infected Chinese cabbages and radishes in three different regions (Taian, Yantai, and Zaozhuang) in Shandong province. A pair of primers was designed and synthesized based on the nucleotide sequences of coat protein (CP) genes of TuMV reported. The CP genes of the six TuMV isolates were cloned by RT-PCR method. The sequences of all the CP genes from the six isolates were sequenced and compared with the CP gene sequences of TuMV reported in GenBank. The results showed that the sequences of the six CP genes were all 867 nucleotides in length, and the isolates shared high sequence homology from 97.0% to 99.4% among them. They also shared high homologies of 91.8% to 100% with the sequences of world-B group isolates, of 89.1% to 91.0% with the sequences of Brassica-Raphanus (BR) pathotype isolates, and of 86.0% to 90.3% with the sequences of basal-B group isolates. TuMV isolates reported so far were devided into four groups based on phylogenetic analysis of the CP gene sequences. All the six isolates analysized in this study belonged to the fourth group, i.e. world-B group. Resistance assay revealed that the transgenic Chinese cabbage containing a CP gene of TuMV was resistant to infections of all the six isolates, although the CP transgene only shared a homology of less than 90%with the CP genes of the six TuMV isolates.
    Synthesis and Identification of Artificial Antigen for Imidacloprid
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    Scientia Agricultura Sinica. 2005, 38(03):  511-515 . 
    Abstract ( 1042 )   PDF (303KB) ( 943 )   Save
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    This study reported that a hapten of imidacloprid, 1-[(6-Carboxylethylthio-3-pyridinyl)methyl]-N-nitro- imidazolidinimine was synthesized by using technical grade imidacloprid reacted withβ-Mercaptopropionic acid in the hot alkalic solution. The hapten was conjugated to bovine serum albumin (BSA) and ovalbumin (OVA) to form the artificial antigens, respectively. The antibody with high titer (2.56×104) was produced after immuning to rabbits. Results showed that the antibody hadhigh affinity to imidacloprid tested by enzyme linked immunosorbent assay (ELISA), which IC50 and IC20 were 20.7 ?g·L-1 and 1.1 ?g·L-1 ; and the crosss-reactibities to the related compounds wereless than 1.4%.
    Computational Analysis of Signal Peptide-Dependent Secreted Proteins in Saccaromyces cerevisiae
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    Scientia Agricultura Sinica. 2005, 38(03):  516-522 . 
    Abstract ( 1391 )   PDF (292KB) ( 1621 )   Save
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    The internet-based software such as the SignalP v3.0, TargetP v1.01, Big-PI predictor and TMHMM v2.0 were combined to predict the signal peptides, and the signal peptide-dependent secreted proteins among the 6700 ORFs in Saccharomyces cerevisiae genome. The results showed that 163 proteins were the secreted ones containing signal peptides among 6700 proteins, and they were secreted via Sec pathway. Among the 163 secreted proteins, the signal peptides of 47 secreted proteins only comprised by H-domain and C-domain, without N-domain, but the signal peptides of other 116 secreted proteins including the complete three domains. There were differences on constitution of signal peptides between the secreted proteins of Saccharomyces cerevisiae and ones of Candida albicans, but the length and amino acids types of their signal peptides were similar in general. There were few of the same signal peptides occurred in the secreted proteins of Saccharomyces cerevisiae genome, in order to compare the homology among the secreted proteins with the same signal peptides. The BLAST 2 SEQUENECES and CLUSTAL W were used to align the two protein sequences and multi-protein sequences, respectively. The alignment result indicated that homology of these sequences with the same signal peptide was very highly conservative in amino acid of complete gene. The effect of the signal peptides in S. cerevisia on expression of foreign eukaryotic secreted proteins was discussed in the paper.
    Studies on Insecticidal Activities and Active Ingredients of Stephania kwangsiensis Lo.
    Scientia Agricultura Sinica. 2005, 38(03):  523-527 . 
    Abstract ( 941 )   PDF (203KB) ( 802 )   Save
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    Insecticidal activities and active ingredients of Stephania kwangsiensis were studied for the first time. The results showed that all parts of Stephania kwangsiensis had contact activity to brown planthopper, Nilaparvata lugens, and the contact activity of methanol extract from tuber was highest, with a LD50 value being 1.5794 ?g/female. l-roemerine was isolated from tuber of Stephania kwangsiensis and identified, and it was the main active ingredient. l-roemerine had high contact toxicity to brown planthopper, with a LD50 value being 0.0443 ?g/female. Contact toxicity of l-roemerine to brown planthopper was 7.48 times that of malathion, the convientional chemical insecticide used for controlling brown planthopper. l-roemerine had also stomach poison activity to brown planthopper.
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION
    Effect of Cadmium on Growth and Nutrition Metabolism in Rice
    Scientia Agricultura Sinica. 2005, 38(03):  528-537 . 
    Abstract ( 881 )   PDF (327KB) ( 1492 )   Save
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    A pot experiment was conducted using four Japonica rice genotypes differing in cadmium (Cd)-tolerance and grain Cd concentration, to study the effect of Cd on growth and nutrition metabolism. Cd was added into soil to form 2 levels, i.e. 0 (CK) and 10 mg·kg-1 (Cd stress), respectively. The results showed that Cd stress significantly reduced grain yield and panicle number per plant, spikelets per panicle, filled spikelet rate and grain weight, and shoot dry weight at various growth stages for all four genotypes. Furthermore, these reductions varied in genotypes. The inhibition extent of genotypes with higher Cd-tolerance was smaller than that of genotypes with lower Cd-tolerance when exposed to Cd stress, and the genotype with higher grain Cd concentration showed more inhibition than one with lower grain Cd concentration. It is indicated that Cd-tolerance is consistent at different growth stages, so Cd-tolerance can be evaluated at early seedling growth. Cd stress significantly increased Cd concentration and accumulation in shoots and grains for all four genotypes, and the Cd-induced increase varied in growth stage and genotype. Cd concentration in shoots and grains became less with the progress of growth, but more for Cd accumulation, being similar to the change of dry weight. The results also showed that the effect of Cd stress on eight mineral nutrient concentrations in grains differed among genotypes and mineral nutrients. When exposed to Cd stress, reduced effect could be noted for grain K, P, Mg, Mn and Zn, thus resulting in reduced concentration. On the other hand, increased effect was found for Fe, Cu and Ca. Moreover, the effect of Cd stress on free amino acid concentration in rice grains varied in amino acids and genotypes. It was interestingly noted that Cd stress inhibited synthesis of S-containing amino acid, such as glutamic acid and cysteine, and the Cd-induced inhibition was severer in Cd-sensitive genotypes than Cd-tolerant ones. Meanwhile, the higher Cd-tolerant genotypes had higher glutamic acid and cysteine concentration in grains than the sensitive ones in all treatments. It is suggested that the metabolism of these amino acids may be associated with the response of Cd tolerance of the rice genotype.
    Comparison of Phosphorous Absorption, Quality and Yield Between High Oil Maize and Common Maize as Influenced by Phosphorous Application
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    Scientia Agricultura Sinica. 2005, 38(03):  538-543 . 
    Abstract ( 1032 )   PDF (268KB) ( 774 )   Save
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    A field trial was carried out to investigate phosphorous (P) absorption, quality and yield between high oil maize and common maize. The results indicated that Tongyou 1 had the lower highest P absorption rate (HAR) and later occurring date of HAR, as compared with Simi25. The highest HAR and the earliest occurring date of HAR was obtained by the treatments of P45 and P75 in Tongyou1 and Simi25, respectively. The total amount of P accumulated by maize plant was gained by P105 treatment in both varieties. P in grain was mainly from P absorption by roots. P in grain of Tongyou1 was largely from P absorption by roots, while that of Simi25 was largely from P translocation from vegetative part. High oil corn, Tongyou1, contained more oil and protein contents, but less starch content and lower grain yield. Appropriate rate of P application enhanced the contents of protein and fatty acid, but the increment of starch content was neglectable.
    Profile Distribution and Storage of Soil Organic Carbon in an Aquic Brown Soil as Affected by Land Use
    Scientia Agricultura Sinica. 2005, 38(03):  544-550 . 
    Abstract ( 1144 )   PDF (286KB) ( 968 )   Save
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    Abstract: Many attempts have been made to estimate the soil organic carbon (SOC) storage under different land uses, especially from the conversion of forest land or grassland into cultivated field, but limited reports were found on the estimation of this storage after cultivated field converted into woodland or grassland, especially in small scales. This study is aimed to investigate the dynamics of SOC concentration, its storage and carbon /nitrogen (C/N) ratio in an aquic brown soil at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences under four land use patterns over 14 years. The four land use patterns were paddy field (PF), maize field (MF), fallow field (FF) and woodland (WL). In each pedon at 0-150 cm depth, soil samples were collected from ten layers. The results showed that the profile distribution of SOC was different under different land uses, indicating the effect of land use on SOC. Soil organic carbon was significantly related with soil total N, and the correlation was slightly closer in nature ecosystems (with R2=0.990 and P<0.001 in both WL and FF, n=30) than in agroecosystems (with R2=0.976 and P<0.001 in PF, and R2=0.980 and P<0.001 in MF, n=30). The C/N ratio in the profiles decreased generally with depth under the four land use patterns, and was comparatively higher in WL and lower in PF. The C/N ratio of the FF was closer to that in the same soil depths of MF than to that of PF. Within 100 cm depth, the annual sequestration of SOC was 4.25, 2.87, and 4.48 t·ha-1 more in WL than in PF, MF and FF, the annual increase rate of SOC being 6.15 %, 3.26 %, and 5.09 %, respectively. As a result, the SOC storage was significantly greater in WL than other three land use patterns(P=0.001, 0.008, and 0.008). As compared with PF, MF, and FF, respectively, while there was no significant difference among the other three land uses. It is suggested that woodland has a great potential in making a significant contribution to C storage and environmental quality.
    Study on WebGIS-Based Farming Environment Quality Assessment System
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    Scientia Agricultura Sinica. 2005, 38(03):  551-557 . 
    Abstract ( 827 )   PDF (426KB) ( 966 )   Save
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    On the basis of establishing the assessment method of farmland production environment quality, with the national environment quality standard as basic criteria, using fuzzy cluster evaluation method, improved standard weight deciding method and hierarchical analysis process as assessment means, and using WebGIS as spacial information platform, a Web-based intelligent environment quality assessment system was developed to support farming. The system has realized the functions as data storage and editing, data maintenance and backup, information query, intelligent assessment and result display. Case studies on the assessment system with the datasets in Yizheng City of Jiangsu Province indicated a good suitability and guidance of the system on environment quality assessment in farming base.
    HORTICULTURE
    Changes of Photosynthetic Characteristics of Cucumber Leaves During Unfolding in Solar-Greenhouse
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    Scientia Agricultura Sinica. 2005, 38(03):  558-564 . 
    Abstract ( 835 )   PDF (410KB) ( 850 )   Save
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    Changes of photosynthetic characteristics of cucumber leaves during unfolding in solar-greenhouse were studied. The results showed that the unfolding rate of cucumber leaves at different stages was different obviously. The leaves unfolded at quicker speed in Oct.-Nov., and the leaf area was the largest on 35 d after leaf came out. While those of Dec. 1 leaves on 45 d, and their largest leaf area were less than those of Oct. 14 leaves. The unfolding rate and the largest leaf area of the leaves which came out on Feb. 1 were among those of leaves came out on Oct.14 and Dec. 1. The pigment content of leaves at different stages increased at prophase, then decreased gradually. The photosynthetic rate increased as leaves unfolding, and reached maximum on about 20th day. The light saturation point and compensation point of leaves came out in each peroid mostly decreased as they spread. AQY changed as single-peak curves, and the peaks appeared on 20-40 d after leaves came out. CE reached maximum on 20-30 d after leaves came out, and the leaves came out on Oct. 14 ascended and descended with the quickest speed, whereas those on Dec. 1 changed with the slowest speed. The Fv/Fm and фPSⅡ increased as leaf area increased, and 40-50 days later, they decreased slowly. During leaves coming out, stomatal and non-stomatal factors existed simultaneously, and they all affected Pn. While the decline of photosynthetic function mainly depended on the non-stomatal limitation in the course of senescene.
    Leaf Photosynthesis in Response to Fruit Thining at Different Phenological Stages of Fruit Development in Peach Trees
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    Scientia Agricultura Sinica. 2005, 38(03):  565-570 . 
    Abstract ( 1032 )   PDF (356KB) ( 838 )   Save
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    Fruit thining (DF) and retaining fruit (CK) were carried out at different phenological stages of fruit development on one-year-old shoot of Okubo peach trees [Prunus persica (L.) Batsch.] through preventing exportation of the assimilates to the non experimental parts of the tree by girdling one-year-old shoot and keeping the same leaves between fruit thining and CK. The results showed that fruit thining significantly decreased net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (E), but significantly increased leaf surface temperature (TLeaf) at midday as compared with CK. Internal CO2 concentration, soluble sugar content, reductive sugar content, starch content except that at the final fruit rapid growth stage, ADP-glucose pyrophosphorylase and amylase activity in source leaves were not significantly affected by fruit thining. There was a significant positive parabolic correlation between Pn and Gs, and a strong positive linear correlation between Pn and E. Moreover, Pn increased with the increase of TLeaf if TLeaf was lower than 38℃, then decreased sharply when TLeaf exceeded this critical temperature for both fruit thining and CK. Pn of fruit thining was lower than that of CK in the same TLeaf, especially if TLeaf was higher than 38℃. It is suggested that the decreased stomatal aperture and increased leaf temperature may be an important mechanism in regulating photosynthesis under a decreased strength of sink demand by fruit thining in fruit trees.
    Cloning of cDNA Fragment of L-Galactono-1,4-Lactone Dehydrogenase and Its Expression in Different Organs of Rosa roxburghii Tratt
    Scientia Agricultura Sinica. 2005, 38(03):  571-575 . 
    Abstract ( 1047 )   PDF (263KB) ( 738 )   Save
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    855 bp cDNA encoding L-galactono-1,4-lactone dehydrogenase (GalLDH) fragment was cloned from fruit of Rosa. roxburghii Tratt by the method of RT-PCR on the basis of the homologous genes of Arabidopsis thaliana, cauliflower, sweet potato, strawberry, etc. in GenBank. Sequensing analysis shows that 79%-92% identity in nucleotide sequence and 75%-87% identity in amino acid sequence to that of strawberry and Arabidopsis thaliana, etc. was observed. Northern blot showed that the expression of GalLDH was significantly different in different organs. The transcription level of GalLDH in fruit was significantly higher than that in leaf, stem and root, respectively. Furthermore, this expression mode was highly correlated with AsA levels.
    Inhibitory Mechanisms of Two Silicon Compounds on Mildew Powder of Melon
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    Scientia Agricultura Sinica. 2005, 38(03):  576-581 . 
    Abstract ( 900 )   PDF (432KB) ( 938 )   Save
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    The seedlings of Melon Yujinxiang were used to study the effect and inhibitory mechanism of silicon compounds on mildew powder. The results showed that the severity of mildew powder of melon seedling decreased significantly by treatments with two silicon compounds. Sodium silicate was more effect on mildew powder than nanosized silicon. Sodium silicate increased. the activity of resistant-enzyme. Peroxidase (POD) activity was increased significantly by sodium silicate treatment after silicon treated and pathogen-inoculation. -1,3-glocosidase (GLU) activity increased significantly after 120 h of treatment by sodium silicate and 120 h after pathogen-inoculation. Silicon of sodium silicate treatment deposited obviously at stomata and epidermis. Nanosized silicon did not induce POD activity. And silicon deposition of nanosized silicon treatment was as the same as sodium silicate treatment.
    Cytological and Molecular Studies on Genomic Exchange and Reconstitution in the Synthetic Allotetraploid Cucumis hytivus
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    Scientia Agricultura Sinica. 2005, 38(03):  582-588 . 
    Abstract ( 1040 )   PDF (319KB) ( 885 )   Save
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    The exchanges and reconstitutions between the two genomes in the allotetraploid Cucumis hytivus Chen & Kirkbride (2n = 4x = 38) were investigated by cytological and molecular means. Among the 108 pollen mother cells (PMC) observed, 50 PMC (about 46.3%) had multivalents, indicating the wide genomic exchange and reconstitution. The average chromosome configuration was 0.56I+17.36II+0.35III+0.26IV+0.046V+0.056VI. Among 446 arbitrary primers, only 5 primers could produce 6 specific bands of C. hytivus. Three of them were selected and converted into sequence characterized amplified region (SCAR) markers. The SCAR markers were used in amplification with 13 Cucumis genotypes, and the results showed that only SAP-03/700 marker was specifically amplified. Compared the sequence of 3 different bands amplified by SAP-03/700 primer pair in C. hytivus, C. sativus var. sativus and C. sativus var. hardwickii, the sequences at 2 ends were similar while the middle parts were different. In addition, about 200 bp of SAP-03/700 was homologous with cucumber mitochorndrial genome, but the directions were contrary.
    Responses of Flower Opening and Senescence to Ethylene and Its Relation with Endopeptidase in Two Cultivars of Cut Rose
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    Scientia Agricultura Sinica. 2005, 38(03):  589-595 . 
    Abstract ( 900 )   PDF (431KB) ( 815 )   Save
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    Cut rose (Rosa hybrida) cv. Samantha and Kardinal were used to investigate the effects of ethylene and its action inhibitor, 1-MCP, on flower opening and senescence, and the activity and types of endopeptidase in petals. The results showed that both cultivars were all sensitive to exogenous ethylene. However, remarkable different tendency of flower morphological changes was observed during and after treatment. Ethylene treatment accelerated the processes of flower opening and senescence, and caused petal abscission in Samantha, while it inhibited flower opening severely, and resulted in bull flower and even wilting directly in Kardinal. Much more dramatic changes were obtained in the petals of Kardinal than in Samantha, although the same tendency was shown in both cultivars regarding that ethylene treatment caused the decline of total soluble protein content and an increase of endopeptidase activity, and 1-MCP treatment had the absolutely opposite effect with ethylene. In addition, more quick and dramatic changes of serine-proteases proportion caused by ethylene, were observed in petals of Kardinal than in Samantha. The results above suggest that the different responses of flower opening and senescence to exogenous ethylene might be related to the changes of endopeptidase activity in petals caused by ethylene treatment in the two cultivars.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    Study on the Protective Efficiency of the Genetic Subunit Bacterin Against Porcine Contagious Pleuropneumonia
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    Scientia Agricultura Sinica. 2005, 38(03):  596-600 . 
    Abstract ( 798 )   PDF (320KB) ( 835 )   Save
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    The efficacy of a new genetic subunit bacterin containing recombinant Apx toxins and serovar 7 of Actinobacillus pleuropneumoniae was determined. Weaned piglets were vaccinated twice intramuscularly with the new genetic subunit bacterin or commerical trivalent formalin-inactivated A. pleuropneumoniae. The antibody of each antigen was detected each week after first immunization. Piglets were challenged by percutaneous intratracheal injection with serovar 1. The protective efficacy of immunization was evaluated by clinical, bacteriological, serological and post-mortem examination. The results suggest that immunization with subunit bacterin could reduce clinical sign and lung lesion, which is more efficacious than bacterins.
    Study of Serial Nuclear Transfer on Goat (Bore)-Rabbit Inter-Species Cloned Embryo
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    Scientia Agricultura Sinica. 2005, 38(03):  601-605 . 
    Abstract ( 1114 )   PDF (744KB) ( 875 )   Save
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    The experiments of serial nuclear transfer were conducted by using the blastomere of inter-species original or serial cloned morula as donor and rabbit oocyte as recipient. Finally serial I and serial II cloned embryos were obtained. Of these, Ⅰserial reconstructed embryos 58 andⅡserial reconstructed embryos 14 .The rate of fusion was 79.5% and 70% respectively and there was no significant difference between them(P>0.05). However, the rate of cleavage respectively was 75.9% and 28.6% and difference between them was very significant (P<0.05). Eventually there was noⅡserial blastocyst obtained, but the rate of Ⅰserial blastocyst was 10.2%.
    Identification of Molecular Marker to Salt Tolerance Gene in Alfalfa
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    Scientia Agricultura Sinica. 2005, 38(03):  606-611 . 
    Abstract ( 861 )   PDF (376KB) ( 921 )   Save
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    The study has established the F2 offspring oblained by crossing salt-tolerant alfalfa with salt-sensitive alfalfa, and the salt-tolerant F2 offspring seedlings was evaluated in a pot culture. With the F2 offspring, the study has obtained molecular marker linked with salt-tolerant genes of alfalfa by using the improved BSA and RAPD marker. The RAPD PCR products were recovered and purified using kit, then were sequenced. The DNA sequence was aligned in GenBank, the result of alignment showed that the DNA sequence was homological with one fragment (347 bp) of the mth2-6e18 of Medicago truncatula, and the similarity were 93%. mth2-6e18 is a molecular marker of cysteine proteases that plant salt inducible gene translated. It is extrapolated that this molecular marker has a significant correlation with cysteine proteases gene.
    Cloning and Sequence Analysis of cDNA Encoding mrjp3 of Apis cerana cerana
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    Scientia Agricultura Sinica. 2005, 38(03):  612-618 . 
    Abstract ( 947 )   PDF (292KB) ( 1372 )   Save
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    By screening the worker(Apis cerana cerana)heads cDNA library, using a fragment of the mrjp3 gene of Apis cerana as probe, 120 positive clones were obtained. The clone containing AccMRJP3 cDNA was selected. Based on the sequencing of the inserts of the positive clone, a sequence of AccMRJP3 cDNA which is 1 887 bp long including a poly(A) tail was obtained. The AccMRJP3 cDNA encompassed an open-reading frame (ORF) with 1 779 bp encoding 593 amino acids. The un-translated regions (UTR) of the 5′end and 3′end are 46 bp and 160 bp long, respectively. Similar to AmMRJP3 and AdMRJP3, the putative AccMRJP3 also has a repetitive region. The comparison of the repetitive region of AccMRJP3, AmMRJP3 and AdMRJP3 shows some differences between them.
    RESEARCH NOTES
    Influences of 60Co-γ Radiation on Flight Behavior and Fecundity of Helicoverpa assulta
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    Scientia Agricultura Sinica. 2005, 38(03):  619-623 . 
    Abstract ( 1057 )   PDF (297KB) ( 903 )   Save
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    Flight capacity and reproduction potential of Helicoverpa assulta after radiated with 60Co-γ in pupal stage 12-24 hours before emergence, were investigated in the laboratory. The results showed that there were no significant negative impact on the average flight distance and speed of the adults under 150-300Gy, and there were no significant differences in the adult longevity between the moths treated and its control. In comparison with the control moths, the fecundity of treated females decreased drastically. Egg hatching rate of F1 hybridization derived from the radiated females and normal males dropped quickly and down to 1.23% when sterilizing dose was up to 300Gy. The fact that female adult was much more sensitive to radiation than the male did, suggested that the method of releasing both the treated male and female at the same time may be used to control the field population of the pest.
    Determination of Fixed Ammonium in Soils Using Low-Temperature Heating Method
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    Scientia Agricultura Sinica. 2005, 38(03):  624-628 . 
    Abstract ( 941 )   PDF (231KB) ( 647 )   Save
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    For reducing the long period of shaking for the release of the fixed ammonium by Silva-Bremner method, a new procedure was proposed. The new procedure is that the soil is heated at low-temperature after removal of the exchangeable ammonium and organic N. A manurial loessial soil was sampled to study the effect of acid volume, temperature and heating time on the release of the fixed ammonium by Silva-Bremner method for making comparison. Through this study, optimal conditions were determined for using such a method: treating soil with 5 ml of 5 mol·L-1 HF-1 mol·L-1 HCl and heating at 100 ℃ for 1.5~2 h. Thirty eight soil samples were collected all over China to compare the results between the two methods. Results show that the two techniques gave virtually the same results for the 38 soils with a coefficient of 0.99, and the relative errors was within 5% for the low-temperature heating method. No significant difference was found in the results between the two methods as shown by T-test for individual pairs of each soil.
    Determination of the Proper Sampling Period for Embryo Rescue from Crosses Between Diploid and Tetraploid Grape Cultivars
    Scientia Agricultura Sinica. 2005, 38(03):  629-633 . 
    Abstract ( 906 )   PDF (265KB) ( 889 )   Save
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    The proper sampling period is one of the most important factors of the grape in ovulo-embryo culture. Through testing the changes of the ovule weight and observing its anatomical structure, the period and mode of ovule(embryo) abortion in crosses between diploid and tetraploid grape cultivars were studied, and the ovules were cultured to determine the proper period of embryo rescue. Unlike the seedless grape varieties, the embryo abortion did not occur at one same time for most seeded varieties crossed with different ploidy, the ovule abortion was only individual action, but not colony one. So the period of sampling had some degree of freedom. The period of ovule(embryo) abortion was correlated with the mature period of the female parent variety. The abortive embryo of early-maturing variety occurred at five weeks after pollination, then the mid-maturing variety and late-maturing variety (with low abortion rate) were at six and nine weeks after pollination comparatively. The proper sampling period was between 6-9 weeks for early-, 7-10 weeks for mid-, and 9-12 weeks for late-maturing varieties after pollination based on the ripenning period of the female parent variety.
    Optimization of Cultivation Conditions for Exopolysaccharide and Mycelial Biomass by Clitocybe sp. Using Box-Behnken Design
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    Scientia Agricultura Sinica. 2005, 38(03):  634-638 . 
    Abstract ( 903 )   PDF (544KB) ( 792 )   Save
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    Response surface methodology (RSM) based on a three-level three-factor Box-Behnken design of experiment was used to optimize the exopolysaccharide content (EPC) and the mycelium biomass in submerged cultivation by Clitocybe sp. AS 5.112. The critical factors selected for the investigation were temperature, time of cultivation and volume of medium, based on the results of previous Plackett-Burman design. By analyzing the response surface plots, the optimum ranges of cultivation temperature, time and medium volume for obtaining over 1 253.00 ?g·ml-1 of EPC were in 24.3-25.8℃, 9.7-10.2 d and 76.0-90.0 ml, respectively. While for obtaining over 8.32 mg·ml-1 of dry cell weight (DCW), the above variables would be in the range of 23.8-24.8℃, 9.6-10.3 d and 71.0-98.0 ml, respectively. By solving the inverse matrix from the quadratic regression equations, the optimal conditions for obtaining 1 265.45 ?g·ml-1 of EPC were 25.0℃, 9.9 d and 83.4 ml, to gain 8.50 mg·ml-1 of DCW were 24.4℃, 9.9 d and 87.1 ml. In order to obtain the maximum yield of EPC and DCW at the same time, the above conditions would be 24.5℃, 9.9 d and 84.7 ml, respectively, in this situation, the maximum predicted EPC and DCW were 1 261.60 ?g·ml-1 and 8.47 mg·ml-1, respectively. The experimental data under various conditions have validated the theoretical values.
    PCR Amplification, Cloning and Sequence Analysis of the ITS and 5.8S rDNA of Oesophagostomum Isolates
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    Scientia Agricultura Sinica. 2005, 38(03):  639-642 . 
    Abstract ( 1052 )   PDF (261KB) ( 856 )   Save
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    The internal transcribed spacer (ITS) and 5.8S rDNA of Oesophagostomum spp isolated from Guangdong Province was amplified by PCR using a pair of conserved primers and the amplicons were cloned into pGEM-T Easy vector. The inserts were successfully sequenced, and the results revealed that the inserts were 828 bp in length and consisted of partial 18S, 28S, and complete ITS-1, 5.8S and ITS-2 DNA sequences. The Oesophagostomum isolates were identified as O.dentatum based on ITS-2 sequence. It was the first time that the complete sequence of ITS-1 and 5.8S rDNA of Oesophagostomum dentatum was reported. The results of the present study have laid a foundation for further studies of Oesophagostomum.