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    20 February 2010, Volume 43 Issue 4
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

    A Comparative Study on Aluminum Tolerance Between Oryza sativa and O.rufipogon in Gaozhou

    FU Xue-lin,CHEN Wei-dong,PAN Chun-hui,FENG Jun-hao,LIU Xiang-dong,LU Yong-gen
    Scientia Agricultura Sinica. 2010, 43(4):  661-669 .  doi:10.3864/j.issn.0578-1752.2010.04.001
    Abstract ( 965 )   PDF (407KB) ( 669 )   Save
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    【Objective】 The tolerance of some rice varieties and O.rufipogon in Gaozhou to aluminum was studied. The experimental varieties of Al-tolerant and Al-sensitive ones were distinguished and Al-tolerant accessions of O.rufipogon in Gaozhou were also screened out. The materials for mapping the genes related to Al-tolerance of O.rufipogon in Gaozhou were tested. 【Method】 In this study, seedling roots of varieties and O.rufipogon accessions or regenerative roots from tillerings of O.rufipogon were treated in 0.5 mmol?L-1 CaCl2 solution with 50 μmol?L-1 Al3+ for 1 d, the relative root elongation (RRE) was used as a parameter to evaluate the aluminum tolerance. 【Result】 Relative root elongation (RRE) of 17 rice varieties were significantly affected by genotypes, Al3+ contents and treatment time (P<0.0001). Nipponbare, L202, Liaojing944, and 88B were Al-tolerant varieties. It is the reliable method to evaluate Al-tolerances of different genotypes in rice with the parameter RRE of seedlings which growing in 0.5 mmol?L-1 CaCl2 solution with 50 μmol?L-1 Al3+ for 1d. Besides, RRE values of 69 accessions of O.rufipogon in Gaozhou were significantly different (P<0.0001), 55 accessions were Al-tolerant with RRE≥0.50. Compared with Nipponbare, an Al-tolerant control variety, RRE values of 37 accessions were larger than that of Nipponbare (RRE=0.6198) and the largest RRE was 1.8730 of GZW020. Analyzing RRE values of regenerative roots from tillerings of 17 accessions of O.rufipogon in Gaozhou, it showed that 13 accessions were Al-tolerant with RRE≥0.50. Meanwhile, the correlation between RRE value of seedlings and RRE value of tillerings of the same accession was significant (R= 0.76012, P=0.0041). It is considered that some accessions of O.rufipogon in Gaozhou contain Al-tolerant genes. Furthermore, Al-tolerance was detected in 2 lines in BC3F2 generation between Huajingxian74, an Al-sensitive variety, and GZW087, one of the Al-tolerant accessions of O.rufipogon in Gaozhou. This indicates that Al-tolerance in GZW087 could be transferred into the backcross generations. 【Conclusion】 Al-tolerance is significantly different among rice varieties. There are abundant Al-tolerance accessions in O.rufipogon in Gaozhou. It has layed an important material foundations for Al-tolerance gene mapping and innovation of rice germplasms in future.

    Trends in Genetic Diversity Among Widely used Inbreds from 1991 to 2001 in China and Application of Three Major Germplasm Groups in Maize Breeding
    MENG Yi-jiang,YAN Jian-bing,TENG Wen-tao,LI Jian-sheng
    Scientia Agricultura Sinica. 2010, 43(4):  670-679 .  doi:10.3864/j.issn.0578-1752.2010.04.002
    Abstract ( 882 )   PDF (461KB) ( 801 )   Save
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    【Objective】 To in vestigate the trends in genetic diversity among widely used inbreds from 1991 to 2001 in China and to compare genetic variation among three major germplasm groups. 【Method】 In this paper, 88 inbreds of 66 maize hybrids which widely used commercially in 1991 through 2001 were used to analyze the changing trends of the genetic base with 111 SSR markers. 【Result】 Firstly, 659 SSR alleles were detected in 66 hybrids with the average of 5.95 per locus. Nei’s genetic diversity index of the widely extended hybrids during the past decade was increased from 0.67 to 0.69 and the allele number increased from 603 to 653. Only 0.9% absent alleles but 8.5% new alleles were detected by comparing the hybrids in 2001 with those released in 1991. Secondly, there were 583 alleles detected with 111 SSR markers in 39 inbreds including 16 from SPT group, 15 from Reid and 8 from Lancaster. Of which the alleles detected in SPT group were the most and took the percentage of 77.4%, Reid and Lancaster groups were 61.5% and 60%, respectively. The alleles frequency difference between Reid and SPT, Lancaster and SPT was both at about 32%, but the frequency difference between Reid and Lancaster was only 25%. Most of the special alleles existed in SPT group (24%), and Reid and Lancaster groups provided fewer (7.9% and 7.3%, respectively). 【Conclusion】 With the introduction of new germplasm and improvement of the old germplasm, the genetic diversity of maize hybrids was not decreased but increased to some extent. There are many unique alleles in local germplasms which maybe become the genetic base to produce elite hybrids when crosses with those abroad. So it is necessary to pay attention to the improvement and utilization of domestic germplasm.

    Study on Innovation and Application of Highly-Male-Sterile Line with High Outcrossing Rate in Millet
    WANG Yu-wen,LI Hui-xia,TIAN Gang,SHI Qin-xiang
    Scientia Agricultura Sinica. 2010, 43(4):  680-689 .  doi:10.3864/j.issn.0578-1752.2010.04.003
    Abstract ( 1088 )   PDF (291KB) ( 571 )   Save
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    【Objective】 Elite cross combinations were bred using highly-male-sterile line with high outcrossing rate and herbicide-resistant restorer line. By this, two-line system hybrid millet could be used in millet production. 【Method】 Improved existing male sterile lines and restorer lines which suited breeding aim were bred by pedigree method. 【Result】 Four highly-male-sterile-lines with high outcrossing rate and fine agronomic traits named Gao117,Gao146,Gao229, and Gao236 were selected. Herbicide-resistant restorer lines with high combining ability like K103, etc.were bred. A set of technical system of breeding two-line system hybrid was found. The first millet hybrid named Changzagu No.2 with herbicide-resistance was bred which suits to late maturing area in China. 【Conclusion】 The puzzle about high-yielding reproduction of male sterile lines and high-yielding seed reproduction of hybrid were solved by having highly-male-sterile lines with high- outcrossing rate.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
    Influence of Silicon on Rice Growth, Resistance to Bacterial Blight and Activity of Pathogenesis-Related Proteins
    XUE Gao-feng,SUN Wan-chun,SONG A-lin,LI Zhao-jun,FAN Fen-liang,LIANG Yong-chao
    Scientia Agricultura Sinica. 2010, 43(4):  690-697 .  doi:10.3864/j.issn.0578-1752.2010.04.004
    Abstract ( 1022 )   PDF (371KB) ( 1020 )   Save
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    【Objective】 The influences of silicon (Si) on rice growth and the activity of pathogenesis-related proteins were investigated to link roles of Si with Xoo resistance in rice. 【Method】 An Xoo-susceptible rice variety (Oryza sativa L. cv. Nipponbare) was grown hydroponically to study the effect of different Si application methods on dry weight of plants with or without inoculation, and the effect of Si addition or not on key enzyme activities and the resistance to Xoo after inoculation. 【Result】 The results showed that shoot and root dry weight were significantly decreased by inoculation of Xoo strain. The total dry weight and Si content in rice were increased significantly after silicon addition. The severity index of the infected plants treated with silicon was decreased by 11.83%-52.12% compared to the control, and the relative immunization efficiency reached 16.55%-75.82%. The activities of β-1,3-glucanase, exochitinase and endochitinase were all quickly increased after inoculation with Xoo strain. The β-1,3-glucanase activity in rice plants supplied with silicon was significantly higher than that in plants deprived of silicon during the eight days after inoculation, and reached the maximum on the eighth day after inoculation with Xoo strain. The exochitinase and endochitinase activities of leaves in silicon-fed plants evidently increased throughout the experimental period. 【Conclusion】 Silicon application could facilitate the rice growth, enhance the enzyme activity of β-1,3-glucanase, endochitinase and exochitinase, reduce severity index, significantly alleviate the damage of Xoo to rice and attain controlling efficacy.

    Glyphosate and Post-Drought Rewatering on Protective Enzyme Activities and Membrane Lipid Peroxidation in Leaves of Glyphosate-Resistant Soybean [Glycine max (L.) Merr.] Seedlings

    YUAN Xiang-yang,GUO Ping-yi,ZHANG Li-guang,WANG Xin,ZHAO Rui,GUO Xiu,SONG Xi-e
    Scientia Agricultura Sinica. 2010, 43(4):  698-705 .  doi:10.3864/j.issn.0578-1752.2010.04.005
    Abstract ( 951 )   PDF (410KB) ( 1016 )   Save
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    【Objective】 The study was performed to explore glyphosate and post-drought rewatering on protective enzyme activities and membrane lipid peroxidation in leaves of glyphoste-resistant soybean seedlings (RR1). 【Method】 Through pot experiment, water stress and glyphosate treatments were conducted at three-trifoliolate leaf stage. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities, and malondialdehyde (MDA) content and relative conductivity (EL) of RR1 were analyzed. 【Result】 In normal water condition, glyphosate increased SOD, POD, and CAT activities, MDA content, and EL of RR1, and which increased with increasing of glyphosate dosage and prolonged time in the first 5 days after glyphosate treatment. Seventeen days later, these indicators declined to some extent. In drought condition, SOD, POD, and CAT activities of RR1 treated with higher glyphosate dosages increased first and then reduced, and that treated with lower glyphosate dosages increased with prolonged stress time. However, MDA content and EL of RR1 treated with each glyphosate dosage increased to the largest on the 5th day, and declined 12 days after rewatering. The SOD, POD, and CAT activities, MDA content and EL of RR1 treated with glyphosate in drought condition were higher than that in normal water condition. 【Conclusion】 In normal water condition, the injury of RR1 caused by glyphosate could be eased through a period of growth and development. The reasons which drought stress aggravated the injury of RR1 caused by glyphosate were metabolic imbalance of reactive oxygen species, changes in protective enzyme activities and increased in the plasma membrane peroxidation. Rewatering after short-term drought stress could enhance the drought–resistant or stress-adaptive ability of the cell membrane.

    PLANT PROTECTION
    QTL Mapping for Adult-Plant Resistance to Stripe Rust in Wheat Cultivar Chuanmai 107
    ZHU Hua-zhong,WANG Zhong-wei,WU Ling,Ravi P. SINGH,J. HUERTA-ESPINO,HE Zhong-hu, HU Jia,CHEN Fang,XIA Xian-chun
    Scientia Agricultura Sinica. 2010, 43(4):  706-712 .  doi:10.3864/j.issn.0578-1752.2010.04.006
    Abstract ( 1159 )   PDF (319KB) ( 685 )   Save
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    【Objective】 The aim of this study was to identify adult-plant resistance gene to stripe rust in wheat cultivar Chuanmai 107 and the closely linked molecular markers, for breeding wheat cultivars with durable resistance. 【Method】 A recombinant inbred line (RIL) population with 148 F5 lines generated from the cross between Chuanmai 107 and Avocet-YrA (highly susceptible) were planted, together with their parents, in Chengdu and Ya’an, China and Toluca, Mexico during 2006 and 2007 cropping seasons for evaluating disease severities. A total of 940 SSR markers were used to screen two parents and the resistant and susceptible bulks, and subsequently the polymorphic SSRs between two bulks were used for QTL mapping based on composite interval mapping method. 【Result】 A major QTL for adult-plant resistance to stripe rust was mapped on chromosome 1BL in the marker interval of Xcwem32–Xgwm818 with genetic distance of 3.9 cM. The QTL was tentatively designated QYr.saas-1BL. It presented resistance to yellow rust resistance in all the three environments and explained 19.3%, 16.9%, and 27.4% of phenotypic variation at Toluca, Chengdu, and Ya’an, respectively. 【Conclusion】 This major QTL is considered as a non-race-specific resistance locus in Chuanmai 107.

    Study on Inheritance and Molecular Makers of Sorghum Resistance to Head Smut Physiological Race 3
    ZOU Jian-qiu,LI Yue-ying,ZHU Kai,WANG Yan-qiu
    Scientia Agricultura Sinica. 2010, 43(4):  713-720 .  doi:10.3864/j.issn.0578-1752.2010.04.007
    Abstract ( 917 )   PDF (513KB) ( 617 )   Save
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    【Objective】 The objectives of the research are screening molecular markers of sorghum resistance gene to head smut physiological race 3 by using SSR. Once the molecular markers are found, it would become true to select resistant lines in the indoor laboratory, and the evaluation in the field may be neglected. 【Method】 Bulked segregation analysis (BSA) was applied in the study. Two segregation population, restorer line population (R population) 2381R/Aisi and maintainer line population (B population) Tx622B/7050B, were used in the research. 【Result】 The resistance to sorghum head smut physiological race 3 is a qualitative trait inheritance. It has a dominant genetic effect. F1 would be resistant, too, provided one of the parents is resistant, It is the first time getting two stable SSR markers which can be used as molecular markers of sorghum resistance genes to head smut physiological race 3, they are Xtxp13 and Xtxp145. Xtxp13 located in linkage group B, and Xtxp145 located in linkage group I. The recombination percentage between marker and resistant gene are 9.6% and 10.4%, respectively. The genetic distances to resistant gene are 9.6 cM and 10.4 cM, respectively. 【Conclusion】 The resistance to sorghum head smut physiological race 3 may be controlled by two mutual independent nonallelic genes, and there is interaction between them. It is found that molecular markers are easier to find in B population than R population during the screening of SSR markers. It may show the different resistance mechanism between restorer line and maintainer line.

    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Effects of Antibiotics Oxytetracycline on Soil Enzyme Activities and Microbial Biomass in Wheat Rhizosphere
    YAO Jian-hua,NIU De-kui,LI Zhao-jun,LIANG Yong-chao,ZHANG Shu-qing
    Scientia Agricultura Sinica. 2010, 43(4):  721-728 .  doi:10.3864/j.issn.0578-1752.2010.04.008
    Abstract ( 858 )   PDF (495KB) ( 1947 )   Save
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    【Objective】 The objective of the experiment is to illustrate the microecological effects of the antibiotic oxytetracycline in wheat rhizosphere, 【Method】 Effects of oxytetracycline (OTC), a tetracycline, on microbial biomass and activities of soil enzymes such as urease, sucrase, phosphatase, hydrogen peroxidase in rhizosphere of wheat such as OTC resistant variety Yannong 21 and OTC sensitive Heyou 1, were studied in the present paper through rhizobox cultural method. 【Result】 The results showed that OTC significantly decreased activities of urease, sucrase (except for root zone), phosphatase, and hydrogen peroxidase in rhizosphere of Heyou 1, however the similar phenomena were only observed in root zone, some near root zone and far root zone of Yannong 21. OTC significantly increased microbial biomass nitrogen and its effects increased with the increase of distance from root surface. In terms of wheat cultivar, the effects on Yannong 21 were stronger than on Heyou 1. OTC significantly decreased microbial biomass and Cmin/Nmin and its effects decreased with the increase of distance from root surface. In terms of wheat cultivar, the effects on Yannong 21 were weaker than on Heyou 1. 【Conclusion】 Microbial activities biomass and soil enzyme activities in wheat rhizosphere could be significantly affected by OTC. For example, in terms of soil enzyme activities, the effects of OTC on OTC-resistant wheat cultivars are weaker than those on OTC-sensitive wheat cultivars.

    Effect of Potassium on Ultrastructure of Maize Stalk Pith and Young Root and Their Relation to Resistance to Stalk Rot
    LI Wen-juan,HE Ping,JIN Ji-yun
    Scientia Agricultura Sinica. 2010, 43(4):  729-736 .  doi:10.3864/j.issn.0578-1752.2010.04.009
    Abstract ( 965 )   PDF (1026KB) ( 877 )   Save
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    【Objective】 The objective of the experiment is to study the mechanism of potassium application on improvement of maize resistance to stalk rot at cell level. 【Method】 Scanning electron microscope and transmission electron microscope were used to observe the effect of K on the ultrastructure of maize stalk pith tissue and young root tip cell influenced by K and pathogen. 【Result】 In K deficient treatment, parenchyma cells of stalk pith had abnormity structure and the cell wall between upper and lower adjacent cell was broken, resulting in the loss of connections between vascular cells and bad supporting capacity. In addition, improved K nutrition also helped in keeping a quite tight arrangement of root cell with thick cell wall, prevented the invading of pathogen effectively. Moreover, K treated root cell had abundant golgi apparatus, which could excrete large amount of secretions to degrade mycelium. Papillary and highly electronic intensity dot were accumulated in the invading point to prevent the development of the mycelium. 【Conclusion】 Improved K nutrition could increase the resistant ability of maize plant to stalk rot, through keeping cell structure stability and preventing the expansion of intracellular space to reduce the chances of pathogen invasions; through reinforcing cell wall and formation intercellular and intracellular material to restrict pathogen further development in host cell.

    Spatial Variability and Influencing Factors of the Concentrations of Cu, Zn, and Cr in Cropland Soil on County Scales
    PANG Su,LI Ting-xuan,WANG Yong-dong,YU Hai-ying,GUO Qi-ling,CHEN Dong-ming
    Scientia Agricultura Sinica. 2010, 43(4):  737-743 .  doi:10.3864/j.issn.0578-1752.2010.04.010
    Abstract ( 936 )   PDF (378KB) ( 864 )   Save
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    【Objective】 Studies on the spatial variability and influencing factors of heavy metals can provide useful informations for the protection of environmental quality of cropland. 【Method】 Geostatistics combined with GIS were used for the analysis of the spatial structral, spatial distribution and influencing factors of copper (Cu), zinc (Zn), and chromium (Cr) concentrations in cropland soil in Shuangliu county, Sichuan province, China. 【Result】 The concentrations of Cu, Zn and Cr in cropland soil belonged to moderate variability, the maximum value and minimum value of the three heavy metals were obviously different. The spatially dependent ranges of concentrations of Cu, Zn, and Cr in soil were 28 281, 45 613, and 45 892 m, respectively. The concentrations of Cu, Zn, and Cr in soil had a moderate spatial dependence, and their spatial variability was caused by structural factors and random factors. 【Conclusion】 The ordinary Kriging interpolation showed that the spatial distribution trends of concentrations of Cu, Zn, and Cr in soil were quite similar. The regions with high concentrations of Cu, Zn, and Cr in soil were mainly distributed in the northwet part of Shuangliu. The results of influencing factors showed that the concentration of Cu in cropland soil was very significantly different among different terrain conditions. Soil parental materials was an important factor affecting spatial variability of the concentration of Cu and Zn. The organic fertilizer application rate was the important factor which affected spatial variability of the concentration of Cu, Zn, and Cr in cropland soil. The influence degree of agricultural conditions and fertilizer application rate on spatial variability of the concentrations of Cu, Zn, and Cr in cropland soil was the highest in social economic conditions .

    Fate of Nitrogen-15 from Organic and Inorganic Sources in Rice-Wheat Rotation Cropping System
    CHEN Yi,WU Chun-yan,TANG Xu,YANG Sheng-mao,WANG Jia-yu
    Scientia Agricultura Sinica. 2010, 43(4):  744-752 .  doi:10.3864/j.issn.0578-1752.2010.04.011
    Abstract ( 1022 )   PDF (297KB) ( 963 )   Save
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    【Objective】 Among the various factors that affect crop yield, N availability is one of the most important limiting factors impeding crop yield increase. 【Method】 In this study, the recovery of a single application of 15N-labeled fertilizer or residues in rice-wheat cropping system was determined for up to 5/6 consecutive growing seasons. The crop residues from the previous season were either incorporated or removed as two different treatments. 【Result】 Results showed that, on average, 17.17% (16.55%-17.79%) of crop-N was derived from N fertilizer during the first growing season, suggesting that approximately 80% of crop N was not directly from the N fertilizer. When 15N-labeled residues were applied, 4.48% of the crop-N was derived from residues in the first growing season. Soil organic matter N contributed 82.83% of the N in the crop when 15N-fertilizer was applied or 87.99% when organic residues were applied. The average recovery of fertilizer-N and residue-N in the soil after the first growing season was 33.46% and 85.64%, respectively. There was a larger difference in the total 15N recovery in plant and soil when N was applied as fertilizer or residues. Incorporation of crop residues following the 15N-fertilizer application did not significantly promote 15N recovery in the crop or soil. On average, only additional 1.46% of N for the fertilizer-applied field or 5.97% of N in the residue-applied field was recovered by the crops during the 2nd and 3rd growing season. After 6 growing seasons, the total recoveries of 15N in crop and soil were approximately 64.38% for fertilizer-applied field and 79.11% for residue-applied field. Although fertilizer-N appeared to be more readily available to crops than residue-N, residue-N replenished soil N pool, especially N in soil organic matter, much more than fertilizer-N after 6 growing seasons. Therefore, residue-N is a better source for sustaining soil organic matter N content. 【Conclusion】 Results of experiment suggest that the long-term effects of fertilizer or residues in the crop and soil are different. However, there was a little difference between the practices of residue incorporation and residue removal following the N fertilizer application.

    Effect of Inoculation with Arbuscular Mycorrhizal Fungus on Nitrogen and Phosphorus Utilization in Upland Rice-Mungbean Intercropping System
    XIAO Tong-jian,YANG Qing-song,RAN wei,XU Guo-hua,SHEN Qi-rong
    Scientia Agricultura Sinica. 2010, 43(4):  753-760 .  doi:10.3864/j.issn.0578-1752.2010.04.012
    Abstract ( 888 )   PDF (266KB) ( 992 )   Save
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    【Objective】 The effect of Arbuscular mycorrhiza fungi (AMF) on plant growth and nutrient utilization in upland rice and mungbean intercropping system was studied. 【Method】 A pot experiment was conducted in greenhouse and AMF colonization rates of rice and mungbean’s root, plant nutrient content and the ability of nitrogen fixation, and the changes of nutrient content in soil were analyzed. 【Result】 The results of the experiment showed that the rate of AMF colonization of rice and mungbean’s root reached 14.47% and 92.2% in intercopping system, and increased by 4.11% and 11.95%, respectively, compared with that in monocropping system. At the same time the nirtrogen content in shoots and roots of mungbean and rice increased by 83.72% and 64.83%, 53.76% and 41.29%, and the content of iron in shoots and roots of mungbean increased by 223.08% and 60.19%, repectively. For the intercropping crops inoculated with AMF, the biomass of mungbean increased by 288.8%, whereas the rice biomass had no significant change in all treatments with or without inoculation of AMF, the number and dry weight of nodules also significantly increased when mungbean inrercropped with rice and inoculated with AMF. In contrast to that of non-inoculation with AMF and monocropping, the content of nitrogen, phosphorus and iron in intercropped mungbean’s nodules with inoculation increased by 80.14%, 69.54%, 39.62%, respectively. Additionally, intercropping with AMF inoculation significantly increased soil nitrogen content, but reduced soil phosphorus content. 【Conclusion】 It is concluded that nitrogen, phosphorus and iron content, the numbers and dry weight of mungbean nodules increased, and the growth of mungbean was improved in upland rice-mungbean intercropping system inoculated with AMF .

    HORTICULTURE

    Identification and Effect Analysis of QTLs Conferring Salt Tolerance at Seedling Stage Using Solanum pennellii LA716 Introgression Lines in Tomato

    YU Qing-hui,LIU Lei,WANG Bai-ke,YANG Sheng-bao,YANG Tao,LI Jun-ming,HOU Xi-lin
    Scientia Agricultura Sinica. 2010, 43(4):  761-768 .  doi:10.3864/j.issn.0578-1752.2010.04.013
    Abstract ( 999 )   PDF (285KB) ( 2726 )   Save
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    【Objective】 The introgression line population, which was developed from a salt-sensitive parent S. lycopersicum M82 and a salt-tolerance wild species S. pennellii LA716, was employed in this paper to identify QTLs conferring salt tolerance at the seedling stage. Meanwhile the primary genetic effect and interaction of some QTLs were also analyzed. 【Method】 Seedlings with four fully developed true leaves were transferred into hydroponic tanks containing 50 L of half-strength modified Hoagland solution. The same amount of salts was added every day to achieve a final concentration of 700 mmol?L-1NaCl + 70 mmol?L-1 CaCl2. After the final salt concentration was reached, the plants were evaluated using a scale of 0 to 10. Dunnett test was used for ANOVA analysis. 【Result】 Seven unambiguous QTLs (Stq2a, Stq2b, Stq6a, Stq7a, Stq7b, Stq8 and Stq10) located respectively on chromosome 2, 6, 7, 8 and 10 were identified, which were responsible for controlling salt tolerance at seedling stage and derived from wild relative S. pennellii LA716. The survival percentage increased by 18.9%-83.8% as compared to the control M82 under this salt stress. QTL possibly involved in IL6-4 and IL6-3 needed to be confirmed in the further experiments. Genetic analysis of some QTLs showed a significant dominant effect with the exception of Stq6b. The interaction of QTLs presented a typically less-than-additive but two QTLs located on chromosome 7 gave a reduced effect. 【Conclusion】 This is the first report to identify QTLs conferring salt tolerance from wild species S. pennellii LA716 at the seedling stage. These identified QTLs would provide a sound base for tomato breeding with salt tolerance.

    The Structure Characteristics of Arthropod Community in Plots of Pear Orchard Intercropped with Different Aromatic Plants
    SONG Bei-zhou,WANG Mei-chao,KONG Yun,YAO Yun-cong,WU Hong-ying,HU Jing-hui,QI Li-ping,BI Ning-ning
    Scientia Agricultura Sinica. 2010, 43(4):  769-779 .  doi:10.3864/j.issn.0578-1752.2010.04.014
    Abstract ( 927 )   PDF (414KB) ( 845 )   Save
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    【Objective】 This paper was aimed to discuss the effects of intercropping aromatic plants on the arthropod community structure in the orchard of pear ‘Huangjin’.【Method】Mentha haplocalyx (Briq.var.piperascens Malinvaud) (Tr1), Tagetes patula L.(Tr2), Ocimum basilicum L. (Tr3) and natural sward (Tr4) intercropped in pear orchard were taken as four treatments and clean tillage (Tr5,CK) as control. The characteristics of arthropod community structure in different intercropping plots were surveyed and analyzed systematicly in the annual growth cycle of pear. 【Result】 The results showed that the characteristics of arthropod community structure were different in different aromatic plants intercropping plots, and no significant difference was found in the family number of arthropod community. However, there was a significant difference in the individual number of arthropod community with an increasing order followed by intercropping Tagetes patula L.(Tr2) and Mentha haplocalyx (Briq.var.piperascens Malinvaud) (Tr1)<Ocimum basilicum L. (Tr3)<natural grass (Tr4)<mono-cultivated pear (Tr5,CK) (P<0.01).The characteristics of different functional groups were different in five intercropping plots. Under the conditions of intercropping aromatic plants in pear orchard, the total family and individual number of these functional groups exhibited significant differences as well as the ratio of predators to pests (P<0.05).The family number of arthropod community showed no significant difference in the same group, but the individuals number, Simpon index, diversity index and evenness were converse (P<0.05). The individual number, Simpon index, diversity index and evenness of arthropod community were different at the growth stage of pear in five intercropping plots. Intercropping aromatic plants in pear orchard could significantly reduce the individual number of arthropod community, and the best effect was observed in the pear fruit enlargement period. 【Conclusion】 Therefore, intercropping aromatic plants in orchard have a certain degrees of benefit in to control the arthropod community structure through reducing pest number and increasing natural enemy number in pear orchard.

    A Spectrum Based Models for Monitoring Leaf Potassium Content of Citrus sinensis (L)cv. Jincheng Orange

    YI Shi-lai,DENG Lie,HE Shao-lan,ZHENG Yong-qiang,MAO Sha-sha
    Scientia Agricultura Sinica. 2010, 43(4):  780-786 .  doi:10.3864/j.issn.0578-1752.2010.04.015
    Abstract ( 898 )   PDF (273KB) ( 630 )   Save
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    【Objective & Method】 Field experiments were conducted to assess the potassium content in leaves of Citrus sinensis (L)cv. Peng’an 100 Jincheng orange by using VIS/NIRS spectral method. Before calibration, principal component analysis (PCA) and partial least square (PLS) techniques were applied in data pre-processing. 【Result】 The order of leaf reflective spectrum intensity was K3>K0>K1>K2>K4 in the visible near-infrared range of 400-1000 nm, where the K fertilizer usage of K0, K1, K2, K3, K4 treatments were 0 g, 30 g, 75 g, 90 g, 120 g(k2O/plant/year) , respectively. The calibration models of potassium content were built by applying PLS and internal cross-validation test method and through processing the reflectance spectrum, the first derivatives, the second derivatives and the reciprocal logarithm spectrum of Peng’an 100 Jincheng leaves using multiplicative scatter correction(MSC). The results showed that the model of the second derivatives calibration of reflectance spectrum had the best predicative ability, the highest correlation coefficient, the smallest root mean square error of predictation (RMSEP) and the smallest absolute bias at 0.82, 0.0038 and -2.34E-05, respectively. 【Conclusion】 The second derivatives of reflectance spectrum could be used to predict the potassium content in Peng’an 100 Jincheng leaves. And 477-515 nm, 541-588 nm, 632-669 nm, 701-718 nm and 754-794 nm were the characteristics of wavelengths of second derivatives of reflectance spectrum predicting potassium content in summer shoot leaves of of Peng’an 100 Jincheng.

    Study on the NaCl Tolerance in Five Plant Species from Dendranthema and Its Relatives
    GUAN Zhi-yong,CHEN Fa-di,TENG Nian-jun,CHEN Su-mei,LIU Pu-sheng
    Scientia Agricultura Sinica. 2010, 43(4):  787-794 .  doi:10.3864/j.issn.0578-1752.2010.04.016
    Abstract ( 932 )   PDF (498KB) ( 820 )   Save
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    【Objective】 In order to establish the indicators for salt tolerance evaluation and screening, and to lay a foundation for further large scale salt tolerance evaluation of related species of Dendranthema and to breed salt tolerant cultivars, salt tolerance of five related species of Dendranthema, i.e., Dendranthema crassum, D. ornatum, D. nankingense, Ajania pacificum and Artemisia japonica, were compared. 【Method】 Five related species of Dendranthema were cultured in Hogland solution supplied with NaCl at different concentrations of 0, 40, 80,120 and 160 mmol?L-1, respectively. The effects of NaCl stress on the morphological characteristics, chlorophyll contents, proline content, malondialdehyde (MDA) content and photosynthetic gas exchange parameters of seedlings were investigated. The salt tolerance of five species was evaluated based on above parameters.【Result】 The results showed that under salt stress, Chl a, Chl b and Chl (a+b) content decreased in five species. The proline content and MDA content increased under salt stress. However, the net photosynthetic rate, stomatal conductance and transpiration rate declined significantly, while intercellular CO2 concentration increased in all the five species under salt stress. The injured leaf area per plant was closely correlated with chlorophyll contents, net photosynthetic rate and MDA content. The rate of injured leaf area per plant, net photosynthetic rate, Chl a, Chl (a+b) contents, and MDA content which closely related to the salt tolerance were screened upon principal component analysis.【Conclusion】Dendranthema ornatum and D.nankingense are sensitive to salt stress, while Ajania pacificum, Artemisia japonica and D. crassum are salt tolerant ones. Compared to salt tolerant species, the salt sensitive species showed much decline in chlorophyll contents and net photosynthetic rate, showed less proline accumulation and a higher MDA content. Correlation and principal component analysis suggested that the chlorophyll contents, net photosynthetic rate and MDA content maybe the most effective physiological indexes for evaluation of salt tolerance of related species of Dendranthema and its relatives.

    STORAGE·FRESH-KEEPING·PROCESSING
    Effects of Different Water Addition Levels on Chinese White Noodle Quality
    YE Yi-li,HE Zhong-hu,ZHANG Yan
    Scientia Agricultura Sinica. 2010, 43(4):  795-804 .  doi:10.3864/j.issn.0578-1752.2010.04.017
    Abstract ( 1076 )   PDF (309KB) ( 808 )   Save
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    【Objective】 Water addition is an important factor influencing noodle preparation, therefore it is crucial to investigate the effects of water addition on noodle quality. 【Method】 Experiment I with 24 wheat cultivars from Shandong and He’nan at three different water addition levels (34%, 35% and 36%), and experiment II with five commercial wheat flours at five water addition levels (34%, 35%, 36%, 37% and 38%) were used to investigate the effects of water addition levels on Chinese white noodle (CWN) quality. 【Result】 Brightness (L* value) of 0h raw noodle sheets was decreased and yellowness (b* value) of 0h raw noodle sheets was increased significantly with increasing water addition. For the flour made from cultivars, when water addition was increased from 34% to 36%, brightness (L* value) of 24 h raw noodle sheets increased firstly and then reduced, yellowness (b* value) decreased firstly and then increased and redness (a* value) was decreased significantly. Brightness (L* value) was the lowest and yellowness (b* value) was the highest at 35% water addition. For commercial flour, when water addition was increased from 34% to 38%, brightness (L* value) of 24 h raw noodle sheets increased firstly and then decreased, yellowness (b* value) decreased firstly and then increased and redness (a* value) was changed insignificantly. Brightness (L* value) was the lowest and yellowness (b* value) was the highest at 36% water addition, however, effects of water addition on color of cooked noodles were not significant. The hardness, viscoelasticity, smoothness and total score were significantly increased with increasing water addition, and increase water addition to a certain level could improve noodle quality significantly. 【Conclusion】 The optimum water addition for soft and mixed wheat cultivars was 35% and for hard wheat cultivar was 36%. Genotype with 1BL/1RS translocation enhanced water absorption, but reduced water retention ability of wheat flour, thus the dough stickiness was increased. The pastiness of dough was more apparent with increasing water addition, which brought inconvenience to practical operation. It was suggested that water addition should be reduced by 1% for 1BL/1RS wheat cultivar based on optimum water addition. The optimum water addition for CWN laboratory preparation from commercial wheat flour was 37%.

    Effect of Moisture Content on Quality of Texturization of Product Extruded from Soy Protein Isolate
    CHEN Feng-liang,WEI Yi-min,ZHANG Bo
    Scientia Agricultura Sinica. 2010, 43(4):  805-811 .  doi:10.3864/j.issn.0578-1752.2010.04.018
    Abstract ( 864 )   PDF (531KB) ( 751 )   Save
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    【Objective】 The effect of feed moisture content on quality of texturization of extruded soybean protein was investigated in order to provide a theoretical basis for producing of textured meat analogue by extrusion technology. 【Method】Soybean protein isolate (SPI) with moisture content at 28%-60% were processed using a DSE-25 pilot-scale twin-screw extruder. The protein solubility of both raw material and extrudates from various treatments were analyzed based on 8 different buffer solutions, which contained only phosphate (P); two reagents, i.e. sodium dodecyl sulfate (P+S), urea (P+U) and 2-mercaptoethanol (P+M); three reagents, i.e. (P+S+U), (P+U+M) and (P+M+S); four reagents, i.e. (P+S+U+M). The chemical cross-linkage of textured soybean protein was further analyzed based on the solubility. The distribution of molecular weight and degree of polymerization were investigated by using SDS-PAGE electrophoresis. The quality of texturization of extrudate from soybean protein was characterized by degree of texturization measurement and scanning electronic microscopy (SEM). 【Result】 With moisture content increasing, the solubility of extrudates in P decreased significantly (P<0.05), the solubility in P+S+M and P+M+U increased dramatically (P<0.05), the degree of forming macromolecule polymer decreased, the fibrous and porous structure in extrudate appeared, and the degree of texturization increased significantly. 【Conclusion】 Increasing moisture content could promote the alignment of soybean globulin, increase the interactions between disulfide bonds and hydrogen bond, disulfide bonds and hydrophobic bonds dramatically, decrease the degree of polymerization, further enhance the quality of texturization in extruded soybean protein.

    Effect of Chitosan on Salicylic Acid and Active Oxygen Metabolism of Navel Orange Fruit
    DENG Yu-yan,MING Jian,ZHANG Zhao-qi,ZENG Kai-fang
    Scientia Agricultura Sinica. 2010, 43(4):  812-820 .  doi:10.3864/j.issn.0578-1752.2010.04.019
    Abstract ( 1096 )   PDF (393KB) ( 1090 )   Save
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    【Objective】 The effects of chitosan treatment on the disease resistance, the content of salicylic acid (SA) and the active oxygen metabolism of navel orange fruit (Citrus sinensis L. Osbeck) cv. Newhall were investigated 【Method】 After harvest, navel orange fruits were treated with 2% chitosan solution for 1 min in different days. The influences of chitosan treatment on the disease resistance of navel orange to Penicillium italicum, the content of SA content and materials related to active oxygen metabolism in navel orange’s peel were detected. 【Result】 The inoculated disease incidence and the expansion of lesion diameter of navel orange were significantly reduced by 2% in chitosan treatment (P<0.01), and fruits dipped into 2% chitosan 2 days before inoculation shown the most significant effect. Two percent treatment effectively enhanced the activities of peroxidase (POD), glutathione reductase (GR) and the levels of free SA and hydrogen peroxide (H2O2), while inhibited the activities of catalase (CAT), ascorbate peroxidase (APX) and the decreased the ascorbate (AsA) content. Besides, the accumulation of glutathione (GSH) was sharply induced in the early time after treatment. 【Conclusion】 Two percent chitosan treatment could induce the disease resistance of Navel orange to the infection of Penicillium italicum, and these resistance reactions relate to the regulation of the content of SA, the levels of active oxygen metabolism and the changes of antioxidant enzymes.

    ANIMAL SCIENCE·RESOURCE INSECT
    Study on the Induction of DNA Damage in Hepatic Cells by Aflatoxin B1 in Ducklings
    WANG Rui-guo,HOU Shui-sheng,SU Xiao-ou
    Scientia Agricultura Sinica. 2010, 43(4):  821-827 .  doi:10.3864/j.issn.0578-1752.2010.04.020
    Abstract ( 894 )   PDF (335KB) ( 643 )   Save
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    【Objective】 Aflatoxin B1 (AFB1) is one of the most potent naturally occurring carcinogens and classified as a group I carcinogen. This study has two objectives: (1) To evaluate the effect of 3, 30, 300 μg?kg-1 BW on DNA damage in hepatic cells in Beijing ducklings at different times after administrated by oral feeding. (2) To study the relationship between the level of DNA damage and concentration of AFB1, time after exposed to AFB1, to provide research model for genotoxicity of AFB1. 【Method】 Ninety-six male Beijing ducklings were randomly divided into 16 groups with 6 ducklings in each one. Each duckling in group 1 was administered orally with 1 mL 25% DMSO solution as control, and low (group 2 to 6), moderate (group 7 to 11), high (group 12 to 16) AFB1 exposure groups were given 1 mL with 0.25, 2.5, 25 μg?mL-1 25% DMSO solution by gavage, respectively. The modified comet assay was performed at 1 h in control group, and at 1, 2, 8, 24, 48 h in AFB1 exposure groups on hepatic cells after AFB1 administration. 【Result】 The results showed that ducklings were sensitive to hepatic DNA damage induced by AFB1, and the level of DNA damage was associated with concentration and time after AFB1 intake. DNA strand breaks reached peak value at 2 h of exposure, and all different doses of AFB1 could induce significantly higher tail length, tail DNA%, tail moment, Olive tail moment than in control group (P<0.05). With AFB1 concentration increasing, the duration of DNA damage prolonged, and under the condition of the same treatment time, the DNA damage was more serious. 【Conclusion】 From the results, three conclusions were drawn as follows: (1) Ducklings are sensitive to DNA damage in live cells induced by AFB1, and low level (3 μg?kg-1 BW) exposure of AFB1 can induce significantly hepatic DNA damage in ducklings. (2) The level of DNA damage reached the peak at 2 h after a single oral administration of AFB1, and at this time the dose-effect relationship was obvious in this experiment. (3) Duckling is an ideal animal model for study of AFB1 genotoxicity, and comet assay is an useful tool for monitoring the hepatic DNA damage induced by AFB1 in ducklings.

    VETERINARY SCIENCE
    Heterogeneity and Secondary Structure Analysis of 3′ Untranslated Region in Attenuated Classical Swine Fever Viruses
    FAN Yun-feng,ZHAO Qi-zu,ZHAO Yun,ZOU Xing-qi,ZHANG Zhong-qiu,WANG Qin,NING Yi-bao
    Scientia Agricultura Sinica. 2010, 43(4):  828-834 .  doi:10.3864/j.issn.0578-1752.2010.04.021
    Abstract ( 880 )   PDF (655KB) ( 558 )   Save
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    【Objective】 The 3′-UTR of CSFV was sequenced and analyzed, for the understanding of the influence of 3′-UTR on replication, multiplication, and virulence of virus. 【Method】 The 3′-UTR of CSFV Thiverval, HCLV and Shimen strains were amplified and sequenced using RT-PCR method. The alignment was carried out using DNAstar and Sequencher software. The RNA secondary structures of different 3′-UTR were predicted using RNAstructure software. 【Result】 The longest 3′-UTR of Thiverval strain was 259 base pairs (bp) with a 32 nt insertion. The shortest 3′-UTR had only 233 bp with a 6 nt insertion. The longest 3′-UTR of HCLV strain was 244 bp with a 17 nt insertion and the shortest 3′-UTR was 235 bp with a 8 nt insertion. At the same time, to maintain the similar 3′-UTR structure, the free energy of vaccine strain is higher than that of virulent strain, and the free energy in 3′-UTR of vaccine strain is rising with length of insert. 【Conclusion】 The 3′-UTR of CSFV vaccine strains have two variable regions. The insertion of attenuated Thiverval and HCLV strains 3′-UTR represent distinct heterogeneity in different clones of the same sample. The insertion of vaccine strains 3′-UTR could affect the stability of the secondary structure, which might be a reason for the attenuated virulence.

    Cloning, Expression and Immunoprotection of the Novel Gene SjPRMT1 of Schistosoma japonicum
    HAN Hong-xiao,PENG Jin-biao,HONG Yang,WANG Xin-zhi,SHI Yao-jun,FU Zhi-qiang,LIU Jin-ming,CHENG Guo-feng,LI Xiang-rui,LIN Jiao-jiao
    Scientia Agricultura Sinica. 2010, 43(4):  835-841 .  doi:10.3864/j.issn.0578-1752.2010.04.022
    Abstract ( 895 )   PDF (395KB) ( 529 )   Save
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    【Objective】 The present study was intend to clone a full length cDNA encoding protein arginine methyltransferase 1 in Schistosoma japonicum, and further access its immunoprotection in mice for schistosomiasis. 【Method】 A full-length cDNA clone encoding a protein arginine methyltransferase was obtained from schistosomula cDNA enriched library, named S.jPRMT1 based on bioinformatics analysis. The expression profiles of SjPRMT1 was determined by real-time PCR using the template cDNAs isolated from 7, 13, 18, 23, 32 and 42 days parasites. The open reading frame was then subcloned into a pET28a(+) vector and transformed into competent E.coil/BL21. The recombinant protein was purified and then the immune characters of antigen were accessed by Western blotting. 【Result】 Bioinformatics analysis indicated that the ORF of S.jPRMT1 is 660 base pairs, which is encoding 219 amino acids. Real-time PCR analysis revealed that there is a highest expression in 18 days schistosomula, and slightly lower in 13 days and 23 days parasites, suggesting that S.jPRMT1 has highly expression in schistosomula stage. The recombinant protein showed a good ability to induce antibodies in mice as examined by ELISA. Animal experiment indicated that the administration of recombinant PRMT1 protein in mice resulted in worm burden reduced by 35.07% and egg burden reduced by 48.66%. 【Conclusion】 A full-length cDNA differently expression in schistosomula was obtained. Results demonstrated that the recombinant PRMT1 protein could induce partial protection against schistosomiasis in mice.

    Localization of Cytokines in Abomasum of Goats Immunized with Recombinant Galectins of Haemonchus Contortus
    ZHANG Li-wu,SUN Yan-ming,XU Li-xin,YAN Ruo-feng,LI Xiang-rui
    Scientia Agricultura Sinica. 2010, 43(4):  842-849 .  doi:10.3864/j.issn.0578-1752.2010.04.023
    Abstract ( 1024 )   PDF (655KB) ( 529 )   Save
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    【Objective】 Cytokines in abomasum of goats immunized with rHco-GAL-f/m were detected in this study. 【Method】 In situ hybridization was used to localize IL-4, IL-6, IL-1?, IL-2,IFN-γ and TNF-α mRNAs in abomasum of the negative control group (A), challenged control group (B), vaccinated-challenged group (C) and vaccinated-unchallenged group (D) goats immunized with rHco-GAL-f/m, and the numbers of cytokine mRNA+ cells in each group were also analyzed. 【Result】 No cytokines were found in the abomasum of group A goats and IL-4, IL-6, IL-1?, IL-2, IFN-γ and TNF-α were detected in the submucosa layer of abomasum of groups B, C and D goats. The difference of IL-4 and IL-6 mRNA+ cell numbers in groups B, C and D was significant (P<0.05) and group C was higher than that of groups B and D. The difference of IL-1?, IL-2 and, TNF-α mRNA+ cell numbers was also significant (P<0.05) among groups B,C and D, and group D was the highest. IFN-γ mRNA+ cells were not significantly different between groups B and C (P>0.05), but IFN-γ mRNA+ cells in group D was significantly different and was higher compared to groups B and C (P<0.05). 【Conclusion】 The findings indicated that the recombinant galectins of H. contortus are capable of inducing local immune responses in abomasum of goats.

    RESEARCH NOTES
    Activity and Types of Starch Debranching Enzyme in Wheat Cultivars Containing Different Starch Contents During the Grain Filling Period
    LIU Xia,TAN Sheng-bing,TIAN Ji-chun,WANG Xian-ze
    Scientia Agricultura Sinica. 2010, 43(4):  850-854 .  doi:10.3864/j.issn.0578-1752.2010.04.024
    Abstract ( 814 )   PDF (387KB) ( 549 )   Save
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    【Objective】 In order to provide a theoretical basis on studying the mechanism of starch debranching enzyme (DBE) further, activity differences and type of DBE during grain filling period of four wheat cultivars were studied. 【Method】Activity differences and type of DBE among Nuomai 1, Guandong 107, Jinan 16, and Lumai 21 were analyzed using native-PAGE and HPLC techniques. 【Result】 Changes of DBE activity of four cultivars had a single-peak curve, and the peak appeared in 14 d after anthesis. HPLC analysis showed that the activity of DBE to amylopectin was similar. There are two types of DBE in the wheat grains, one is isoamylase, and the other is limit dextrinase. 【Conclusion】 Though starch constitution of four cultivars is different, the DBE activity has a similar activity change of single-peak curve and the activity to amylopectin is similar in vitro.

    Breeding of Male Sterile Line of Aromatic Indica Rice with Yellow-Green Leaves Marker
    LIU Guo-min,GAO Bi-jun,WEN Shao-shan,JIAO Jun
    Scientia Agricultura Sinica. 2010, 43(4):  855-861 .  doi:10.3864/j.issn.0578-1752.2010.04.025
    Abstract ( 815 )   PDF (405KB) ( 747 )   Save
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    【Objective】 The applied CMS sterile line and maintainer line of aromatic indica rice with marker character was bred. 【Method】 The CMS sterile line of aromatic indica rice with marker character was bred by using general crossing and natural segregation mutation yellow-green leaves plant. 【Result】 The selected yellow-green leaves mutation male sterile line has yellow-green leaves from seedling stage to mature stage. It can be distinguished from the general leaves easily. No degeneration phenomenon in yellow was found. The aromatic plant lines identified by hot water method were selected as aromatic indica rice sterile lines with yellow-green leaves marker. Its plant height was 41.5-56.5 cm. Its leaves and glumes were yellow-green. Its leaf sheath, auricles and edge of leaves were pruple-red in color. Its tillering capacity was moderate. The panicle length of Huangbiao 3A was 24.9 cm. The spikelet number per panicle of it was 145. The cereal grain of it was long grain like a shuttle. The 1000-grain weight of it was 28 g. Its growing period was 85 d. The setting percentage of its maintainer line basal panicle was hight and seeds were full. The stigma of it was purple-black in color, bigger in size, and good in exsertion rate. When it was test crossed and general reciprocal crossed with others green rice plant, its F1 generation all appeared normal green. The average segregation rate of its F2 generation population was 2.92﹕1, 2.76﹕1, and 2.96﹕1, respectively. The segregation ratio accorded with 3﹕1 by χ2 test. It indicated that the yellow-green leaves were recessive inheritance and controlled by a pair of recessive genes. 【Conclusion】 The indica rice male sterile line with yellow-green leave marker had scents and a significant difference with general rice in leaf color. Its yellow-green leaf is controlled by a pair of recessive genes. Its label character yellow-green leaf is stabilization in heredity. When it is crossed with restoring lines, the general combining ability of F1 is evidence. It indicates that the sterile line is restored easily.

    Intraspecific Predation Between Stratiolaelaps scimitus and Hyposipis chianensis
    W

    WANG Zi-qing,LIU Yang-xi,CHEN Hong,FAN Qing-hai,LUO Jia
    Scientia Agricultura Sinica. 2010, 43(4):  862-867 .  doi:10.3864/j.issn.0578-1752.2010.04.026
    Abstract ( 867 )   PDF (233KB) ( 1029 )   Save
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    【Objective】 The characteristics of intraspecific predation between Stratiolaelaps scimitus and Hyposipis chianensis were investigated to provide knowledge of combined release of the two predatory mites. 【Method】 The intraspecific predation of S. scimitus and H. chianensis at different stages was tested with or without natural prey, Tyrophagus putrescentiae. The development of nymphs and fecundity of adult females of both predators was also studied. 【Result】 In the presence of natural prey, the intraspecific predation was rare at all stages of both predators. While in the absence of natural prey, the intraspecific predation occurred frequently. The predation level was correlated with the stages of both predators and prey. Nymphs of H. chianensis never preyed on larvae of S. scimitus. Preying on eggs and larvae of H. chianensis, 80% and 100% nymphs of S. scimitus could develop into adults and the developmental periods of nymphal mites were 7.88 d and 7.30 d, respectively. Fed on eggs of S. scimitus, only 30% of nymphs of H. chianensis could develop into adults. Adult females of both predators preying on each other laid significantly fewer eggs than those preying on T. putrescentiae, which showed the population of both predators couldn’t increase normally. 【Conclusion】 S. scimitus and H. chianensis were not suitable for each other as a prey, and they would avoid to prey on each other when suitable preys were available. Therefore, the two predator mites could be combinable released at the high population density of pests.

    Characteristics of Nitrogen Absorbed by Ericoid Mycorrhizal Fungi and Impact on Growth of Rhododendron fortunei
    YIN Li-juan,ZHANG Chun-ying,YANG Bing
    Scientia Agricultura Sinica. 2010, 43(4):  868-872 .  doi:10.3864/j.issn.0578-1752.2010.04.027
    Abstract ( 1080 )   PDF (212KB) ( 1290 )   Save
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    【Objective】 Research on the characteristics of ammonium, nitrate and organic nitrogen utilization by ericoid mycorrhizal fungi and impacts on growth in vitro of Rhododendron fortunei was carried out to determine the suitable nitrogen sources in ericoid mycorrhizal (ERM) fungal cultivation and test the effects of ERM on host plant growth in substrate with different nitrogen sources. 【Method】 Mycelial dry weight of ERM fungal strain in the different nitrogen source media was used as the index to assess nitrogen utilization. These ERM fungal strains were also inoculated on seedlings of Rhododendron fortunei on different nitrogen source substrates, and the effect of ERM fungi on the host plant was evaluated by dry weight of the seedlings. 【Result】 Nitrogen sources had a significant effect on fungus biomass. Fungal growth was the best on ammonium and nitrate, moderate on arginine and Bovine Serum Albumin (BSA), and poor on medium without nitrogen. Inoculated plants grew better than non-inoculated plants regardless of nitrogen sources, and grew best on BSA. 【Conclusion】 Ammonium and nitrate were suitable N source for the growth of the ERM strains. Inoculation with these ERM fungi increased the capacity of Rhododendron fortunei to utilize nitrogen source, especially nitrate and BSA nitrogen.

    Identification and Eukaryotic Expression of GSTe-3 Gene of Silkworm (Bombyx mori)
    PAN Min-hui,XU Yuan,YU Quan-you,LIU Jia,LIU Di,ZHAO Dan-hong,LU Cheng
    Scientia Agricultura Sinica. 2010, 43(4):  873-880 .  doi:10.3864/j.issn.0578-1752.2010.04.028
    Abstract ( 814 )   PDF (603KB) ( 797 )   Save
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    【Objective】 Glutathione S-transferases (GSTs) are a superfamily of multifunctional enzymes found in almost all living organisms. They play important roles in detoxification of endogenous and exogenous toxic substance. It will lay a foundation for the detoxification mechanism of silkworm to study on GSTs of Bombyx mori. 【Method】 BmGSTe3 gene was cloned and analyzed by bioinformation and molecular biology method. The expression of BmGSTe3 was analyzed in silkworm by RT-PCR. BmGSTe3 gene was eukaryotic expressed in sf9 cells by Bac-to-Bac Baculovirus Expression System. 【Result】 The BmGSTe3 is composed of 5 exons and 4 introns and its CDS length is 512 bp. BmGSTe3 contains 15 possible transcription regulatory elements in the upstream of 2 500 bp and two domains, which N-terminal domain is composed of 7 motifs, namely b-a-b-a-b-b-a, while C-terminal domain is composed of 5 ? helixs. BmGSTe3 has a conservative Ser catalyse site, belongs to Epsilon family members and express only in hemolymph and brain. BmGSTe3 protein has good GSTs enzyme activity. 【Conclusion】 BmGSTe3 belongs to Epsilon family members and its protein has good GSTs enzyme activity