Table of Content

16 November 2015, Volume 48 Issue 22

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Rapid Identify the Sources of Unintended Variations of Seed Soluble Proteins in Genetically Modified Rice by Using PTN System

ZHAO Yan, LI Yan-yan

Scientia Agricultura Sinica. 2015, 48(22):  4397-4407.  doi:10.3864/j.issn.0578-1752.2015.22.001

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【Objective】The objective of this study is to establish a PTN（parent control-transgenic plant-nontransgenic control) system for the safety assessment of genetically modified (GM) rice, to provide technical supports for GM rice safety assessment by tracing the technical sources of unintended variations of soluble proteins in GM rice seed according to the comparative analysis of substantial equivalency.【Method】The transgenic rice lines (T), the parent variety controls (P) and other genetic background related non-transgenic controls including regeneration lines from tissue culture (NR) and segregated negative offspring lines (NS) were collected, according to the technological principle for GM rice development. Two glyphosate-resistant GM rice lines T13 and T23, which harboring 2mG2-epsps transgene, and their respective control samples (P, NR, NS) were used as experimental materials, while seed soluble protein contents and components as research subjects. The technical sources of unintended variations from GM rices were interpreted and traced on the basis of the multiple comparison analysis results of rice protein variations among PTN samples. The rice soluble proteins were prepared by sequential extraction method, the albumin, globulin, prolamin and glutelin were extracted successively with distilled water, 5% NaCl, 70% ethanol and 0.1 mol·L-1 NaOH. Bradford method was used for the seed protein content analysis. Analysis of protein components was done by SDS-PAGE method. 【Result】 The contents of seed total soluble protein of GM rice lines T13 and T23 were significantly decreased by 3.29% and 6.84%, respectively, and those variations are mainly affected by the glutelin content changes. While the top grade difference value from GM rice lines and their corresponding parents was less than that from the two natural parent rice varieties P1 and P2, indicating the variations of seed soluble protein content from GM rice are inside the scope of safety. Comparing to their respective parents, the components of albumin and prolamin proteins of GM rice lines T13 and T23 had no variation, but several components of globulin and glutelin varied significantly or extremely significantly, mainly shown as increase or decrease in content. The content of 56 kD and 24 kD globulin of T13 line increased significantly while the content of 65 kD globulin of T23 line decreased extremely significantly than their corresponding parent P1 and P2. The variation tendency of glutenin components from GM rice lines T13 and T23 was similar, mainly shown as the content of 19-23 kD and 33-38 kD glutelin components increased significantly as well as the content of 100 kD and 9 kD glutenin decreased significantly, when compared with their corresponding parent controls. The remarkable variation was that two new glutenin components of 41 kD and 56 kD presented in GM rice lines，while these new variation glutelin components also existed in the NR and NS control samples. The unintended variation characteristics of seed soluble proteins from GM rice lines T13 and T23 were basically consistent with that from their corresponding NR control samples. Additionally, there were unique unintended variations concerning seed albumin content and globulin components in NS23 line.【Conclusion】The content variations of seed total soluble protein from GM rice line are mainly affected by the glutelin content changes, with less variation range than the difference value of natural rice varieties. Components of albumin and prolamin proteins in GM rice seed did not vary notably, but several components of globulin and glutelin varied significantly. The unintended variations of soluble proteins in GM rice seed mainly derived from the somaclonal variations of tissue culture, with little compact caused by transgene insertion mutation.

The Genetic Constitution of Transgressive Segregation of the 100-Seed Weight in A Recombinant Inbred Line Population NJRSXG of Soybean

ZHANG Ying-hu, MENG Shan, HE Jian-bo, WANG Yu-feng, XING Guang-nan, ZHAO Tuan-jie, GAI Jun-yi

Scientia Agricultura Sinica. 2015, 48(22):  4408-4416.  doi:10.3864/j.issn.0578-1752.2015.22.002

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【Objective】 The present study aimed at exploring the QTL and their allele effects of the 100-seed weight in a recombinant inbred line (RIL) population for revealing the genetic mechanism of transgressive segregation, and providing guidance for breeding for different seed size types in soybeans. 【Method】 The RIL (recombinant inbred line) population NJRSXG derived from a cross between Xinjin 2 and Gantai 2-2 was tested and measured for their 100-seed weight in five environments from 2009 to 2011. The genetic map with 400 SSR markers was established for QTL mapping using the mixed model based composite interval mapping (MCIM) method in QTL Network V2.1 software. Based on the QTL mapping, the QTL-allele constitutions of each line of the RIL population was obtained, and the corresponding QTL-allele matrix was established. 【Result】 The 100-seed weight of the parents, Xinjin 2 and Gantai 2-2, were 16.92 g and 14.14 g, respectively, with those of the RILs ranging from 12.09 g to 25.01 g, showing an obvious transgressive segregation. The genotypic coefficient of variation (GCV) was 16.06%, and the overall heritability was 96.17% from a joint dataset analysis. Ten additive QTL and nine epistatic QTL pairs were detected in the joint dataset using an MCIM method. The phenotypic variation explained by additive QTL was ranged from 0.69% to 14.93%, and the four major QTLs, i.e., Sw-05-2, Sw-08-1, Sw-12-1 and Sw-17-1, were 6.91%, 14.93%, 7.80%, and 5.01%. The Sw-13-3 with both additive effect and epistasis effects had not been reported before. The phenotypic variance of epistatic QTL pairs was small, and ranged from 0.31% to 3.44%. The genetic components of 100-seed weight was estimated from the mapping results, and the analysis of variance for the joint dataset, the genetic contribution due to additive QTL, epistatic QTL pairs, and collective unmapped minor QTL were 47.91%, 13.06%, and 35.19% of the phenotypic variation, respectively. From the mapping procedure, the allele effects of all the loci were also obtained, and the genetic constitution of the QTL-alleles for each line of the RIL population and its parents was used to establish the QTL-allele matrix. The two parents have seven and three loci with positive additive effects respectively; therefore, this is a complementary pair of parents. No lines of the RIL population had all positive alleles or all negative alleles, indicating a hidden potential of recombination, and the lines with larger seed weight had more positive alleles, while the lines with smaller seed weight had more negative alleles, which implies that recombination among loci was the major cause for transgressive segregation of the 100-seed weight in the RIL population. In addition, it was also found that there was still a possibility to improve the 100-seed weight through further recombination. 【Conclusion】 The transgressive segregation of 100-seed weight can be found in a RIL population; 10 additive QTL and 9 epistatic QTL were detected using the joint dataset tested under five environments. The transgressive segregation was caused by recombination among loci between parents, and the potential for further improvement through recombination among RILs still exists.

Molecular Cloning and Arabidopsis Ectopic Expression of a Phytochrome B gene from Brassica oleracea

SUN Guang-hua, YUAN Huan-huan, FAN Xiao-cong, GU Hai-ke, SONG Mei-fang, XIAO Yang, MENG Fan-hua, GUO Lin, YANG Qing-hua, ZHAN Ke-hui, YANGJian-ping

Scientia Agricultura Sinica. 2015, 48(22):  4417-4427.  doi:10.3864/j.issn.0578-1752.2015.22.003

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【Objective】Cabbage (Brassica oleracea L.) is one of the most widely grown vegetable crops in the world. Cabbage is grown in spring and fall, however varieties need to be made suitable for cultivation all the year round. Study on the response of cabbage phytochromes to light and temperature is an important basis for crop improvement with respect to extending growth periods. Phytochromes of interest here are the red/far-red reversible photoreceptors. Among them, phyB is an essential red light receptor that predominantly mediates seedling photomorphogenesis and shade-avoidance response. The objective of this study was to isolate the phytochrome B gene in cabbage (i.e., BoPHYB), to explore its functions on seedling de-etiolation and shade avoidance by ectopic expression in Arabidopsis, and evaluate its potential in cabbage breeding. 【Method】The cDNA sequence of BoPHYB was isolated from leaves of a self incompatible line 12C. Bioinformatic analyses were employed to predict its function domains and to build a phylognetic relationship tree among plant phyB homologs. The pJIM19-Myc-BoPHYB binary construct was electroporated into the Agrobacterium tumefaciens strain GV3101 and then introduced into Arabidopsis thaliana (both of the wild type and phyB-9 mutant) via a floral dip method. Transgenic plants were selected on germination plates containing 50 mg/mL kanamycin for Myc-BoPHYB. Homozygous T3 or T4 transgenic plants were used for testing the seedling hypocotyl elongation and shade avoidance responses. 【Result】The reading frame of BoPHYB possesses 3 507 bp and encodes 1 168 amino acid residues (128.9 kD) deduced from the DNA sequence. Similar to both phyB protein of Arabidopsis thaliana (i.e., AtphyB) and Brassica rapa (i.e., BrphyB), BophyB contains one GAF domain, two PAS domains, one HisKA domain, and one HATPase_c domain. Phylogenetic analysis indicated that BophyB belongs to the same branch as BrphyB and AtphyB, while showing low similarity to phyB proteins from monocotyledonous species, such as common wheat, corn and rice. Compared with the wild type Col-0, the transgenic lines overexpressing BophyB in A. thaliana exhibited much shorter hypocotyl elongation under red and white-light conditions. Their adult plants displayed dwarf stature with dark green leaves and short petioles under long-day and short-day conditions.【Conclusion】In this study, we cloned BoPHYB gene, and evaluated it with AtPHYB in crop improvement. Taking on similar structures and functions with AtphyB, BophyB promotes seedling de-etiolation under red and white-light conditions and inhibits shade avoidance responses in mature plants under long-day and short-day conditions.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Absorption Characteristics of Ammonium Ion of Roots in Different Nitrogen Use Efficiency Rice Varieties

ZHANG Xiao-guo, XU Chun-mei, CHEN Song, JI Cheng-lin, ZHANG Xiu-fu, WANG Dan-yingZHANG Xiao-guo, XU Chun-mei, CHEN Song, JI Cheng-lin, ZHANG Xiu-fu, WANG Dan-ying

Scientia Agricultura Sinica. 2015, 48(22):  4428-4436.  doi:10.3864/j.issn.0578-1752.2015.22.004

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【Objective】Two rice varieties were exposed to different levels of external ammonium ion (NH₄⁺) condition to examine the responses and its differences. The research will further reveal the mechanisms of nitrogen use efficiency (NUE) in different absorption properties by analyzing different performances and absorption characteristics.【Method】Two rice varieties of QLSM (High-NUE) and HK3 (Low-NUE) were cultivated hydroponically, and then treated with 3 NH₄⁺ concentrations (Low, Middle, High) for 15 days at tillering stage. Furthermore, the morphological characteristics, nitrogen content, nitrogen accumulation, root activity, root respiration and root transmembrane NH₄ ⁺ fluxes were determined.【Result】The results showed that QLSM grew well under low NH₄⁺ condition and showed no significant difference with its control in plant height and tillers. It showed that the total dry matter weight and root N accumulation increased by 25.9% and 74.2% in QLSM, respectively. Whereas, low NH₄⁺ condition significantly reduced plant height, tillers, total dry matter weight and root N accumulation of HK3 by 10.1%, 26.4%, 19.5% and 2.3%, respectively. Furthermore, compared with CK, N content in roots and shoots of the two varieties decreased under low NH₄⁺ condition. Meanwhile, the root activity of QLSM and HK3 sharply reduced by 76.0% and 78.2%, and the root respiration intensity also significantly decreased by 29.5% and 33.8%. The results suggested that root activity and root respiration intensity did not contribute to NH₄⁺ absorption under low NH₄⁺ condition. Moreover, under the condition of low NH₄⁺, NH₄⁺ influx was more pronounced in QLSM, while HK3 showed NH₄⁺ insensitivity in the root meristem zone.【Conclusion】It is concluded that high NH₄⁺ absorptive capacity under low NH₄ ⁺ is associated with enhanced NH₄⁺ influx in the root meristem zone.

Effects of Interaction of Wheat Straw Residue with Field and Nitrogen Applications on Branches and Spikelets Formation at Different Positions in Large Panicle Hybrid Rice

DONG Ming-hui, GU Jun-rong, CHEN Pei-feng, HAN Li-yu, QIAO Zhong-ying

Scientia Agricultura Sinica. 2015, 48(22):  4437-4449.  doi:10.3864/j.issn.0578-1752.2015.22.005

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【Objective】The objective of the study is to investigate the effect of wheat straw-residue with field and nitrogen applications on the formation of branches and spikelets of hybrid japonica rice with large panicle.【Method】 A field experiment was conducted with the two applications of wheat straw to field (no wheat straw residue applied to field, T0; all wheat straw residue applied to field, T1) and three nitrogen (N) rates ( 225 kg·hm^-2, N1; 300 kg·hm^-2 , N2; 375 kg·hm^-2 , N3) by using the hybrid japonica rice cultivar, Yongyou 1540 as material. 【Result】 All wheat straw residues applied to field could increase the yield, but not significantly. N rates significantly influenced the yield, and at the N rate of 300 kg·hm^-2 the yield was significantly higher than at the N rate of 225 and 375 kg·hm^-2. The branch and spikelet formation of large panicle hybrid rice varied with their position at a whole rice panicle. The wheat straw and N rates significantly influenced the formation of the branches and spikelets. Compared with T0, the number of differentiated and retrograded total branches and spikelets were all significantly decreased under T1, and the retrograded number decreased more than the differentiated, resulting in the survived number being higher than those under T0. The wheat straw did not significantly affect the formation of the primary branches, but significantly affected the formation of the secondary branches and spikelets. N rates significantly affected the primary and secondary branches and spikelets. The number of differentiated and survived total branches and spikelets at the N rate of 300 kg·hm^-2 were highest among three N rates, while the retrograded number and percentage were lowest. Under the treatment of T0N2, the number of differentiated branches and spikelets were highest, but the number of retrograded branches and spikelets under T1N2 treatment were significantly higher than other treatments, which indicated that the survived number were highest. The wheat straw and N rates did not significantly affect the primary and secondary branches and spikelets at the upper part of a panicle, but significantly affected the formation of the branches and spikelets at the middle and basal part. It is worth noting that the differentiation and degradation of secondary spikelets at the basal part greatly affected the formation of the total spikelets. The survived primary or secondary branches and spikelets were significantly positively correlated with the yield and grain number per panicle. The differentiated and survived branches and spikelets were negatively correlated with the productive panicle number and seed setting rate, but significantly positively correlated with  1 000- grain weight.【Conclusion】There was a difference on the formation rules of branches and spikelets at the different parts of a panicle of the hybrid japonica rice with large panicle. The wheat straw and N rates significantly affected the formation of the branches and spikelets, especially the secondary branches and spikelets at the middle and basal part. The interaction effects existed between the wheat straw-residue applied to field and N rates. All wheat straw-residues applied to field and optimum nitrogen rates were conducive to the formation of branches and spikelets.

Plant Height Affects Nitrogen Absorption and Utilization in Rice with Similar Genetic Background

CHEN Chen, WANG Yi, YANG Bin, ZHU Zheng-kang, CAO Wen-ya, LUO Gang, ZHOU Juan, WANG Xiang-ju, YU Xiao-feng, YUAN Qiu-mei, ZHONG Jun, YAO You-li, HUANG Jian-ye, WANG Yu-long, DONG Gui-chu

Scientia Agricultura Sinica. 2015, 48(22):  4450-4459.  doi:10.3864/j.issn.0578-1752.2015.22.006

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【Objective】To clarify the relationship between the plant height and the nitrogen absorption and utilization in rice populations derived from CSSSL (chromosome single segment substitutive lines) progenies. 【Method】 To investigate the relationship between the plant height and the yield, yield components, nitrogen absorption, and utilization, a total of 114 lines derived from chromosomal single segment substitution lines (CSSSLs) were employed in hydroponic culture in 2010 and 2011. Basing on the distribution of the plant height, these CSSSLs could be clustered by MinSSw method into six categories (namely A, B, C, D, E, and F in the order from short to tall statue). 【Result】As the plant height increased from category A to F, the yield, total nitrogen absorption at maturity, total dry matter at maturity, nitrogen absorption at the heading stage, nitrogen absorption per panicle, and daily nitrogen absorption quantity all increased. However, the nitrogen content in a percentage of the whole plant and the growth period showed no significant differences among the categories. The panicle number per unit area and nitrogen absorption at the grain-filling phase showed no significant differences among the categories A to E, while they showed significant increases in category F. Further analysis revealed that the total nitrogen absorption at maturity depended more on the dry matter weight rather than the nitrogen content in percentage, more on the nitrogen absorption at the heading stage rather than those at the grain-filling stage, more on the nitrogen absorption per panicle rather than the panicle number per unit area, and more on the daily nitrogen absorption quantity rather than the growth duration. In addition, the dry matter production efficiency and nitrogen utilizing efficiency per grain production (NUEg) showed limited change, while the N harvest index showed a decreasing trend. Referring to the category F, these three indices all showed a decreasing trend, while the NUEg and N harvest index showed greater extent of change. Therefore, the major indices for improving the nitrogen utilization efficiency should be set according to the plant height.【Conclusion】As the lines increased in the plant height, the nitrogen absorption at maturity increased. However, this was accompanied by the decreases in N harvest index and N grain production efficiency. This trend was more prominent in lines with exceptional tall plant height.

PLANT PROTECTION

Effect of Petals Fall off on Botrytis Fruit Rot in Strawberry

HAN Yong-chao, ZENG Xiang-guo, XIANG Fa-yun, YANG Xiao-fang, YUAN Hua-zhao, CHEN Feng-ying, GU Yu-cheng

Scientia Agricultura Sinica. 2015, 48(22):  4460-4468.  doi:10.3864/j.issn.0578-1752.2015.22.007

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【Objective】The role of petal senescence in Botrytis fruit rot (BFR) of strawberry was defined and the relationship between the speed of petal fall and the incidence of BFR was analyzed. The results will provide a practical basis for BFR control and the evaluation of strawberry resistance or tolerance to BFR.【Method】Trial 1: Field trials were conducted on the strawberry cv. ‘Sweet Charlie’. Senescent petals on the surface of at least 2 000 fruits were removed. The incidences of BFR were evaluated after 8 days with high humidity in plastic greenhouses. Trial 2: Field trials were conducted in Mar. 2013, 2014 and 2015 on 11 cultivars. For each cultivar, numbers of senescent petals left on the strawberry surface were recorded at 7, 14, 21 and 28 days after white bud (DAB), 20 petals per cultivar. Percentages of fallen petals were calculated. The BFR incidences were investigated at the peak of BFR. The correction between the fallen petal rates and the BFR incidences were analyzed using Excel 2007. Trial 3: The petal fall rates and the number of residual petals on fruits of 33 cultivars were investigated and the correction between the two was analyzed.【Result】The BFR incidence was 4.2% at the beginning of the investigation. After 8 days, the average BFR incidence increased to 7.3% and 25.3% for the treatment of deblossoming and control, respectively. For most fruits, the infection origin was the overlap of senescent petals and fruits. For each cultivar, the trend of petal fall rates from year to year was consistent. The fallen petals of all cultivars increased with time; however, the petal-off speeds among cultivars were significantly different. For example, the fallen petal rates of ‘Jingyao’ at 7 DAB in the year 2013, 2014 and 2015 were 99.0%, 79.8% and 94.4%, which were significantly higher than ‘Jingyu’ (61.0%, 24.0% and 62.5%) and ‘Sweet Charlie’ (26.0%, 3.8% and 31.9%). The results of the correlation analysis showed that the BFR incidences were significantly negatively related with the fallen petal rates at the 7 DAB in different years (P＜0.05 in 2013; P＜0.01 in 2014 and 2015). The fallen petal rates at the 7 DAB was significantly negatively correlated with the number of residual petals on fruits (P＜0.01). 【Conclusion】Senescent petals is the main way for Botrytis cinerea to infect the strawberry fruit, therefore, removal of the senescent petals can significantly reduce the BFR incidences. There was significant correlation between fallen petal rates and BFR incidences on strawberry. Strawberry resources which petals fall off early are potential varieties with BFR resistance for the trait of disease escape.

Identification of Ecdysone Synthesis Pathway Genes and Analysis on the Impact of Food Deprivation on Larvae Development of Bactrocera dorsalis Hendel

CONG Lin, JIANG Xuan-zhao, YANG Wen-jia, XU Kang-kang, DOU Wei, RAN Chun, WANG Jin-jun

Scientia Agricultura Sinica. 2015, 48(22):  4469-4482.  doi:10.3864/j.issn.0578-1752.2015.22.008

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【Objective】 As one of the most important endohormones, ecdysone plays an important role in regulating the development of insects and responding to environmental factors. The objective of this study is to investigate the expression profiles of ecdysone synthesis pathway genes in Bactrocera dorsalis Hendel in various tissues and different conditions, providing theoretical knowledge to understand the mechanisms of metamorphosis and the stress response. 【Method】RT-PCR and RACE technologies were applied to clone the ecdysone synthesis pathway genes BdCyp302a1, BdCyp315a1 and BdCyp314a1. And quantitative PCR (qPCR) was carried to evaluate the mRNA expression patterns of ecdysone synthesis pathway genes BdNvd, BdCyp306a1, BdCyp302a1, BdCyp315a1 and BdCyp314a1 at different larval developmental stages (1- to 8-day-old larvae), tissues (prothoracic gland mixture, fat body, midgut, Malpighian tubes, integument and trachea), and starvation condition. Further, the impacts of food deprivation on larvae development were also examined in this research.【Result】The open reading frames (ORF) of BdCyp302a1 (GenBank accession number: JQ027284), BdCyp315a1 (GenBank accession number: KC515377) and BdCyp314a1 (GenBank accession number: JQ229645) were finally obtained. The analysis indicated that the protein sequences were highly conserved, which harbored typical and P450 motifs, such as Helix-C/I/K, PERF motifs, heme-binding domains and prolin/glycine rich domain. The results of qPCR showed that the expression levels of BdNvd, BdCyp306a1 and BdCyp314a1 were stable in the first four days at the larval stage, but significantly elevated in the last two days, which were up-regulated for 7.33, 10.89 and 7.82 folds comparing to the lowest level, respectively. And the expression levels BdCyp302a1 and BdCyp315a1 were stable at the larval stage. The expression profiles showed that all of the ecdysone synthesis pathway genes were traceable in the selected tissues. The highest relative expression levels of BdNvd, BdCyp306a1 and BdCyp315a1 were observed in the prothoracic glands, and no significant differences among other tissues. The expression levels of BdCyp302a1 followed the precedence order: fat body > prothoracic glands > integument/Malpighian tubes > trachea/midgut. The expression level of BdCyp302a1 in the fat body was 30 folds greater than that in midgut. And the expression abundances of BdCyp314a1 were extremely higher in the midgut, Malpighian tubes and fat body than in other tissues. Starvation could shorten the larval duration by prepupation. The larvae began to pupate in 6 h after food deprivation and the pupation rate increased with time extended. And the measurements indicated that the length and width of pupa were affected by starvation, which were significantly decreased in the treated group. However, no significant difference was detected in the survival rate. The expression levels of BdNvd, BdCyp302a1 and BdCyp314a1 were significantly elevated at 6 h post food deprivation, and down-regulated at 48 h. However, the expression levels of BdCyp315a1 were not relevant to nutrition condition.【Conclusion】Ecdysone synthesis pathway genes were transcribed differently in larval tissues, and played a vital role in mediating larva-pupa metamorphosis and nutrition stress.

SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT

Effects of Recommended Fertilization Based on Nutrient Expert in Winter Wheat and Summer Maize Rotation System

WANG Yi-lun, BAI You-lu, WANG Lei, LIU Ju, HAN Yan-lai, TAN Jin-fang

Scientia Agricultura Sinica. 2015, 48(22):  4483-4492.  doi:10.3864/j.issn.0578-1752.2015.22.009

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【Objective】The aim of the experiment is to study the scientific fertilization technology of a winter wheat and summer maize rotation system. 【Method】This field experiment was conducted to study the effect of nutrient expert for wheat and hybrid maize, and Agro Services International Inc (ASI) recommended fertilization on grain yield, economic benefit, nutrient accumulation, fertilizer use efficiency, anniversary balance of phosphorus and potassium of winter wheat and summer maize in Gangqu and Hebi.【Result】The results showed that yield was significantly increased by 24.75%-65.26% and 8.18%-35.53% respectively with the treatment of applying fertilizer in two years, nitrogen fertilizer increased the yield by 31.14% and 24.40%, phosphate fertilizer was 11.62% and 9.42%, potassium fertilizer was 11.52% and 8.64%, and the average income increased were 9 369, 4 095 and 3 923 yuan/hm² respectively. Compared with a conventional fertilizer application, the nutrient expert recommended fertilization increased grain yield by 6.63% and 4.63%, and economic benefit by 18.27% and 20.48%, the accumulation of plant N, P and K was increased by 7.87%, 12.72% and 4.79%, the ratio of output to input was 4.01, the effect was the same as the ASI recommended fertilization. Based on the nutrient expert recommend fertilization, the agronomic efficiency of N, P2O5, and K2O was 10.99, 10.67 and 10.69 kg·kg^-1, and fertilizer use efficiency was 35.82%, 22.30% and 45.33% respectively in anniversary rotation cycles, the phosphorus and potassium was increased by 49.6 and 71.5 kg·hm^-2 respectively with returning whole straw of winter wheat and summer maize into the soil. 【Conclusion】Fertilizer application recommended by the nutrient expert for wheat and hybrid maize optimized the ratio of nitrogen, phosphate and potassium fertilizer, promoted the absorption and utilization of plant N, P, K in winter wheat and summer maize, increased yield, economic benefit and fertilizer use efficiency, kept the anniversary surplus of phosphorus and potassium in winter wheat and summer maize rotation system. In conclusion, the nutrient expert for wheat and hybrid maize are convenient and fast, and can be used to recommend fertilizer application in the winter wheat and summer maize rotation system.

Effects of Irrigation Regimes on Yield and Grain Filling of Rice (Oryza sativa L. ) in Cold Region

ZHAO Li-ming, LI Ming, ZHENG Dian-feng, GU Chun-mei, NA Yong-guang, XIE Bao-sheng

Scientia Agricultura Sinica. 2015, 48(22):  4493-4506.  doi:10.3864/j.issn.0578-1752.2015.22.010

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【Objective】This paper discusses the influences of irrigation regimes on the tiller dynamics, dry matter accumulation, and grain-filling characteristics of rice in cold regions to deepen our understanding of the regulation of the grain-filling process. This study provides a theoretical basis for guiding the high yield and high-efficiency cultivation of rice.【Method】Kendao 24 and Kongyu 131 (two rice cultivars widely planted in northeastern China) were planted in the field with three types of irrigation regimes, namely, heavy irrigation with alternating wetting and drying (W₁), light irrigation with alternating wetting and drying (W₂), and irrigation with shallow water (W₃). The influences of such irrigation regimes on the yield and grain filling of rice in cold regions were analyzed. 【Result】The irrigation treatments caused significant effects on the number of stem and tiller, percentage of earbearing tiller, dry matter accumulation, dry matter transmission in the stem-sheath after heading sprouting, grain-filling properties, and yield and its components. W₂ and W₁ treatments effectively controlled the ineffective tillering, increased the seed setting rate, reduced the height of the plant, and decreased the lengths of the third and fourth internodes from the top. Under W₂ treatment, the percentage of earbearing tiller increased, the dry matter accumulation and transport capability was enhanced, and the 1000-grain weight increased significantly. The filling characteristics showed that the relationship between the fresh weight of grain and the days after anthesis was a quadratic curve relation under different irrigation regimes. The simulation effect of Kendao 24 was better than that of Kongyu 131, and the maximum grain fresh weight of W₂ treatment was the largest in the two varieties. W₂ treatment had a large grain-filling rate, which showed a single peak curve, and an early rapid growth; it also started filling early and reached the maximum grain-filling rate immediately. Grain dry weight can be analyzed by the Richards equation. The correlation coefficient ranged from 0.9940 to 0.9995. The high final weight of a kernel (A), initial grain-filling potential (R₀), high maximum grain-filling rate (G_max), and mean grain-filling rate (G_mean) of W₂ treatment were the highest. Between the two varieties, Kongyu 131 presented a shorter time reaching the maximum grain-filling rate (T_max) value than Kendao 24. However, the G_max and G_mean values of Kendao 24 were higher than those of Kongyu 131. In terms of production, the processing actual output of W₂ treatment increased by 13.91% to 28.26% and by 5.31 to 9.95% in 2012 compared with those of W₁ and W₃ treatments, respectively. However, the actual output of W₂ treatment increased only by 22.05% to 25.67% and by 5.15% to 7.70% in 2013 compared with those of W₁ and W₃ treatments, respectively. Therefore, the yield increasing way of W₂ treatment was achieved by the reasonable allocation of plant agronomic traits, high dry matter accumulation capability and proportion, strong stem and sheath dry matter transport capacity, and formation of high-quality population. High final weight of a kerne (A) and initial grain-filling potential (R₀) increased, the T_max value was shortened, the G_max value and the G_mean value were increased. The effect of the secondary rachis branch was greater than that of the primary rachis branch, which significantly increased the secondary branch grain number and yield, harvest index, 1000-grain weight, and seed setting rate, thereby causing a high grain yield.【Conclusion】Irrigation regimes had a great effect on the yield formation and regulation of the grain-filling process of rice in cold regions. Regarding production, W₂ treatment was more suitable to be applied to achieve high-yield and high-efficiency cultivation of rice in cold regions, whereas W₁ and W₃ treatments were not conducive to the increase in rice yield in cold regions.

HORTICULTURE

Effects of Precise Fertigation on Soil Properties and Fruit Yield and Quality of Cucumber Grown in Solar Greenhouse

GU Li-li, WEI Min, HOU Jia-lin, YANG Feng-juan, SHI Qing-hua, WANG Xiu-feng

Scientia Agricultura Sinica. 2015, 48(22):  4507-4516.  doi:10.3864/j.issn.0578-1752.2015.22.011

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【Objective】Irrigation and fertilization are key techniques for protecting cultivated vegetables. The objective of this study was to investigate the effects of different fertigation methods on soil properties and cucumber growth in a solar greenhouse，and to provide theoretical guidance for efficient fertigation, as well as the control of secondary soil salinization.【Method】Cucumber variety ‘Xinjin 11’ was used as the experimental material, and six treatments were arranged, including traditional border irrigation along with regular top dressing (CK1), conventional drip irrigation along with regular top dressing (CK2), daily fertigation of 1/4 dose Yamazaki special formula without microelement nutrients (T1), daily fertigation of 1/4 dose Yamazaki special formula with microelement nutrients (T2), daily fertigation of 2/4 dose Yamazaki special formula with microelement nutrients (T3), daily fertigation of 3/4 dose Yamazaki special formula with microelement nutrients (T4). The effects of daily fertigation with a nutrient solution on physical-chemical and biological properties of soil and yield and quality of cucumber fruits were investigated.【Result】Compared with traditional border irrigation along with a regular top dressing and a conventional drip irrigation along with regular fertigation, daily quantitative fertigation with a nutrient solution decreased soil bulk density, increased soil porosity, and reduced soil EC value. The amount of fungi in soil dropped, while those of bacteria and actinomyces rose significantly, the activities of Urease, Invertase and Catalase in the soil were considerably enhanced, and the growth of cucumber plants was promoted. Daily fertigation with 1/4 unit of the Yamazaki special formula plus trace elements led to the largest fruit number and highest yield of cucumber, when compared to traditional border irrigation and conventional drip irrigation. Daily fertigation with a nutrient solution partially improved the quality of cucumber fruits. Water and fertilizer saving rate reached more than 30% and 70%, respectively. 【Conclusion】Daily quantitative fertigation with 1/4 unit of the Yamazaki special formula plus trace elements could be recommended as a new fertilization management mode for soil cultivated cucumber in a solar greenhouse.

Effects of Different Breaking Dormancy Ways on the Photosynthetic Characteristics and Activities of Protective Enzymes of ‘Misty’ Blueberry Leaves

WEI Xin, WEI Yong-xiang, GUO Dan, SUN Bin, WANG Xing-dong, LIU Cheng

Scientia Agricultura Sinica. 2015, 48(22):  4517-4528.  doi:10.3864/j.issn.0578-1752.2015.22.012

Abstract ( 373 )   HTML ( 1 )   PDF (502KB) ( 401 )   Save

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【Objective】As evergreen leaf and low chilling requirement of ‘Misty’ blueberry, the influence mechanism of photosynthetic characteristics, protective enzyme activities, phenophase and fruit quality of functional leaf under greenhouse conditions for different breaking dormancy ways were studied to provide the theoretical basis for earlier dormancy, earlier breaking dormancy and maturity in advance of blueberry in greenhouse.【Method】Using the 5-year-old ‘Misty’ blueberry as the material, 2 treatments and 1 control were set: the treatment 1 (dormancy in cold stores at Sep.22th, out-store at Oct.8th, 384 h for dormancy), the treatment 2 (dormancy in greenhouse at Nov.4th, warming at Nov.20th, 384 h for dormancy) and control (0 h for dormancy) were designed. The activities of CAT, POD, PPO, ASP, photosynthetic physiology, chlorophyll fluorescence parameters, soluble sugar, titratable acidity and Vc during the exhibition heading stage to the maturity of the fruit were determined, and the main phenophase was recorded;【Result】The Pn, Tr, Gs, ΦPSⅡ, Fv/Fm, qP, POD, PPO and ASP in leaves of the 2 treatments and 1 control exhibited a single peak changing trend, the Ci and NPQ showed a declining-rising trend, the CAT rose gradually, the peaks and valleys for treatment 2 were later than the other two treatments; March 20th, 2014, the last season’s functional leaves were substituted by the new leaves of treatment 1and 2 to maintain the normal metabolism, the photosynthetic capacity of non new leaves were weak, the growth of plants were inhibited; The maturity of blueberry can be brought forward during treatment 1, but the plant reached sprouting, blossoming and fruit ripening were longer than treatment 2, the date of leaf sprouting and stretching date of leaf were affected obviously. The phenophase of non-dormant fruits were longer than dormant fruits after warming. The differences were not significant except for Vc content and berry yield per plant between treatment 2 and treatment 1, and the economy characteristics of breaking dormant fruits were significantly higher than non-dormant fruits. 【Conclusion】The reason for the decline after warming of Pn in ‘Misty’ blueberry maybe lead by restricted of PSⅡ system and the decline of antioxidant enzymes in leaves. Which the fruit quality, the per fruit weight, the grain yield per plant was significantly lower than breaking dormant treatments in non-dormant treatment were because the difference in photosynthetic parameters, chlorophyll fluorescence parameters and activities of protective enzyme in blueberry. Treatment 2 can be used as a reference standard for conventional greenhouse cultivation of blueberry in Dalian.

STORAGE·FRESH-KEEPING·PROCESSING

Quantitative Analysis of T₂ Peak Area and the MRI Images of Japonica Rice with Different Moisture Contents

SONG Wei, LI Dong-shen, QIAO Lin, SU An-xiang, HU Wan-jun

Scientia Agricultura Sinica. 2015, 48(22):  4529-4538.  doi:10.3864/j.issn.0578-1752.2015.22.013

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【Objective】Moisture content is one of the main factors that influence the storage and drying of japonica rice, this study is mainly to discuss the mathematical relationship between the signal per mass and moisture content of japonica rice by extracting the MRI image grey value and fitting the mathematical equation of grey and moisture content which provide a new way for rapid moisture determination of japonica rice. 【Method】 The japonica rice moisture content was adjusted to 14.963%, 15.830%, 16.232%, 16.299%, 18.340%, 19.581%, 20.707%, 22.290%, and 24.259%, while data collection of japonica rice with different moisture content after equilibrium moisture content was based on low field NMR technology (LF-NMR). The qualitative inversion and imaging of the data was applied in low field NMR CONTIN program, and fitting the mathematical relationship between the moisture content and the peak of T₂₁,T₂₂ of Japonica rice. Acquiring the data of grey value of MRI image of japonica with different moisture contents by using MATLAB software, fitting the equation of grey value and moisture content, and explore the inner relationship of LF-NMR data and moisture content. 【Result】 Experimental research shows that, different inversion peak of japonica rice with different containing moisture of peak time is relatively stable, but with the increasing of moisture content, japonica rice moisture protons of degrees of freedom is increasing, and peak time slightly increases. To obtain the fitting equation of moisture content and low-field nuclear magnetic inversion peak T₂₁ area by using the linear fitting method. The equation is y=0.0013x-2.0938 (r²=0.9984, P<0.01). The T₂₂ peak of japonica rice which less than 16% is not appear. When japonica rice with higher moisture content, T₂₂ peak area increases with the increase of moisture content, and has a significant correlation. The fitting equation is y=0.0082x+16.074 (r²=0.9817). The peak area of T₂₃ decreased with the increase of moisture content in japonica rice. When the moisture content of Japonica rice increased, the average gray value image is decreasing. The average gray value of the image was analyzed and the regression equation was obtained which is y=-2.251x+42.712 (r²=0.861). The gray data of the image was collected, analyzed and built by R2014a MATLAB. We find that the low moisture content of gray level is higher than the high moisture content of gray level. However, under the same gray level, pixel gray of japonica rice with high moisture content appear frequency is higher than low moisture content of japonica rice, reflecting proton density and signal intensity of japonica rice with high moisture content is more uniform than the japonica rice with low moisture content which is proved that the distribution of moisture in japonica rice is not uniform when the moisture is too low. Combined with MRI images, the moisture of the rice was mainly concentrated in the embryo and back of the japonica rice, the high moisture content of japonica rice overall proton density and proton signal intensity is uniform and low moisture content of japonica rice of proton density and proton signals of uniform strength is poor. It is proved that the low moisture content of rice internal moisture distribution inhomogeneity, combined with MRI image shows low moisture content of japonica rice’s moisture mainly concentrated in the embryo and back, and high moisture content of japonica’s internal moisture distribution is more uniform. 【Conclusion】It has a high correlation between moisture contents and LF-NMR data of japonica rice. Rapid detection of moisture content of japonica rice and moisture distribution can be used LF-NMR technology, with japonica rice MRI image we can have a direct observation of Japonica rice moisture status.

ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT

The Regulatory Mechanism of the Lipid Metabolism Pathways During Male Germ Cell Differentiation in Chickens

ZUO Qi-sheng, ZHANG Lei, LIAN Chao, XIAO Tian-rong, WANG Ying-jie, TANG Bei-bei, WANG Fei, JI Yan-qin, LU zhen-yu, ZHAO Rui-feng, ZHANG Wen-hui, ZHANG Ya-ni, LI Bi-chun

Scientia Agricultura Sinica. 2015, 48(22):  4539-4550.  doi:10.3864/j.issn.0578-1752.2015.22.014

Abstract ( 392 )   HTML ( 3 )   PDF (2198KB) ( 774 )   Save

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【Objective】This research explores the regulatory mechanism of the lipid metabolic signaling pathways and its related genes during the process of chickens’ male germ cell differentiation to provide a basis for improving the efficiency of the in vitro induction system. 【Method】Fluorescence activated cell sorting (FACS) was used to obtain highly purified ESC (embryonic stem cell), PGC (Primitive germ cells) and SSC (spermatogonial stem cells), to extract total RNA from each type of cell. High throughput analysis methods-RNA-seq and Microarray were used to sequence the transcriptome level of obtained cells. Gene ontology analysis (GO) and the KEGG database were used to look for lipid metabolism signaling pathways and related genes. RA (Retinoic acid), the end-product of retinol metabolism pathway, was used to induce ESC in vitro differentiation into male germ cell combination with Piloty’s Acid. qRT-PCR was used to detect the expression changes of the genes involved in the retinol metabolic pathways. 【Result】From the results of RNA-seq, we found that there were 328 genes in 27 lipid metabolic pathways that were continuously involved in lipid metabolism regulation in the process of ESC differentiation into SSC in vivo. Some of these pathways, included retinol metabolism. primary bile acid synthesis, steroid hormone biosynthesis, metabolism of fatty acid metabolism, glyceride metabolism and the steroid biosynthesis pathway. In the retinol metabolism pathways; ADH5 was expressed in PGC specifically; ALDH1A1 increased persistently throughout the entire development process; both two genes were involved in retinoic acid synthesis in the cell. CYP26b1 was involved in the degradation of retinoic acid and down expressed throughout the entire development process. The experiment that induced ESC differentiation to SSC with RA shows that the changing process of ADH5, ALDH1A1 and CYP26b1 family genes were consistent with RNA-seq results. SSC-like cells generated in RA induced group was significantly higher than the control group and Piloty's Acid + RA group. The results of injecting the inhibitor into embryos showed that retinol pathway was inhibited and the expression levels of SSC-specific cell surface marker gene :integrinβ1 and integrinα6 was significantly lower than CON group and BLANK group after 18 days of incubation. 【Conclusion】 According to the above results the lipid metabolism-retinol metabolism pathway plays an important role in the process of chicken male germ cell differentiation. The process of inducing ESC to germ line cells differentiation by RA showed that there were some small embryos in D2 which became larger in D4 and D6 before these embryos dissociated in D8. The spermatogonial stem cell like cells appeared in D10 reducing the number of SSC-like cells when retinoid path signal was suppressed in the process of induction, so as in the process of incubation when the pathway be suppressed.

Construction and ESTs Analysis of SSH Library from Host Cells Infected by Theileria annulata

ZHAO Hong-xi, LIU Jun-long, LI You-quan1, YANG Cong-shan, ZHAO Shuai-yang, LIU Juan, LIU Ai-hong, XIE Jun-ren, TIAN Zhan-cheng, LIU Zhi-jie, LIU Guang-yuan, YIN Hong, GUAN Gui-quan, LUO Jian-xun

Scientia Agricultura Sinica. 2015, 48(22):  4551-4563.  doi:10.3864/j.issn.0578-1752.2015.22.015

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【Objective】Theileria annulata can transform B lymphocytes、dendritic cells and macrophages it infects. Parasitized cells can be immortalized and acquire the ability to proliferate continuously as tumor cells in vitro culture. This study was carried out to construct a suppression subtractive hybridization (SSH) library in host cells transformed and non-transformed by T. annulata and to screen for schizont genes of T. annulata and differential genes of host cells from T. annulata schizont transformed cells and PBMCs of uninfected calves .【Method】 The total RNA and mRNA samples were extracted from T. annulata schizont transformed cells and PBMCs of uninfected calves, and the cDNA were synthesized by reverse transcription respectively. The cDNA subtracted library of host cells transformed and non-transformed by T. annulata was constructed using SSH technology, with cDNA from T. annulata transformed cells as the “tester” and cDNA from PBMCs of uninfected calves as the “driver”. Positive clones randomly chosen were sequenced and analyzed by bioinformatics. Furthermore, real-time PCR was employed to detect significant changes of part of differential genes from the cDNA subtracted library.【Result】A total of 364 effective differentially Expressed Sequence Tag (ESTs) were obtained via DNA sequencing from 454 positive clones, ranging from 350 to 1200 bp insert size. After comparing the sequences with BLASTn in the GenBank, these ESTs belonged to 192 gene sequences. Sixty of ESTs matched to T. annulata genes (11 ESTs were T. annulata protease genes, 10 T. annulata membrane protein genes, 7 T. annulata hypothetical protein genes, 5 apoptosis related T. annulata protein genes, 5 T. annulata ribosomal protein genes, 4 T. annulata cell-cycle protein genes, 4 T. annulata antigen protein genes and 14 T. annulata other genes), 131 bovine genes (19 were bovine tumor related genes) and one unknown gene. A total of 285 ESTs gene functions were annotated with Gene Ontology (GO) on the basis of biological process, cellular component, molecular function. Most of these were associated with cell, cellular processes, binding, catalytic, metabolic processes and biological regulation. Differential expressed genes from T. annulata transformed host cells were verified by real-time PCR, The results showed that the mRNA abundance of HCLS1 and SENP5 from bovine in transformed cells was 2.06 and 1.32 times that of non-transformed cells.【Conclusion】A SSH cDNA library of bovine cells infected by T. annulata was successfully constructed, and gene sequences of T. annulata schizonts and host cells transformed by T. annulata were obtained in this study. We acquire two bovine tumor related genes which possibly influence the host cell immortalized by real-time PCR. Our observations establish a foundation for better understanding of the molecular mechanisms of interactions between T. annulata and host cells.

Identification and Expression Analysis of Cathepsin O Gene in Silkworm (Bombyx mori)

SU Jing-jing, CHEN Si-yuan, ZHANG Kui, YU Shuang, LI Yu-tian, LIANG Hang-hua, ZHAO Yu-zu, CHAO Hui-juan, CUI Hong-juan

Scientia Agricultura Sinica. 2015, 48(22):  4564-4573.  doi:10.3864/j.issn.0578-1752.2015.22.016

Abstract ( 482 )   HTML ( 1 )   PDF (1743KB) ( 657 )   Save

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【Objective】The objectives of this study are to clone Cathepsin O gene (BmCatO) of silkworm (Bombyx mori), analyze its mRNA expression features, obtain polyclonal antibody through prokaryotic expression, protein purification and immune rabbit, and to provide a theoretical basis for further studying the function of Cathepsin O in B. mori. 【Method】 The full-length of BmCathepsin O cDNA was acquired by rapid-amplification of cDNA ends (RACE). And then its expression profiles were investigated by RT-PCR. Cathepsin O sequences from other species were downloaded from NCBI, the deduced amino acid sequences of putative BmCathpsin O were aligned using the Clustal X program, and the phylogenetic tree was constructed using MEGA 6.0 software. Specific primers were designed to amplify the high specificity fragment, and the PCR product was ligated to the PET32a vector, which was then transformed into Rosetta (DE3) E. coli to obtain recombinant protein by IPTG induction, BmCathepsin O recombinant protein was purified by Ni+ affinity chromatography, finally the recombinant protein was used to immue rabbit to get antibody. 【Result】 BmCathepsin O was clustered on nscaf2943 which was located on chromosome 14 in B. mori genome, and the gene number in SilkDB database was BGIBMGA009231. There are two spliced variants. Variant 1 has an ORF (open reading frame) of 1 071 bp, encodes 356 amino acids. The protein molecular weight is predicted to be 36 kD, and isoelectric point is 8.594. Variant 2 has an ORF of 942 bp, encodes 313 amino acids. The predicted protein molecular weight is 40 kD, isoelectric point is 7.951. Both the two variants are comprised of six exons and five introns, but partial deletion is occurred in the 6th exon of variant 2. Both variants contain a signal peptide, conserve Inhibitor I29 and Pept-C1 domain structure. Phylogenetic analysis showed that Cathepsin O from invertebrate was clustered alone, and BmCathepsin O was most closely related to Cathepsin O from Chilo suppressalis. RT-PCR results showed that Cathepsin O mRNA was specifically and continually expressed in B. mori hemocytes. The expression level of variant 1 was significantly higher than variant 2, but two variants had the same change tendency in hemocytes. BmCathepsin O recombinant protein was obtained by prokaryotic expression system and purified using Ni+ affinity chromatography, then the anti-rabbit polyclonal antibody was prepared by immuizing rabbit using purified protein. The titer of antiserum generated was 1﹕ 1 280 000 by ELISA. Western blot analysis showed that this antibody could bind with BmCathepsin O recombinant protein specifically.【Conclusion】BmCathepsin O was cloned and its expression patterns were investigated. The BmCathepsin O recombinant protein was prepared and purified, and finally anti-rabbit polyclonal antibody was acquired by immuizing rabbit.

RESEARCH NOTES

The Effects of Density and Nitrogen Management on the Yield and Physiological Indices of Spring Maize under Plastic-Covered Ridge and Furrow Planting in Loess Plateau East of Gansu

ZHANG Jian-jun, FAN Ting-lu, DANG Yi, ZHAO Gang, WANG Lei, LI Shang-zhong

Scientia Agricultura Sinica. 2015, 48(22):  4574-4584.  doi:10.3864/j.issn.0578-1752.2015.22.017

Abstract ( 417 )   HTML ( 4 )   PDF (476KB) ( 552 )   Save

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【Objective】 This research aims to determine the optimal planting density, amount of nitrogen utilization, and pattern for nitrogen utilization, so as to develop reasonable measures for cultivation.【Method】 In this research, the cultivar “Xianyu335” was applied as research material. Two nitrogen utilization amounts (namely 150 and 225 kg/ha), 2 densities (namely 6×10⁴ and 7.5×10⁴ plants/ha), and 5 nitrogen topdressings at different growth stages (namely 100% base manure, 100% topdressing at jointing stage, 50% base manure+50% topdressing at jointing stage, 50% base manure+30% topdressing at jointing stage+20% topdressing at tasseling stage, and 50% base manure+10% topdressing at jointing stage+40% topdressing at tasseling stage) were set under plastic-covered ridge and furrow planting. Through a 3-year field test, the effects of planting density, nitrogen utilization amount, and nitrogen application pattern on arid-field spring maize yield and physiological indexes were investigated. 【Result】Within the ranges of nitrogen utilization amount and density used in this research, under the same nitrogen utilization amount, maize yield increased extremely significantly with the enhancement of planting density, while such indexes as Pn, Tr, and Gs declined. However, under the same planting density, yield differences among various nitrogen utilization amounts were not significant, despite the fact that yield was greater under high nitrogen utilization amounts than under low ones. Meanwhile, under the same density and the same nitrogen utilization amount, yield differences among various nitrogen utilization patterns were all extremely significant, Pn, Gs and Tr were highest in a ratio of base manure to topdressing at the jointing stage reaching 50%:50% and WUE changed the same as yield did. Compared with a one-step fertilizer application before sowing or at the jointing stage, stage-by-stage topdressing can delay chlorophyll decline in maize leaves at a later-growth period, improve the production and transportation of photosynthetic matters, and optimize yield composition; and such effects are especially salient when the ratio of base manure to topdressing at the jointing stage amounts to 50%:50%. Therefore, the coordinated enhancement of both yield and physiological indexes of spring maize in rain-fed areas of the eastern Gansu Province can be realized through the combined optimization of planting density and a pattern for nitrogen utilization.【Conclusion】Under the experimental conditions of this research, a proposed model represents a high-yield, nitrogen-saving, highly-efficient, and environment-friendly cultivation model suitable for rain-fed agricultural areas of the eastern Gansu Province. Under this model, a planting density of 7.5×10⁴ plants/ha is adopted with a nitrogen utilization amount of 150kg/ha and a 50%: 50% ratio of base manure to topdressing at the jointing stage.  

Regulation Effect of Wheat and Oat Residue on Growth of Continuous Cucumber Cropping and Soil Microbial Community Structure

WU Feng-zhi, SHEN Yan-hui, ZHOU Xin-gang, SUN Yi-wen

Scientia Agricultura Sinica. 2015, 48(22):  4585-4596.  doi:10.3864/j.issn.0578-1752.2015.22.018

Abstract ( 457 )   HTML ( 1 )   PDF (3095KB) ( 432 )   Save

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【Objective】The objectives of this study were to clarify the effect of wheat, oat residue on growth of the continuous cucumber cropping and soil microbial community structure, the aim of the study was to investigate the effect of different residues on the soil environment of the continuous cropping cucumber, to provide the theoretical basis for the improvement of the soil environment. 【Method】Cucumber as the receptor plant, to 4 years of continuous cropping melon soil as the research object, studies the effect of adding 2% according to weight ratio of 2% wheat, oat stubble and their mixed stubble (1%:1%) on cucumber seedling growth and the different growth period of the soil microbial community structure. 【Result】Different stubble significantly increased the band number of soil bacteria and fungi, oat、wheat and oat mixed residue significantly increased the Shannon and evenness indices of soil fungal community compared to the control and wheat handled after 20 days treatment (P＜0.05). Oat residue significantly increased the band number of the soil bacteria and wheat residue significantly increased the Shannon and evenness indices of the soil bacteria community compared to oat, wheat and oat mixed residue after 30 days treatment. Wheat and oat mixed residue increased the band number. Shannon and evenness indices of the soil bacteria community treatment were significantly higher than the control after 40 days treatment. Different residue treatment has no effect on the band number, Shannon and evenness indices of the soil fungi community after 40 days treatment. Wheat, wheat and oat mixed residue could significantly increase the plant height, stem diameter and whole plant of fresh weight (P＜0.05). 【Conclusion】 Wheat, wheat and mixed oats residue can promote the growth on continuous cropping of the cucumber seedlings and different stubbles treatment in different periods were different effects of the continuous cropping cucumber soil microbial community structure, increased the soil microbial number of bands, and improved Shannon and evenness indices. Crop straw added into the soil of continuous cropping melon is a simple and effective biology method to alleviate the continuous cropping obstacle.

Study on Safety of Cefquinome Sulfate Uterus Infusion in Dairy Cows

ZHANG Dao-kang, LIU Yi-ming, LU Yong-qiang, XU Fei, WANG Tian-kun, YANG Yu-ze, Li Xiu-bo

Scientia Agricultura Sinica. 2015, 48(22):  4597-4602.  doi:10.3864/j.issn.0578-1752.2015.22.019

Abstract ( 479 )   HTML ( 2 )   PDF (362KB) ( 343 )   Save

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【Objective】The objective of this experiment is to study comprehend the effect of cefquinome sulfate uterus infusion on the normal body temperature, production performance and bacteria in the uterus of dairy cows. 【Method】Ten healthy dairy cows were selected in this experiment. The selected cows were fed normally and not given any antibiotics systemicly or in uterus within 30 days before the test. There were not any antimicrobial drugs in daily ration and drinking water of cows. The total daily milk yields of all experimental cows were recorded 1 day before administration (early, middle and late yield). On the day of administration, the rectal temperature was measured and recorded, then the uterus secretion was collected and detected. The edge and inside of the vagina were disinfected with 75% alcohol before collection, then uterus secretion was received by sterilization of Uterus Syringe for Animal Use. One piece of cefquinome sulfate uterus infusion (dose:25ml:900mg/piece) was injected into uterus of each cow for 2 times，and its interval of the administration was 72 h. During the administration and sampling period, the cows were treated normally. Daily milk yields and rectal temperature of all experimental cows were recorded, respectively, on day 1, 3, 5, 7 and 10 after the last administration. Uterus secretion was collected and detected on the day10 after the last administration. The differences of daily milk yield，rectal temperature and the changes of pathogen in uterus secretion before and after administration were compared and analyzed.【Result】The mean daily milk yield of experimental cows of 1 day before administration and day1, 3, 5, 7 and10 after the last administration were 28.8, 29.2, 29.7, 29.6, 29.9 and 30.2 kg, respectively. There was a certain increase overall, but there were some fluctuations during the period. The X2 test results showed that there was no significant difference of daily milk yield between each time point (P＞0.05). At the same time, the mean value of rectal temperature of each time point was 38.5, 38.5, 38.4, 38.4, 38.4 and 38.4℃, respectively, and there was also no significant difference between each time point (P＞0.05). The results showed that when cows were administrated recommended dosages of cefquinome sulfate uterus infusion, there were no significant differences in indicators all above before or after the administration (P＞0.05). Pathogen detection results showed that the number of Escherichia coli, Streptothrix, Staphylococcus and Corynebacterium pyogenes were 3, 3, 2 and 1 before administration and 2, 0, 1 and 0 after administration, respectively. The number of pathogenic bacteria in the uterus secretion decreased after administration. At the same time, new pathogens were not detected. 【Conclusion】Cefquinome sulfate uterus infusion had no harmful effect on the normal body temperature, production performance and bacteria in the uterus of dairy cows, which indicated that cefquinome sulfate uterus infusion is safe for dairy cows when administrated according to the recommended dosing regime.