Table of Content

10 August 2005, Volume 38 Issue 08

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES

Mapping of Heading Date QTLs in Rice (Oryza sativa L.) Using Single Segment Substitution Lines

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Scientia Agricultura Sinica. 2005, 38(08):  1505-1513 . 

Abstract ( 1302 )   PDF (343KB) ( 1157 )   Save

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Heading date (HD) is an important agronomic trait in rice. Appropriate heading date is a prerequisite for attaining the desired yield level in rice breeding programs. It is very important for rice improvement to map heading date quantitative trait loci (QTLs). Single segment substitution lines (SSSLs) containing only one segment of donor chromosome are useful tools for precise mapping of QTLs and for the evaluation of gene action. In this research, the QTLs for heading date on the substituted segments of 52 rice SSSLs derived from 6 advanced backcrosses were identified through t-test for means comparisons between SSSLs and the recipient parent Huajingxian 74. QTLs were detected with a significance of P≤0.001. A total of 20 QTLs were identified on 10 rice chromosomes with the exception of chromosomes 5 and 6. The QTL additive effect ranged from -5.9 to 1.1, and the additive effect percentages of the QTLs ranged from -7.4% to 1.4%. Eight QTLs were mapped in intervals less than 10.0 cM. qHD-3-1, a dominant gene for early heading, has been mapped using a F2 population developed from a cross between a SSSL and Huajingxian 74. In mapping population the segregation ratio of early and late heading plants was in accordance with 3:1. qHD-3-1 was located between microsatellite markers PSM304 and RM569 on the short arm of chromosome 3 at genetic distances of 2.4 cM and 5.1 cM, respectively.

Analysis of Waxy Proteins in Chinese Winter Wheat Cultivars Using SDS-PAGE and Molecular Markers

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Scientia Agricultura Sinica. 2005, 38(08):  1514-1521 . 

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A total of 306 wheat cultivars and advanced lines from China, US and Australia were screened for the Waxy protein by SDS-PAGE. The results indicated that 46 of these cultivars were the null Wx-B1 type. The proportion of individuals with null Wx-B1 in 120 F2 progenies derived from the Jimai19×Yumai47 was 1/4 approximately, in accordance with the theoretical ratio. Three STS and 1 SSR markers were used to analyze the wheat cultivars with different types of Waxy proteins. Validation of the markers was carried out for the detection of Wx-7A, Wx-4A and Wx-7D genes. The results indicated that a 1172 bp-fragment was amplified with Wx-7A specific STS marker from the wild genotypes, while the fragment was absent for the mutant with null Wx-A1; a 440 bp-fragment was detected with Wx-4A specific STS marker from the wild genotypes, whereas, the fragment was absent for the mutant with null Wx-B1; a 940 bp-fragment was amplified with Wx-7D specific STS marker from the wild genotypes, and a 360 bp-fragment was found for the mutant such as 'Baihuomai' with null Wx-D1; and a 204 bp-fragment was detected with Wx-7D specific SSR marker from the wild genotypes, while the fragment was absent for the mutant with null Wx-D1. These markers are useful tools to identify wheat cultivars with mutant and normal alleles of the Waxy genes in marker-assisted selection of wheat breeding programme.

Comparison of Genetic Diversity of Twelve Elymus Species Using ISSR and SSR Markers

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Scientia Agricultura Sinica. 2005, 38(08):  1522-1527 . 

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In order to compare the usefulness of ISSRs and SSRs in Elymus species, 33 ISSR primers and 137 wheat SSR primer pairs were employed to detect 12 species of Elymus in this study. The results indicated that 18 ISSR primers and 14 wheat SSR primer pairs were available to analysis genetic diversity of Elymus species. PCR analysis for 12 species showed that both ISSR and SSR markers appear high polymorphism, whose percentage of polymorphic bands were 84% and 91%, respectively. The results of cluster analysis based on ISSR and SSR markers were coincided highly with ploidy level and morphologic taxonomy. For 12 species, ISSRs (10.2) got a MI (marker index) value 1.4 folds higher than that of SSRs (4.3), whilst SSRs had a higher MI than that of ISSRs for 4 near related species, E. excelsus, E. cylindricus, E. tangutorum and E. dahuricus. Mantel test revealed that the relation of genetic similarity matrix between ISSRs and SSRs was significant (r=0.856, t=6.446) for 12 species, but not significant (r=0.679, t= 1.595) for 4 near related species. The variance of maker utility and relateness between the two types of markers at different consanguinity levels showed different effective diversity detection scopes of ISSRs and SSRs.

Genetic Analysis of Upland Cotton Germplasm Obtained from Introduced DNA from Island Cotton

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Scientia Agricultura Sinica. 2005, 38(08):  1528-1533 . 

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The genomic DNA of island cotton (Gossypium barbadense L. cv. Hai7124) was introduced into the upland cotton (G. hirsutum L. cv. Shiyuan321) by pollen tube pathway technique. New germplasm of high quality of fiber and a mutant with obviously change of morphology were obtained. Genetic analysis of the mutant indicated that the phenotype of the mutant was possibly controlled by a dominant allele that has homologous lethal effect. The result of SSR (simple sequence repeats) analysis showed that at least some exogenous DNA fragments were integrated into the genome of upland cotton Shiyuan321. It is deduced that some of the DNA fragments were integrated by homologous recombination mechanism.

Tagging and Utilization of Bruchid Resistance Gene Using PCR Markers in Mungbean

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Scientia Agricultura Sinica. 2005, 38(08):  1534-1539 . 

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Polymerase chain reaction (PCR) conditions suitable for discriminating mungbean bruchid resistance genotypes were determined. Sixteen accessions were examined with 56 random primers which produced different PCR bands among them. These mungbean accessions can be classified into 4 groups, i. e., the wild-type resistance group (TC1966), the cultivar resistance group (V2709), the progeny resistance group(VC3890A2/TC1966-23) and the susceptible varieties with their progenies group. Mungbean cultivars with bruchid resistance or susceptibility and their crosses F2 of bruchid resistance wild-type with susceptible cultivar were used as materials in this experiment. By using BSA method, two codominant PCR markers were identified through the resistant (susceptible) bruchid cultivars bulks and the resistant (susceptible) bruchid bulks of a F2 population. There was a 1.03 kb band in the susceptible individuals and a 1.79 kb or two 1.79 kb/1.03 kb bands in the resistant individuals. It is sreculated that the markers are closely linked with TC1966 bruchid resistance/ susceptible elleles, and they can be applied in bruchid resistance identification of the mungbean and markers-assisted selection in bruchid resistance breeding of mungbean.

TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY

Quantitative Analysis of Fat Content in Brown Rice by Near Infrared Spectroscopy (NIRS) Technique

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Scientia Agricultura Sinica. 2005, 38(08):  1540-1546 . 

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Based on NIRS technique and partial least squares (PLS) algorithm, two calibration models were established to analyze quantitatively fat content (FT) in brown rice grain and brown rice flour, respectively. The determination coefficients (R2) of these two models for FT were 94.44% and 95.54%, and the root mean square errors of cross validation (RMSECV) were 0.09% and 0.08%, respectively. In external validation, the R2 value between the true value and predicted value were 79.51% and 87.10% for FT in brown rice grain and brown rice flour, and the root mean square errors of prediction (RMSEP) were 0.24% and 0.26%, and the average relative errors were 4.11% and 3.30%, respectively. These results indicated that the method of NIRS has relatively high accuracy in prediction tests for FT in brown rice grain and brown rice flour and that the two mathematic models established in the present study should be useful for nutrient quality improvement in rice breeding program.

Effects of Nitrogen Fertilizer Rate on Nitrogen Metabolism and Protein Synthesis of Superior and Inferior Wheat Kernel

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Scientia Agricultura Sinica. 2005, 38(08):  1547-1554 . 

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Effects of nitrogen fertilizer rate on nitrogen metabolism and protein synthesis of the superior and inferior wheat kernel were studied. The results showed that the protein content and accumulation amount of the superior kernel were higher than that of the inferior kernel during filling, and that GS (glutamine synthetase) activities during 21 days after anthesis and free amino acids content during 28 days after anthesis in super kernel were significantly higher than that of inferior kernel, which accounted for the faster protein accumulation in the superior kernel. At maturity, with the same nitrogen fertilizer rate, the content of albumin, gliadin, glutenin and GMP (glutenin macropolyer) of superior kernel was higher than that of inferior kernel, while the globulin content in superior kernel was lower. Appropriate application of nitrogen fertilizer increased the protein content and accumulation amount in kernel, and decreased the difference in free amino acids content, soluble protein content and GS activity between superior kernel and inferior kernel, and the difference in protein content and accumulation amount. With nitrogen supply increased from 150 kg·ha-1to 240 kg·ha-1, protein content of inferior kernel increased, but no significant difference occurred in protein content of superior kernel. With the nitrogen fertilizer rate increased, the content of protein components increased by different extents, and the content of glutenin and GMP of inferior kernel improved mostly, showing that nitrogen addition effects on the content of protein and its components occurred mainly on inferior kernel.

Effects of Stubble Height and Clipping Stage on Regrowth Performances of Zea mexicana

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Scientia Agricultura Sinica. 2005, 38(08):  1555-1561 . 

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A fieldplot experiment in 2002 and 2003 was conducted to study the effects on regrowth performances (including the yield and forage nutritive quality of the regrowth) of Zea mexicana cut at different clipping stages with different high stubbles. The plant height was regarded as the criteria to establish the clipping stage. The treatments cut at different stages with the same high stubble and cut at different stubble height with the same high plant. The approximate analysis method was utilized to evaluate the forage nutritive quality of the regrowth, and the conception of regrowth coefficient (RGC) was introduced to determine the regrowth performances of Zea mexicana in this experiment. The findings of the experiment demonstrated that the regrowth yield and gross energy (GE) yield of treatment Ⅱ clipped with 30 cm stubble and 95 cm plant were higher than the control (stubble height: 20 cm) and treatment Ⅰ(stubble height: 10 cm), reached 11.60 kg·m-2 (fresh weight) and 278 kJ·m-2，respectively. The crude protein content and nitrogen free extract content of the regrowth of treatment Ⅱ were higher，while the crude ashes content and acid detergent fiber content were reverse. The regrowth yield and GE yield of treatment Ⅳ clipped with 20 cm stubble and 130 cm plant had no significant difference to those of the control，and were significantly higher than those of treatment Ⅲ (plant height: 65 cm) in this experiment. The regrowth forage nutritive quality of treatment Ⅲ was the highest of the five treatments. According to the regrowth yield and forage quality，the treatment with RGC≈2.5 had the best regrowth performances，and the cutting mode with 30cm stubble and 95cm plant was able to make Zea mexicana be high yield and high quality.

Comparison and Cluster Analysis of Photosynthetic Characters of Different Sugarcane Varieties

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Scientia Agricultura Sinica. 2005, 38(08):  1562-1569 . 

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By using CI-301PS photosynthesis system, the main photosynthetic parameters of 152 sugarcane genotypes were measured. The results showed that differences of photosynthetic characters among the tested varieties were extreme significant. Cluster and discrimination analysis techniques were used to study photosynthetic characters of 152 different varieties of sugarcane. Cluster analysis was used to classify the photosynthetic characters of sugarcane varieties and 152 different genotypic varieties of sugarcane were classified into 7 groups according to these indexes, then by means of discrimination analysis, photosynthetic character indexes (Pn, E, WUE) had significant effects on classification were selected and 7 discrimination models with better distinguishing abilities were established.

PLANT PROTECTION

Preparation, Characterization and Application of Anti-harpinxoo Antibody

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Scientia Agricultura Sinica. 2005, 38(08):  1570-1573 . 

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Polyclonal anti-Harpin rabbit antibody has been successfully prepared by using purified harpin protein as immunogen. The ELISA titer of antiserum against harpin was about 1:2000. Western blot analysis showed that the antiserum could bind to the expression harpin protein specifically. Hrf1 gene, coding harpin, expression in transgenic rice detected by anti-Harpin rabbit antibody. The rabbit antibody against harpin can be used to study the biological function, harpin localization and hrf1 gene expression in other plants further.

Microsatellite Marker of the Resistance Gene YrSpP to Wheat Stripe Rust

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Scientia Agricultura Sinica. 2005, 38(08):  1574-1577 . 

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Spaldings Prolific is one of the 15 wheat cultivars in the set of differential cultivars used in Europe and the World. SSR analysis was performed between a near-isogenic line(NIL) Taichuang29*6/Spaldings Prolific carrying the resistance gene YrSpP to wheat stripe rust and its recurrent parent Taichung29.88 SSR primers on 2B chromosome were screened, and reproducible polymorphic DNA fragment was amplified by WMC441. Genetic linkage was tested on 162 segregating F2 plants. It showed that microsatellite marker WMC441 was linked with the resistance gene YrSpP to wheat stripe rust, and genetic distance was 10.9cM.

Induced Resistance by the Filtration of Bipolaris maydis Race T Toxin Cultivation

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Scientia Agricultura Sinica. 2005, 38(08):  1578-1584 . 

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Resistance to maize southern leaf spot disease was induced by the low concentration of filtration of Bipolaris maydis race T cultivation in an experiment. The nuclear neterogeny corn C103 was used as the test material .The lesion area on the leaves was significant difference by connalysis The lesion areas on pretreated leaves were (0.3±0.05)－(0.9±0.5) mm2, but that in the control were （23.1±8.7）mm2. At the same time, the changes of peroxidase, phenylalanine, ammonialyase, malondialdenvde activities were determined. During 0－96 h inspection, phenylalanine, ammonialyase activities increased by 64.2%, peroxidase activities increased by 41.2%, but the malondialdenvde content decreased by 29.7% compared with the control. It seems that the low concentration of filftration of B. maydis race T cultivation itself can be used as an elicitor to enhance the induced resistance.

Toxicity Analysis of Truncated Insecticidal Crystal Protein Cry1Ba3 from Bacillus thuringiensis

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Scientia Agricultura Sinica. 2005, 38(08):  1585-1590 . 

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To determine the minimal active fragment of Cry1Ba3 protein, six fragments of cry1Ba3 gene with different length were amplified using PCR with different specific primers. These fragments were cloned into pET-21b vector at BamHI and SalI restriction enzyme sites, and then introduced into E. coli BL21 strain. After induced with IPTG, the proteins expressed by different fragments were analyzed by SDS-PAGE, and the result showed that all these truncated proteins could be expressed in E. coli BL21. Bioassay result against Plutella xylotella showed that the minimal active fragment of Cry1Ba3 protein was located between amino acid No. 22 and No. 655. Because the insecticidal activity of the truncated protein containing amino acid No. 54-655 was declined significantly, and No. 22-627, No. 85-655 was lost completely, while the toxicity of fragment including amino acid of No. 22-655 was not changed with original Cry1Ba3

SOIL & FERTILIZER·WATER-SAVING IRRIGATION

Effects of Different Fertilization Systems on Soil Microbe and Its Relation to Soil Fertility

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Scientia Agricultura Sinica. 2005, 38(08):  1591-1599 . 

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An experiment was carried out based on long-term fertilizer experiments in fluvo-aquic soil in Changping County, Beijing, China, to study effects of long-term different fertilization systems on soil microbe and its relation to soil fertility. The main results are as follows: (1) The amount of soil bacteria and fungi of the treatments of applying chemical fertilizers only were less than that of long-term fallow soil, but actinomycetes were by contrary. (2) Combined applying chemical fertilizers only had higher amount of actinomycetes and similar amount of bacteria and fungi compared with the soil without fertilizer-applied. (3) Soil of balanced fertilization of N, P, K (NPK treatment), as a whole, had similar amount of bacteria, fungi and actinomycetes with N, NP, NK, PK treatments (unbalanced fertilization). (4) Combined application N, P, K chemical fertilizers with manure or crop straw had a significant effect of increasing amount of soil microbe. Treatments of NPK+M, NPK+1.5M and NPK+S not only had more amount of soil bacteria, fungi and actinomycetes than those of in CK, N, NP, NK, PK, NPK treatments, but also had more amount of bacteria and actinomycetes than and similar amount of fungi with that of in fallow soil. (5) Treatments of long-term applying chemical fertilizers only had less amount of nitrogen-fixing bacteria, ammonifers, cellulose-decomposing and denitrifying bacteria, but higher amount of nitrifying bacteria than that of fallow treatment. Soils of applied with chemical fertilizers only had more numerous amount of nitrogen-fixing, nitrifying and cellulose-decomposing bacteria but less numerous amount of ammonifers and denitrifying bacteria compared with that of in no fertilizer-applied soil. Soil of balanced fertilization of N, P, K (NPK treatment) had more amount of ammonifers, nitrifying and cellulose-decomposing bacteria, similar amount of nitrogen-fixing bacteria and less amount of denitrifying bacteria than that of in soils of unbalanced fertilization treatments (N, NP, NK, PK). Combined use of N, P, K chemical fertilizer with manure or crop straw promoted the increase of the amount of nitrogen-fixing bacteria, ammonifers, denitrifying, nitrifying and cellulose-decomposing bacteria. The amount of these physiological functional microbe in NPK+M, NPK+1.5M and NPK+S treatments were higher than that of in those treatments of only applied with chemical fertilizers. NPK+M, NPK+1.5M and NPK+S even had more amount of nitrogen-fixing bacteria, ammonifers, denitrifying and nitrifying bacteria than that of in fallow soil. (6) There was a positive correlation between the contents of soil nutrient and amount of soil microbe.

Responses of Nitrogen Uptake and Yield of Winter Wheat to Nonuniformity of Sprinkler Fertigation

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Scientia Agricultura Sinica. 2005, 38(08):  1600-1607 . 

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Field experiments were conducted to investigate the effects of nonuniformity of sprinkler fertigation and the amount of fertilizers applied through fertigation on nitrogen uptake and crop yield during two growing seasons of winter wheat from 2002 to 2004 at an experimental station in Beijing. In the experiments the seasonal averaged Christiansen irrigation uniformity coefficient (CU) varied from 72% to 84%. Except for the fertilizer applied before planting, fertilizer was applied with the sprinkler irrigation system with a seasonal averaged CU for fertigation varied from 71% to 85%. Three levels of fertilizer applied varying from 0 to 180 kgN/hm2 were used in the experiments. The experimental results demonstrated that sprinkler fertigation uniformity had insignificant effects on nitrogen uptake and crop yield for the uniformity range tested. Also, the influence of fertilizer applied through sprinkler fertigation on crop yield was minor, while total nitrogen content for stem and nitrogen uptake increased with increasing fertilizer applied. Consequently, field experimental results obtained from this study supported that the target sprinkler uniformity of CU ≥ 75% suggested by the current national standard is high enough for minimizing the negative effects of nonuniformly applied water and fertilizers on nitrogen uptake and crop yield.

Comparison and Evaluation of Soil Stability Affected by Macromolecule Materials

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Scientia Agricultura Sinica. 2005, 38(08):  1608-1615 . 

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Some macromolecule materials, widely used for soil surface conditioning in agricultural field at present, were selected to determine their effects of simulated surface application on soil aggregate-related physical properties, including on surface film-formation, soil erosion-resistance, changes in dry/wet particle-size distribution, soil aggregation and water-stability, as well as hydraulic conductivity, and to make comparison and evaluation of soil stability associated with the tested materials. The results suggested that the SQ (stability quotient), A% (percentage of dry-sieved aggregates >2 mm) and WMWD (wet-sieved mean-weight diameters) be used as main index to measure soil dry/wet aggregate stability or to evaluate soil stability of macromolecule materials. In comparison of the tested materials, the highest values in SQ, A% and WMWD associated with M-PAM (polyacrylamide) surface treatment showed that MPAM had the strongest effects on film-formation, erosion-resistance, and aggregate water-stability and can be recommended as practices combined with water-saving irrigation and soil conservation tillage in dryland soil. With EBT (emulsified bituminous material) treatment, the least A%, but the higher SQ and WMWD indicated that EBT had stronger aggregate water-stability and can be used on slope and sandy land for protecting soil against water erosion. With CLP (crosslinked polyacrylamide) treatment, the higher A%, but the lower SQ and WMWD suggested that CLP had the weaker wet aggregate water-stability and is suitable for water and fertilizer conservation in seasonal drought soils, and especially is applicable for water-saving cultivation management of cash crops. This study has provided informations for the development of new-type macromolecule materials in agricultural land application.

The Yield Response of Vegetable to Phosphate Fertilizer and Soil Phosphorus Accumulation in a Chinese Cabbage-capsicum Rotation

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Scientia Agricultura Sinica. 2005, 38(08):  1616-1620 . 

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The yield response of Chinese cabbage and capsicum to phosphorus fertilizer was studied by field location experiment. The status of residual phosphorus and the content of total phosphorus in vegetables were also investigated under different dose of applying of phosphorus fertilizer. The safe and economic dose of P fertilizer were recommended based on the regression equation and the status of residual phosphorus in the soils for two years’ field fertilizer experiment. The results showed that the yield of Chinese cabbage and capsicum was increased significantly by applying phosphorus. The model of Quadratic+ plateau could express the yield response of Chinese cabbage and capsicum to phosphorus fertilizer. The highest yield of Chinese cabbage and capsicum were calculated according to the regression equation were 186.71kg•hm-2, 339.00 kg•hm-2 respectively. The content of total phosphorus of Chinese cabbage and capsicum, total phosphorus and Olsen-P in the profile of 0～20cm soil were increased gradually accompanying with the increase of P fertilizer application. Phosphorus was absorbed luxuriously with applying high level phosphorus fertilizer. The economic and safe phosphorus dose was 112.5 kg•hm-2 in Chinese cabbage and 225.0 kg•hm-2 in capsicum. Applying P 450.00 kg•hm-2, 675.00 kg•hm-2 for 2 times, did not increase the yield of Chinese cabbage.

Effects of Irrigation Regime on Growth of Elymus sibiricus Swards

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Scientia Agricultura Sinica. 2005, 38(08):  1621-1628 . 

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Promoting sustainable development of improved grassland is an essential way to solve the feed shortage of livestock in ecton areas of Northern China. Irrigation is the key strategy for developing sown grassland. To evaluate the effects of full irrigation vs irrigation during the key growing stage on above-ground and under-ground growth of Elymus sibiricus, field experiments were conducted during 2001-2003 on Bashang plateau in Hebei Province. The results indicated that irrigation observably improved the above-ground biomass and plant height, and the irrigating time played a more important role than irrigating amount as indicated by the results of the irrigation trial during the key growing stage. And it was showed that irrigation also increased root weight density, root length density and the under-ground biomass, although the effect of irrigation treatments on under-ground biomass was not significant.

HORTICULTURE

Simulation of Leaf Area and Dry Matter Production in Greenhouse Tomato

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Scientia Agricultura Sinica. 2005, 38(08):  1629-1635 . 

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A simulation model for greenhouse tomato leaf area was developed based on the product of thermal effectiveness and PAR (TEP). Then a process based greenhouse tomato dry matter production simulation model was developed by integrating the greenhouse tomato leaf area simulation model. The model was validated by independent experimental data from Shanghai and Nanjing. The results showed that the model can predict leaf area and total dry weight of greenhouse tomato more accurately than traditional models, which calculates leaf area (LA) with specific leaf area (SLA) and growing degree day (GDD). When using the model based on TEP, the coefficient of determination (R2) and the root mean squared error (RMSE) between simulated and measured leaf area (LA) based on the 1:1 line are 0.9743 and 0.0515 m2·plant-1, respectively. When using the model based on TEP, the R2 and RMSE between simulated and measured total dry weight based on the 1:1 line are 0.9360 and 522.7104 kg·ha-1, respectively. For the prediction of plant total dry weight, the prediction accuracy of TEP based model is 56% and 72%, respectively, higher than that of GDD and SLA based model.

Agrobacterium Mediated Transformation of BADH to the AtNHX1 Transgenic Tomato (Lycopersicum esculentum L. 'Moneymaker')

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Scientia Agricultura Sinica. 2005, 38(08):  1636-1644 . 

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To evaluate the effects of combined salt tolerant mechanisms, BADH gene from Atriplex hortensis was introduced into the T2 generation of transgenic tomato (L. esculentum 'Moneymaker') line X1OEA1 containing AtNHX1 by Agrobacterium tumefaciens mediated transformation. PCR, Southern blot, RT-PCR and betaine measurement indicated that BADH was integrated into the genome of X1OEA1 and functioned properly. Physiological responses of the double transformant to 200 mmol·L-1 NaCl treatment, reflected by photochemical efficiency of PSⅡ(Fv/Fm), relative electronic conductivity (Rc/Rc'), chlorophyll content (Chla+b, Chla/b) and net photosynthetic rate (Pn), were better than those in X1OEA1. The double gene transformed tomato TT0-2 showed the least decrease of Fv/Fm value while the salt concentration increased gradually, and the relative electronic conductivity of TT0-2 and X1OEA1 line T2 plant were 3.6 and 4.2 times higher under 200 mmol·L-1 NaCl treatment compared with normal condition. The stem's dry weight and fresh weight of TT0-2 were 12.5% and 19.8% higher than that of X1OEA1 line T2 plant, respectively, at the same time, the leaves' dry weight and fresh weight of which were 22.5% and 14.0% higher. The results indicated that multigene transformation could further improve salt tolerance of plant. Furthermore, the transformation system of tomato was optimized. The results have proved that Timentin is a better antibiotic than cefotaxim for the effective transformation of tomato.

Study on Induction of Tetraploid Grapes

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Scientia Agricultura Sinica. 2005, 38(08):  1645-1651 . 

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Tetraploids were induced successfully from in vitro Vitis.vinifera cv. Jingxiu and Red Globe by soaking shoot segments in colchicine solution and adding colchicine in the culture medium. Ploidy levels were determined by flow cytometry. The results showed that the soaked-treatment had increased efficiency of inducing tetraploids than one of adding in medium. Tetraploid plants were obtained from the shoot segments soaked in colchicine solution at concentrations of 2000 mg • L-1 or lower during 48 h or shorter time after two to four regenerations of micropropagation. However, when soaking was extended to 3 to 4 d at colchicines concentrations of 2000 mg • L-1 or when colchicine concentration was increased to 3000 mg • L-1 for 3 to 4 d, or 4000 mg • L-1 for 2 to 4 d, pure tetraploids were easily obtained during first micropropagation regeneration. The optimal conditions for inducing tetraploids were under soaking shoot segments for 3 to 4 d with colchicine at a concentration of 3000 mg · L-1. The rate of induction was 16.7-23.3%.

Formation and Physicochemical Properties of Pressure-Induced Gels

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Scientia Agricultura Sinica. 2005, 38(08):  1652-1657 . 

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The effects of different pressuization times (5-120 min) and N-ethlmaleimide (NEM,1-10 mmol·L-1) on physicochemical properties of gels induced from 14% (w/v) β-Lactoglobulin (β-Lg) at pH 7.20 under 800 MPa at 30℃ were investigated. The results showed that the hardness and breaking stress of gels were not influenced by increasing pressurization time. The gel showed network structure like honeycomb. The aperture of structure became larger with increasing pressurization time but not broken.The gels kept a high WHC with increasing pressurization time, suggesting that protein-water interaction in gel was not changed significantly during pressurization. The protein solubilized from gels with Tris-Glycine-Na2EDTA buffer or in the same buffer containing 8 mol·L-1 urea and 0.5% SDS decreased with increasing pressurization time. SDS-PAGE patterns were markedly different depending on the presence of β-mercaptoethanol (β-ME). In the absence of β-ME, the bands of dimer, trimer, tetramer and high molecular aggregates were appreciably detected in addition to monomer. In contrast, in the presence of β-ME, only monomer band was detected. The result suggests that disulfide bonding is the primary driving force for gelation under pressurization. Gels were not induced by adding 10 mmol·L-1 N-ethlmaleimide gelation of β-Lg at 800 MPa and the content of sulfhydryl group decreased. It is, therefore, suggested that the formation of gel from β-Lg under pressurization results from intermolecular cross-linkages via oxidation of thiol groups and sulfhydryl-disulfide interchage reactions at neutral pH.

ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT

Genetic Diversity and Phylogeny Status of Luxi Cattle

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Scientia Agricultura Sinica. 2005, 38(08):  1658-1663 . 

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A total of 87 individuals of Luxi cattle from Juancheng County and Liangshan County, Shangdong Province, were sampled by simple random sample in typical colony. Twenty one blood proteins and enzymes loci were detected by polyacrylamide gel electrophoresis (PAGE) and starch gel electrophoresis(SGE). In the meantime, the data of 7 loci of 13 cattle populations in China and other countries were collected and phylogeny relationships were studied. The results showed that: 9 out of 21 loci were polymorphism (42.86%); the level of genetic variation in Luxi cattle population was relatively high, the mean hoterozygosity was 0.1416. The Luxi cattle have a close phylogeny relationships with the cattle populations of east and south of Asia and this confirms further the facts that Luxi cattle are the cross breed between the Bos taurus and Bos indicus in China, but it is not possible of having blood lineage of Bali cattle in Luxi cattle. Now the size of breeding population in Luxi cattle should be enlarged to maintain the genetic diversity level of population.

Effects of Follicle Size and Bovine Follicular Fluid on Developmental Competence of Bovine Oocytes Following Maturation, Fertilization and Culture in vitro

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Scientia Agricultura Sinica. 2005, 38(08):  1664-1668 . 

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Experiments were conducted to study the effects of follicle size and bovine follicular fluid (BFF) on developmental competence of bovine oocytes derived from abattoir ovaries following in vitro maturation, fertilization and culture. In experiment 1, bovine COCs (cumulus oocyte complex) derived from follicle of different sizes were allocated to four treatments according to follicles size:＞8 mm; 2-8 mm; preantral follicle (PF); and mix above COCs together (mix). The result showed that follicle size directly affected the development of oocytes and mixing all sizes of follicle oocytes together could stimulate development of immature oocytes from PF. In experiment 2, 10% of bovine follicular fluid (BFF) derived from competent follicles (＞8 mm ), small follicles(2-8 mm ) or all sizes of follicles (mix) were supplemented to the maturation medium. Following in vitro maturation, feitilization and culture, more COCs in three treatments reached cleavage and blastocyst than no BFF control group (P<0.05). However,10% of BFF from competent follicles made the oocytes and embryos sticking together and may easily cause some of them lost. In experiment 3, different concentrations (10%, 20% and 40%) of BFF from all follicles (＞2 mm) were supplemented to the maturation medium. The results showed that different concentrations of BFF could support in vitro maturation of COCs and subsequent development capacity, however, 20% and 40% of BFF could seriously cause oocytes and embryos adhered together. Therefore adding 10% of mixed BFF in maturation medium is the best choice.

Analysis of the Complete Genome of a Strain swCH25 of Swine Hepatitis E Virus Isolated from Xinjiang

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Scientia Agricultura Sinica. 2005, 38(08):  1669-1674 . 

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To analyze the full length sequence of swCH25, isolated from a pig fecal sample in Xinjiang in 2001, eight overlapping fragments of swCH25 genomes were amplified with reverse transcription nested polymerase chain reaction (RT-nPCR) and the 5′ and 3′ ends were amplified with RACE. The PCR products were cloned into pMD18-T Vector and sequenced. The result showed that its genome consisted of 7 243 nt excluding the poly(A)tail, and contained three ORFs(ORFs1-3) that encoded proteins of 1 707, 674 and 114aa. Sequence analysis revealed that the overall nucleotide sequence identity of swCH25 was 73.5%-75.7% and 83.5%-89.8% with HEV genotypeⅠ-Ⅲ and Ⅳ, respectively. Compared with HEV genotypesⅠ-Ⅲ and Ⅳ，the ORF1 of swCH25 shared 71.6%-74% and 82.3%-89.4% sequence identity at nucleotide level and 80.7%-86.1% and 94.3%-96% identity at amino acid level, the ORF2 shared 78.4%-81.3% and 87.1%-90.9% sequence identity at nucleotide level and 89.7%-93.8% and 97.2%-98.2% identity at amino acid level and the ORF3 shared 84.4%-87.3% and 95.4-96.8% sequence identity at nucleotide level and 74.8%-83.2% and 93.8%-97.4% identity at amino acid level. The phylogenetic tree constructed based on the full genomic sequence confirmed that swCH25 belong to genotype Ⅳ and were most closely related to T1, a prototype human HEV strain of genotype Ⅳ isolated from patients with acute hepatitis in China. This finding further supports the notion that the hepatitis E is a zoonosis.

The Lapinized Chinese Strain of Classical Swine Fever Virus：a Retrospective Review Spanning Half a Century

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Scientia Agricultura Sinica. 2005, 38(08):  1675-1685 . 

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Classical swine fever (CSF), a list A disease of Office International des Epizooties, is caused by classical swine fever virus (CSFV) belonging to the Flaviviridae family. The well-known lapinized Chinese strain of CSFV, also known as C-strain, was developed in China in the middle 1950s. In the past half a century, the vaccine has been proved to be safe and immunogenic in pigs of essentially any age. It is of high efficacy. It provides immunized animals with broad-spectrum, sometimes lifelong, protection, which is contributed by cell-mediated immunity and humoral immunity, against essentially all genotypes or subgenotypes of the virus. The maternal antibodies derived from immunized sows can confer solid protection of their offspring from disease; however they have been proved to inhibit the successful immunization of C-vaccine. The complete genome of C-strain, together with those of its parent Shimen and dozens of established and field strains, has been sequenced and annotated. Recently, the reverse genetics system of C-strain has been developed, resulting in several C-strain-derived candidate marker vaccines. Many countries manage to control or even eradicate CSF with the aid of C-strain vaccination. In spite of these efforts, the eradication of the disease worldwide remains a big challenge and needs a long way to go, and provably still resort to genetically modified C-strain. This paper reviews the different aspects of the vaccine, which has stood the test of half a century.

Establishment of Reverse Genetics System of Highly Pathogenic H5N1 Avian Influenza Virus A/goose/Guangdong/1/96

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Scientia Agricultura Sinica. 2005, 38(08):  1686-1690 . 

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A/goose/Guangdong/1/96(GSGD/1/96) is the first highly pathogenic H5N1 avian influenza virus isolated from the mainland of China. It is the HA gene donor of the Hong Kong 97 H5N1 viruses and the ancestor of current H5N1 viruses circulating in the mainland of China. In the present study, the authors have established an eight-plasmid reverse genetics system and rescued GSGD/1/96 (R-GSGD/1/96) through cell transfection. Animal studies confirmed that the rescued virus maintained the biological properties of the wild type GSGD/1/96 virus (W-GSGD/1/96). Both R-GSGD/1/96 virus and W-GSGD/1/96 are highly pathogenic for chickens with intravenous pathogenecity index (IVPI) of 2.01 and 2.10, respectively. The viruses could not replicate in mice, though lower titer viruses could be recovered from the lungs of few mice 1-2 days after inoculated intranasally with 106EID50 of the viruses. The successfully establishment of the reverse genetics system of GSGD/1/96 will enable us to conduct extensive studies of the molecular basis of the evolution of H5N1 avian influenza viruses.

RESEARCH NOTES

Cloning of LMW-GS Genes from Synthetic Hexaploid Wheat 'RSP'

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Scientia Agricultura Sinica. 2005, 38(08):  1691-1698 . 

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RSP is a synthetic hexaploid wheat (Triticum turgidum-Aegilops tauschii) between a tetraploid wheat (T. turgidum L.) and an Ae. tauschii accession with highly tolerant to sprouting, which is of importance to maintain wheat flour making quality. LMW-GSs together with HMW-GSs, control wheat flour making quality directly. To investigate the LMW-GSs from RSP, using PCR amplification of the genomic DNA, three novel LMW-GS genes (i.e. LMWRSP-1, LMWRSP-2 and LMWRSP-3) were isolated from 'RSP', among which LMWRSP-2 (GenBank accession number: AY676682) is a pseudogene due to one stop code in its coding regions. The coding regions of LMWRSP-1 (GenBank Accession number: AY676681) and LMWRSP-3 (GenBank accession number: AY676683) are 825 and 915 bp, respectively. They encode two LMW glutenin subunits with 274 and 304 amino acid residues, respectively. Multiple sequence alignment analysis indicated that LMWRSP-1 and LMWRSP-3 have the highest similarity scores to the known LMW-GS genes encoded by Glu-A3 and Glu-D3, respectively.

Changes of Biochemical Properties of Agricultural Waste Materials During Composting in High Temperature and Static State

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Scientia Agricultura Sinica. 2005, 38(08):  1699-1705 . 

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An experiment was conducted with mixed materials of chicken excrement and wheat straw to study the changes of temperature, enzyme, and number of microorganisms during an aeration composting process in a static state. Results showed that the temperature was lower at the bottom while higher at middle and top positions of the device. The temperature of the organic materials in the device rose from the ambient temperature to 50℃ by 7-8 h, and that maintained above 50℃ lasted 198-483 h. The time duration of high-temperature was in agreement with the requirement standard of killing the pathogenic microorganism. When the temperature was up to about 55℃ at the high-temperature stages, the activity of the cellulose enzymes reached a maximum value of 0.457 mg glucose/(g·24h), the sucrose enzyme reached a maximum of 87.836 mg glucose/(g·24h), and the dehydrogenase reached 21.62 μl H＋/(g·24h). The urea enzyme activity was peaked at a value of 0.932 mg NH3/(g·24h). At the later composting stage when temperature became declined, the activity of polyphenol oxidase enzyme reached its maximum of 6.23 mg gallicin/(g·2h). The highest bacterium number was found to be 2.51 1012CFU/g and actinomyces to be 3.68 108CFU/g in two days. Fungi number was relatively high at the beginning of composting while with the temperature rise, it became decreased, and at later stage of compost with temperature decline, fungi rose slowly. As a whole, the number of fungi was low whereas that of bacteria and actinomyces was much higher.

A Study on Corn Root Growth and Activities at Different Soil Layers with Special Bulk Density

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Scientia Agricultura Sinica. 2005, 38(08):  1706-1711 . 

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A study on corn root growth and activities at different soil layers with special bulk density was conducted using pot cultivation in a field experiment. The results showed that corn root growth and activities were greatly affected by soil BD（bulk density）in deep soil layers. Corn root number, root dry matter, root length and root activities decreased with the increase of soil BD in deep soil layers. The larger the soil BD, the more significant the decrease. The amount of total corn root decreased with the increase of average soil BD. More air roots were observed in a smaller average soil BD. For Yuyu23, its root couldn't penetrate a length of 20 cm in soil layers with a soil BD of 1.6 g·cm-3. It was found that root growth had certain compensative effect in soil layers with smaller soil BD, but such an effect was too limited to make up for the adverse effect caused by larger soil BD.

Construction of Subtractive cDNA Libraries of Eimeria tenella to Maduramycin and Diclazuril by Suppression Subtractive Hybridization

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Scientia Agricultura Sinica. 2005, 38(08):  1712-1716 . 

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In order to clone and identify differentially expressed genes in Eimeria tenella relating to drug resistance to Diclazuril and Maduramycin, the cDNA from sporulated oocysts of the drug-sensitive strain of E.tenella was used as driver and the cDNAs from sporulated oocysts of two drug-resistant strains were used as tester to construct subtractive cDNA libraries using the technique of suppression subtractive hybridization(SSH). PCR amplification revealed that the two subtractive cDNA libraries of Maduramycin and Diclazuril-resistant strains of E.tenella contained approximated 96% and 98% recombinant clones, respectively. Plasmid inserts were PCR amplified and the lengths were 250 bp-1.0 kb. The results of dot-blot hybridization showed that six clones were over-expressed in the drug-resistant strains. Sequence analyses revealed that three and four cDNA fragments were likely to represent novel genes relating to resistance to Maduramycin and Diclazuril, respectively. These results have provided the foundation for cloning full-length genes and studying molecular mechanism relating to drug-resistance in E.tenella.