Table of Content

10 February 2009, Volume 42 Issue 2

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Apomixis——The Process of Asexual Seed Formation

Scientia Agricultura Sinica. 2009, 42(2):  377-387 .  doi:10.3864/j.issn.0578-1752.2009.02.001

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Apomixis is a natural trait of reproduction in which embryo is formed without the union of male and female gametes. It is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization, leading to embryo development. According to this international prevalent idea, only unreduced apomixis, nor reduced apomixis, is referred to it. Apomictic processes have been observed in more than 400 plant species spanning 40 different families in angiosperms and are most common in the Poaceae, Asteraces, Rosaceae and Rutaceae, but appears to be absent in important crops. This paper is concerned with some aspects of apomixis, such as cytoembryoic mode, distribution in angiosperms, new species or straits with trait of apomixes. The progress of genetics, molecular mechanism of apomixis, and its application prospect in agriculture and the ecological significance were discussed.

QTL Mapping for Adult-Plant Resistance to Leaf Rust in CIMMYT Wheat Cultivar Saar

Scientia Agricultura Sinica. 2009, 42(2):  388-397 .  doi:10.3864/j.issn.0578-1752.2009.02.002

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【Objective】 The CIMMYT wheat cultivar Saar has exhibited a high level of adult-plant resistance to leaf rust, stripe rust and powdery mildew in Europe, Asia, and South America, and identification of its QTL for leaf rust resistance will play an important role in breeding wheat cultivars for durable resistance. 【Method】 A total of 142 SSR and 209 DArT markers were used to map QTL for resistance to leaf rust in a recombinant inbred line (RIL) population with 109 F6 families derived from the cross Avocet/Saar. The field trials were conducted in Baoding, Hebei province and Xinxiang, Henan province in 2006－2007 cropping season. 【Result】 Linkage analysis indicated that the genetic map consisting of 142 SSR markers and 209 DArT markers covered 21 wheat linkage group with a total genetic distance of 3083 cM. Using composite interval mapping (CIM), five QTLs for resistance to leaf rust were detected on chromosomes 1BL, 2DS, 5BL, 6AL and 7DS, explaining 4.5%-6.4%, 12.2%-12.5%, 4.9%-11.2%, 4.9%-7.8%, and 14.0%-67.6% of phenotypic variance, respectively. 【Conclusion】 The QTLs and their closely linked molecular markers identified in this study will benefit to marker-assisted selections and wheat germplasm enhancement in breeding wheat cultivars for leaf rust resistance.


QTL Analysis of Grain Size and Related Traits in Winter Wheat Under Different Ecological Environments


Scientia Agricultura Sinica. 2009, 42(2):  398-407 .  doi:10.3864/j.issn.0578-1752.2009.02.003

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【Objective】 QTL associated with grain size and related traits was identified and the phenotypic effects of them were estimated. The stability of QTL across different environments were detected. 【Method】 Using a set of 142 recombinant inbred lines (RILs) derived from Chinese winter wheat varieties Yu8679 and Heshangmai, five agronomic traits of grain length (GL), grain width (GW), grain thickness (GT), grain volume (GV) and 1000-grain weight (TGW) were evaluated in four different ecological environments of Beijing (2006 &2007), Hefei (2007) and Chengdu (2007), respectively. Based on 142 RILs, a genetic map comprising 170 SSR markers and two EST markers (Tx23-24 and Tx37-38) was generated. According to the genetic map and phenotypic data, quantitative trait loci (QTL) were located for these agronomic traits using the composite interval mapping method. 【Result】 A total of 93 QTL involving all wheat chromosomes except 1D and 6A were identified for these five traits over four environments. Among them, 17, 16, 18, 21 and 21 QTL for GL, GW, GT, GV and TGW were identified, respectively. In addition, 18 genomic regions with plenty of QTL were detected on 1A, 1B, 2A, 2D, 3A, 3B, 5A, 5B, 5D, 6A, 6D, 7B and 7D in this study. 【Conclusion】In the present study, 93 QTL for grain size and related traits were detected, which will provide useful information for molecular assistant selection (MAS) in wheat genetic improvement.


Correlation Analysis and QTL Mapping for Traits of Kernel Structure and Yield Components in Maize


Scientia Agricultura Sinica. 2009, 42(2):  408-418 .  doi:10.3864/j.issn.0578-1752.2009.02.004

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【Objective】 The correlation of traits of kernel structure with yield components was investigated and quantitative trait loci (QTL) for these traits were analyzed in this paper. 【Method】 Two hundred and twenty-six F2:3 lines from the cross of Qi 319×Huangzaosi in two different environments (spring-sown in Beijing and summer-sown in Henan) were used to conduct correlation analysis, principle component analysis, simulated calculation of rate of kernel production (RKP) and QTL mapping. 【Result】 Kernel yield per ear (KYE) showed significant correlation with most traits of kernel structure, especially with kernel depth (KD). Principle component analysis indicated that KD, kernel thickness (KT), ear length (EL), rate of kernel production (RKP) and KD/ear semidiameter (EsemiD) determined the performance of KYE. As the parameter reflecting the distribution of assimilation in ear, RKP was influenced by KD, KD/EsemiD, EL and Kernel Width (KW). Simulated calculation of RKP also showed that KD/EsemiD had a close relationship with RKP. A total of thirty-six QTLs for traits of kernel structure and yield components were detected. It was found that some QTLs detected in different environments were located in the same genetic regions. Several chromosomal regions with QTL cluster relevant to multiple traits were also detected. 【Conclusion】Traits of kernel structure have high correlations with yield components. The detection of genetic regions with QTL cluster might be helpful to the understanding of genetic mechanism of maize yield.


Sequence Analysis of a- and b-Subunit Genes in a Novel Soybean Germplasm Characterized by Absence of a- and b-Subunit of 7S Globulin


Scientia Agricultura Sinica. 2009, 42(2):  419-424 .  doi:10.3864/j.issn.0578-1752.2009.02.005

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【Objective】 The objective of this study was to elucidate whether the α- and β- null character was result from the absence or variance of α- and β-subunit genes. 【Method】 SDS-PAGE technique, PCR amplification, cloning and sequencing methods were used. 【Result】 With specific primers for α- subunit, the PCR band pattern between (α+β)-null type and normal type was identical, but the PCR band pattern of β-subunit gene was unique. For PCR amplified DNA fragment of the α-subunit gene, a high degree of nucleotide homology (90.9%) exists between the (α+β)-null type and normal type. Sequenced difference mainly exists in 5′-flanking. While, for β-subunit gene, a low degree of nucleotide homology (53.1%) was exists. Furthermore, a short inverted sequence was detected in PCR amplified DNA fragment of the β-subunit gene.【Conclusion】The deficiency character of α- and β-subunit of (α+β)-null type is not related to the deletion of a chromosome segment with the genes encoding α- and β-subunit of soybean 7S globulin. Differences exist in both α- and β-subunit gene sequence between (α+β)-null type and normal type soybean. Further studies to confirm whether the differences in gene sequence are main reason that result in the absence of α- and β-subunit are necessary.


Cloning and Expression of Key Enzyme Gene GalAT in Ramie Pectin Biosynthesis


Scientia Agricultura Sinica. 2009, 42(2):  425-433 .  doi:10.3864/j.issn.0578-1752.2009.02.006

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【Objective】 The aim of this study was to isolate the cDNA partial sequence of key enzyme gene GalAT for pectin biosynthesis in ramie [Boehmeria nivea (L.) Gaud], and understanding of the expression of GalAT gene in different tissues of ramie. 【Method】 Degenerate primer RT-PCR method was used to clone GalAT gene, bioinformatics methods were used to analyze cDNA sequence obtained and putative amino acid sequence, and fluorescence real time quantitative PCR method were used to study the expression of GalAT gene in different tissues. 【Result】 The cDNA partial sequence of GalAT gene from ramie variety Zhongzhu 1 was cloned. The cloned cDNA was 986 bp in length which encoded 328 amino acid sequences (GenBank accession number: EU 131377). This is the firstly reported GalAT gene in ramie. The cDNA sequence and putative amino acid sequence of GalAT shared high identity with previously reported Arabidopsis thaliana galacturonosyltransferase 4: 77 % and 83%, respectively; and the putative amino acid sequence and A. thaliana's galacturonosyltransferase 4 was gather to a same group; GalAT can be expressed in different kinds of ramie tissues, and its mRNA accumulated most abundantly in root. 【Conclusion】 It was inferred that the sequence obtained is cDNA partial sequence of GalAT gene, and can express in any tissue of ramie. GalAT mRNA accumulated abundantly most in root and GalAT expression in ramie tissues was root>leaf>bast>or≈xylem.


Relationship of Mitochondrial Genes CoxⅡ and atpA with Cytoplasmic Male Sterility in Ramie


Scientia Agricultura Sinica. 2009, 42(2):  434-445 .  doi:10.3864/j.issn.0578-1752.2009.02.007

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【Objective】This study aimed at probing into the correlation of mitochondrial genes CoxⅡ and atpA with the cytoplasmic male sterility (CMS) in ramie [Boehmeria nivea (L.) Gaud.]. 【Method】The CMS related CoxⅡ and aptA gene fragments were cloned from the mitochondrial DNA of ramie CMS line and its maintainer and restorer lines (fertile lines) by using PCR and degenerated primer strategy. The primers were designed according to the reserved sequences in the encoding region of mitochondrial genes CoxⅡ and atpA of some dicotyledons from GenBank. The complete CoxⅡ and atpA genes were obtained by means of amplifying the 3′ and 5′ end unknown sequences of these gene fragments using DNA Walking method. Based on the complete gene sequences and gene expression patterns (RT-PCR), the differences of these two genes between ramie CMS line and the fertile lines were analyzed. 【Result】The amplified CoxⅡ and atpA gene fragments showed 95% and 97% homology with the analogous genes from some dicotyledons. The complete CoxⅡ and atpA genes each had an intact open reading frame. The CoxⅡ gene showed no difference between ramie CMS line and fertile lines at the levels of mtDNA sequence, transcription and protein. However, compared to the fertile lines, atpA gene from CMS line showed obvious difference at the levels of mtDNA, amino acid sequence and the secondary structure of protein. And an abnormal low expression of atpA gene in CMS line at the budding stage and late-blooming stage was revealed by RT-PCR analysis. 【Conclusion】The correlation of CoxⅡ gene with ramie CMS could be excluded, but the result suggested a close relationship of ramie CMS with the variation in DNA sequence and / or abnormality in expression of atpA gene in CMS line.


TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Measurement and Analysis of Stable Carbon and Nitrogen Isotope of Amino Acids in Wheat Grain


Scientia Agricultura Sinica. 2009, 42(2):  446-453 .  doi:10.3864/j.issn.0578-1752.2009.02.008

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【Objective】 To measure the stable carbon and nitrogen isotope composition of amino acids in wheat grain by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). 【Method】 The N-pivaloyl-isopropyl (NPP) derivatives of the protein amino acids, which hydrolyzed with 6M HCl in wheat grain Linfen 50744, and standard amino acids were measured by GC-C-IRMS.【Result】 Analysis of stable carbon and nitrogen isotope composition of N-pivaloyl-isopropyl (NPP) amino acid standard esters shows the mean reproducibility of δ13C is 0.47‰ and δ15N is 0.28‰. Good results can be got as less isotope fractionation is observed in this study. The δ13C values of NPP derivatives were from -28.7‰ to -34.7‰, and the δ15N values of NPP derivatives were -6.2‰ to 9.5‰. Amino acids can be divided into two categories according to δ13C, and three categories according to δ15N by hierarchical cluster analysis. 【Conclusion】 It is feasible to determine the composition of stable carbon and nitrogen isotope of amino acids in wheat with NPP amino acid esters by GC-C-IRMS, which will make great significance to reveal the difference of metabolism and synthesis of amino acids under adverse environment.


Evaluation of Lignan Contents of Newly Bred Flax Varieties (Lines) in China


Scientia Agricultura Sinica. 2009, 42(2):  454-459 .  doi:10.3864/j.issn.0578-1752.2009.02.009

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【Objective】 This study is to determine the relative contributions of genotypes and the interactions between genotype and location on variation of lignan contents in flaxseeds. 【Method】 Using HPLC, lignan contents of eleven flax varieties planted at four representative locations in 2005 and 2006 were determined. 【Result】 The results showed that lignan contents ranged from 6.487 to13.127 mg?g-1 of 11 varieties planted in 88 locations. The highest content was found in line 97047, and the lowest in line Yi 04. In the four locations tested, Bashang in Hebei Province gave the highest total lignan contents, and the lowest contents were from those grown in Yili of Xinjiang. Genotype, location and interactions between genotype and location have significant influence on variation in lignan contents in all varieties. The stability of lignan content in different varieties also differed significantly. Lines 97047 and Yi 04 showed high stability. 【Conclusion】 Genotype is the most important factor that affects the lignan content in flaxseed, therefore it would allow for an improvement of lignan contents by breeding. Different varieties have different feasible planting areas. Line 97047 contains the highest lignan content among all varieties tested. It is also adapted to a wide range of flax planting areas.


Analysis of Gene Expression Profiles in Tobacco Roots Under Osmotic Stress


Scientia Agricultura Sinica. 2009, 42(2):  460-468 .  doi:10.3864/j.issn.0578-1752.2009.02.010

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【Objective】The objective of this experiment is to study the drought resistance defense mechanism in tobacco plant. 【Method】 The changes of gene expression in osmotic stressed tobacco (Nicotiana tabacum L) roots were analyzed by cDNA microarray analysis. RNAs of tobacco roots with or without (CK) PEG treatment after 48 h under -1.2 MPa were extracted and subjected to analysis of cDNA microarray based on Arabidopsis genomic sequence. 【Result】 There were about 126 differently expressed genes (with ratio values ≥2 or ≤0.5) among 31 182 genes set in a microarray plate，in which 79 genes were up-regulated and 47 down-regulated by osmotic stress. Among the up-regulated genes, a lot of them such as ABA responsive protein，calcium signaling responsive protein and protein kinase were found in signaling transduction pathway, suggesting that signaling transduction in roots under osmotic stress was activating. Meanwhile, some hydrolase genes in relation to membrane system and transporter were also up-regulated under osmotic stress. But some genes regulating growth and development of tobacco plant, such as the genes of gibberellin-responsive protein, nitrate reductase 2 (NR2) and so on, were down regulated. Some genes of E3 ubiquitin ligase, the key components in ubiquitin-mediated protein degradation pathway, were also down regulated. Moreover, 58 unknown function genes were also detected in the experiment. The functions of those genes in plant osmotic stress response needed to be elucidated in the future. 【Conclusion】 By analyzing the differently expressed genes, some valuable information for explaining the molecular mechanism of drought-resistance of tobacco plant were highlighted.


Analysis of Conservation Tillage Pattern and the Factors Influencing Farmers Adoption in Typical Ecological Region in China


Scientia Agricultura Sinica. 2009, 42(2):  469-477 .  doi:10.3864/j.issn.0578-1752.2009.02.011

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【Objective】 The objective of this study is to understand the conservation tillage modes and farmers’ adoption, and to reveal the factors influencing farmer adoption. 【Method】 A face-to-face investigations on peasant household were carried out in main demonstration area of conservation tillage of typical ecological region: the Northeast China plain, the North China plain, the Chengdu plain, and the Northwest China oasis. The original data were obtained and the cognition of peasant households on conservation tillage technology was analyzed. 【Result】 Results of research indicate that the conservation tillage adoption rate is higher in the North China plain and the Chengdu plain, the conservation tillage adoption rate is lower in Northeast China plain and the Northwest China oasis. There are some adaptive conservation tillage types in different areas. These tillage types are wide-row and narrow-row rotation planting and leaving high stubble and cutting stubble combined with ridge of tillage mode in the Northeast China plain, rotary tillage seeding technique for sowing wheat under the best row of the corn stalk, no-tillage seeding technique for sowing corn and others under the best row of the whole wheat stalk in the North China plain, no-tillage seeding technique for sowing wheat and others under the best row of the whole rice stalk in Chengdu plain. They have obvious effect on yield increase. The data show that yield increase, government’s demonstration and guide, the example of neighborhood are major factors attracting farmer adopting conservation tillage technology. However, no-matching equipment inhibited the extension of conservation tillage technology. 【Conclusion】 The extension of conservation tillage measures and modes should be determined according to different regional conditions and main limiting factors because of the different ecological factors and productive conditions. The conservation tillage technology should be popularized and developed.


Relationship Between Bio-Thermodynamics Characteristic and Soluble Sugars Components in Storage of Ultradried Seeds


Scientia Agricultura Sinica. 2009, 42(2):  478-485 .  doi:10.3864/j.issn.0578-1752.2009.02.012

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【Objective】 The seeds of elm (Ulmus pumila L.), maize (Zea mays L.) and safflower (Carthamus tinctorius L.) with different characteristics of desiccation-tolerance and chemical component were chosen to study the relationship between moist content for seed storage and the molecular mobility as well as the soluble sugar. 【Method】 The EPR spectra of the spin labeled axes of seeds with different moist contents were examined with CP (3-carboxy-proxyl) as a spin probe and using 2Azz as a measure of molecular mobility. DSC and HPLC were used to measure glass transition temperature and the content and composition of sugar.【Result】 The changes of molecular mobility in ultradried seeds with different moisture contents were opposite to the changes of storage stability, which supposed that molecular mobility could be used as a simple method to predict the optimum moisture content of ultradried storage. The safflower seed own higher value of Tg than elm and maize seeds, there was a higher content of raffinose in safflower than the content in elms or maize. 【Conclusion】 Molecular mobility was compatible with the optimum moisture content, and the temperature of glass transition (Tg) could not be used solely to predict precise conditions of optimum storage. The optimum moisture content of ultradried storage may be related to the matter accumulated during the mature dehydration.


PLANT PROTECTION

Comparison of Differentiating Capacity of Two Sets of Differential Lines Using Isolates of Magnaporthe grisea Collected from China’s Yunnan Province


Scientia Agricultura Sinica. 2009, 42(2):  486-491 .  doi:10.3864/j.issn.0578-1752.2009.02.013

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【Objective】 The objective was designed to compare the differentiating capacity of two sets of differential lines. 【Method】 A total of 418 blast monoconidial isolates collected from 27 counties of Yunnan Province were tested using two sets of differential varieties which hold nine different resistance genes. One set is Japanese differential varieties, another set contained two Japanese differential varieties and seven monogenic lines which developed using susceptible variety Lijiangxintuanheigu (LTH) as recurrent parent (IRBL lines). Both of them hold the same set of resistance genes. The differentiating capacity of IRBL lines to Yunnan isolates was compared with that of Japanese differential varieties. 【Result】 The result showed that the differentiating capacity of IRBL lines was better than Japanese differential varieties to rice blast fungus colleted from Yunnan. These monoconidial isolates were divided into 126 races based on the reactions to IRBL lines, while they were divided into 95 races using Japanese differential varieties. 【Conclusion】 The result indicated that the monogenic differential varieties with same genetic background are better than that of complex background.


Inheritance of Resistance to Phytophthora sojae in Soybean


Scientia Agricultura Sinica. 2009, 42(2):  492-498 .  doi:10.3864/j.issn.0578-1752.2009.02.014

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【Objective】 The objective of this study was to reveal the mechanisms of resistance to Phytophthora sojae in soybean [Glycine max (L.) Merr]. 【Method】 Four crosses between materials with complete or partial resistance were used to reveal the inheritance of resistance using the hypocotyls inoculation or root inoculation technique. 【Result】 The complete resistance in soybean cultivars (lines) Yudou25 and Zheng92116 was controlled by a single dominant gene (Rps), while the partial resistance in General and Conrad by one additive major gene plus additive-dominant polygene. The heritability values of resistance in development were about 90%, those of major and polygene were 41.31%-74.84% and 15.60%-50.36% in F2, and 54.21%-77.05% and 13.52%-38.24% in F2:3, respectively. The complete resistance and partial resistance were controlled by different genetic systems. 【Conclusion】 Both kinds of resistance can be used in soybean improvement, and it would be effective to conduct selection in early generations for high resistance in breeding, combining partial resistance with specific Rps genes to provide long term management of Phytophthora root rot as well as to avoid the boom-and-bust cycle of single gene deployment.


Genetic Diversity of Potato Scab Pathogens in China Based on 16S rDNA Sequences


Scientia Agricultura Sinica. 2009, 42(2):  499-504 .  doi:10.3864/j.issn.0578-1752.2009.02.015

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【Objective】 Phylogenetic tree was constructed from 15 standard potato scab pathogen strains and 34 scab-causing strains isolated from 8 provinces in China based on the 16S rDNA gene sequences. 【Method】 16S rDNA sequences were obtained using Streptomyces genus universal primers and genomic DNA as amplified template by PCR technique. BLASTn algorithm was used to search alignment for the sequences of 16S rDNA gene from the 49 strains against GenBank nucleotide database. Among them, strains with higher sequence homology were used to construct a phylogenetic tree by Clustal X 1.8 and MEGA 2.1 softwares. 【Result】 Based on the results of phylogenetic analysis, the 34 scab-causing strains tested in this paper were attributed to the Streptomyces genus. Among them, 12 strains belong to S. scabies, 8 to S. galilaeus, 6 to S. bobili, 2 to S. diastatochromogenes, 1 to S. turgidiscabies, 1 to S. acidiscabies, 1 to S. setonii, and 3 to S. enissocaesilis. Moreover, S. galilaeus, S. bobili and S. enissocaesilis are identified as novel potato scab pathogens for the first report. Four strains were isolated from Shandong province, 3 from Inner Mongolia province and 3 from Shaanxi province, 2 from Hebei province, 2 from Shanxi province, 1 from Heilongjiang province. 【Conclusion】 Results suggested that genetic diversity and complex regional distribution existed for potato scab pathogens in China.


Identification of Type III Secration System in Erwinia amylovora and Analyse of HrpA in Erwinia spp.


Scientia Agricultura Sinica. 2009, 42(2):  505-510 .  doi:10.3864/j.issn.0578-1752.2009.02.016

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【Objective】 The objective of this study was to investigate the TTSS in Erwinia amylovora and the HrpA selection pressure in Erwinia spp. 【Method】 Bioinformatics strategies were used in this study by BLAST scan to search the Erwinia amylovora genomic nucleotide database and compare their homology, and analyze the selection pressure about the surface protein HrpA which is associated with the interaction between Erwinia spp. and the hosts. 【Result】 Twenty-seven TTSS- like proteins were identified in the 40 kb pathogenecity island. In contrast, the selection pressure value for HrpA was strongly elevated by comparison with those of housekeeping genes and HrpN. The comparison among multi HrpA sequences showed that most of the HrpA N terminus were subjected to positive selection and the C terminus were subjected to purifying selection. Erwinia spp. phylogenetic tree based on HrpA showed that there were two distinct groups. Analysis indicated that different modes of selection operated after separation of species. 【Conclusion】 The TTSS in Erwinia amylovora lies between 3.14 Mb to 3.18 Mb and the pathogen uses this system to invade the host. At the bacterial cell surface, the TTSS has a filamentous-like structure, HrpA, which serves as a conduit for the transfer of effectors into the plant cell. HrpA has a strong selection pressure in its evolutionary history. This paper has some positive significance in revealing the host range and plant resistance.


Fatty Acid Type of Ralstonia solanacearum Strains and the Relationship with Pathogenicity


Scientia Agricultura Sinica. 2009, 42(2):  511-522 .  doi:10.3864/j.issn.0578-1752.2009.02.017

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【Objective】 The objective of the study was to analyze the relationship between the fatty acid and pathogenicity of Ralstonia solanacearum. 【Method】 The fatty acid types were divided into 3 groups, FAT Ⅰ, Ⅱ, Ⅲ. FAT Ⅰ was characterized with＞0.8 avirulent index, 0% infected mortality, belonging to the non-pathogenicity type, FAT Ⅱ with 0.6-0.8 avirulent index, 6.7%-100% infected mortality, belonging to Transition-virulent type in which the pathogenicity was changeable to cause high and low mortalities to the tomato plantlets, FAT Ⅲ with ＜0.6 avirulent index, 100% stable infected mortality. 【Result】 Using cluster analysis to group the fatty acid, principle component analysis was used to select key factors of fatty acid, discrimination analysis was used to build up the discrimination model, three fatty acid of 14:0(X1), 17:0(X9), 18:0(X13) were put into the model set as follow: Y1=-16.3353 + 0.0012X1 + 0.0056X9 - 0.0016X13，Y2=-3.4928 + 0.0002X1 + 0.0003X9 + 0.0025X13，Y3= -9.1550 - 0.0003X1 + 0.0039X9 + 0.0042X13. 【Conclusion】 The accurate rate for discrimination was up to 90.00%. The model of fatty acid type for R. solanacearum was built to provide experiences for computer-based standardized analysis of the pathogen evolution under species level, furthermore with the new idea for other pathogen differentiation.


Lethal and Sub-Lethal Effects of Transgenic Rice Containing cry1Ac and CpTI Genes on the Pink Stem Borer


Scientia Agricultura Sinica. 2009, 42(2):  523-531 .  doi:10.3864/j.issn.0578-1752.2009.02.018

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【Objective】 Lethal and sub-lethal effects of transgenic rice containing cry1Ac and CpTI genes on the pink stem borer(Sesamia inferens) were studied to collect information for ecological risk assessment on insect-resistance to transgenic rice.【Method】 In vitro insect-feeding bioassay was conducted to evaluate the lethal and sub-lethal effects of transgenic rice lines (ⅡYouKF6 and KF6) on S. inferens at four different growing stages, i.e., seedling, tillering and elongation, booting, milk and maturing.【Result】Transgenic rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration of 50% and 100% of individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 days. Secondly followed by tillering and elongation stage, 50% and 100% of S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 days, respectively. Moreover, corrected mortalities for 6 days feeding on transgenic lines at this stage were significantly higher than that at booting and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration of 50% of S. inferens significantly extended and its corrected mortalities for 6 days feeding also declined remarkably. However, lethal effect of ⅡYouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting and milk and maturing stages did not present significantly lethal to S. inferens and it showed the longest lethal duration of 50% of individuals and the lowest corrected mortalities for 3 and 6 days feeding. A few larvae of S. inferens could survive, pupate and emerged on these two transgenic lines at boot and milk and maturing stages. Sub-lethal effect of two transgenic lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling and tillering and elongation stages could delay the development of larvae and pupae and decrease pupation rate, but no effect was shown on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effects were observed in pupal stages, pupation and eclosion rates. There were no significant differences for larval and pupal development, pupation and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stages. Larval and pupal weights significantly declined, but no influence was shown on fecundity, when S. inferens infested on transgenic rice at any stage. 【Conclusion】 There were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens at different developmental stages, and the effects gradually decreased with the increase of growing stages of rice plant.


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

Effects of Partial Mineral Nitrogen Substitution by Organic Fertilizer Nitrogen on the Yields of Rice Grains and Their Proper Substitution Rate


Scientia Agricultura Sinica. 2009, 42(2):  532-542 .  doi:10.3864/j.issn.0578-1752.2009.02.019

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【Objective】Field experiments were carried out to study the optimum substitution of partial mineral-fertilizer- nitrogen (N) by organic-fertilizer-N and to provide a base for the commercial development of mixed organic and mineral fertilizers for rice. 【Method】 Field experiments were done in Changshu city, Jiangsu province under different substitution rates and four N fertilizer rates. 【Result】 Grain yields of 8 242-10 187 kg?hm-2 (4007) and 10 048-11 654 kg?hm-2(Changyou 1) were obtained when 180 kg N?hm-2 was applied with a percentage of organic-fertilizer-N in total N being 15%-30% or 240 kg N?hm-2 with a percentage of organic-fertilizer-N in total N being 10%-20%, which corresponds to application of 1 500-3 000 kg?hm-2 of common compost fertilizer, compared with inorganic nitrogen fertilizer treatment. Compared with inorganic nitrogen fertilizer treatment, a more steady supply of nitrogen could be maintained when certain amounts of organic-fertilizer-N were applied together with inorganic-fertilizer-N. Nitrogen accumulation in 4007 and Changyou 1 were 172.6-256.4 kg?hm-2 and 185.9-235.6 kg?hm-2, respectively, when 180 kg N?hm-2 was applied with a percentage of organic-fertilizer-N in total N being 15%-30% or 240 kg N?hm-2 with a percentage of organic-fertilizer-N in total N being 10%-20%. In these treatments, the highest nitrogen use efficiency was obtained in 4007 (36.6%-48.1%) and Changyou 1 (34.3%-40.0%). 【Conclusion】 Application of mixed mineral-fertilizer-N and organic-fertilizers-N had a better or the same effects on the yields of rice grains and N use efficiency could be significantly increased compared with the single application of mineral nitrogen fertilizer. The best substitution of mineral fertilizer N by organic fertilizer N were 15%-30% or 10%-20% when 180 kg N?hm-2 or 240 kg N?hm-2 was applied in terms of rice fertilization.


Effects of Chemical Fertilizer and Organic Manure on Rice Yield and Soil Fertility


Scientia Agricultura Sinica. 2009, 42(2):  543-551 .  doi:10.3864/j.issn.0578-1752.2009.02.020

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【Objective】 The objective of this study was to probe the effects of chemical and organic fertilizers on rice yield, soil organic matter and soil nutrients. 【Method】 Field investigation and soil sample analysis methods were adopted on a long-term experiment in Qiyang, Station, Hunan province, China. 【Result】 The combined use of chemical and organic fertilizers was an optimum way for high yield and improvement of soil fertility. Application of both chemical and organic fertilizers significantly increased soil organic matter, and application of organic fertilizers increased soil organic matter by 48% compared with the chemical fertilizer. Organic fertilizers made a great contribution to improvement of soil total nitrogen and hydrolysable nitrogen than chemical fertilizer N, but less contribution to soil total P and available P than that of chemical fertilizer phosphorus. The organic fertilizer increased soil total N by 30% and hydrolysable N by 16% while the chemical P fertilizer increased 30% more total P and 115% more available P than did the organic fertilizer. 【Conclusion】 Combined use of chemical fertilizer and manure is important for high yield of rice and improvement of soil fertility.


Monitoring Spatial Patterns of Cropland Phenology in North China Based on NOAA NDVI Data


Scientia Agricultura Sinica. 2009, 42(2):  552-560 .  doi:10.3864/j.issn.0578-1752.2009.02.021

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【Objective】 Time series of NDVI dataset was used in this study to investigate spatial patterns of cropland phenology in North China region. 【Method】 A smoothing algorithm based on an asymmetric Gaussian function was firstly applied to the NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. The cropping system and its related phenology in North China were then estimated based on the smoothed NVDI time-series dataset. 【Result】 The cropping pattern of cropland in North China is mainly characterized by double cropping system and shows a distinct spatial difference, gradually becoming complex as moving toward to the north from the south. Under this cropping system, the starting dates and the ending dates of first growth season in North China vary over space, and regions with double cropping system present a significant advance than those regions with single cropping. On the contrary, the phenology of second growth season including both the starting and the ending dates shows no much difference among regions. 【Conclusion】 Spatial patterns of cropping system and phenology in North China are highly related to its geo-physical environment. In addition, several anthropogenic factors such as crop variety, cultivation levels, irrigation and fertilizers can profoundly influence phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.


Mechanisms of the Removal and Remediation of Phenanthrene and Pyrene in Soil with Mixed Cropping of Alfalfa and Rape


Scientia Agricultura Sinica. 2009, 42(2):  561-568 .  doi:10.3864/j.issn.0578-1752.2009.02.022

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【Objective】 To evaluate the potential of multispecies rhizoremediation in decontaminating polycyclic aromatic hydrocarbons (PAHs) contaminated soil and its impacts on plant accumulations of PAHs. 【Method】 Pot experiments were conducted to investigate the mechanisms of the removal and remediation efficiencies of PAHs under different planting models using two plant species, alfalfa (Medicago sativa L.) and rape (Brassica campestris L.) in a greenhouse. 【Result】 Results showed that multispecies rhizoremediation rather than monoculture have the evident potential to enhance pollutants removal in soils with initial phenanthrene concentrations of 20.05-322.06 mg?kg-1 and pyrene of 20.24-321.42 mg?kg-1. At the end of the 70 d experiment, the extractable PAHs in soils with mixed cropping of alfalfa and rape were lower than that in monoculture. About 65.17%-83.52% of phenanthrene and 60.09%-75.34% of pyrene were removed from the soils in mixed cropping, respectively. As compared to monoculture with rape, mixed cropping removed in 43.26% of phenanthrene and 40.38% of pyrene from soils in average and relative to monoculture with alfalfa, 11.03% of phenanthrene and 16.29% of pyrene was removed. Alfalfa or rape did take up PAHs from the soils obviously; the concentrations of PAHs in root or shoot monotonically increased while ones in the soils were higher, and under the same treatment conditions, the concentrations of PAHs in root or shoot were lower in mixed cropping than that in monoculture, and in the shoot lower than in the root. Despite the presence of vegetation evidently enhanced the remediation of PAHs in soil environment, contributions of abiotic loss, plant accumulation and degradation was much lower than ones of microbial degradation and plant-microbial interactions in the process of phytoremediation. Thus plant-microbial interactions are the main mechanisms for the remediation enhancement of soil PAHs pollution under mixed cropping models. 【Conclusion】 Results from this study suggested a feasibility of the establishment of multispecies phytoremediation to improve the efficiency of bioaugmentation in decontaminating PAHs contaminated soils, decreasing crop accumulations to PAHs and reducing risks associated with PAHs.


Effect of Returning Farmland to Forest (Pasture) and Changes of Precipitation on Soil Erosion in the Yanhe Basin


Scientia Agricultura Sinica. 2009, 42(2):  569-576 .  doi:10.3864/j.issn.0578-1752.2009.02.023

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【Objective】The aim of this study is to provide some references for decrease of soil loss and for improvement of ecological environment in Yanhe Basin of Loess Plateau by quantitatively assessing effect of returning farmland to forest (pasture) and changes of precipitation on soil erosion. 【Method】 The daily precipitation data from 35 gauges in the period of 1950-2000, soil type map, a digital elevation model (DEM), land use maps based on the interpretation of Landsat TM images acquired in 1997 and 2000 and NDVI maps from the images were used. The RUSLE was used as a model to calculate the unit soil loss and some suitable methods were also used to calculate the value of each erosion factor. Finally, the factor values and soil loss were calculated, the maps of the factor values and soil loss in each spatial unit were obtained. 【Result】 Firstly, the rainfall factor R value changed significantly from 775.32 MJ?mm?hm-2?h-1?a-1 in 1997 to 1 292.07 MJ?mm?hm-2?h-1?a-1 in 2000 primarily because of the change of precipitation. Secondly, the combined effect of the changes of slope cropland to forest land, pasture and the change in precipitation and the changes of the practice of engineering and tillage resulted in soil loss increased from 3 012 t?km-2?a-1 in 1997 to 4 671 t?km-2?a-1 in 2000. Thirdly, the C factor value which was defined by the land use and vegetation cover was 0.1714 before the change of slope cropland to forest land and pasture and 0.1592 after the change of slope cropland to forest land and pasture. The changes of C factor value resulted in the decrease of soil loss in this basin.【Conclusion】Returning from slope cropland to forest or pasture by itself decreased soil loss by 7.84%, whereas the precipitation itself increased soil loss by close to 71.28%, but both together increased soil loss by 59.26%. The effect of returning of the slope cropland to forest or pasture is obvious in decreasing soil loss.


HORTICULTURE

Molecular Cloning of A Non-Heading Chinese Cabbage Nitrate Reductase Gene (BcNR) and Transformation into Arabidopsis thaliana


Scientia Agricultura Sinica. 2009, 42(2):  577-587 .  doi:10.3864/j.issn.0578-1752.2009.02.024

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【Objective】 A full length cDNA of nitrate reductase gene (BcNR) was isolated from the non-heading Chinese cabbage (Brassica campestris ssp. chinensis) cultivar Suzhouqing, and transformed into Arobidopsis thaliana for functional identification. 【Method】 The full-length cDNA was isolated by RT-PCR, subsection PCR and (5′/3′)-RACE techniques. Bioinformatics methods were used to sequence analysis and protein structure analysis. An efficiently expression vector pCAM-BcNR was constructed and transformed into Arabidopsis thaliana by Agrobacterium mediated depressor permeating method. Transgenic Arabidopsis thaliana plants in T0 were obtained by resistance screening and PCR identification. The expression of BcNR in positive plants treated with 30 mmol?L-1 KNO3 was detected by real-time PCR method, and the nitrate reductase activities of transgenic plants and wild type plants were determined. 【Result】 The full-length cDNA sequence of 3 049 bp in length contained an open reading frame of 2 733 bp encoding 910 amino acids. The deduced amino sequence was highly homology to Arabidopsis thaliana, Nicotiana benthamiana, Brassica napus and Solanum tuberosum and other high plants. This protein shares common structural features with NRs from other higher plants and other eukaryotes. It was also proved that this clone was the style of NADH-NR. The sequence was accepted by GenBank (Accession number EU662272). GUS PCR analysis revealed that the recombinant plasmid was integrated into the transgenic Arabidopsis thaliana plants in T0. Compared with wild Arabidopsis thaliana, the transgenic plants exhibited an enhanced level of NR and nitrate reductase activity (NRA) of leaves under NO3- inducement. 【Conclusion】 Full length BcNR gene was firstly isolated and characterized from non-heading Chinese cabbage and introduced into Arabidopsis thaliana for preliminary functional identification. This study lays a foundation for further utilization of this gene in genetic modification of nitrate content in vegetable production.


Effects of Low Temperature on Leaf Proteome from Cucumis sativus of Different Genotypes


Scientia Agricultura Sinica. 2009, 42(2):  588-596 .  doi:10.3864/j.issn.0578-1752.2009.02.025

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【Objective】 The purpose of this project was to separate protein spots induced by low temperature in cucumber leaves of two genotypes, and reveal the mechanism of cucumber responding to low temperature. 【Method】Two cucumber genotypes (Cucumis sativus L. cv Xintaimici and Jinyan 4) were both treated with low temperature (15/15℃) and normal temperature (25/18℃) under the light of 100 μmol?m-2?s-1 for 7 d to study the changes of leaf proteome. The total proteins were extracted by three-steps, separated by two-dimensional gel electrophoresis (2-DE) and analysed through MALDI-TOF mass spectrometry. 【Result】 SDS-PAGE showed that few proteins were extracted by hydrophilic solutionⅠ. The extracts of solution Ⅱand Ⅲ were separated through 2-DE. Compared with treatment of normal temperature, low temperature made ‘Xintaimici’ genotype to produce 7 special protein spots, 2 up-regulated protein spots, 2 down-regulated protein spots and 5 unexpressed protein spots, and allowed ‘Jinyan 4’ to produce 7 special protein spots, 1 up-regulated protein spot, 4 down-regulated protein spots and 9 unexpressed protein spots. Three special protein spots, which were highly expressed under low temperature, were identified to be the large subunit of ribulose 1,5-bisphosphate carboxylase. 【Conclusion】There were few hydrophilic proteins in cucumber leaves. Low temperature influenced leaf proteome in two cucumber genotypes and different cultivars expressed different proteins. Ribulose 1,5-bisphosphate carboxylase may be related to low-temperature tolerance in cucumber leaves.


A Method for Constructing Core Collection of Malus sieversii Using Molecular Markers


Scientia Agricultura Sinica. 2009, 42(2):  597-604 .  doi:10.3864/j.issn.0578-1752.2009.02.026

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【Objective】 The method for constructing core collection of Malus sieversii based on molecular markers data was proposed. 【Method】 According to 128 SSR allele of 109 M. sieversii, an allele preferred sampling strategy was used to construct M. sieversii core collection using UPGMA cluster method according to Nei & Li, SM and Jaccard genetic distances by stepwise clustering and compared with the random sampling strategy. The number of lost allele and t-test of Nei's gene diversity and Shannon's Information index were used to evaluate representative of core collections. 【Result】 Compared with the random sampling strategy, allele preferred sampling stragegy could construct more representative core collections. SM, Jaccard and Nei & Li genetic distance had not distinct difference for construction of M. sieversii core collection. SRAP data and morphological data showed that allele preferred sampling strategy was a good sampling strategy for constructing core collection of M. sieversii.【Conclusion】 Allele preferred sampling strategy combined with SM, Jaccard and Nei & Li genetic distances using stepwise clustering is a suitable method for constructing M. sieversii core collection.


Effect and Functional Mechanism of Exogenous Gibberellin on Flowering of Peach


Scientia Agricultura Sinica. 2009, 42(2):  605-611 .  doi:10.3864/j.issn.0578-1752.2009.02.027

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【Objective】 This experiment was conducted to study the effect of gibberellin and its possible mechanism on flower formation of peach. 【Method】 At the stage of flower induction, 100 mg?L-1 of GA3 was sprayed on the leaves of peach [Prunus persica (L.) Batsch.] cv. Bayuecui. Using the methods of anatomy, immunohistochemistry and semi-quantization, the in situ distribution of GAS and the expression of the key genes involved in peach flower formation in the apical meristem were studied during the period of flowering differentiation. 【Result】 The stage of flowering induction of ‘Bayuecui’ peach in Beijing was before July 10. The flower induction and further differentiation of flower organs of peach were significantly inhibited by leaf-spraying of GA3 at the concentration of 100 mg?L-1 during its flower inducing stage. The flower rate was only 11.67% after treatment. The distribution of GA1 in the apical meristem changed along with the process of flower bud differentiation. From June 13 to July 25, the GA1 signal of the control was detected mainly in the vascular bundle at the base of the flower buds. Meanwhile no GA1 signal was detected in the apical meristem. After being treated by GA3, the distribution was similar to the control from June 13 to July 3. But on July 13, GA1 signal was detected in the apical meristem accompanied by an increase of GA1 signal in the vascular bundle at the base of flower buds. GA1 signal weakened significantly in both vascular bundle and apical meristem on July 25. The expression of gene PpLEAFY and gene MADS6 in flower buds could only be detected on October 10 in GA3 treatment. 【Conclusion】 The critical period of flower induction of ‘Bayuecui’ peach in Beijing was in early July, during which leaf-spraying with 100 mg?L-1 GA3 could inhibit the flower induction and the further differentiation of the flower bud effectively. GA1 in the gibberellin family was the suppressors for flower induction in peach. Its effect was affected by the stages of flower bud differentiation. The expression of the key genes PpLEAFY and MADS6 involved in flower formation were inhibited by GA3 treatment.


STORAGE·FRESH-KEEPING·PROCESSING

Effects of Harvest Maturity on Quality and Chilling Injury of Juicy Peaches During Low Temperature Storage


Scientia Agricultura Sinica. 2009, 42(2):  612-618 .  doi:10.3864/j.issn.0578-1752.2009.02.028

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【Objective】 This research investigated the effects of different harvested maturities on quality attributes and chilling injury of peach fruit (Prunus persica L. Batsch cv. Hujingmilu) in low temperature storage, and further explore the optimal harvested maturity, which is useful for guiding storage technique of soft peaches in south China. 【Method】 Changes in rotten rate, flesh firmness, total soluble solids (TSS), titratable acidity (TA) and ascorbic acid, respiration rate, relative leakage rate, browning index, superoxide dismutase (SOD) and peroxidase (POD) of ‘Hujingmilu’ peaches were investigated at 1℃ for 28 days. 【Result】 As compared to the fruits with 7-8 maturity-degree at 1℃, the fruits with 9 maturity-degree showed a stronger tolerance to cold stress, and kept better quality during low temperature storage periods. In addition, the fruits with 9 maturity-degree showed an increase in activities of SOD and POD, reducing accumulation of free radical and alleviating chilling injury. 【Conclusion】 Thus, 9 maturity-degree should be suggested as the best harvest maturity of juicy peaches in low temperature storage.


Effects of Controlled Atmosphere on Cell Wall and Cuticle Composition and Quality of Jujube Fruit (cv. Huping)


Scientia Agricultura Sinica. 2009, 42(2):  619-625 .  doi:10.3864/j.issn.0578-1752.2009.02.029

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【Objective】 The effects of controlled atmosphere (CA) on cell wall and cuticle composition and quality of jujube fruit (cv. Huping) were investigated, and the potential role of cuticle in fruit storability was elucidated in this paper, which could provide a theoretical basis for fruit storage. 【Method】 Jujube fruits were stored at (-1±1) ℃ in air and CA with 10% O2 plus 0% CO2, respectively. The softening rate, firmness, total soluble solids (TSS) and titratable acidity (TA) of fruits were assayed, the composition of flesh cell wall materials (CWM) and cuticle layer were determined using Fourier transform infrared spectroscopy. 【Result】 Compared with low temperature storage in air, CA with 10% O2 plus 0%CO2 significantly reduced softening rate and maintained fruit firmness, TSS and TA content during the whole storage periods. Moreover, relatively more esterified pectins and lignin-like phenols in the flesh CWM and less linear long-chain aliphatic compounds in cuticle layer were found in the fruits stored in CA condition. 【Conclusion】 CA may reduce the softening rate of jujube fruit and extend its storage life by regulating the metabolic pathway of cuticle layer along with that of flesh cell wall and catabolism in fruit.


Chitosan Inhibiting the Growth of Phytopathogenic Fungi and Control of Postharvest Diseases of Fruits


Scientia Agricultura Sinica. 2009, 42(2):  626-635 .  doi:10.3864/j.issn.0578-1752.2009.02.030

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The antimicrobial activity of chitosan and its application in postharvest decay control of fruits are reviewed. Chitosan as a broad spectrum fungicide can inhibit the phytopathogenic fungi at different stages of life cycle, including the formation, germination and germ tube elongation of spores and mycelial growth. Moreover, the antimicrobial activity of chitosan can be influenced by its molecular weight, degree of deacetylation, concentration, pH value and the kind of solvent. The antimicrobial mechanism is not always well-known although the issues that chitosan could play its role in extra or intercellular have been reported. The efficacy of chitosan in fruit decay control maybe due to its antimicrobial performance, its role as an elicitor and regulator. And the synergetic effect of chitosan in combination with other methods can improve its application in horticultural commodities storage.


Stability of Antifungal Substance Produced by Actinomycete CCTCC M207210 and Its Application


Scientia Agricultura Sinica. 2009, 42(2):  636-641 .  doi:10.3864/j.issn.0578-1752.2009.02.031

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【Objective】 The paper aimed at investigating the stability and potential application of the antifungal substance in the cell-free liquid culture of Actinomycete CCTCC M207210. 【Method】 The antifungal ability of the cell-free liquid culture of Actinomycete CCTCC M207210 was tested on agar media after pretreatment of heat, acid, alkali, and ultraviolet radiation. The cell-free liquid culture was added into apple juice medium and sprayed on apple surface after inoculation of patulin-producing Penicillium expansum SP2204 and SP2205. After a period of cultivation of 12 d, 7 d respectively, the diameter of rotten spot in apple was measured and patulin production in the apple juice culture was tested to evaluate the inhibitory ability of the cell-free culture in practical application. 【Result】 Heating, acidic and alkaline treatment, and ultraviolet radiation could destroy, to some extent, the antifungal activity of the cell-free liquid culture of Actinomycete CCTCC M207210. The antifungal activity was completely destroyed when the cell-free liquid culture was pretreated at 100℃ for 60 min or subjected to ultraviolet radiation (30 W, 245 nm, 15 cm distance) for 90 min. The liquid culture showed the most stable antifungal activity at the original pH (5.7) and more stable at a little alkaline pH than acidic condition. Extension rate of the rotten spots was reduced by 25% when the liquid culture was sprayed on the apple surface 120 h after the inoculation of P. expansum. Patulin production was reduced by 90% when the liquid culture was added in the apple juice cultivation of P.expansum in ratio of 40% (v/v). 【Conclusion】 The antifungal substance in the cell-free liquid culture of Actinomycete CCTCC M207210 showed high resistibility to heat, acidic and alkaline conditions, and ultraviolet radiation, and had great potential in application of inhibiting the growth and patulin production of P. expansum for apple storage and apple juice production.


ANIMAL SCIENCE·RESOURCE INSECT

Effects of Glycerol on Rumen Fermentation, Urinary Excretion of Purine Derivatives, Digestibility, Energy Metabolism and Nitrogen Balance in Simmental Steer


Scientia Agricultura Sinica. 2009, 42(2):  642-649 .  doi:10.3864/j.issn.0578-1752.2009.02.032

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【Objective】The objective of this study was to evaluate the effects of glycerol supplementation on rumen fermentation, urinary excretion of purine derivatives, nutrients digestibility, energy metabolism and nitrogen balance of steers.【Method】 Eight ruminal cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment and fed with basic diet and added with glycerol at 0, 100, 200 and 300 g per steer per day, respectively. 【Result】 The results showed that ruminal pH, ratio of acetate to propionate and ammonia nitrogen of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were lower than steers supplemented with glycerol at 100 g?d-1 and the control significantly (P＜0.05). Total VFA concentration, the molar proportions of propionate and butyrate of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than steers supplemented with glycerol at 100 g?d-1 and control significantly (P＜0.05). Ruminal DM, OM, NDF and ADF degradation of corn straw, and ruminal DM and OM degradation of concentrate of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than the control significantly (P＜0.05). Ruminal CP degradation of concentrate of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were lower than steers supplemented with glycerol at 100 g?d-1 and the control significantly (P＜0.05). Allantoin concentration and urinary excretion of purine derivatives of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than steers supplemented with glycerol at 100 g?d-1 and control significantly (P＜0.05). Dietary OM, EE, CP, NFE, NDF and ADF digestibilities of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than the control significantly (P＜0.05). Digestible energy and metabolizable energy of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than the control significantly (P＜0.05). Retenion energy of steers supplemented with glycerol at 200 g/d and 300 g/d were higher than the control and supplemented with glycerol at 100 g?d-1 significantly (P＜0.05). Retenion nitrogen of steers supplemented with glycerol at 200 g?d-1 and 300 g?d-1 were higher than steers supplemented with glycerol at 100 g?d-1 and the control significantly (P＜0.05). 【Conclusion】 These results indicated that the optimum dose of glycerol supplementation was 200 g?d-1.


Prokaryotic Expression of FAT/CD36 Fusion Protein and the Specific Effects on the Deposition of Visceral Fat in Cockerel Chicks


Scientia Agricultura Sinica. 2009, 42(2):  650-656 .  doi:10.3864/j.issn.0578-1752.2009.02.033

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【Objective】Fatty Acid Translocase (FAT/CD36) is an important carrier protein involved in the transmembrane transportation of fatty acids and cellular triglyceride accumulation. This experiment was designed to get a better understanding of the role of FAT/CD36 in the adipose deposition by active immunization method. 【Method】Chicken FAT/CD36 extracellular antigen domain partial gene fragment was cloned, inserted into the prokaryotic expression vector pET-32a(+) between BamHⅠand XhoⅠsites, and translated in Escherichia coli BL21 (DE3). Then, sixty 22-day-old yellow-feathered broilers were randomly divided into male, female control groups and two experiment groups inoculated i.m. with 1 mg of the chicken FAT/CD36 and bovine serum albumin (BSA) immunogens on 34 d, 49 d and 63 d, respectively. At the end of trial, all birds were sacrificed for the fat deposition evaluation. 【Result】 A 29 kD recombinant chicken FAT/CD36 fusion protein was expressed in Escherichia coli BL21 (DE3). After induced for 6 hours by adding IPTG to a final concentration of 0.1 mmol?L-1, the fusion protein amounted up to 32% of the total bacterial protein expressed and existed mainly in inclusion body, which was further purified by affinity chromatography and dialysis. The levels of serum anti-FAT/CD36 antibody in both male and female treatment groups gradually elevated and were significantly higher than that in each control group after the first immunization. It was interesting to find that the active immunization of FAT/CD36 specifically decreased the percentage of visceral fat in male but not female broilers, whereas the thickness of subcutaneous fat was unchanged. 【Conclusion】 The results indicated the role of chicken FAT/CD36 in the regulation of adipose with gender- and site-specific manner, which provided a further understanding of the fat deposition mechanism in avian.


The Effect of Chromium Picolinate on Oxidative Damage in New Born Porcine Hepatocyte


Scientia Agricultura Sinica. 2009, 42(2):  657-662 .  doi:10.3864/j.issn.0578-1752.2009.02.034

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【Objective】 This experiment was designed to assess the effect of different levels of chromium picolinate (CrPic) on oxidation in new-born porcine hepatocyte. 【Method】 Three-day-old new born piglets were chosen as hepatocyte donors, hepatocytes were isolated enzymatic and mechanical methods. Porcine hepatocytes were cultured in medium in which added 0, 8, 200, 400 μmol?L-1 of CrPic for 48 hours. The levels of reactive oxygen species (ROS), the contents of malondialdehyde (MDA) in hepatocytes, the activities of lactate dehydrogenase (LDH) in medium and DNA strand breaks (by comet assay) were examined to investigate the effect of CrPic on porcine hepatocytes. 【Result】 Compared with control, the treatment groups have no significant differences in ROS level in hepatocytes, LDH activities in medium and DNA strand breaks (P＞0.05), however, 8 μmol?L-1 CrPic was significantly decreased MDA content in hepatocytes (P＜0.05). Compared with 8 μmol?L-1 CrPic group, the other parameters were markedly increased in 400 μmol?L-1 CrPic group (P＜0.05). Meanwhile, with the levels of CrPic increasing, analysis revealed a significant quadratic trend between CrPic and ROS (or LDH) (P＜0.05). 【Conclusion】 The appropriate amount of CrPic inhibits lipid peroxidation in cells, enhances antioxidation of porcine hepatocyte, however, 400 μmol?L-1 of CrPic has no effects on the antioxidation and oxidative damage.


Screening for Porcine Calsarcin-1 Interacting Proteins by Yeast Two-Hybrid System


Scientia Agricultura Sinica. 2009, 42(2):  663-668 .  doi:10.3864/j.issn.0578-1752.2009.02.035

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【Objective】 The function of Calsarcin-1 was studied in the formation of skeletal muscle fiber and signaling pathway regulation through the screening for porcine Calsarcin-1 interacting proteins by yeast two-hybrid system. 【Method】 The pGBKT7-CS1 bait vector without toxicity or auto-activation was constructed with the Calsarcin-1 gene of Landrace pig, firstly. Then the mRNA was isolated from the skeletal muscle of the adult Landrace and purified ds-cDNA by SMART technology. Ds-cDNA was amplified by long distance PCR. At last, the Calsarcin-1 interaction proteins were screened through co-transformation with bait vector and ds-cDNA prey library. With the alignment of interacted gene in GenBank, the function of Calsarcin-1 was analyzed.【Result】 In this study, pGBKT7-CS1 bait expression vector was constructed. The ss-cDNAs of the porcine skeletal muscle with full length 3’ end were isolated and the ds-cDNAs were synthesized. Four proteins interacting with Calsarcin-1 were identified. The Calsarcin-1 showed the important function in maintaining the structure of Z line through interacting with ACTA1 and ACTN3, while involved to calcium ion regulation through CASQ1 and TNNT3 possibly.【Conclusion】 According to the result, it is presumed that the Calsarcin-1 affected the formation of Z-line and the calcium binding by combination with these identified proteins and participated in the calcium ion regulation and maintaining the cytoskeleton stabilization. By this way, the calcium ion concentration also affected other factors and signaling pathways related to the slow and fast muscle fiber formation and transformation.


Assessment of Genetic Relationships Among the Plateau Merino Populations in China Using Microsatellite DNA Markers


Scientia Agricultura Sinica. 2009, 42(2):  669-676 .  doi:10.3864/j.issn.0578-1752.2009.02.036

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【Objective】 Assessment of genetic relationships among the Chinese Plateau Merino breeds was made by using microsatellite DNA markers for the purposes of understanding of their genetic background and providing basic information for supporting conservation of genetic resources and genetic improvement. 【Method】 Using 15 microsatellite DNA markers, the Gansu Alpine Merino and the Qinghai Merino populations were analyzed along with the other two foreign sheep breeds and seven indigenous Chinese sheep populations in order to examine their population genetic structure and differentiation. 【Result】 The phylogenetic analysis, principal component analysis and the Bayesian clustering approach were employed to analyse the data and it was observed that the 11 populations conld be divided into three genetic types. In particular, the Gansu Alpine Merino and Qinghai Merino formed a single cluster. 【Conclusion】 This study, using microsatellite DNA makers, reveals that the Gansu Alpine Merino and Qinghai Merino have a similar genetic background, in alignment with their breeding histories, thus they can be treated as a single genetic unit in future genetic resource conservation and improvement programs.


Proteome Analysis of the Development of Hypopharyngeal Gland of High Royal Jelly Producing Bees and Native Italian Bees





Scientia Agricultura Sinica. 2009, 42(2):  677-687 .  doi:10.3864/j.issn.0578-1752.2009.02.037

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【Objective】 The study is to investigate the proteome profile of the hypopharyngeal gland (HG) of high royal jelly producing bees (A. m. ligustica) and native Italian bees (A. m. ligustica) on day 1, day 3 and day 6. 【Method】 Two-dimensional gel electrophoresis was used in this experiment and parts of proteins were identified by comparison of those proteins already identified in the proteome complement of the HG and royal jelly. 【Result】 The results showed that 210, 192 and 230 proteins were detected in the proteome profile of high royal jelly producing bees on day 1, day 3 and day 6, respectively, which is significantly higher than those detected in native Italian bees, 169, 188 and 212, correspondingly. While 6-day-old HG expressed the significant highest number of proteins in two strains (P＜0.05). This indicates the HG of high royal jelly producing bees express more active than that of native Italian bees and day 6 is the most active expressional stage. For high royal jelly producing bees, 119 proteins presented on all images of days 1, 3, and 6, among which 21 proteins were remarkably up-expressed and 14 were significantly down-expressed along with the development of the HG. For the native Italian bees, 107 proteins were consistently resolved to the 3 images, 15 proteins showed significant up-expression and 19 down-expressed significantly (P＜0.05). Proteins well resolved to the images on day 1, day 3 and day 6 of high royal jelly producing bees and native Italian bees were 145, 138 and 175, respectively. Among them, 28, 31, 44 proteins showed a significant higher expression in high royal jelly producing bees than those of native Italian bees, while 14, 19, 25 proteins expressed significant higher in native Italian bees than those of high royal jelly producing bee (P＜0.05). Proteins specific expressed in the HG of high royal jelly producing bees and native Italian bees were 65, 54, 55 and 24, 50, 37 on day 1, day 3 and day 6, respectively. By comparison of already identified proteins from HG and royal jelly, major royal jelly proteins could be detected in the protein profile of the two honey bee strains starting from day 3. 【Conclusion】 The HG of high royal jelly producing bees express more active than that of Italian bees during 6 days development after eclosion and it has the most expressional activity on day 6. The proteins well resolved to all images are the housekeeping proteins which are indispensable for the development of the HG, but marked difference exists in their expression pattern. The proteins specific expressed on different days indicate that different developing stage of HG need specific proteins to regulate its growth. The 3-day-old HG begins to secret royal jelly.


VETERINARY SCIENCE

Rescue of Infectious Foot-and-Mouth Disease Virus in vivo from Full-Length cDNA Clone of Asia1 Type


Scientia Agricultura Sinica. 2009, 42(2):  688-693 .  doi:10.3864/j.issn.0578-1752.2009.02.038

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【Objective】The aim of the study was to develop a reverse genetics platform of infectious foot-and-mouth disease (FMDV) in vivo, which is a base for the construction and function researches of viruses. 【Method】 The full-length genome of FMDV Asia1/JS/China/2005 strain was assembled into a mammalian expression vector downstream of a T7 promoter. The recombinant plasmids, pFMDV-A were linearized with NotI enzyme and cotransfected into BHK-21 cells with pcDNAT7P plasmids that could express T7 RNA polymerase to research reverse genetics of FMDV. 【Result】 The transfected cells were serially passaged, and the third passage showed apparent cytopathogenicity effect (CPE) within 48 h, the CPE were observed after 10 h in fourth passage. The results of the RT-PCR, indirect immunofluorescence, and electron microscope showed that FMDV was rescued successfully in vivo from the full-length cDNA clone of FMDV. The recovered virus contained genetic tags. Repeat experiments also obtained recovered virus with the established method. The rescued virus showed a similar pathogenicity in suckling mouse (LD50) compared to its wild-type virus. 【Conclusion】 Plasmid-based reverse genetics system was developed in authors’ laboratory for efficient and stable generation of infectious FMDV.


Development of Colloidal Gold Strip for Differentiating Antibody of AIV-Infected Flocks from Vaccinated Ones


Scientia Agricultura Sinica. 2009, 42(2):  694-700 .  doi:10.3864/j.issn.0578-1752.2009.02.039

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【Objective】 A rapid assay based on colloidal gold immunochromato graphic method was developed to identify AIV-infected chickens from those immunized with invactivated vaccine, which was charactered with rapid and simple handling on spot by even unskilled feeder. 【Method】 The NS1 gene of H9N2 subtype influenza A virus was cloned into vector pGEX-KG to construct the recombinant plasmid KG-NS1, which was then transformed into E. coli BL21-DE3 competent cells and induced by IPTG. After analysed by western-blot, the purified product was used as diagnostic antigen in development of a colloidal gold immunochromatographic assay (GICA) strip for the NS1 antibody detection. The specificity and sensitivity of the strip were evaluated, and the sera from experimental and clinical samples were tested. 【Result】 The fusion protein GST-NS1 (r-NS1) was about 52 kD and showed immunologic competence. Using the purified r-NS1, a GICA strip was developed for the NS1 antibody detection with high specificity and acceptable sensitivity, whose results were decided through the observation of the test line in red or not (red indicated positive result) by naked eye within 25 min. Tested by the strip, only the sera of r-NS1 protein and AIV-infected read positive, but the sera of other antigen read negative. Using the GICA strip, the NS1 antibody of the experimental AIV-infected chickens was identified. The NS1 antibodies were detected as early as the third day post- infection and maintained for around two weeks. It was about 80% experimental sample and 9.1% clinical samples detected positive with the strip. 【Conclusion】 GICA is a visual, specific, rapid and simple detection method and it is feasible to apply to distinguish between vaccinated and virus-infected poultry in field screening. It is worth to be popularized.


Screening of the Monoclonal Antibodies Against the Membrane Proteins of Chicken Embryo Fibroblast Which Can Block the Infection of IBDV


Scientia Agricultura Sinica. 2009, 42(2):  701-705 .  doi:10.3864/j.issn.0578-1752.2009.02.040

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【Objective】To establish an efficient assay for screening monoclonal antibodies (McAbs) against the membrane proteins of chicken embryo fibroblast (CEF) for further studies of the cellular receptors of infectious bursal disease virus (IBDV). 【Method】 McAbs against the membrane proteins of CEF were prepared by cell fusion. The monolayer CEF pre-incubated with the CEF-specific McAbs for 2 h were infected with IBDV and incubated with F22-EA6-Biotin postinfection. Then, the cells were reacted with Streptavidin-HRP and finally stained by AEC. The inhibitory percentage of IBDV infection was calculated by counting the IBDV-infected cells to determine the inhibition efficiency of the CEF-specific McAbs. 【Result】 Compared with the control cells, the IBDV-infected cells pretreated with CEF-specific antibody significantly decreased; Supernatant fluids of total of 768 hybridomas were analyzed. The results of immunohistochemistry assays showed that six ones (1A5, 1H11, 2B12, 3G1, 4D10 and 4B8) have the abilities to block the infection of IBDV to CEF, and among which 4B8 can perfectly block the infection. 【Conclusion】 This novel method is a sensitive and specific assay for the screening of CEF membrane protein-specific McAbs which can block the infection of IBDV to CEF, and these McAbs can be used for the further investigations of the cellular receptors of IBDV.


Effects of Traditional Chinese Medicine Compound Polysaccharides on Anti-Oxidation Function of Chicks


Scientia Agricultura Sinica. 2009, 42(2):  706-713 .  doi:10.3864/j.issn.0578-1752.2009.02.041

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【Objective】To observe the influence caused by different concentrations of traditional Chinese medicine compound polysaccharides, astragalus polysaccharides (APS), angelica polysaccharides (ASP), epimedium herb polysaccharides (EPS) on the activity of SOD, GSH-Px, CAT, GR and the content of MDA in serum of healthy Roman chicks. 【Method】Two hundred and sixty one-day-old chicks were divided into thirteen groups at a random distribution and each group has 20 chicks. Then hypodermically inject the physiological saline, traditional Chinese medicine compound polysaccharides，APS, ASP and EPS into the chicks for seven days continuously, and get blood on the 7th, 14th, 21st, 28th, 35th and 42nd to test the activity of SOD, GSH-Px, CAT, GR and the content of MDA in serum. 【Result】The results of the experiment showed that the activities of SOD, GSH-Px, CAT and GR were obviously increased (P＜0.05) and the content of MDA decreased after injecting the chicks with traditional Chinese medicine compound polysaccharides, APS, ASP and EPS. For the groups treated with traditional Chinese medicine compound polysaccharides，the activities of SOD, GSH-Px, CAT, GR in serum were predominantly higher and the content of MDA was predominantly lower. 【Conclusion】Traditional Chinese medicine compound polysaccharides, APS, ASP and EPS all can promote the chicks’ ability of anti-oxidation. Among them, traditional Chinese medicine compound polysaccharides is the strongest.


RESEARCH NOTES

Influence of High Temperature Stress on Composition and Accumulation Configuration of Storage Protein in Rice


Scientia Agricultura Sinica. 2009, 42(2):  714-718 .  doi:10.3864/j.issn.0578-1752.2009.02.042

Abstract ( 1374 )   PDF (355KB) ( 937 )   Save

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【Objective】 To evaluate the influence of high temperature stress on the quality formation of storage protein in rice, since the protein content and its composition in endosperm are important target to improve rice quality and nutrition value. 【Method】 A treatment of high temperature stress during filling stage was conducted to analyze the influence of high-temperature stress on the composition and accumulation configuration of storage protein in rice. 【Result】 Filling process, single-grain weight, accumulation process and accumulation configuration of storage protein in grain at 25℃ treatment were coincide with these at natural condition. Filling process of grain was accelerated and single-grain weight was reduced by 35℃ treatment. Not only content of crude protein was increased, but also the composition and accumulation configuration of storage protein changed by high temperature stress. The relative content of prolamin was decreased by 7.5% compared to control. Although the relative content of glutelin, the staple storage protein, not changed with high-temperature stress, but the relative content of two glutelin subunits was reduced by 12.7%. Simultaneously, the pro-glutelin of 57 kD and the glutelin polymer above 57 kD was improved by 19.5%. 【Conclusion】 These data in this trial indicated that the composition and accumulation configuration of storage protein in rice grain changed with high temperature stress, and the reduction of content of two glutelin subunits and prolamin has no relation with the ability of nitrogen supplied to grain and with the ability of protein synthesis, but has close correlation with procedure of transformation, transport, aggregation and degradation of post-translation protein under the condition of high-temperature stress.


Ultrastructure of Sunflower Resistance to Rust Induced by Oligosaccharide


Scientia Agricultura Sinica. 2009, 42(2):  719-724 .  doi:10.3864/j.issn.0578-1752.2009.02.043

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【Objective】 Electron microscope technique was used to study the inhibitory effects of oligosaccharide on the infection of Puccinia helianthi on sunflower, to unravel the mechanism of oligosaccharide elicitors at the cytology level. 【Method】Treated with oligosaccharide, 2 days later, sunflower was inoculated with Puccinia helianthi, the ultrastructure of pathogen and host was investigated with scanning and transmission electronic microscopy. 【Result】 Some uredospores on the induced plant were sunken and the germination was inhibited. The host cells of sunflower produced defense structures and material related to the infection. The host cell wall was thickened and deeply stained，dark material deposited under the cell wall and the walls of haustoria thickened and extra-haustorial matrix was found to be enlarged; some haustoria became malformed and disintegrated, deformation and vacuolation of host organelles occured，finally the whole host cell disintegrated，collapsed. 【Conclusion】 Oligosaccharide has inhibitory effects on the pathogen infection and sunflower leaves were induced resistance to the rust disease.


Effects of Long-Term Continuous Cropping System of Cotton on Soil Physical-Chemical Properties and Activities of Soil Enzyme in Oasis in Xinjiang


Scientia Agricultura Sinica. 2009, 42(2):  725-733 .  doi:10.3864/j.issn.0578-1752.2009.02.044

Abstract ( 918 )   PDF (324KB) ( 1258 )   Save

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【Objective】 The objective of the experiment is to study the effect of long-term cotton continuous cropping on soil physical-chemical and biological characters. 【Method】 Both cotton micro-experiment and conventional chemical methods were adopted to study the changes of soil physical-chemical properties and soil enzyme activities under long-term continuous cropping. 【Result】 Results showed that compared with 1 year cropping, both soil organic matter content and soil salt content were increased by 10.56%, 18.09%, 37.34%, 55.64% and 122%, 132%, 124%, 146%, respectively, under 5-20 years continuous cropping, while soil bulk density began to decline. With the time of continuous cropping increasing, the soil alkali-hydrolyzable N content was remarkably raised, but the soil available K content was decreased by 60.4%, 35.9% and 39.8% under 5-20 years continuous cropping, the soil available P content was enhanced in 5-year continuous cropping and then stable in 10, 15 and 20 years continuous cropping. The activities of urase, catalase, protease, invertase and phosphatase decreased in 5-10 years continuous cropping, while those enzyme activities increased in 15-20 years, the soil peroxidase activity increased with the continuous cropping year increasing. 【Conclusion】 In the oasis area of Xinjiang, under long-term continuous cropping, stalk returning can ameliorate soil physical characters, increase soil salt content, but soil N, P, K proportion was imbalanced. The enzyme activity of soil decreased in a short period of time (from 1 to 10 years), the obstacles of continuous cropping were more obvious.


Genetic Analysis and RAPD Marker of Creeping Habits in Ground-Cover Chrysanthemum


Scientia Agricultura Sinica. 2009, 42(2):  734-741 .  doi:10.3864/j.issn.0578-1752.2009.02.045

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【Objective】 In order to provide bases for molecular assisted breeding, and for cloning creeping habit related genes from the ground-cover chrysanthemum, the inheritance traits of creeping habit were studied, and the RAPD markers related to this habit were screened. 【Method】 F1 population was derived from interspecific cross between ‘Zaoyidalihong’ (female parent) and ground-cover chrysanthemum ‘03(6)-12’ (male parent). The plant type was divided into creeping, erect and intermediate (non-creeping and non-erect) types according to the branching angle of main branches. Individuals of each plant type in F1 were randomly selected, and self-cross was made to generate the F2 population. BC1 population was obtained from back cross of the selected individuals with ‘03(6)-12’. The segregation ratio of different plant types was documented in seven populations. The gene bulk of creeping and erect plant type in F1 population was constructed by using bulked segregant analysis (BSA) method. 200 RAPD arbitrary primers were used to screen creeping habit related molecular markers. 【Result】 Genetic analysis and chi-square test showed that creeping or erect type in ground-cover chrysanthemum likely controlled by an incomplete dominance major gene as well as polygene. A RAPD marker A-10555 linked to creeping gene were screened, the validity of this RAPD maker was verified by replicate tests and testing individual plant in F1 population, the maker was 7.96 cM far from the loci controlling creeping/erect 【Conclusion】 It is feasible to divide plant type into creeping, erect or intermediate types by branching angle of main branch, F1, F2 and BC1 population were useful population for segregation investigation of plant type in ground-cover chrysanthemum. The marker obtained in this study is closely linked to loci controlling creeping or erect, and is promising in molecular assisted breeding.


Genetic Effect of three Loci related with Growth and Carcass Traits in Swine


Scientia Agricultura Sinica. 2009, 42(2):  742-747 .  doi:10.3864/j.issn.0578-1752.2009.02.046

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【Objective】 The objective of this study was to study the polymorphism of porcine three loci of PIT1, HDAC1 and IGF2 and its relationship with the growth and carcass traits in swine. 【Method】 The polymorphism of three genes was analyzed by PCR-RFLP method. The genotypic effects of such genes on growth and carcass traits were analyzed. 【Result】 CC genotype of PIT1, GG of HDAC1 and AA of IGF2 had favorable effect on growth and the age at 100 kg liveweight is 6-9days less than the contrary genotypes. The effects of CC genotype of PIT1, the GG genotype of HDAC1 and the BB genotype of IGF2 on lean percentage were 3-5 percent higher and on backfat thickness were 2-3 mm lower than the contrary genotypes. The index of growth traits increased relevantly.【Conclusion】 The favorable genotypes of thoese genes could be regarded as molecular markers in selection of lean type pigs.


Effects of Dietary Concentration to Forage Rate on Microbial Protein Recycling in Rumen of Goats


Scientia Agricultura Sinica. 2009, 42(2):  748-754 .  doi:10.3864/j.issn.0578-1752.2009.02.047

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【Objective】Studies on effects of dietary concentration to forage rate on microbial protein recycling in rumen of goats were carried out using a technique of fluorescence-labeled bacteria (FLB). 【Method】 In an experiment, 4×4 Latin squares were conducted by using four Xuhuai goats with permanent cannulas, and diets were divided into A (10﹕90), B (30﹕70), C (50﹕50), and D (70﹕30) by varying concentration to forage ratios, which concentrated food were corn-soybean meal, while forage was straw. 【Result】 The result showed that, rumen micro-ecosystem was changed significantly by concentration to forage rate. The highest protozoal density was recorded in group C which the dietary concentration to forage rate was set as 50:50, whereas densities of both protozoa and bacteria were lowest in group A; grazing rates of rumen protozoa on bacteria were 429.5, 366.74, 389.48, and 402.2 cells?cell-1?h-1, respectively in group A, B, C, and D. When the corresponding values expressed as bacteria-N were: 2.319, 1.98, 2.103, and 2.172 pg N?cell-1?h-1, respectively.【Conclusion】Extrapolating the assimilation of quantity of nitrogen by ciliates on bacteria of Xuhuai goat with different diets, there were 136.49, 369.02, 485.99, and 440.56 mg N/(d?capita) in groups A, B, C, and D, respectively. It was estimated that the protein losses due to microbial recycling were 0.853, 2.306, 3.370, and 2.754 g/(d?capita), respectively, with group C recording the highest bacterial protein loss and turnover rates (3.07%).