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Table of Content

    10 April 2006, Volume 39 Issue 04
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES
    Mapping of the QTLs for Grain Shape Using Single Segment Substitution Lines in Rice
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    Scientia Agricultura Sinica. 2006, 39(04):  647-654 . 
    Abstract ( 1012 )   PDF (297KB) ( 1684 )   Save
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    【Objective】Grain shape (grain length, grain width and length-width ratio) is a main index of rice appearance quality. For molecular breeding in rice, two QTLs controlling grain shape were mapped.【Method】The mapping populations were developed from the single segment substitution lines (SSSLs) in indica background of Huajingxian 74 and the two QTLs of grain shape were mapped using SSR markers.【Results】The grain width QTL, Gw-8, was mapped on the long arm of chromosome 8 between RM502 and RM447 with genetic distance of 0.3 cM. RM502 and RM447 located on the same clone AP005529 and the physical distance between RM502 and RM447 was 55.0 kb. The grain length QTL, gl-3, was located near the centromeric region of rice chromosome 3 between RM6146 and PSM377 with genetic distance of 1.5 cM and 11.0 cM, respectively.【Conclusion】The QTLs for grain shape in rice can be mapped using SSSLs. Mapping of Gw-8 and gl-3 has laid a foundation for cloning of the QTLs and molecular breeding of appearance quality in rice.
    Adaptation of CIMMYT Wheat Germplasm in China's Spring Wheat Regions
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    Scientia Agricultura Sinica. 2006, 39(04):  655-663 . 
    Abstract ( 1260 )   PDF (326KB) ( 933 )   Save
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    【Objective】Information on adaptation of CIMMYT wheat germplasm in China would greatly enhance wheat breeding efficiency in China's spring wheat regions. 【Methed】Twenty-five spring wheat cultivars including 10 from CIMMYT and 15 from China, were sown at 9 locations in China and 4 management environments in Obregon Station at CIMMYT in 2001 and 2002 seasons, and grain yield, yield components, and other agronomic traits were investigated. 【Result】CIMMYT cultivars were characterized by more spikes and grains per spike, medium thousand kernel weight, and high grain yield with broad adaptability. The photoperiod sensitive cultivars from Heilongjiang province performed tall plant height, late maturity, medium spike number, but low grains per spike, thousand-kernel weight, and grain yield. The other Chinese cultivars had medium plant height, early maturity, low spike number and medium grains per spike, but high thousand kernel weight, and medium grain yield. CIMMYT cultivars performed short plant height, earlier maturity, and a little lower grain yield when planted in China's spring wheat regions compared with that in CIMMYT. The photoperiod sensitive cultivars had taller plant height, later maturity, and much lower grain yield, while the other Chinese cultivars showed taller plant height, a little later maturity, and a little lower grain yield with almost the same thousand kernel weight when they were planted in CIMMYT. 【Conclusion】It is recommended to directly use CIMMYT wheat in production in Yunnan, Qinghai, and Xinjiang provinces. CIMMYT wheat can also be used in production in such provinces as Inner Mongolia, Gansu, and Ningxia provinces, and are more suitable as crossing parents in these areas; while only can be used as crossing parents in Heilongjiang province. In order to improve the shuttle breeding efficacy, and taking into account the genotype mean repeatability for major traits, Chinese scientists should focus on lines with large grain size when selecting materials in CIMMYT for China, choosing lines with short plant height, late maturity for Yunnan, and lines with a little tall plant height and early maturity for Inner Mongolia, Gansu, Ningxia and Xinjiang, lines with a little tall plant height and around the same maturity for Qinghai, while lines for high latitude environment with a little tall plant height and late maturity for Heilongjiang.
    Relationship Coefficient Analysis Among Winter Wheat Varieties and Their Parents in Shandong Province after Liberation
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    Scientia Agricultura Sinica. 2006, 39(04):  664-672 . 
    Abstract ( 909 )   PDF (438KB) ( 1264 )   Save
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    【Objective】 This paper is to probe the relationship and genetic diversity of the winter wheat varieties that selected from liberation to now in Shandong Province. 【Method】 The coefficient parentage is used to analyze the 2145 combinations of 66 winter wheat varieties in nine varieties exchanging. 【Result】 It showed that the relationship exists among 67.44% combinations, the range of COP value of all varieties is 0.00-0.8203 with the average value 0.06249, 21.53% of pedigrees Relationship Coefficients (RC) are higher than the average. The RC of varieties of every year became bigger along with the time, fell in the 90's, and then increased again. The varieties RCs in each year were bigger than that between years, less that that between early and present varieties, while became larger between medium-term and latter varieties. The variety genetic contributions of the same age decreases with the time. The result of clustering analysis on varieties COP values on the basis of the WAP method showed that 63 varieties can be united into 6 big clusters based on different years, and the left three varieties, Xuzhou438, Qida195, Yannong 78 were made into a cluster at the value of 0. The RCs of the 17 varieties which have been extended many area for a long time in Shandong Province were little, with bigger genetic difference, and all those varieties were selected from overseas parents' combinations. The breeding genetic resources of Shandong Province can be traced back to four big core parents system of Biyu, Villa Glori (Zhongnong 28), Luofulin and Youzi wheat on the ground of pedigree analysis. 【Conclusion】 The genetic differences and diversity between varieties were little by little after 1950's.
    Tagging a Novel Yellow Rust Gene YrG775 Derived from Aegilops ventricosa with AFLP Marker
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    Scientia Agricultura Sinica. 2006, 39(04):  673-678 . 
    Abstract ( 1160 )   PDF (996KB) ( 1156 )   Save
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    In this study, the F2 populations crossing by Xinong97148×Guinong775 was Inoculated with the pathology strains CY32 to test their resistance. The Chi-square tests results showed the yellow rust resistance of guinong775 was controlled by two duplicate genes. Screened 128 AFLP primer combinations, the primer combination M8P15 had a polymorphic band about 1200bp linked to the YrG775 (temporarily designed), one of the two duplicate gene. F2 segregations analysis confirmed the band co-segregated with this gene and only Aegilops ventricosa one of the original parents of guinong 775 had this polymorphic band. Since the Yr17 the only yellow rust resistance gene known to be derived from Aegilops ventricosa had no resistance to the pathology strains CY32, the gene YrG775 identified in this paper might to be a novel yellow rust resistance gene.
    TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY
    Studies on the Characteristics of Rice Plant with Heavy Panicle
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    Scientia Agricultura Sinica. 2006, 39(04):  679-685 . 
    Abstract ( 1007 )   PDF (264KB) ( 1156 )   Save
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    【Method】Using 15 indica rice varieties with different panicle weight, some plant type characteristics in heavy panicle type of hybrid rice (HPT) and their relation to yield and its components were studied. 【Result】The leaf area index (LAI) of HPT varieties was lower than that of medium panicle type (MPT) and light panicle type (LPT) varieties, but its decreasing rate of LAI and efficient LAI after heading was slower and had much higher percentage of efficient LAI, specific leaf weight and ratio of grain to leaf area (cm2) in comparison with MPT and LPT varieties. The length, width, thickness and area of top 3 leaves of HPT varieties were significant larger than those of MPT and LPT varieties, and these components of top 3 leaves were significantly and positively correlated with the number of spikelets and filled grains, grain weight per panicle and grain yield. The flag leaf in HPT varieties was erect with sorrow leaf angle, and their leaf angle of 2nd and 3rd leaf from top increased in sequence. The plant height of HPT varieties were higher than that of MPT and LPT varieties, and their leaf site of top 3 leaves also increased in sequence. Therefore, HPT varieties had an ideal plant type and could increase the utilization efficiency of sunlight energy. 【Conclusion】The ideal plant type characteristics and their adjuncts for HPT varieties were proposed in this paper.
    Potassium Supply Affected Plant Nitrogen Accumulation and Translocation and Grain Protein Formation in Winter Wheat
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    Scientia Agricultura Sinica. 2006, 39(04):  686-692 . 
    Abstract ( 1040 )   PDF (399KB) ( 1091 )   Save
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    【Objective】In order to elucidate the regulation mechanism of potassium on plant nitrogen accumulation, translocation, grain protein and protein components formation. 【Method】Two winter wheat (Triticum Aestivum L.) cultivars differing in grain protein content, Ningmai 9 (low protein) and Yangmai 10 (medium protein) were grown to investigate the effects of different potassium rates on plant nitrogen accumulation, translocation of pre-anthesis nitrogen reserves, leaf potassium content at anthesis, and their relationships to the contents of grain protein and protein components.【Result】The potassium supply enhanced total protein content, but the effects of potassium on the contents of globulin and gliadin were significant whereas that was insignificant on glutenin content as compared with the non-potassium treatment. Thus, the ratio of Glu/Gli decreased markedly. Potassium fertilization very markedly enhanced pre-anthesis nitrogen accumulation and stored nitrogen translocation through increasing leaf potassium content at anthesis. Higher leaf potassium content at anthesis very significantly increased post-anthesis nitrogen accumulation of Yangmai 10, but for Ningmai 9, slightly. Compared with Ningmai 9, the role of potassium in raising the contents of grain protein and protein components was greater for Yangmai 10.【Conclusion】Under the experimental condition, the results suggest that post-anthesis nitrogen accumulation, which was very significantly increased by higher leaf potassium content at anthesis, is the vital physiological basis for determining grain protein formation of Yangmai 10, while pre-anthesis stored nitrogen translocation is for Ningmai 9, and the reasonable potassium rate for synchronously improved grain yield and quality of weak gluten wheat Ningmai 9 and medium gluten wheat Yangmai 10 could be K2O 150 and 225 kg·ha-1, respectively.
    Effects of Different Tillage System on the Root Properties and the Yield in Hybrid Rice
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    Scientia Agricultura Sinica. 2006, 39(04):  693-701 . 
    Abstract ( 983 )   PDF (464KB) ( 1445 )   Save
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    【Objective】To ascertain the root properties of hybrid rice and mechanism of increasing yield under different tillage system. 【Method】 The effects of no-tillage (NT) and conventional tillage (CT)on root properties and yield of direct broadcasted (DB) hybrid rice and raise seedlings and transplanted (RT) hybrid rice on the conditions of field experiments were studied. 【Results】 The results showed that the root/shoot ratio, root dry weight, root absorbing surface area and root active absorbing surface in NT at maximum tillering stage were higher than those in CT. Furthermore, the root weight and root weight density in 0-5 cm soil layer and the specific root length in 5-10 cm and 10-20 cm soil layer of NT at mature stage were higher than those of CT no matter which rice establish method was adopted. The root length and root length density and root surface area in 0-5 cm soil layer of NT at mature stage were higher than those of CT, and also the total 32P activity absorbed by rice roots and oxidation ability of rice roots of NT rice at maximum stage were 40.72% and 13.81% higher than those of CT on the average in RT, respectively. In DB condition, the total 32P activity absorbed by roots and the root oxidation ability in NT at maximum stage, booting stage and full heading stage were 54.56% and 12.59%, 19.53% and 24.06%, 2.80% and 74.19% higher than those of CT on the average, respectively. In addition, the partitioning of 32P absorbed by root into aerial parts in NT rice at booting stage was 13.78% higher than that of CT on the average, while the root residual rate of 32P in NT at the same stage was 6.84% lower than that in CT rice on the average. The effective panicle in NT was lower than that in CT, while the spikelet number per panicle in NT was higher than that in CT no matter which rice establish method was adopted. The rice yield of NT rice reached to 8979.0 kg·ha-1and 8588.0 kg·ha-1, increasing by 2.30%, 1.19%, compared with CT on the average on DB and RT condition, respectively, although the difference was not significant between CT and RT. 【Conclusion】 The rice yield superiority in NT was obvious compared with in CT, which was the reaction of good root properties in NT.
    Effects of Molybdenum on the Precursors of Chlorophyll Biosynthesis in Winter Wheat Cultivars Under Low Temperature
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    Scientia Agricultura Sinica. 2006, 39(04):  702-708 . 
    Abstract ( 1321 )   PDF (596KB) ( 1497 )   Save
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    【Objective】 The objective was to probe the site where the biosynthesis of chlorophyll was blocked under Mo deficiency at low temperature which led to the decrease of chlorophyll in winter wheat cutivars. 【Method】The precursors of chlorophyll synthesis were analyzed in winter wheat cultivars in soil culture, miniblock culture, solution culture in order to study the effects of Mo on chlorophyll biosynthesis without Mo addition (CK, soil available Mo 0.112 mg·kg-1) and Mo addition (+Mo, 0.13 mg·kg-1 Mo was added). Levulinic acid (LA), the analog ofδ-aminolevulinic acid (ALA) was also introduced in the experiment. 【Result】The ratios of Chla/Chlb was constant between CK and Mo treatment while it increased at low temperature which indicated that Mo deficiency did not inhibited the transformation of Chl a to Chl b at low temperature. Under Mo deficiency, the contents of protochlorophyll (Pchl), Mg-ProtoporphyrinⅨ (Mg-ProtoⅨ), protoporphyrinⅨ (protoⅨ), uroorphyrinogenⅢ (UroⅢ) decreased, and that of UroⅢ decreased significantly (P<0.01), while ALA and glutamate increased significantly compared to Mo treatment, which suggested that the transformation from glutamate (Glu) or ALA to UroⅢ was inhibited. The content of ALA reversed after addition of LA, it was higher in Mo treatment than in CK, thus disclosed that the transformation from ALA to UroⅢ was blocked under Mo deficiency. 【Conclusion】 The results indicated that the transformation from ALA to UroⅢ was blocked under Mo deficiency, thus inhibited the biosynthesis of chlorophyll and led to the decrease of chlorophyll of winter wheat cultivars.
    PLANT PROTECTION
    Structure and Expression Pattern of Several Putative Cdc42-Interacting Proteins in Magnaporthe grisea
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    Scientia Agricultura Sinica. 2006, 39(04):  709-714 . 
    Abstract ( 1217 )   PDF (513KB) ( 1133 )   Save
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    【Objective】 MgCdc42 (Cdc42 in Magnaporthe grisea), with high homology to ScCdc42 (Cdc42 in Saccharomyces cerevisiae), has been demonstrated to involve in its morphogenesis and infection process. To further dissect the signaling network, the putative MgCdc42-interacting proteins were analyzed. 【Method】 ScCdc42-interacting protein sequences were first used to BLAST against the M. grisea genome database to retrieve their corresponding analogs. Subsequently, conserved domains of these proteins were compared and expression patterns of their encoding genes in different MgCdc42 mutation states were analyzed by semi-quantitative RT-PCR.【Result】All retrieved analogs of ScCdc42-interacting proteins from the M. grisea database have conserved domains as those in S. cerevisiae. Expression of their encoding genes increased in MgCdc42CA mutant, and decreased in MgCdc42KO mutant. However, MgBem1, Chm1 and MgGic1 in MgCdc42DN mutant remained the same expression level as that in the wild type although MgBem4, MgBoi2, MgCdc24, MgGic2, MgRga1 and Mst20 decreased as expected.【Conclusion】 Taking together, we conclude that there may exist a similar Cdc42 signal pathway in M.grisea as in S. cerevisiae and MgCdc42 plays a key role in the pathway.
    Evaluation of Biocontrol Trichoderma on Biology Security
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    Scientia Agricultura Sinica. 2006, 39(04):  715-720 . 
    Abstract ( 1170 )   PDF (317KB) ( 1400 )   Save
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    【Objective】To detect bio-safety of Trichoderma, to evaluate the impact on partial ecological factor after the application of Trichoderma.【Method】Inoculate spores of Trichoderma into seeds, soil and water by means of conventional test methods, to detect its survival in water and its effects on rhizosphere microorganisms and growth of melon, as well as toxicity on mice and white rabbits.【Result】The majority of Trichoderma were safe to sweet-melon seeds and could increase significantly germination ratio, the number of fibrous roots and improve the growth of melon seedling. Trichoderma viride T23 did not show significant effects on the number of fungi, bacteria and actinomyces in rhizosphere soil of sweet-melon and water-melon. Spores of Trichoderma could not germinate in river, well water, rainwater and tap water. Conidiaspores and chlamydospores could survive in water for 12-20 days and 20-30 days, respectively. Trichoderma had no harm on the growth of fish. Meanwhile, it had low toxicity on rats in both stomach and skin toxicity experiments, and no allergic reaction to rabbit skin and mucous membrane of eyes.【Conclusion】Trichoderma is in-noxious and has no pollution , as same as other microbial pesticide. It is no risk using Trichoderma to control soil-spreading diseases.
    Impacts of Environmental Factors on Degradation of Cry1Ab Insecticidal Protein in Leaves of Bt Rice
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    Scientia Agricultura Sinica. 2006, 39(04):  721-727 . 
    Abstract ( 1182 )   PDF (408KB) ( 1304 )   Save
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    【Objective】The environmental fate of Bt insecticidal protein released by Bt rice plants in paddy soils is a key issue in its ecological risk assessment. 【Method】 In the present study, impacts of soil water content, pH and temperature on the degradation of Cry1Ab protein expressed in leaves of Bt rice KMD2 were studied in the laboratory. Three types of paddy soils were used, i.e., blue clayey paddy soil, pale paddy soil on quaternary red soil, and marine-fluvigenic yellow loamy paddy soil. Ground powders of KMD2 leaf-blades were mixed with each type of soil, and degradation dynamics of Cry1Ab were determined using standard ELISA QuantiplateTM kit (EnviroLogix, USA).【Result】The degradation rate of Cry1Ab was high at the early experimental stage, but it slowed down steadily at middle and later stages, which could be described by exponential equations with the half-life period of degradation determined as 1.8-4.0 d. 【Conclusion】The soil water content, pH and temperature could affect the degradation of Cry1Ab, but soil pH and temperature were relatively greater. In general, Cry1Ab degradations were slower under lower soil pH and temperature conditions, especially for marine-fluvigenic yellow loamy paddy soil.
    Cloning and Sequence Analysis of gp41 Gene of Clanis bilineata Nuclear Polyhedrosis Virus
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    Scientia Agricultura Sinica. 2006, 39(04):  728-733 . 
    Abstract ( 1149 )   PDF (306KB) ( 1015 )   Save
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    【Objective】Aim of this research is to clone and analyses the gp41 gene of Clanis bilineata Nuclear Polyhedrosis Virus (CbNPV), which will be helpful to obtain the molecular information of this virus.【Method】CbNPV was purified from Clanis bilineata larva, the genomic DNA was extracted, and a DNA fragment library of the virus was constructed by shotgun. The positive clones were sequenced and we analyzed the open reading frame which has high identity with the gp41 gene of most baculovirus. 【Result】The gp41 gene of CbNPV is 933 bp long and encodes a protein of 310 amino acids. The amino acid sequence analysis indicated that the CbNPV GP41 has 53%-61% and 56%-73% identities with Group I and II NPVs GP41 proteins, respectively. 【Conclusion】The result indicates that the CbNPV isolated by the authors is a novel baculovirus and the CbNPV has more closer relationship with Group II NPVs.
    Gene Cloning and Tissue-Specific Expression of Gqα in Helicoverpa armigera
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    Scientia Agricultura Sinica. 2006, 39(04):  734-740 . 
    Abstract ( 1063 )   PDF (450KB) ( 959 )   Save
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    【Objective】In order to find out the tissue-specific expression of Gqα in Helicoverpa armigera, 【Method】a full-length cDNA, Gqα, was cloned by RACE and named as GqαHarm. And its spatio-temporal expression pattern was studied by Semi-quantitative RT-PCR analysis. 【Result】 GqαHarm was obtained from the antennae. And its open reading-frame was 1062bp, encoding 353 amino acid residues. GqαHarm shares high identity (>90%) with reported Gqα from other insects and the homology with Bombyx mori and its close sib population Mamestra brassicae reached 97.73% and 96.88%, respectively. Semi-quantitative RT-PCR analysis showed that Gqα was not only expressed in antenna, but also in the head without antenna, thorax, leg and wing of H. armigera. There was no obvious difference in the expression in tissues. Moreover, it was also expressed in labial palpus, maxillary palpus and proboscis. Gqα was expressed in egg with a highest level, and in imago with a lowest level; and there was no significant diffenrence in the expression at different stages for the larva and the pupae. 【Conclusion】The spacial and temporal expression pattern indicated that GqαHarm was a ubiquitous protein in Helicoverpa armigera .
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION
    Soil Conservation Tillage--The Highest Priority for Global Sustainable Agriculture
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    Scientia Agricultura Sinica. 2006, 39(04):  741-749 . 
    Abstract ( 1164 )   PDF (271KB) ( 1143 )   Save
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    As viewed from the impacts of agricultural activities on global change and on sustainable agriculture, thus causing an increased and urgent demand for global soil conservation tillage, this paper traces soil conservation tillage research progress in the past, the on-going, and the pioneer science studies abroad, and the current research progress in China. It analyzes the disparities in research aspects in China, from research conducted in length, depth, and methods to its application, as compared to others abroad. As China is a big country with severe soil and water losses, and land degradation problems, however, the current area under conservation tillage only accounts for 0.2% of the area worldwide, and only about 0.1% of China's total arable land area, this situation is indeed far from the increased demand of soil conversation due to the continuing increased degradation of land resource and soil quality. Therefore, strengthening research on soil conservation tillage systems, and soil conservation management in a long-term of "energy-saving and carbon-sequestrating" is of great significance not only for China, but also for global change and sustainable development in agriculture. In view of the lagged behind in soil conservation tillage research and development, and the faced challenge in China for catching up with others, and the involved multiple complicated science problems, and uncertainty factors in agro-ecosystems, such as the interaction of "tillage management-biological progress-environmental change", and the processes of energy and carbon flow, especially the special concerns on carbon sink/source uncertainty in agro-ecosystems, it is necessary using integrated system analysis methodologies, by means of long-term field and theoretical experience abroad, and the developed modeling approaches with interdisciplinary knowledge, to enhance research strength and level for improving carbon sink/source management, mitigating agricultural contribution to global warming, and promoting sustainable agriculture.
    Effects of Land Use on Soil Organic C and Microbial Biomass C in Hilly Red Soil Region in Subtropical China
    Wang XiaoLi,,,,,
    Scientia Agricultura Sinica. 2006, 39(04):  750-757 . 
    Abstract ( 1272 )   PDF (483KB) ( 1301 )   Save
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    【Objective】In order to assess the impacts of land use change on soil organic carbon (SOC) and soil microbial biomass carbon (SMBC), the contents of SOC and SMBC of surface soil samples (0-20 cm) were investigated. 【Method】The dense sampling (the density of sampling for paddy and dry land is 3-4 per ha, for orchard is 2-3 per ha and for woodland is 0.2-0.5 per ha) and the field surveys in Kenfu demonstration area of environmental immigrants of the northwest of Guangxi, a hilly landscape of red soil area of subtropical China were carried out. 【Result】The average contents of SOC, SMBC and the ratio of SMBC and SOC were respectively (17.53±5.02) g·kg-1, (278±174) mg·kg-1 and (1.56±0.84)% in the area, respectively. The average contents of SOC, SMBC and the ratio of SMBC and SOC of the woodland were (17.53±5.02) g·kg-1, (278±174) mg·kg-1 and (1.58±0.39)%, respectively. Compared with the woodland, the contents of SOC and SMBC and the ratio of SMBC and SOC of the paddy field increased by 15.5%, 84.0% and 73.9% (P<0.01); The content of SOC of the dry land (17.50±4.89 g·kg-1) decreased slightly (P>0.05) compared with the woodland, that of SMBC and SMBC/SOC decreased by 29.1% and 24.2% (P<0.01); The content of SOC, SMBC and SMBC/SOC of the orchard decreased by 26.8%, 46.1% and 26.1% compared with the woodland (P<0.01). In addition, there were significant correlations between SOC and SMBC in different land use except the paddy field. 【Conclusion】This study indicated that the conversion of woodland into paddy field increased the accumulation of SOC and the microbial activity evidently in the hilly landscape of red soil area of subtropical China. However, the conversion of woodland into dry land or orchard reduced the content of SOC and the microbial activity to different degrees.
    Soil Water Effect and Productivity in Poplar and Wheat-Corn Agroforestry System
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    Scientia Agricultura Sinica. 2006, 39(04):  758-763 . 
    Abstract ( 1123 )   PDF (342KB) ( 803 )   Save
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    【Objective】An experiment was carried out to study the rule of soil water consumption in poplar agroforestry system in water-lacking plain area in order to provide the arguments for the sustainability of poplar agroforestry from the viewpoint of water. 【Method】 Soil water content was measured by neutron machine and production of crops and poplar was measured. 【Result】Results indicated that in 2-5 years tree system: (1) the water consumption of poplar ageoforestry system is higher than the mode of sole wheat-corn by 24%; The pondage decreased by 32.1 mm in 0-4 m depth, which equaled 3.3% of the total pondage; It trended that soil from 2 to 4 m depth was becoming dry because no water supplement. (2) The production of crops in agroforestry decreased seriously because of lacking of soil water and illumination and so on, production of wheat and corn in 3 years agroforestry system decreased by 35%.【Conclusion】Poplar agroforestry system popularized in Haihe low plain threatens the security of water and food production.
    The Spatial-Temporal Variability of Soil Organic Matter and Its Influencing Factors in Suburban Area of Beijing
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    Scientia Agricultura Sinica. 2006, 39(04):  764-771 . 
    Abstract ( 1237 )   PDF (535KB) ( 1935 )   Save
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    【Objective】The objective of this study was to explore the spatial-temporal variability of soil organic matter (SOM) and its influencing factors, and to provide a firm scientific foundation for soil fertility assessment and management. 【Method】SOM content in arable layer in 1980, 1990 and 2000 in Daxing County of Beijing was obtained by collecting data in the Second National Soil Survey (SNSS) and recent measures. The general statistics and geostatistics methods were used to analyze the data. 【Result】The average SOM content at different times were 9.64 g·kg-1, 12.76 g·kg-1 and 12.69 g·kg-1, respectively. The semivariance analysis showed that their spatial correlation distances at different times were 80.5 km, 59.2 km and 49.0 km, respectively, showing a descending trend. Kriging method was applied to estimate the unobserved points and as a result SOM content contour maps were derived, and the map indicated a decreasing trend from north to south across the county for SOM content. The SOM content had been classified into six categories (bellow 6, 6 to10, 10 to 12, 12 to 15, 15 to 20 and above 20 g·kg-1) according to the standards set by SNSS. The SOM changed slowly from low to high category based on the accumulation of SOM in the low category from 1980 to 2000. During the last 20 years, the area with the highest and the second highest category of SOM content changed from 0 to 8.0% and 14.3% of the total area. The area with the third category for SOM content increased from 23.0% to 37.1% of the total area, respectively. The area with the forth category for SOM content decreased little, about 2.19% of the total area. The area with the fifth category for SOM content decreased sharply, about 50.4% of the total area. 【Conclusion】SOM content increasing trend might be attribute to the widespread practices of mulching and organic manure application. With the yield improvement, some regions have exhibited SOM deficit and attention should be paid to the fertilization of SOM.
    HORTICULTURE
    Evaluation of Salt Resistance of Cucumber at Seed Germination and Rootstock-Seedling Stages
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    Scientia Agricultura Sinica. 2006, 39(04):  772-778 . 
    Abstract ( 1123 )   PDF (259KB) ( 1301 )   Save
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    【Objective】Salt resistance ability screening of different genotypes of cucumber (scion) and rootstock is the basis research work for the evaluation of salt resistance ability. 【Method】Salt resistance of 20 cucumber cultivars at seed germination stage and 22 species of rootstocks at seedling stage were evaluated by using cluster analysis. Relative trend of germination, relative percentage of germination and relative germination index of cucumber seed and salt injury index of rootstock were used to detect the salt resistance of cucumber seeds and rootstock. 【Result】Zaoduojia, Huazao 2, Zhongnong 8, Jinyu 1 and Jinyou 3 held high resistance to salt stress, whereas Jinguan 1, Xuyou 1, Jinchun 5, Jinchun 4, Dongfangmingzhu, Xiangzao 3, Tezao 1 and Jinyou 1 were moderately salt tolerant, but Baipihuanggua, Ningfeng 8, Meinong 4, Jinchun 3, Jinza 4, Jinza 2 and Jinchun 2 cucumber cultivars were sensitive to salt stress. Rootstocks could be clustered to two groups, Cucurbit pepo L. cv. Chunbaiyu, Zaoqingyidai and Jizao xiuyu, Cucurbita moschata Duch. cv. Tiejiangjun F1were sensitive to salt stress whereas the other species of rootstocks were tolerant to salt stress, and salt resistant rootstocks could be clustered to three subgroups, Lagenaria siceraria Standl. var. clavata Makino cv. Xiaoganhugua, Tongxinhugua, Hanlongbiyu and Chaofeng8848 showed the highest salt resistance, Cucurbit ficifolia cv. Heizinangua exhibited tolerant, whereas the other thirteen species showed more salt resistance. 【Conclusion】Salt resistance ability varied with different genotypes of cucumber(scion) and rootstock, and the salt resistance ability of cucumbers and rootstocks could be screened at germination stage and seedling stage, respectively.
    Effects of Restricted Root Volume on Growth and Development of Young Peach Trees
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    Scientia Agricultura Sinica. 2006, 39(04):  779-785 . 
    Abstract ( 940 )   PDF (212KB) ( 1070 )   Save
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    【Objective】The root restriction method and root volume were studied in order to control the growth of peach in high density orchard. 【Method】The effects of root confinement on the vegetative and reproductive growth of young peach trees, nectarine Huaguang, were investigated during the first 3 years after planted in buried bed, raised bed and box, respectively. 【Result】Root confinement inhibited the vegetative growth of the above-ground parts. The biomass and weight of winter pruning decreased as well as the length and diameter of shoot with root confinements. Root confinement had no noticeable effects on the height, trunk diameter and canopy size of trees if root volume was bigger than 150 L. Trees grown in raised bed and box had smaller vegetative vigor than those in fabric-lined trench. The improvement of flower formation was observed in the second season after treatment but not in the first season. Proper root volume increased fruit-set rate and yield without affecting fruit size and SCC. But too small root volume reduced those indexes.【Conclusion】The proper root volume and root restriction method were discussed and the volume 100-150 L for peach Huaguang in high density (1 m×2 m) was recommended. The root volume should be relatively smaller for the method of fabric-lined trench.
    Analysis of Influence on Different Raw Materials on Volatile Aroma Compounds of Ciders
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    Scientia Agricultura Sinica. 2006, 39(04):  786-791 . 
    Abstract ( 1265 )   PDF (357KB) ( 1610 )   Save
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    【Objective】The aim is to analyze the influence on different raw materials including apple juice concentration and ten varieties of fresh apple juices on volatile aroma compounds of ciders.【Method】Multivariate analysis was carried out by SPME/GC/MS to detect the major volatiles. 【Result】Significant principal components allowed the structure of the database to be visualized as a function of the raw material, that is, cider made from fresh apple juice versus cider made from apple juice concentrate. Feasible and robust discriminant rules could be used to classify the fresh and concentrated cider and the obtained classification was >93%. The most discriminating variables for typifying ciders according to their raw materials were 3-methyl-1-butyl acetate and ethyl acetate. The main volatile aroma compounds of ciders on the basis of cider varieties are 3-methyl-1- butyl acetate, 2-phenylethyl acetate, butyl acetate; ones of ciders on the basis of dessert and juice varieties were 1-hexanol, 1-butanol, haxanoic acid. 【Conclusion】We thus have an analytical tool to detect fraudulent practices.
    The Relationship Between Lignification and Endogenous Hormone Content of Excised Bamboo Shoots
    Scientia Agricultura Sinica. 2006, 39(04):  792-797 . 
    Abstract ( 1189 )   PDF (368KB) ( 1212 )   Save
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    【Objective】In order to study the mechanism of lignification and research on the impacts of endogenous hormone (IAA, GA3, ABA) on lignification in excised bamboo shoots. 【Method】The relationship between endogenous hormone (IAA, GA3, ABA) levels and enzyme activities related to lignification of Phyllostachys praecox f. preveynalis and Phyllostachys pubescens Mazel were investigated. 【Result】The content of GA3 and IAA in the two bamboo shoots declined continuously, but ABA content increased initially and declined later. The content of endogenous hormone (IAA, GA3, ABA) in excised bamboo shoots of Phyllostachys praecox f. preveynalis were higher than those of Phyllostachys pubescens Mazel. The activities of phenylalanine ammonia lyase (PAL), 4-coumarate CoA ligase (4CL) and peroxidase (POD) increased initially and declined later during the storage. The content of lignin and cellulose and firmness of bamboo shoots continuously increased. The activities of PAL, 4CL and POD were significantly correlated with the ratio of ABA/GA3. 【Conclusion】These results indicated that the ratio of ABA/GA3 is very important for lignification in excised bamboo shoots. The lignification of excised bamboo shoots maybe retarded when the activities of PAL, 4CL and POD were inhibited by decreasing ABA/GA3 ratio.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    The Evidence of the Origin of a Polymorphic High Molecular Weight Protein in Sow Milk
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    Scientia Agricultura Sinica. 2006, 39(04):  798-801 . 
    Abstract ( 1007 )   PDF (323KB) ( 778 )   Save
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    【Objective】 High molecular weight proteins (HMWP) in sow milk showed four variants of A, B, C, and D by SDS-PAGE, the origin of HMWP-B was studied by this paper.【Method】The experiment is carried out by immunoblotting with the rabbit anti- HMWP-B polyclonal antibody. 【Results】The results show that there is no HMWP-B in the serum of the sow, and suggest that HMWP-B is synthesized and secreted by mammary cell. Besides, the result of immunoblotting of cow and rabbit milk with the rabbit anti- HMWP-B polyclonal antibody indicated that there is no homologous protein of HMWP-B in cow and rabbit milk. So, it was presumed that HMWP-B might only exit in sow milk. 【Conclusion】The result of this study provides a proof for the hypothesis that HMWP-B is not originated from the blood.
    PCR-SSCP Analysis on Exon 2 of Growth Differentiation Factor 9 Gene in Goats
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    Scientia Agricultura Sinica. 2006, 39(04):  802-808 . 
    Abstract ( 986 )   PDF (325KB) ( 1086 )   Save
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    【Objective】The objectives of the present study were firstly to detect polymorphisms in the growth differentiation factor 9 (GDF9) gene, and secondly to investigate the association between GDF9 gene and high prolificacy in Jining Grey goats. These results will provide a scientific basis for marker-assisted selection for high prolificacy in goats.【Method】The GDF9 gene which controls the fecundity of Belclare and Cambridge ewes was studied as a candidate gene for the prolificacy in Jining Grey goats. According to the sequence of ovine GDF9 gene, four primer pairs were designed to detect single nucleotide polymorphism of exon 2 of GDF9 gene in both high fecundity goat breed (Jining Grey goat) and low fecundity goat breeds (Boer goat, Wendeng dairy goat, Liaoning Cashmere goat, Beijing native goat) by PCR-SSCP. 【Result】The results indicated that the homology of nucleotide sequence of exon 2 of GDF9 gene between goats and sheep was 99 percent. The products amplified by primer 1 and primer 4 displayed polymorphism. For primer 1, three genotypes (AA, AB and BB) were detected in all five goat breeds. The sequencing results indicated that there was one single nucleotide mutation (G26→A26) at exon 2 of GDF9 gene in goats, but this mutation did not cause amino acid change. Frequency of allele A was 0.9128, frequency of allele B was 0.0872 in Jining Grey goats. The does with genotype AA had 0.54 (P<0.01) or 0.63 (P<0.01) kids more than those with genotype AB or BB in Jining Grey goats, respectively. For primer 4, three genotypes (CC, CD and DD) were detected in all five goat breeds. The sequencing results showed that there was one single nucleotide mutation (G792→A792) at exon 2 of GDF9 gene in goats, and this mutation resulted in an amino acid change: valine→isoleucine. Frequency of allele C was 0.9266, frequency of allele D was 0.0734 in Jining Grey goats. The does with genotype CC had 0.57 (P<0.01) or 0.62 (P<0.01) kids more than those with genotype CD or DD in Jining Grey goats, respectively.【Conclusion】These results preliminarily showed that the GDF9 gene is either a major gene that influences the prolificacy in Jining Grey goats or a molecular marker in close linkage with such a gene.
    The Contrast of The Damage to Animal and Plant Cell by Secondary Metabolites of Rhizoctonia leguminicola
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    Scientia Agricultura Sinica. 2006, 39(04):  809-813 . 
    Abstract ( 865 )   PDF (373KB) ( 818 )   Save
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    【Objective】The damage effect and cellular biological relationship of animal and plant cell by Rhizoctonia leguminicola and its secondary metabolites was stueied. All these can provide new thoughtfulness for the study on toxicology. 【Method】The Rhizoctonia leguminicola and the secondary metabolites of Rhizoctonia leguminicola were interfused into feedingstuff of the rabbit, and these rabbits were fed for 17 days, then the rabbits were killed and pathological obserbvation of brain, liver, kidney was carried out under optical microscope and TEM. 【Result】In the experiment of the damage effects of cells from animal and plant body by the secondary metabolites of Rhizoctonia leguminicola, the rabbit brain and lymphocyte showed vacuolar degeneration, and the granule of ribosome was broken off in neurocyte, and also expressed dilatation of RER. And the plant root tissue expressed the structural damage, and the cell showed vacuolar degeneration and breach of the inner membrane. 【Conclusion】These results show that the reason of poisoning of Rhizoctonia leguminicola to animal is that SW in the secondary metabolites bring into important play, and this effect is identical with locoweed toxicosis basically. The damage of the plant cell had positive correlation with the content of SW in the the secondary metabolites of Rhizoctonia leguminicola. It is suspected that SW is not only a kind of important toxin in the toxicosis of animal, but also a sort of chemical substance in the cell damage of legume plant.
    Study on the Construction and Expression of SM Strain of Classical Swine Fever Virus E2 Gene in E.coli
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    Scientia Agricultura Sinica. 2006, 39(04):  814-818 . 
    Abstract ( 1257 )   PDF (390KB) ( 1248 )   Save
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    【Objective】The E2 gene of Classical swine fever virus was expressed in prokaryotic expression system to obtain soluble fusion protein. 【Method】 Four antigen regions of E2 gene were amplified from recombinant plasmid S21 by the Polymerase Chain Reaction (PCR). The four amplified fragments were cloned into pMAL-P2X vector, respectively. It was identified that the position and the size and the reading frame of the four recombinant vectors were all correct by RCR, restriction digestion and the sequence analysis. Then the four recombinant vectors were transducted into four expression germs and 16 strains of germs were obtained. 【Results】SDS-PAGE indicated that these germs could express antigen region of E2 gene of CSFV and Western-blot indicated that these objective proteins could be recognized by the positive serum of CSFV and monoclonal antibody which is to E2 gene of CSFV. 【Conclusion】The antigen regions of the aimed gene were selected to be expressed, which could benefit the expression of soluble fusion proteins, and the speciality of serological reaction is satisfied.
    Establishment of the Method of Immunohistochemistry Assay for the Detection of Scrapie by Monoclonal Antibody
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    Scientia Agricultura Sinica. 2006, 39(04):  819-824 . 
    Abstract ( 1166 )   PDF (408KB) ( 791 )   Save
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    【Objective】The method of immunohistochemistry assay for the detection of Scrapie by monoclonal antibody was established.【Method】Genomic DNA was isolated from the ovine whole blood. Using the polymerase chain reaction to amplify the core part of PrP from the ovine Genomic DNA. By using the recombinant DNA technology, the recombinant protein of core part of PrP was obtained. Then using standard methodology of myeloma cell fusion, monoclonal antibodies were obtained to detect Scrapie by immunohistochemistry.【Results】The recombinant protein of core part of ovine PrP was obtained and a panel of six hybridoma cell lines secreting specific antibodies to core part of PrP related to Scrapie were established from one fusion between myeloma Sp2/0 and spleen cells from mice immunized with the purified recombinant protein. Four hybridoma cell lines can be used in immunohistochemistry assay for the detection of Scrapie.【Conclusion】The recombinant core part of PrP and special Mabs was obtained by using recombinant DNA and myeloma cell fusion technology. So the special monoclonal antibody developed in authors university can be used to detect PrPsc of Scrapie by immunohistochemistry.
    Enhanced Protective Efficacy of Avian Influenza DNA Vaccine with Expressive Vector pCAGGS
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    Scientia Agricultura Sinica. 2006, 39(04):  825-830 . 
    Abstract ( 1522 )   PDF (460KB) ( 1684 )   Save
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    【Objective】 To improve the protective efficacy of H5 subtype avian influenza DNA vaccine, the HA gene of A/Goose/GuangDong/1/96(H5N1) [GD/1/96(H5N1)] was inserted into pCAGGS, which contains chickenβ-actin promoter, and was designated as pCAGGHA5. 【Method】The monolayer 293T cells were transfected by pCAGGHA5 and pCIHA5, which contained HA gene of GD/1/96(H5N1). The HA protein expression was detected by indirect immunofluorescence assay 24-48 h after transfection and confirmed by western blotting analysis. To evaluate the vaccine efficacy, groups of 3-week-old SPF chickens were intramuscular inoculated with 100 μg or 10 μg of pCIHA5, pCAGGHA5, respectively. A group of chickens were injected with 200 μl PBS as control. Four-weeks after the single vaccination, all chickens were challenged with 100 LD50 of highly pathogenic GD/1/96(H5N1). 【Results】 In vitro expression results indicated the gene in the pCAGGS vector was better expressed than that in the pCI vector. The chickens in the 100μg and 10μg pCAGGHA5 immunized groups were completely protected from virus challenge (no disease signs, no virus shedding and no deaths), and 100μg pCIHA5 immunized groups only provided partial protection, while the chickens in the pCIHA5 immunized group and the control group died within ten days. 【Conclusion】 Results shown that expressive vector optimization enhanced the protective efficacy of H5 subtype avian influenza DNA vaccine.
    RESEARCH NOTES
    Correlation Between Genetic Distance and Yield Heterosis of Hybrid Aromatic Rice
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    Scientia Agricultura Sinica. 2006, 39(04):  831-835 . 
    Abstract ( 1197 )   PDF (252KB) ( 1197 )   Save
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    【Objective】 Correlation between genetic distance and heterosis in an important question in hybrid rice breeding. 【Method】 The genetic distance of the aromatic rice parents and the relativity analysis were studied by SSR in this article. 【Result】 The relativity coefficient was partial to small(-0.257-0.292)between SSR genetic distance and heterosis of four yield traits. The correlation between the genetic distance of the aromatic rice parents selected and the yield heterosis was not significant. 【Conclusion】So, SSR markers selected in this study couldn't predict rice heterosis. The research indicated that different or opposite results would be gained with different materials. Thus, the analysis of genetic distance based on molecular markers predicting the yield heterosis need to be studied further.
    Establishment of Math Models of NIRS Analysis for Protein Contents in Seed and It′s Application in Rice Breeding
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    Scientia Agricultura Sinica. 2006, 39(04):  836-841 . 
    Abstract ( 958 )   PDF (302KB) ( 1186 )   Save
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    【Objective】To analyze the genetic variability of protein content in rice hybrid progenies, the feasibility of building calibration model to estimate crude protein content in intact rice kernel by near-infrared reflectance spectroscopy (NIRS) was studied. It is beneficial to provide the parameter and improve nutritional quality in grain breeding program. 【Method】Using 191 rice samples with a broad range of crude protein content, 5.90%-14.50%, as materials, the chemometrical method of partial least square regression was used to establish the calibration model. 【Result】 The optimal model was developed by the spectral data pretreatment of the first derivative + vector normalization in 11 998.9 cm-1-5 449.8 cm-1 and 4 601.3 cm-1-4 246.5 cm-1, by analyzing different spectral data pretreatment and light frequency ranges. This model's determination coefficient and relative standard deviation (RSD) were 0.9886 and 0.021, respectively. The model showed significant correlation and lower error between near-infrared value and true value, and had lower root of mean square errors than 0.4. The crude protein contents of another 205 seed samples (nondestructive brown rice) from the F2 populations of 20 crosses were estimated by the calibration model. The Mahalanobis distance of 203 individuals in F2 populations predicted by the model were lower than 0.3, and showed higher calibration precision. The results showed those populations had wide variation among individuals in crude protein content. In general, the great majority was in the middle of both counterpart parent, but some of them were found higher or lower than their parents in crude protein content, and the highest value reached 15.3%. 【Conclusion】Good calibration equation was successfully developed for protein content, the equation show satisfactory determination coefficients. The samples were scanned by NIRS and analyzed the protein content in parents and hybrid progenies. Finally, a probably effective way to improve protein content of rice was proposed: Firstly,the breeder makes some crosses between promising rice varieties with high yield and good quality and rice resource germplasm with high protein content, and secondly, the NIRS is used to evaluate protein content of the nondestructive brown rice in their early progeny population. This NIRS-assisted-selection could be a very efficient method to improve protein content in rice breeding programs.
    Localization and Function Analysis of Wheat Glycogen Syntheses Kinase (TaGSK 1)
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    Scientia Agricultura Sinica. 2006, 39(04):  842-847 . 
    Abstract ( 1024 )   PDF (550KB) ( 1486 )   Save
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    【Objective】The localization and function of wheat glycogen synthase kinase (TaGSK1) in plant cells was studied. 【Method】Tagsk1 gene linked with gfp gene was transformed into Arabidopsis via Agrobactiria. Arabidopsis containing gfp was used as control, the distribution of TaGSK1 in root cells was observed with laser confocal microscope. Different transgenic plants were planted in MS medium containing different concentrations of NaCl for screening salt-tolerant plants. Using the wild type Arabidopsis as control, the length of taproots was measured on the seventh day and the lateral roots number was counted on the ninth day. 【Result】 It was found that the green fluorescence of fused protein TaGSK-GFP distributed in cytoplasm of the transgenic plant cells, and mainly in root meristem and stelar sheath, where new roots would develop. Significant difference (P<0.01) existed between transgenic plants and their control plants about the root number and length. 【Conclusion】It is suggested that TaGSK1 localized in cytoplasm and could improve cell proliferation, development, anti-osmotic and anti-stress ability of transgenic plants.
    Analysis on Contribution of Yield Components to Main Fiber Traits in Upland Cotton (Gossypum hirsutum L.)
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    Scientia Agricultura Sinica. 2006, 39(04):  848-854 . 
    Abstract ( 971 )   PDF (308KB) ( 771 )   Save
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    【Objective】An experiment was carried in 2003-2004 to elucidate the contribution from 3 yield components to 3 fiber traits for indirect selection fiber traits.【Method】Using additive-dominance-maternal genetic model (ADM model) which considered genotype × environment interaction effects (GE) in F1 intraspecific (Gossypum hirsutum L.) hybrids of (5×5) complete diallel cross for two years, the contribution ratios and contribution effects were analyzed from 3 yield components to 3 fiber traits.【Results】There were highly significant additive effects contribution from 3 yield component traits to 3 fiber traits (CRAS ranging from 12% to 76%), and boll weight had high dominance contribution ratio on micronaire (CRD =58%). Both boll number and lint percentage had most high maternal effects contribution ratio on fiber length(CRM=100%), while boll weight had a constraint effect on maternal effects of fiber length (CRM=-60%). There was a large contribution of dominance by environment interaction effects of lint percentage on fiber length, and maternal by environment interaction effects of boll weight and lint percentage on fiber length (CRDE=47%,CRME=56% and CRME=33%), and constraint maternal by environment interaction effects of lint percentage on fiber length (CRME= -83%). There was a high dominance by environment interaction contribution effects of boll number on fiber strength and boll weight on micronaire (CRDEs were CRDE= -40% and CRDE= -87%). Any individual parent could have the most contributions of additive and maternal effects due to yield component traits on fiber traits. There were most additive contributions on fiber length of these parents from boll weight of parent 3, boll number of parent 5, and on fiber strength from boll number of parent 3 and boll weight of parent 5, and negative largest additive contribution on micronaire from boll number of parents 3 and 5. The dominant effects of micronaire were mainly influenced by boll weight for many crosses. 【Conclusion】There existed large different contribution ratios from 3 yield components to 3 fiber traits, and any individual cross and parent could have the different genetic components contributions due to yield component traits on fiber traits.
    Effects of Phosphorus-Deficiency Stress on Ethylene Emission in Asparagus Bean Seedlings
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    Scientia Agricultura Sinica. 2006, 39(04):  855-859 . 
    Abstract ( 983 )   PDF (292KB) ( 797 )   Save
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    【Objective】To probe the role of ethylene in asparagus bean [Vigna unquiculata W. ssp. sesquipedalis (L.) Verd] response to phosphorus-deficiency stress. 【Method】Changes of ethylene emission in seedlings of 3 asparagus bean cultivars differing in tolerance to phosphorus-deficiency were studied in 2 treatments (+P and -P) in soilless-culture experiment. 【Result】Ethylene emission in asparagus bean seedling increased under P-deficiency stress. The increase of ethylene emission in root of cv. Luhuabai (high P-deficiency-tolerance) > cv. Xianggangqing (middle P-deficiency-tolerance) >cv. Erlubai (low P-deficiency-tolerance). The increase of ethylene emission in older leaf and stem of cv. Erlubai>cv. Xianggangqing> cv. Luhuabai. The increase of ethylene emission in youngest fully-expanded leaf of cv. Luhuabai >cv. Erlubai>cv. Xianggangqing. There was a little increase of ethylene emission in younger leaf and stem. 【Conclusion】The results indicated that the increase of ethylene emission in asparagus bean root and older stem and leaf might induced morphological changes in root and stem under phosphorus deficiency stress, then enhanced the ability of phosphorus acquisition and free radical scavenging in root, enhanced translocation of nutrient and water, thus enhanced the adaptability of asparagus bean seedlings to phosphorus deficiency stress .
    Cloning and Sequence Analysis of the 18S Ribosomal RNA Gene from Four Trichinella Isolates
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    Scientia Agricultura Sinica. 2006, 39(04):  860- . 
    Abstract ( 873 )   PDF (299KB) ( 1043 )   Save
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    【Objective】The taxonomy and species identification of Trichinella spiralis has been received attention by many scholars. The authors try to determine the different Trichinella spiralis isolates through molecular genetic mechanism and be the base of the traditional taxonomy. The gene segment in 18S ribosome RNA gene of four Trichinella isolates were cloned and sequenced. 【Result】The sequence was compared and analysed by using DNAsis software, and the results showed that the homology of 18SrRNA gene of HH and T. spiralis was 99.4%, that of HC and Trichinella nativa was 99.3%. The Swine isolate belong to T. spiralis, the Dog isolate belongs to T. nativa. The result was consistent with the traditional taxonomy. 【Conclution】The result has provided a strong evidence for the traditionary taxonomy and be the base of the epidemiology and precention to Trichinellosis.