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Table of Content

    10 June 2005, Volume 38 Issue 06
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES
    Comparative Studies on Genetic Diversities Between In-situ and Ex-situ Conserved Germplasm of Oryza rufipogon
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    Scientia Agricultura Sinica. 2005, 38(06):  1073-1079 . 
    Abstract ( 1317 )   PDF (363KB) ( 1030 )   Save
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    Ex-situ conservation of Oryza rufipogon genetic resources has been well done and about 6000 accessions were preserved in the National Genebank and vegetative nurseries. However, whether they could be representative for the whole genetic integrity of Oryza rufipogon has also been concerned. In this study, two populations with their in-situ and ex-situ conserved groups in Dongxiang County, Jiangxi Province, were selected to study the genetic diversity by using SSR. The results indicated that, the genetic diversity indices of in-situ and ex-situ conserved groups of Anjiashan population were 0.5000 and 0.3555, respectively. The genetic diversity index of ex-situ conserved group was only 71.1% of that of in-situ conserved group. Moreover, all ex-situ preserved samples were clustered together in the dendrogram and was one branch of the whole "tree". For Shuitaoshu population, the distance of genetic diversity index of in-situ group (0.4100) and that of ex-situ group (0.4577) was very small, and all ex-situ samples clustered together with in-situ samples. It seems that the ex-situ conserved group could be representative for the genetic diversity of the original population. However, six of the fourteen ex-situ samples were close to the samples with the successive numbers, meaning that about 42.9% ex-situ samples were redundant. Furthermore, genetic diversity study on the total samples of in-situ and ex-situ collections from above two sites also showed similar results with those of Anjiashan site. Based on the above results, it is concluded that the genetic diversities of ex-situ preserved groups used in this study can not be representative for the genetic diversities of the original populations, and thus referres that the genetic variation contained in the preserved O. rufipogon genetic resources in China is relatively low and there are some redundant samples in the genebanks. Therefore, re-collection of genetic resources of O. rufipogon and getting rid of the redundant samples based on evaluation are necessary.
    QTL Analysis of Some Agronomic Traits in Rice Under
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    Scientia Agricultura Sinica. 2005, 38(06):  1080-1087 . 
    Abstract ( 1302 )   PDF (481KB) ( 1228 )   Save
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    The culm length, panicle length, spikelets per panicle and panicle exsertion were evaluated by using F2:3 population including 200 lines, derived from a cross of indica and japonica Milyang23/Jileng1 under five different environments of Beijing (natural normal growing environment), Kunming (natural low temperature condition), Gongzhuling of China (cold water irrigation) and Chuncheon of Korea (natural normal growing environment and cold water irrigation), and QTLs of these traits were analysed by using SSR markers. The results showed that 44 QTLs related to these agronomic traits were detected under five different growing environments, and these QTLs are located on eleven charomosomes except chromosome 9. The QTLs for qCL1a, qCL1b, qCL5a, qCL6b, qPL1a, qPL3a, qPL6b, qPL6c, qPL7b, qSP8b, qSP1c, qSP11a, qSP12 and qPE1 have been detected in more than two growing environments, which were little affected by environments, were stable QTLs. Among them, qCL1a, qCL1b, qPL1a, qSP1c and qPE1 explained 24.2%-55.2%, 22.7%-39.9%, 12.5%-27.7%, 14.4%-33.5% and 26.6%-28.7% of observed phynotypic variation, respectively, which were major genes mainly appeared over dominance. These QTLs cause the increase of culm length, panicle length, spikelets per panicle and panicle exsertion under low temperature, showing that these QTLs are correlated with cold tolerance.
    Review and Prospect of Wheat Kernel Hardness and Its Molecular Genetics Basis
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    Scientia Agricultura Sinica. 2005, 38(06):  1088-1094 . 
    Abstract ( 1494 )   PDF (300KB) ( 824 )   Save
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    Kernel hardness, controlled by a major gene located on the short arm of chromosome 5D, is one of the most important wheat quality characteristics and determines marketing and classification of common wheat. With the development of hardness measuring, the molecular genetic basis of kernel hardness has rapidly progressed. It is known that Pina and Pinb form the molecular basis of wheat kernel hardness and lacking of PINA or mutation in Pinb caused wheat endosperm become hard. Endosperm structure and genetic basis of hardness are summarized in order to provide useful information in understanding the formation of grain hardness.
    Genetic Study of Thermo-Sensitive Male Sterility on Thermo-Sensitive Male Sterile Wheat Line A3314
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    Scientia Agricultura Sinica. 2005, 38(06):  1095-1099 . 
    Abstract ( 1232 )   PDF (247KB) ( 1046 )   Save
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    To establish the two-lines hybrid wheat seeds production system, which is easy-using and low-cost, and to breed the thermo-sensitive male sterile wheat lines that could be used in wide-range areas, experiments on genetic study of the thermo-sensitive male-sterile wheat line A3314(the sensitive stage of fertility exchange is booting, the daily average temperature of fertility exchange is 18℃, when the daily average temperature is less than 18℃ during the fertility sensitive stage,the male fertility of A3314 is male-sterile, but it will be male-fertile when the daily average temperature is over 18℃ during the sensitive stage.), which was bred by applying the technology of Chinese invention patent ZL00105488.0, were conducted through self setting of F2 and BC1F1 population of A3314/Silverstar and K3314A/A3314 under given conditions. That is to say, under sterile condition(the daily average temperature is less than 18℃, A3314 showed male sterility, i.e. sowing at the time suitable for wheat growing in Huang-Huai (the valleys of Huanghe river and Huaihe river) winter wheat producing area, Yunnan-Guizhou winter wheat producing area, Northwest spring wheat producing area and Northeast spring wheat producing area.) , sowing in autumn, the male-fertility of A3314 was male sterile, with Silverstar as the pollen parent. Obtaining F2 population of A3314/Silverstar and BC1F1 population of A3314//A3314/Silverstar was obtained. Under fertile condition (sowing in spring or summer in Huang-Huai winter wheat producing area and Yunnan-Guizhou winter wheat producing area), the male-fertility of A3314 was male fertile, with K3314 as the female parent. F2 population of K3314A/A3314 and BC1F1 population of K3314A//K3314A/A3314 was obtained. At the same time, the different daily average temperatures of A3314 were controlled by artificial climatic box. Analysis on the findings of these experiments showed that male fertility of no-1B/R K type thermo-sensitive male sterile wheat line A3314 was the same as 1B/R K type male sterile wheat line K3314A, and the male fertility of A3314 might be controlled mainly by two pairs of segregate excessive genes besides cytoplasm genes (table1), especially rfv1sp derived from T.spelta var.duh. 1BS chromosome was a major effect gene in A3314, which was not the same as the major male sterile gene rfv1 of K3314A, and might be a pairs of allies (table2), and rfv1sp gene had thermo-sensitivity, but rfv1 gene had no thermo-sensitivity.
    Identification and Genetic Analysis of Transgenic Wheats with Bcl and Rip Genes
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    Scientia Agricultura Sinica. 2005, 38(06):  1100-1105 . 
    Abstract ( 1073 )   PDF (496KB) ( 879 )   Save
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    Detection at molecular level and anti-disease identification of the T1, T2 and T3 transgenic wheats with Bcl and Rip genes indicated that segregation ratios of nptⅡ selective gene and functional gene Rip were consistent with Mendel's law,but functional gene Bcl was not in T1 generation. Southern blot showed that the alien genes had integrated into wheat genome and could be inherited to the following generations. The results also showed that there was just one copy of the alien genes in most T1 plants and most T2 homologous lines had two copies. After artificial inoculation of powdery mildew and wheat take-all, the transgenic plants demonstrated some resistance to them. And analysis of several agronomic traits indicated that transgenic plants had little difference in tiller, main spike length, spikelet number of main spike except plant height.
    Genetic Analysis on Heterosis of Lint Yield and Fiber Traits of F1 and F2 Hybridization Between "O" Type and Long-Fruit-Branch Plant Type in Sea Island Cotton
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    Scientia Agricultura Sinica. 2005, 38(06):  1106-1112 . 
    Abstract ( 1066 )   PDF (197KB) ( 634 )   Save
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    Two lint yield and five fiber quality traits of 9 parents and their 20 F1 crosses (5×4) of sea island cotton in three years were analyzed by the genetic model of additive-dominance and their interactions with environments by MINQUE(1) approaches. The results indicated that there was a negative better-parental heterosis in 5 fiber quality traits, pre-frost lint yield and total yield of F1 and F2 crosses between "0" and long-fruit-branch plant type varieties in sea island cotton. There was a positive low mean heterosis in fiber strength and a negative mean heterosis in Micronaire, but they were low. The positive mean heterosis of F1 and F2 in total lint yield reached 42.1% and 21%, respectively. Generally speaking, the heterosis in fiber quality traits of F1 and F2 was low, but there existed some crosses that their F1 had better-parent heterosis and degenerated F2 heterosis slowly, and crosses have better-parent heterosis in total lint yield of F1 and F2. Pre-frost lint yield could be selected with fiber length or fiber fineness, while it is very difficult to select pre-frost lint yield with fiber strength or there is a difficult to select total lint yield with fiber length, strength, fineness. The phenotypic correlation analysis shows that it is available to use heterosis of pre-frost lint yield with fiber length, strength and fineness synchronously,it is very difficult to use heterosis in total lint yield with fiber length, fineness.
    TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY
    Effects of 1,2,4-Trichlorobenzene and Naphthalene Stress on Photosynthetic Characteristics of Rice at Heading Period
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    Scientia Agricultura Sinica. 2005, 38(06):  1113-1119 . 
    Abstract ( 910 )   PDF (514KB) ( 743 )   Save
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    The effects of 1,2,4-trichlorobenzene (TCB) and naphthalene (NAP) on photosynthetic characteristics of rice leaves were studied. The results showed that chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), photochemical efficiency (Fv/Fm), quantum yield of PSII (ΦPSII), potential activity of PSII (Fv/Fo) and photochemical quenching (qP) and non-photochemical quenching (qN) decreased under TCB and NAP stress. The effects of TCB were more serious than that of NAP, while the sensitivity of Shanyou 63 was higher than that of Wuyunjing 7. Under low concentration of organic pollutants, stomatal limitation was a dominating factor for Pn decrease. Under high concentration of organic pollutants, the decrease of Pn was due mainly to stomatal limitation and the non-stomatal limitation. High concentration of pollutants suppressed the synthesis more strongly, and finally reduced the grain yield. Among all of the chlorophyll fluorescence kinetics of parameters, both Fv/Fo and qN are more sensitive to TCB and NAP than the other parameters. Therefore, both Fv/Fo and qN would be the sensitive reference indicator of harm of organic pollutants on rice.
    Effects of the Ratio Between Basal N and Top Dressing N on Grain Starch Formation in Weak Gluten Wheat Variety Ningmai 9 and Its Enzymes Activities
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    Scientia Agricultura Sinica. 2005, 38(06):  1120-1125 . 
    Abstract ( 981 )   PDF (389KB) ( 780 )   Save
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    Effects of the ratio between basal N and top dressing N on wheat grain starch formation and its physiological basis were studied. Compared with the treatment of basal N: top dressing N 5:5, the treatment of basal N: top dressing N 7:3, with low accumulation rates of amylose, amylopectin and starch from 7th to 28th and amylose content, was high in the contents of amylopectin and starch at maturity, meanwhile, sucrose phosphate synthase (SPS) activity, sucrose content in flag leaves, and sucrose synthase (SS) activity in grains were low, which could increase sucrose content in grains. At the same time, the activities of AGPP (ADP-glucose pyrophosphorylase), SSS (soluble starch synthase), GBSS (granule bounded starch synthase) were low, therefore, the accumulated starch amount was low. The activities of AGPP, SSS, GBSS were positively correlated to the rates of amylose, amylopectin and total starch accumulating and grain filling, which indicated that these three enzymes played a role in promoting the grain starch accumulation of wheat.
    Effects of Plant Density on Forage Nutritive Value of Whole Plant Corn
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    Scientia Agricultura Sinica. 2005, 38(06):  1126-1131 . 
    Abstract ( 861 )   PDF (433KB) ( 1001 )   Save
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    In a field experiment, the effects of plant density (75 000, 112 500 and 150 000 plant/ha) on forage nutritive value were studied. The main results were as follows: with the increase of plant population, fresh matter and dry matter yield per plant of corn decreased significantly, but those per hectare of corn increased significantly, and higher grains yield was gotten at higher plant density. Forage nutritive quality of whole plant corn changed, and crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen free extract (NFE) and general energy (GE) yield increased significantly. It could harvest more forage matter yield and improve forage nutritive value of whole plant corn through the increase of the plant density of corn by applying plant growth regulators.
    Effects of Nitrogen Rates on Activities of Key Regulatory Enzymes for Grain Starch and Protein Accumulation in Wheat Grown Under Drought and Waterlogging from Anthesis to Maturity
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    Scientia Agricultura Sinica. 2005, 38(06):  1132-1141 . 
    Abstract ( 1046 )   PDF (699KB) ( 842 )   Save
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    Effects of nitrogen rates on activities of key regulatory enzymes for grain starch and protein accumulation in two wheat varieties (Triticum aestivum L.) under drought and waterlogging from anthesis to maturity were studied in a cement pool culture experiment. Total three water treatments were established from anthesis to maturity, i.e. waterlogging, drought and moderate water supply (CK). Under each water treatment, two nitrogen levels of 120 and 240 kg·ha-1 were implemented. Both drought and waterlogging significantly reduced glutamine synthetase (GS) and glutamate pyruvic aminotransferase (GPT) activities in flag leaf, compared with CK. Nitrogen increased sucrose phosphate synthase (SPS), GS and GPT activities in flag leaf under drought and waterlogging. Sucrose synthase (SS), soluble starch synthase (SSS), granule-bounded starch synthase (GBSS), GS and GPT activities in grains decreased with the progress of grain filling. Drought and waterlogging reduced SS and GS activities while drought increased GPT activity in grain, and waterlogging reduced GPT activity. Nitrogen increased SS activity in grain under CK and drought, while reduced it under waterlogging. Nitrogen increased SSS, GBSS, GS and GPT activities under both drought and waterlogging. Drought increased amylose accumulating rate and protein content while waterlogging reduced them. Under drought and waterlogging nitrogen reduced amylose and amylopectin accumulating rate, while increased protein content in grain. Nitrogen increased protein accumulation under CK and drought while reduced protein accumulation under waterlogging.
    Knowledge Model and GIS-Based Crop Potential Productivity Evaluation
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    Scientia Agricultura Sinica. 2005, 38(06):  1142-1147 . 
    Abstract ( 1116 )   PDF (305KB) ( 785 )   Save
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    The concept of knowledge model was introduced, and the knowledge model of crop potential productivity estimation has been set up by the factor attenuation of solar radiation, temperature, water, soil, fertilization, irrigation and the social factor. Based on the support of MapInfo 5.5 systemic development platform and knowledge model, with MapInfo development language including MapBasic and VB6.0, an analysis system on crop potential productivity was developed by integrating the knowledge engineering and database. The computer aid decision of crop potential productivity has been realized. An application example in Jiangsu province was provided, by comparing to the practical yield per unit area, the potential yield per unit area, potential coefficiency, potential productivity were analysized qualitatively, the regional superiority of crop production was decided.
    PLANT PROTECTION
    A Preliminary Analysis of Pathotypes of Xanthomonas oryzae pv. oryzae and the Resistant Reactions of Main Japonica Rices in the Yunnan Plateau
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    Scientia Agricultura Sinica. 2005, 38(06):  1148-1155 . 
    Abstract ( 1085 )   PDF (241KB) ( 706 )   Save
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    The pathogenicity of 36 isolates of Xanthomonas oryzae pv. oryzae (Xoo), which were collected from japonica rices in the Yunnan Plateau, was evaluated on 29 rice varieties including a set of 7 varieties to identify pathogenicity, ie. Haonuoyang, TN1, Kogyoku , Zhengzhuai, IR26, Nanjing 33 and Kinmaze, which may be considered as a set of differential varieties for Xoo races from Yunnan japonica rice. The efficiency of the 7 varieties was further confirmed. The results showed reversible and specific reactions between isolates and varieties. The isolates were classified into 9 pathotypes from pathotype I to Ⅸ according to their pathogenic reactions on the 7 rice varieties. The pathotype Ⅴ was the epidemic while pathogen Ⅶ was the most pathogenic. Most japonica varieties being grown in the Yunnan plateau were susceptible to Xoo. The rice lines IRBB21 (Xa-21), Zhachanglong (Xa-22t,Xa-24t)and IR1545-339 (xa-5), which were resistant to all the isolates tested, can be used as donors of resistant genes for bacterial blight in japonica rice breeding in the Yunnan Plateau.
    A SSR Marker for Leaf Rust Resistance Gene Lr19 in Wheat
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    Scientia Agricultura Sinica. 2005, 38(06):  1156-1159 . 
    Abstract ( 1265 )   PDF (290KB) ( 725 )   Save
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    Microsatellite was carried out in Thatcher, six near?isogenic lines and F2 progeny of TcLr19 × Thatcher to develop molecular markers for leaf rust resistance gene Lr19. Thirteen primer pairs were screened, of which one primer pair Xgwm44 displayed polymorphsim in the population of TcLr19, Thatcher, and their F2 generation. One marker closely linked to Lr19 resistance trait was obtained, and was named as Xgwm44139bp with the genetic distance 0.9 cM. The research shows that Lr19 has more potential in marker-assisted breeding programs in wheat and has leid a foundation for mapping genetic map, physical map and the eventual cloning.
    Increase of Fusarium- and Verticillium-Resistance by Transferring Chitinase and Glucanase Gene into Cotton
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    Scientia Agricultura Sinica. 2005, 38(06):  1160-1166 . 
    Abstract ( 1352 )   PDF (312KB) ( 932 )   Save
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    Fusarium and Verticillium wilt are two important diseases in cotton in the world. Traditional breeding method does not have resistance germplasm. Chitinase and -1,3-glucanase are two factors with synogestic effects involved in the plant defense system. Based on this fact, a series of plant expression vectors either harboring chitinase gene or -1,3-glucanase gene or both were constructed. The two genes are expected to be expressed and localized in vacuole or in extra-cellular space. The transformation of cotton was conducted by pollen-tube pathway method. Molecular analysis of transgenic cotton plants by polymerase chain reaction and Southern hybridization, and successive repeated selection of transgenic cotton lines in greenhouse and fungi-infected nurseries during the period of 1996-2000 demonstrated that the transgenic cotton lines with Fusarium wilt and Verticillium wilt resistance were obtained. Meanwhile, the above anti-fungal genes have been integrated into insect-resistant cotton variety GK19 which resulted in the development of transgenic lines resistant to both cotton boll worm as well as Fusarium and Verticillium wilt.
    Detection of Predation on Bemisia tabaci by Using SCAR Markers
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    Scientia Agricultura Sinica. 2005, 38(06):  1167-1173 . 
    Abstract ( 1166 )   PDF (314KB) ( 894 )   Save
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    DNA markers of Bemisia tabaci (Gennadius) were developed to detect the remains of whitefly in the gut of Propylaea japonica (Thunberg) reared in lab and various predators collected in cotton fields. An approximately 350 bp DNA fragment of B. tabaci, absent in other closely related prey species, cotton and in the predators banding pattern, was identified by random amplified polymorphic DNA (RAPD) analysis. After cloning and sequencing the target fragment (347 bp, AY841800 in GenBank), one pair of sequence-characterized amplified region (SCAR) primers was developed, amplified single band of ca. 240 bp. Specificity tests performed with this pair of primers showed the presence of the band for B. tabaci in all stages and in both sexes. The target DNA fragment of B. tabaci was equally detected in P. japonica adult fed with 10 red-eyed nymphs of B. tabaci and in all predator species collected in cotton fields. The detection rate of B. tabaci DNA in predators, such as the larvae of P. japonica, Harmonia axyridis, Chrysopa spp., adult Orius sauteri and spiders, was over 50%.
    The Bioactivity of Mutant Isolates from Botrytis cinerea
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    Scientia Agricultura Sinica. 2005, 38(06):  1174-1181 . 
    Abstract ( 861 )   PDF (349KB) ( 870 )   Save
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    Fifteen mutant isolates were obtained by ultraviolet ray mutation from parent strain Botrytis cinerea BC-4 and 3 mutant isolates, i.e. BC4-1, BC4-2 and BC4-15, showed strong herbicidal activity, among them, BC4-1 was the best for inhibiting the germination and growth of Digitaria sanguinalis L. and Amaranthus retroflexus L. The results also showed that different pH of PD media had different influences on herbicidal activity and pH 4.0 was the best among the pH values tested. The crude toxin could be extracted using chloroform, petroleum ether and ethyl acetate, and the ethyl acetate extracts had a strongest inhibitory activity on the germination and growth of D. sanguinalis L .and A. retroflexus L. One component with an absorbent peak at 271 nm was separated and obtained from the crude toxin by HPLC. The component, at concentration of 100 mg·L-1, could strongly inhibit the growth of D. sanguinalis L. and could completely inhibit seed germination of D. sanguinalis L. and A. retroflexus L.at concentration of 50 mg·L-1.
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION
    Iron and Zinc Contents in Japonica Hybrid Rice Based on CMS-D1 System
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    Scientia Agricultura Sinica. 2005, 38(06):  1182-1187 . 
    Abstract ( 1078 )   PDF (217KB) ( 665 )   Save
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    Iron and zinc contents of rice were analyzed with 208 rice lines, including japonica hybrids, corresponding restorers, maintainers (CMS-D1 system). The results indicated that the iron contents were ranged from 14.49 to 38.06 mg·kg-1 in brown rice, and from 5.50 to 27.81 mg·kg-1 in polished rice. The zinc contents were from 11.64 to 42.39 mg·kg-1, and from 10.95 to 36.74 mg·kg-1, respectively, in brown and polished rice. Obviously, the mean contents of iron and zinc in brown rice were, respectively, 2.11 and 1.23 times of that in polished rice. At the same time, content correlation coefficients of iron or zinc in brown and polished rice were 0.271 and 0.684, respectively, and significant correlation was also found between iron and zinc contents. On average, iron and zinc contents of restorers were higher than that of maintainers, and the contents of hybrids were ranged between those of their parents either in brown or polished rice, except a few hybrids, which displayed hybrid vigor in the contents. Therefore, it is possible to develop hybrid rice which is reach in iron and zinc elements.
    Study on the Key and Sensitive Stage of Winter Wheat Responses to Water and Nitrogen Coordination
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    Scientia Agricultura Sinica. 2005, 38(06):  1188-1195 . 
    Abstract ( 799 )   PDF (259KB) ( 688 )   Save
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    Pot experiments were carried out to study the effect of nitrogen application on winter wheat under different status of soil moisture, so that the key and sensitive stage of winter wheat responses to water and nitrogen coordination were decided. The results showed that the application of N fertilizer was more effective at early stage than at late stage, and at the lower N rates than at the higher N rates under non-irrigated conditions, N treatment had greet effect on spikelet bearing number and grain number per spike, but had no effect on 1 000-grain weight. Grain yield and yield component responses to N treatment were greater under irrigated conditions than under non-irrigated conditions. The jointing stage was the key and sensitive stage of winter wheat responses to water and nitrogen coordination. The grain yield, grain number per spike and 1000-grain weight increased when water and N fertilizer were applied at this stage. The mechanism is that the growth and development, absorption and application of nitrogen, and root activities of winter wheat increased when fertilizer and water were applied at this stage.
    Nutritional Effects of Soybean Root Architecture in a Maize/Soybean Intercropping System
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    Scientia Agricultura Sinica. 2005, 38(06):  1196-1203 . 
    Abstract ( 1005 )   PDF (222KB) ( 755 )   Save
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    In the present study, two soybean genotypes differing in root architecture were employed to evaluate the effects of soybean root architecture on N and P nutrient status and crop growth in a maize/soybean intercropping system. The results showed that land equivalent ratio (LER), biomass and N/P content of crops significantly increased in the maize/soybean intercropping system. LER was also higher in maize intercropped with Baxi10, the soybean genotype with a shallow root system, than that in maize intercropped with Bendi2, the soybean genotype with a deep root system, indicating that soybean root architecture may play an important role in the maize/soybean intercropping system. The greater LER in the legume-grass intercropping system (such as the maize/soybean intercropping system) could be mainly attributed to the greater N uptake as indicated by the competition ratio of maize to soybean (CRms), while the differences in LER between maize intercropped with different soybean genotypes might have resulted from different soil P uptake. Soybean genotype with a shallower root system was advantageous not only for soil P uptake but also for N uptake by both crops.
    Geostatistical and GIS Analyses on Total Soil P in the Typical Area of Dongting Lake Plain
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    Scientia Agricultura Sinica. 2005, 38(06):  1204-1212 . 
    Abstract ( 1497 )   PDF (532KB) ( 1253 )   Save
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    A typical ecological unit of Dongting Lake plain was selected as experimental site. Approximate grid approaches were employed for the sampling scenario in 2004 with 651 Global Position System (GPS) established spots sampled in topsoil (0-20cm). The purpose of this paper is to evaluate various data processing methods, including logarithmic transformation, robust statistics, excluding outliers and Box-Cox transformation for evaluating total soil P content with normal distribution. The result showed that Box-Cox transformation was applied in order to achieve normality in the data set and to dampen the effect of outliers. Geostatistical analyses were carried out, including calculation of experimental variograms and model fitting. The best theoretical model for semivariogram of total soil P were spherical model. The ordinary kriging estimates of total soil P concentration were mapped. The integrative comparisons of semivariogram parameters with different trend of the kriging prediction errors of total soil P indicated that the 2-order trend effect was preferable. Kriging standard deviations (KSD) were regarded as the standard deviations of the interpolated pixel values and provided valuable information for which will increase the accuracy of the total P mapping. Spatial distribution and hazard assesment of total soil P in the typical area of Dongting Lake plain were investigated using geostatistics and geographic information system (GIS) techniques such as probability kriging on the basis of the software ArcGIS Desktop. Probability distribution of total soil P at different levels will be helpful to conduct hazard assessment, optimal fertilization and develop management practices to control the non-point sources of P pollution.
    Effect of Long-Term Fertilization on Cropland Soil Fauna Community in Loess Soil, Shaanxi, China
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    Scientia Agricultura Sinica. 2005, 38(06):  1213-1218 . 
    Abstract ( 1164 )   PDF (328KB) ( 625 )   Save
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    The relationship between long-term fertilization and cropland soil fauna was studied at the station's experiment research network for soil fertility and fertilizers in Shaanxi Loess soil from Jul. 2001 to Oct.2002 in Shaanxi. Six types of long-term fertilization were carried out in this study including control (CK), abandonment (ABAND.), nitrogenous and phosphorus and potassium fertilizers (NPK), straw and NPK (SNPK), organic material and NPK (MNPK) and double MNPK. Seventy-two soil samples were collected and 5 495 species of cropland soil fauna were obtained by handsorting and Cobb method at 4 times, belonging to 6 phyla, 11 classes, 22 orders, 61 familia, 2 superfamilia and 35 genus. The result showed that different fertilization had significant effect on cropland soil fauna (F = 2.24,P <0.007). The number of crop soil fauna was related to soil physicochemical properties caused by long-term fertilization. The result of principal component analysis, focusing on the number of 15 key soil fauna species group's diversity, evenness of community and the total soil fauna individuals, indicated that the effects of SNPK, NPK, MNPK and 1.5MNPK were significantly different on cropland soil fauna, in which, SNPK and NPK had a positive effect on cropland soil fauna,and MNPK and 1.5 MNPK had a negative effect, others cannot been explained. By principal component Ⅰ, the synthetic effect of different fertilization on the total soil fauna individuals and the group was most significantly, and the effect was little on evenness and diversity. By value of eigenvectors, the maximum one was 9.6248, and the least one was -1.0904, which means that the effects of six types of fertilization on cropland soil fauna are unbalance.
    HORTICULTURE
    Simulation of the Development of Tomato in Greenhouse
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    Scientia Agricultura Sinica. 2005, 38(06):  1219-1225 . 
    Abstract ( 1520 )   PDF (308KB) ( 885 )   Save
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    A simulation model for tomato development in greenhouse was developed based on the concept of physiological development time (PDT) and the photo-thermal reactions of tomato in greenhouse. The model was validated by independent experimental data from Shanghai and Nanjing. The results showed that the simulated results agreed well with the measured ones. The root mean squared error (RMSE) for germination, seedling, flowering, fruit setting, and harvest development stages was 0, 1, 1.87, 2.69 and 3 days, respectively. The prediction accuracy of this model is remarkably higher than that of the Growth Degree Day (GDD) based model (RMSE is 0, 7.91, 8.86, 13.58 and 12.59 days, respectively, for germination, seedling, flowering, fruit setting, and harvest development stages).
    Simulation of the Development of Tomato in Greenhouse
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    Scientia Agricultura Sinica. 2005, 38(06):  1219-1225 . 
    Abstract ( 937 )   PDF (308KB) ( 1086 )   Save
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    A simulation model for tomato development in greenhouse was developed based on the concept of physiological development time (PDT) and the photo-thermal reactions of tomato in greenhouse. The model was validated by independent experimental data from Shanghai and Nanjing. The results showed that the simulated results agreed well with the measured ones. The root mean squared error (RMSE) for germination, seedling, flowering, fruit setting, and harvest development stages was 0, 1, 1.87, 2.69 and 3 days, respectively. The prediction accuracy of this model is remarkably higher than that of the Growth Degree Day (GDD) based model (RMSE is 0, 7.91, 8.86, 13.58 and 12.59 days, respectively, for germination, seedling, flowering, fruit setting, and harvest development stages).
    Effects of Short-Term Chilling Stress on the Photosystems and Chloroplast Ultrastructure in Sweet Pepper
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    Scientia Agricultura Sinica. 2005, 38(06):  1226-1231 . 
    Abstract ( 1170 )   PDF (441KB) ( 948 )   Save
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    By determining fluorescence parameters, composition of fatty acids, active oxygen species and activities of some antioxidant enzymes, the effects of chilling stress (4 oC) in the low light (100 μmol·m-2·s-1) on chilling-sensitive plants were studied. After 6 h of chilling stress (4 oC) in the low light (100 μmol·m-2·s-1), the maximal photochemical efficiency of PSII (Fv/Fm) of sweet pepper leaves decreased by 35.6%, and the oxidizable P700 decreased by 60%. However, chilling stress in the dark had no effect on both of them. Unsaturation of fatty acids in thylakoid membrane was accelerated, which might be helpful to stabilize photosynthetic apparatus. Distortion and swelling of grana caused by chilling in the dark probably decreased activities of antioxidant enzymes, which resulted in the accumulation of active oxygen species. On the contrary, photooxidation might be related to the disintegration and unstacking of grana. Chilling stress induced photoinhibition of PSII and PSI, and active oxygen species might be one of the factors causing the decrease of the oxidizable P700. PSI seemed to be more sensitive to chilling in the low light than PSII.
    Anatomical Observations of Anther Development of NCa, a Cytoplasmic Male Sterile Line in Rapeseed( Brassica napus L.)
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    Scientia Agricultura Sinica. 2005, 38(06):  1232-1237 . 
    Abstract ( 1013 )   PDF (489KB) ( 1049 )   Save
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    A cytoplasmic male sterile (CMS) line, named NCa, was obtained from the backcrossing descendents of hybridization between two amphidiploid species of Brassica napus L. (AACC, 2n =38) and B. carinata (BBCC, 2n =34), respectively. The anatomical observations on the anther development of NCa by light microscope and transmission electron microscope showed that the abortion of the anther development occurred at the later mono-nucleus microspore (MNM) stage. The microspore mother cell of NCa could pass through meiosis and form tetrads and then tetrads could release microspores as the same as the fertile line. The released microspores with one nucleus could continuously develop and form pollen wall soonly. The protoplast and nucleus of MNM degraded in succession and just left the empty pollen wall at last or with large vacuoles. The tapetum development was similar to that of the fertile anther up to tetrad stage but after that the protoplast of tapetal cell was rich in small vacuoles and degenerated gradually. Anther development of NCa sterile line was obviously different from all of the other kinds of CMS lines examined before, because its abortion stage revealed here was later than any of the examined CMS types and it formed pollen wall soon after microspores released and remained that until pollen degradation.
    Study on Germination Barriers and Hydropriming Treatment of Triploid Watermelon Seeds
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    Scientia Agricultura Sinica. 2005, 38(06):  1238-1243 . 
    Abstract ( 1157 )   PDF (329KB) ( 931 )   Save
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    For overcoming germination barriers of triploid watermelon seeds, six cultivars of triploid watermelon seeds were designed to hydropriming by soaking in 0.1% H2O2 aerated water or water for 2 h following 24 h, 34 h and 48 h of incubation at saturated relative humidity. Germination viability and seedling growth rate of the seeds significantly increased by 38%-56% in hydropriming treatments. The germination percentage of the six cultivars increased in various degrees from 14% to 66% according as different cultivars. The 34 h and 48 h of incubation hydropriming combined with H2O2 treatment showed the best result. The beneficial effects of hydropriming were maintained as dehydration after primed seeds were redried to original moisture content and stored. The investigation of seed and embryo structure with soft X-ray indicates that germination barriers of triploid watermelon are seedcoat related, and that hydropriming can overcome these barriers.
    Changes of Aroma Constituents in Apricot During Fruit Development
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    Scientia Agricultura Sinica. 2005, 38(06):  1244-1249 . 
    Abstract ( 996 )   PDF (363KB) ( 1031 )   Save
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    The aroma constituents present in apricot fruit during three different developmental stages were studied. The three stages include mature green stage, commercial ripe, and tree ripe stage. The fruits were sampled by simultaneous distillation-extraction. The concentrated extracts were analyzed by capillary gas chromatography-mass spectrometry. The aromatic constituents behaved differently during the fruit developmental period. Alcohols, aldehydes, ketones, lactones, esters and acids were the major constituents in the sample extracts. A total of 35 compounds were identified in the mature green stage, including (E)-2-hexenal, linalool, α-terpineol, (E)-2-hexen-1-ol, hexanal, 1-hexanol. Forty-five compounds at commercial ripe stage were detected, among them the important compounds were (E)-2-hexenal, linalool, α-terpineol, hexanal, ocimenol and geraniol. Meanwhile, 44 were found at tree ripe stage, and the main components were linalool, (Z, Z, Z)-methyl 9, 12, 15-octadecatrienoate, α-terpineol, γ-decalactone, γ-dodecalactone, butyl acetate, hexyl acetate. The maximum of C6 aldehydes and alcohols were found at mature green stage, diminishing in concentration as ripening proceeded. Several terpenic alcohols were found at different stages of ripening. Their maximum concentrations were found at commercial ripe stage. To the contrary, the presence of lactones and ketones was not detectable until the commercial ripe stage. Some esters were also found such as butyl acetate, 3-hexenyl acetate, hexyl acetate, 2-hexenyl acetate, etc. Except 2-hexenyl butanoate and 2-hexenyl hexanoate , the levels of others increased during fruit maturation.
    Analysis of Aroma Components of Ecolly Dry White Wine by Gas Chromatography/Mass Spectrometry
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    Scientia Agricultura Sinica. 2005, 38(06):  1250-1254 . 
    Abstract ( 1162 )   PDF (353KB) ( 936 )   Save
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    The aroma components in Ecolly dry white wine were extracted by solvent extraction. According to the analysis by gas chromatography/mass spectrometry, 32 peaks were separated and 21 components were identified. The identified constituents represent 99.58% of the total content. The main components were 1-Pentanol; butanedioic acid, diethyl ester; phenylethyl alcohol; butanedioic acid, hydroxy-, diethyl ester, (+)-; benzeneethanol, 4-hydroxy-; succinoic acid, 2-hydroxy-3-methyl-, diethyl ester; 1-propanol, 3-(methylthio)-; 5-oxotetrahydrofuran-2-carboxylic acid, ethyl ester; 2(3H)-uranone, 5-ethyldihydro-; tartaric acid diethyl ester. Compared with Ugni Blanc white wine, Ecolly white wine has typical characteristics.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    Studies on the Nuclear Transfer of Rabbit
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    Scientia Agricultura Sinica. 2005, 38(06):  1255-1259 . 
    Abstract ( 747 )   PDF (270KB) ( 655 )   Save
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    Factors affecting the efficiency of nuclear transfer (NT) in rabbits were examined in the present study. When 100 V·mm-1 of pulse strength and 15μs of pulse duration were employed, 3 and 4 electronic pulses resulted in significantly more cytoplasts fused with donor cells compared with 2 electronic pulses (P<0.05), but no significant difference was found in the cleavage rate of reconstructed embryos among the three groups (P>0.05). When the duration and number of electronic pulse were fixed at 15μs and 3 times, increase of pulse intensity from 100 V·mm-1 to 150 V·mm-1 and 200 V·mm-1 resulted in a significantly decrease in the cleavage rate of reconstructed embryos (P<0.05), although the fusion rate did not significantly differ among the three groups (P>0.05). Significantly more reconstructed embryos cleaved and developed to blastocysts when they were derived from donor embryos at the 8-16-cell stage, in comparison with the reconstructed embryos derived from donor embryos at the compact morulae stage (P<0.05), although the fusion rate was similar (P>0.05). Activation of cytoplasts prior to fusion increased the cleavage rate (P<0.05) and blastocyst development (P<0.05) of reconstructed embryos, but decreased the fusion rate (P<0.05) compared with cytoplasts activated post fusion. More reconstructed embryos developed to blastocysts when they were cultured in TCM+3%OCS at the first 48 h and then cultured in TCM199+10% FCS, in comparison with the reconstructed embryos cultured in either TCM199+10%FCS or TCM199+3%OCS (P<0.05). When 22 NT embryos were transferred into the oviducts of one recipient rabbit, one rabbit was delivered to birth. In conclusion, either electrofusion parameter or developmental stage of donor embryos have a significant effect on the efficiency of NT, NT embryos require different concentration of serum at their different development stages.
    Construction of Phage Antibody Library and Screening of Monoclonal Antibodies Specific for Porcine Adipocytes
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    Scientia Agricultura Sinica. 2005, 38(06):  1260-1263 . 
    Abstract ( 1156 )   PDF (295KB) ( 1191 )   Save
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    Using subtractive immunization technique, Balb/C mice were immunized with porcine adipocytes, and their spleen cells were harvested. The genes of VH and VL were amplified by RT-PCR and a ScFv phage library of anti-porcine adipocytes was constructed with the amplified V gene. The library was selected using porcine adipocytes as panning antigen by 3 rounds of binding-elution-enrichment procedure. Monoclonal antibodies against porcine adipocytes were acquired by screening. Fifty-one out of 96 randomized clones were demonstrated to have binding capacities to porcine adipocytes, with the positive ratio as much as 53%, while the negative results were observed when reacted with porcine hepatocytes. This strategy may provide an alternative new approach to antibodies.
    Cloning and Expression of a Fusion Protein of Muramidase-Released Protein and Extracellular Protein Factor of Streptococcus suis Type 2 and Its Protection
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    Scientia Agricultura Sinica. 2005, 38(06):  1264-1269 . 
    Abstract ( 1043 )   PDF (353KB) ( 963 )   Save
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    Two fragments of mrp gene (1 801-2 513bp) and epf gene (1 783-2 563bp ) were amplified from genomic DNA of Streptococcus suis type 2 isolate strain SS2-1 by polymerase chain reaction (PCR) technique. The PCR products were later cloned into plasmid vector pET-32a via restriction endonuclease and then transformed into host strain BL21. Through relevant endonuclease digest , the positive recombinant bacteria were identified, which were expressed by IPTG of optimal concentration, respectively. Also, the antigenicity of expressed recombinant proteins (rMRP and rEPF) were determined by Western-blot. After verified positive immunity, the fragments of mrp and epf linked by PCR was cloned into pET-32a again. By the above method with IPTG, the recombinant protein consisted of rMRP and rEPF with molecular weight 74kD was obtained. Next, the antigenicity analysis by Western-blot showed that the recombinant protein had the conserved epitopes of MRP and EPF, respectively. In order to further determine the antigenicity of recombinant proteins (rMRP, rEPF and rMRP-EPF), rabbits were immunized, positive (immunity with bacterial vaccine) and negative controls (non-immunity) were set. After 21d, challenged by Streptococcus suis type 2 isolate strain SS2-1,rMRP-EPF immunized rabbits were protected more than alone. Compared to rMRP 25%,rEPF 0%, bacterial vaccine 100%, rMRP-EPF beared protection rates of 50%. It is concluded that rMRP-EPF possesses good antigenicity.
    Construction and Immunogenicity of Recombinant Phage Expressing the F Gene of Newcastle Disease Virus
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    Scientia Agricultura Sinica. 2005, 38(06):  1270-1274 . 
    Abstract ( 992 )   PDF (312KB) ( 676 )   Save
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    The F gene segment deleted the F0 signal sequence, with a length of 1566bp, and coding for 522 amino acids, was amplified by PCR. The F gene fragment was then inserted into the EcoRⅠsite of pR vector to obtain recombinant plasmid pR-F. The recombinant plasmid was used to transform E.coli E2, the host bacteria of T4 phage, and infected with lysozyme-defective phage T4-Z1. The F gene was integrated into genome of T4-Z1 by homogenous recombination. The recombinant phage were screened by PCR and designated as T4-Z1-F. Oil-emulsion vaccine was prepared with concentrated phage T4-Z1-F and used to inoculate 10-day-old specific-pathogen-free(SPF) chickens, all birds were given a booster at the age of 25-days. The result showed that the recombinant F protein was highly immunogenic, and was able to induce specific antibody against NDV to partially withstand virulent NDV challenge.
    RESEARCH NOTES
    Study on Gene Differential Expression in Roots and Leaves Between Hybrid CRI47 and Its Parents at Seedling Stage
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    Scientia Agricultura Sinica. 2005, 38(06):  1275-1281 . 
    Abstract ( 1411 )   PDF (258KB) ( 554 )   Save
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    The patterns of gene differential expression in roots and leaves between CRI47 and its parents at seedling stage were analyzed by using DDRT-PCR, and the relationship between the hybrid yield traits and patterns of gene expression was also studied. The main results were as follows: (1) Differential expression bands in roots and leaves accounted for 38.8% and 65.2% of their total numbers of detected bands,respectively. The differential expression bands in leaves were richer than those in roots, which explained that some useful genes to heterosis maybe begin to express in seedling leaves. (2) Four types of differential expression were detected between the hybrid and its parents: I. Bands expressed in both parents but not in F1; II. Bands expressed in one parent but not in F1 and another parent; III. Bands expressed only in F1 but not in both parents; IV. Bands expressed in one parent and F1 but not in another parent. Percentages of the four types accounted for 6.5%, 10.6%, 6.5% and 15.2% in roots and 4.4%, 17.9%, 15.1% and 27.8% in leaves, respectively. The tendency of proportion in four types in roots and leaves was consistent, which indicated the type of bands expressed only in one parent and F1 played main role in CRI47 yield. (3) Increase of boll number per plant was the main cause of high yield formation in CRI47, which also indicated the type of bands expressed only in one parent and F1 contributed to CRI47 yield. These results showed that there were closely relationship between differential expression genes and heterosis at seedling stageof cotton.
    A Preliminary Research on Debao Pony Ear Marginal Tissue Fibroblast Cell Cultured by Collagenase Technique
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    Scientia Agricultura Sinica. 2005, 38(06):  1282-1288 . 
    Abstract ( 893 )   PDF (457KB) ( 749 )   Save
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    The Debao pony ear marginal tissue fibroblast cell line (NDPEM 2/2) was successfully established using collagenase technique. The characterizations of the cell line were identified as follows: the cells were adherent and of density limitation, and the population doubling time (PDT) of cells made with the collagenase technique was 35.9 h. Chromosome analysis showed that the frequency of cell chromosome number to be 2n = 64 was 91.3%~92.8%. Confirmed by isoenzyme analysis, this cell line had no cross-contamination. Tests for microbial contamination from bacteria, fungi, yeasts or mycoplasma were negative. This newly established cell line meets all the standard quality controls of ATCC. It will provide a precious genetic resource for the reservation of the Debao pony breed, as well as an effective experimental material for the genetic studies on Debao ponies. Collagenase technique was compared with primary explant technique in getting the primary cell at the same time, the former is very fast and the population doubling time (PDT ) of the later is 48 h.