Scientia Agricultura Sinica

Molecular Mapping of QTLs for Cold Tolerance at the

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Scientia Agricultura Sinica. 2005, 38(02): 217-221 .

Abstract ( 864 )

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The quantitative trait loci (QTLs) for cold tolerance at the bud bursting period (CTBP) were identified by using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molecular linkage map of 97 SSR markers was constructed by using interval mapping and covered a total length of 1357.3 cM with an average distance of 13.99 cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the percentage of seedling stand after treated under low temperature at the bud bursting period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosome 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RM11, respectively, which explained the range of the observed phenotypic variance from 11.5% to 20.5%. qCTBP4, which is detected on RM273-RM303 of chromosome 4, is explained 20.5% of the observed phenotypic variance. The effect of qCTBP4's allelic gene comes from Jileng1.

Effect of Temperature on the eui Gene Expression of TGMS Rice

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Scientia Agricultura Sinica. 2005, 38(02): 222-227 .

Abstract ( 929 )

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Effect of temperature on the eui gene expression of TGMS rice Changxuan 3S were analyzed under the condition of natural ecology and different artificial temperature. The results were as following: There was a negative correlation between panicle elongation and natural temperature at 9-20 days before flowering, and the negative correlation of the panicle elongation with mean diurnal temperature at 12-17 days (from pollen mother cell formation to meiosis) before flowering was the most significant. In the thermo-sensitive period of the eui gene, when Changxuan 3S was treated with the condition of constant 22℃,24℃,26℃,28℃, the eui gene could express under the treatment of 22℃, 24℃, 26℃, respectively, and the lower the temperature treated, the longer the panicle elongation was, while the expression of the eui gene was inhibited at temperature 28℃.

Allelic Variation and Genetic Diversity at HMW Glutenin Subunits Loci in Yunnan, Tibetan and Xinjiang Wheat

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Scientia Agricultura Sinica. 2005, 38(02): 228-233 .

Abstract ( 1108 )

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Allelic variation and genetic diversity at HMW glutenin subunits loci, Glu-A1, Glu-B1 and Glu-D1 were investigated in 64 accessions of three unique wheat varieties from western China using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Two HMW glutenin patterns (i.e. null, 7+8, 2+12 and null, 7, 2+12) in 34 Yunnan wheat accessions, 3 HMW glutenin patterns (i.e. null, 7+8, 2+12, null, 6+8, 2+12 and null, 7+8, 2) in 24 Tibetan accessions and 1 HMW glutenin pattern (null, 7, 2+12) in 6 Xinjiang wheat accessions were found. The Tibetan accession TB18 was found to be with a rare subunit 2 encoded by Glu-D1. A total of 4 (i.e. Glu-A1c, Glu-B1a, Glu-B1b, Glu-D1a), 5 (i.e. Glu-A1c, Glu-B1d, Glu-B1b, Glu-D1a, Glu-D1？） and 3 alleles （i.e. Glu-A1c, Glu-B1a, Glu-D1a） at Glu-1 locus were identified among Yunnan, Tibetan and Xinjiang unique wheat accessions, respectively. For Yunnan wheat, Tibetan wheat and Xinjiang wheat, the Nei's mean genetic variation indexes were 0.1574, 0.1366 and 0, respectively, which might indicate the higher genetic diversity of Yunnan wheat and Tibetan wheat as compared to Xinjiang wheat. Among the three genomes of hexapliod wheats of western China, the highest Nei's genetic variation index was appeared in B genome with the mean value of 0.2674, while the indexes for genomes A and D were 0 and 0.0270, respectively. It might be reasonable to indicate that Glu-B1 showed the highest, Glu-D1the intermediate and Glu-A1 always the lowest genetic diversity.

Expression of Soybean 24 kDa Oleosin Gene in Escherichia coli

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Scientia Agricultura Sinica. 2005, 38(02): 234-240 .

Abstract ( 1134 )

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Four bacterial expression vectors were constructed, which carry the full-length, the N-end truncated, the C-end truncated soybean 24 kDa oleosin gene as well as the fused fragment with the genes encoding the heat-labile toxin B subunit and CS6 B subunit from E.coli. The growth of host cells was depressed when the full-length 24 kDa oleosin gene was expressed in E. coli either as the native fragment or as a tandem unit fused with bacterial genes, with a reduction to about one-third of the growth rate of control culture. Deletion of the DNA sequence encoding 152 amino acids near the C terminus of the 24 kDa oleosin could not overcome this toxicity. However, the toxicity can be overcomed by deletion of the sequence encoding the 74 amino acids of the N terminal region of the protein. When products induced by IPTG were detected by SDS-PAGE and Western blotting, only the 24 kDa oleosin gene fragment truncated 222 oligonucleotides at N terminus could express and accumulate the target protein in E.coli host BL21(DE3) or Rosseta(DE3).

Genetic Diversity and Evolution of Adzuki Bean (Vigna angularis) Germplasm Resources Based on RAPD Markers

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Scientia Agricultura Sinica. 2005, 38(02): 241-249 .

Abstract ( 1050 )

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RAPD variation was assessed in 163 accessions of adzuki bean from China, Japan, Korea, Bhutan, Nepal and Vietnam. 285 bands, including 261 polymorphic bands, were detected by 27 RAPD primers. Among those bands observed in wild, weedy and cultivated adzuki bean, the rates of polymorphism were 85.82%, 80.46% and 83.52%, respectively. There were species-specific bands in the three races. The order of genetic dispersion was: wild adzuki bean＞weedy adzuki bean＞cultivated adzuki bean, and the order of Gst was: wild adzuki bean＜weedy adzuki bean＜cultivated adzuki bean. The weedy adzuki bean has close genetic relationship with wild adzuki bean assessed by the difference of genetic dispersion. From the average of genetic similarity coefficient, a relative close genetic relationship was observed in the weedy adzuki bean, whereas the wild and cultivated adzuki bean, as two pole of evolution, has high genetic variation. The material from Southwest China and South Japan has relatively high genetic dispersion, low Gst and average of genetic similarity coefficient. The cluster analysis showed that eight groups can be clustered when genetic similarity coefficient was given as 0.32. It appears that the cluster has obviously associated with the genetic races and different adzuki bean geographical regions.

Analysis of Genetic Diversity of Sweetpotato Landraces in China

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Scientia Agricultura Sinica. 2005, 38(02): 250-257 .

Abstract ( 985 )

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Genetic diversity of 48 sweetpotato landraces, randomly sampled from 4 regions （Anhui, Fujian, Henan and Guangdong）in China, was analyzed using RAPD, ISSR and AFLP markers. Both 30 RAPD and 14 ISSR primers and 9 AFLP primer combinations generated 227, 249 and 260 polymorphic bands, respectively. AFLPs were better than RAPDs and ISSRs in terms of the number of polymorphic bands detected and the experimental stability. These three molecular markers revealed the similar results that Chinese landraces possess high genetic diversity, and the genetic variation of Guangdong landraces was significantly (at 0.01 level) higher than that of the landraces from other three regions. These results support the hypothesis that China was the secondary center of sweetpotato diversity and also showed that Guangdong was the earliest region where sweetpotato was introduced to China. In this study, the combined RAPDs, ISSRs and AFLPs dataset appeared to be appropriate in resolving the sweetpotato varietal relationships. These landraces can be divided into two groups by UPGMA cluster based on genetic distances, one mainly includes 8 landraces from Guangdong, and another consists of the remaining landraces from Guangdong and landraces from the other three regions. Thus, the utilization of Guangdong landraces should be specially considered in sweetpotato breeding.

A Study on Characteristics of Photosynthesis in Super High-yielding Hybrid Rice

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Scientia Agricultura Sinica. 2005, 38(02): 258-264 .

Abstract ( 927 )

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The morphological features and photosynthetic characteristics of 7 hybrid rice combinations with different canopy structure and super high-yielding potential were studied in comparison with Shanyou 63.The results showed that 4 combinations having significant increase in grain weight per plant compared with Shanyou 63 have advantages including (1) a smaller light extinction coefficient resulted from the more erect leaf blades and longer flag leaves enhanced the capacity of source supply on the basis of significant increase of sink demand (i.e. spikelets per panicle), (2) a higher rate of canopy photosynthesis during grain filling and higher rates of flag leaf photosynthesis at saturating light intensity during different stages (i.e. booting stage,10 days after heading, 30days after heading), (3) More dry matter accumulated in stems and sheaths before heading and translated to grains after flowering efficiently.

Effect of Source-sink Ratio on Grain Filling and The Source-sink Characteristics of High Yield Varieties of Mid-season Hybrid Rice

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Scientia Agricultura Sinica. 2005, 38(02): 265-271 .

Abstract ( 900 )

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Effect of source-sink ratio on grain filling was investigated via 18 mid-season rice hybrids with two cultural methods. The results showed that there was a high significant effect of source-sink ratio on grain filling, and the effect was mainly in the middle-lower part of a panicle, rather than the upper part of a panicle. The most sensitive index for effect of source-sink ratio on grain filling was grain plumpness index>seed setting percentage >grain filling rate. High-yield combinations with 9 t theory grain yield, 11 t potential grain yield and a seed setting percentage of 80% had the following source-sink characteristics: spikelet number 160-220 per panicle, effective panicles180×104-240×104 per hm2, 1000-grain weight 28-30 g,leaf-grain ratio 6.66-7.52 mg per grain, seed setting percentage 80%-90%, grain filling rate 96.5%-97.5%, grain plumpness index 78%-87%, grain weight 4.3-5.0 g per panicle.This study provided a scientific and practical basis for high yield breeding and cultivation of hybrid mid-season rice.

Differences in Starch Chain Length Distribution and Structure Characteristics of Early-indica Rice Under Different Temperature Treatments During Grain-filling

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Scientia Agricultura Sinica. 2005, 38(02): 272-276 .

Abstract ( 889 )

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Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-season indica rice cultivars were investigated under the environment-controlled conditions. The plants at flowering stage were subjected to two temperature treatments until maturity (the mean daily air temperature, 22℃ and 32℃ for optimum temperature treatment and high temperature treatment, respectively). The result showed that high temperature during grain-filling period significantly decreased the long B-chain content and increased the intermediate B-chain content. But the effect of high temperature on other starch chains appeared to be cultivar-dependant. The crystalline characteristics of rice starch were also affected by temperature during grain-filling. Period.The intensity at 18°2θ of X-ray diffraction pattern of rice samples under high temperature was higher than those under optimum temperature, though all rice starches performed A-crystalline type. Moreover, the intensity at 17°2θ was positively correlated with intermediate B-chain content and negatively correlated with long B-chain content.

Accumulation Pattern of Gliadin Fractions α, β, γ, ω and Regulation of Nitrogen

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Scientia Agricultura Sinica. 2005, 38(02): 277-282 .

Abstract ( 968 )

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Gliadin, the major storage protein in endosperm, affected grain quality in spring wheat by its content and composition. Eighteen cultivars differing in HMW-GS were used in the study to approach the accumulation pattern of gliadin fractionsα,β,γ,ωand regulation of three kinds of nitrogen source. The results showed that the content of gliadin in grains increased gradually along with the process of grain-filling, but the accumulation intensity and final content differed evidently among cultivars with different HMW-GS compositions. Of all the subunit types used here, cultivars with subunits 7+9 and 2+12 had smaller accumulation intensity and lower final content. During grain-filling, four gliadin fractions had the same trend of increase, but differed in accumulation course. The dynamic trends of gliadin accumulation were similar in different nitrogen treatments whose effects on initial amount, accumulation intensity and final level of accumulation varied with cultivars. Of three nitrogen fertilizer types, the amide-form nitrogen source was better to the formation and accumulation of gliadin as well as its four fractions.

Development and Testing of a Dynamic Knowledge Model for Wheat Cultural Management

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Scientia Agricultura Sinica. 2005, 38(02): 283-289 .

Abstract ( 1143 )

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By adopting the principle of system analysis and technique of mathematical modeling to knowledge expression system for wheat management, a dynamic knowledge model with temporal and spatial characters for digital wheat management was developed by extracting and formulating the fundamental relationships and quantitative algorithms of wheat growth indices and management criteria to variety types, ecological environments and production levels. With incorporation of the soft component characteristics, a component-based knowledge model system for digital wheat management was established on the platforms of Visual C++ and Visual Basic. The system realized two major functions as design of pre-sowing cultural plan and prediction of regulation index dynamics. The module of cultural plan design included the sub-models for determination of target yield and quality, suitable variety, sowing date, population density and sowing rate, fertilization strategy and water management, and the module of regulation index dynamics included the sub-models for suitable development stages, spike differentiation stages, dynamics of growth indices, source-sink indices and nutrient indices. Simulation studies on the knowledge model with the data sets of different eco-sites, cultivars, soil types and so on, and comparative field experiments indicated a good performance of the knowledge model system in decision-making and wide applicability. The present knowledge model system overcomes the shortcomings as specific site limitation and low quantification of traditional wheat cultivation patterns and expert systems, and lays a foundation for facilitating the digitization of wheat management.

Changes in Starch Accumulation and Activity of Enzymes Associated with Starch Synthesis Under Different N Supplying Date

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Scientia Agricultura Sinica. 2005, 38(02): 290-296 .

Abstract ( 1010 )

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In this paper the changes in grain filling, starch accumulation and activity of enzymes associated with starch synthesis in two different hybrid rice varieties were analyzed under different N supplying dates (earlier-date-emphasized, mean-date-emphasized and later-date-emphasized). The results showed that the N application of later-date-emphasized could promote grain filling rate, increase grain weight and amylopectin content. The time reaching a maximum activity in three enzymes of ADPglusoce pyriphosphorylase (ADPG), starch synthesis enzyme (SSS) and starch branching enzyme (SBE) in grains of two different rice varieties were not changed obviously, but the mean and maximum activity of these three enzymes changed，and the changes of SSS and ADPG were bigger than SBE as N supplying date changed. The N application of earlier-date-emphasized increased SSS activity and the N application of later-date-emphasized increased ADPG and SBE activities. The mean SSS activity in whole filling period, and ADPG and SBE activities at middle and late filling stage were significantly or very significantly correlated with grain filling rate and accumulating rate of amylose and amylopectin. Both of ADPG and SBE played an important role to the changes of amylose and amylopectin content. The N application of later-date-emphasized increased amylose and amylopectin accumulating rate.

Study of the Adult-plant Resistance at Different Growth Stages to Stripe Rust in Wheat

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Scientia Agricultura Sinica. 2005, 38(02): 297-301 .

Abstract ( 833 )

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Resistance of five adult-plant resistant (APR) wheat (Triticum aestivum) genotypes at six growth stages and under two temperatures was investigated in greenhouse and in a field trial. Chinese cultivar Chuanyu 12 displayed high to intermediate susceptibility in greenhouse but was highly resistant in the field. 'Weebill' showed an intermediate susceptibility in the greenhouse and also in field. Chapio, Tukuru and Saar, known to carry combinations of Yr18 and 2-3 additional minor genes, displayed highly resistant in both experiments. Greenhouse experiments showed that the lower susceptibility of APR was initiated at tillering, and latent period of APR genotypes was generally longer as the growth stage progressed. It is concluded that APR to stripe rust can be best characterized in field trials although significant correlations are seen between field severity and greenhouse measured susceptibility and latent period.

Effect of Exogenous MJA Treatment of Tea Plants on the Growth of Geometrid Larvae

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Scientia Agricultura Sinica. 2005, 38(02): 302-307 .

Abstract ( 1018 )

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The effect of tea plants Camellia sinensis induced by exogenous methyl jasmonate (MJA) on lipoxygenase (LOX), polyphenol oxidase (PPO) and proteinase inhibitor (PI) activity in the leaves of tea plants, as well as the growth and midgut proteinase activity of geometrid Ectropis obliqua larvae were studied. MJA significantly induced LOX, PPO and PI activity in tea leaves of tea plants. When geometrid larvae have fed on leaves of tea plants treated with MJA, the activities of the high alkaline trypsin-like enzyme and chymotrypsin-like enzyme in their midgut were significantly inhibited, but the activities of the low alkaline trypsin-like enzyme in their midgut were unaffected, leading to imbalance between different types of proteinase activity in the midgut of the larvae and in turn, the growth were inhibited. This chain of responses may be an important mechanism of the direct resistance induced by MJA-treatment of tea plant on geometrid larvae.

Development of Enzyme Immunoassays for Pyrethriods

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Scientia Agricultura Sinica. 2005, 38(02): 308-312 .

Abstract ( 855 )

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3-phenoxybenzoic acid (PBA) was used as generic hapten in order to generate broad specificity antibody against a group of pyrethriod insecticides. Assay performance was improved by use of a coating antigen, which possessed a six-carbon spacer arm between the hapten and carrier protein. Typical detection limits for PBA was 0.193 ?g·ml-1with an I50 value of 3.707 ?g·ml-1. Different cross-reactions with the closely related pyrethriods,including permethrin, fenpropathrin, cypermetnrin, cyhalothrin and deltamethrin, were observed, with I50 value of 4.066, 4.232,4.286,4.874,8.979 ?g·ml-1, respectively; There was a low cross reactivity for fenvalerate with an I50 value of 77.360 ?g·ml -1. The result developed in this study indicated the antibody was practicable to screen the residues of pyrethriod insecticides.

Breeding Resistant Rice Varieties From Transgenic Parental Lines with Cry1Ab and Xa21 Genes and Their Field Performance

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Scientia Agricultura Sinica. 2005, 38(02): 313-319 .

Abstract ( 957 )

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Two transgenic rice lines: Zhendao88 with Cry1Ab gene and Shengdao301 with Xa21 gene were crossed. The genetic segregation pattern and stability of the transgenes in the hybrid progenies were studied by testing selection marker genes (including bar gene and gus gene) and Southern blot analysis. The result shows that in hybrid progenies the bar gene and Xa21 gene co-inherited and co-expressed, respectively. Basta resistance assay and Gus histochemical staining assay indicated that the F2 generation showed a typical Mendel segregation ratio of 9:3:3:1 and stable homozygotes of Cry1Ab and Xa21 began to appear in the F3 generation. Southern blot assay of F3 generation and parental lines showed that the Cry1Ab gene and Xa21 gene could be steadily inherited. By field breeding, we finally acquired 3 transgenic lines with good agronomic traits: SK-1, SK-2, and SK-3, which all showed obvious resistance to stripe stem borer (Chilo suppressalis) and Xanthomonas oryzae pv. oryzae. The yield potentials were about 20% higher than those of Zhendao88 and Shengdao301; the quality was similar and some features were better.

Effect of CO2 Concentration on Nitrogen Metabolism of Winter Wheat

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Scientia Agricultura Sinica. 2005, 38(02): 320-326 .

Abstract ( 922 )

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Hoagland's solution of water culture medium was used to study the effect of CO2 elevated on nitrate metabolism of wheat under normally natural light and light-shaded conditions. NO3--N, NH4+-N, nitrate reductase activity, total uptake N by wheat plants during solution cultural period and total N in plants were determined for comprehensive evaluation of the effect. Results showed that under both natural light and light-shaded conditions, addition of CO2 increased NO3--N uptake and its assimilative capabilities by plants. However, there were some difference between shoots and roots. With increase of CO2 concentration, the concentration of NO3--N and NH4+-N as well as nitrate reductase activity all decreased in shoots while the difference was not so distinct in roots, and the nitrate reductase activity did not decrease, but increase. Since NO3--N uptake by plants from the solution and the total N in plants were much enhanced by CO2 addition, it may be concluded that addition of CO2 has resulted in rise of nitrate absorption, assimilation and metabolism of wheat.

Distribution Characteristics of Microbial Biomass Phosphorus in Different Soil Aggregates in Semi-arid Area

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Scientia Agricultura Sinica. 2005, 38(02): 327-332 .

Abstract ( 890 )

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Seven soils with different land use types were collected from semi-arid area and treated by dry-sieving. Distribution of microbial biomass P (MBP), available P (AP), organic P (OP), labile organic P (LOP), moderately labile organic P (MLOP), moderately resistant organic P (MROP) and highly resistant organic P (HROP) were studied. The results showed that the content of MBP and OP in whole soil and aggregates were 5.86-12.24 mg·kg-1, 0.12-0.35 g·kg-1, the irrigated arable soil and the grassland soil had the highest and lowest value, respectively. The amounts of MBP and OP in large aggregates (＞2 mm) were higher than in small aggregates (＜2 mm), and the AP in small aggregates was higher than in large aggregates. The result also showed that large aggregates had higher content of MROP and HROP, large and small aggregates were both rich in LOP and MLOP. These results suggest that the large aggregates may be the pool of soil P transformation, and the small aggregates are the source of soil available P. There were significant correlation between MBP and different types of soil phosphorous.

Recovery of Labeled Nitrate-N in Different Soil Layers by Two Kind of Crops

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Scientia Agricultura Sinica. 2005, 38(02): 333-340 .

Abstract ( 1129 )

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The difference on the utilization of labeled nitrate-N in different soil layers between two kind of crops, spinach and wheat, as well as two varieties of wheat was studied by means of soil column experiment. The results show that the recovery rate of labeled nitrate-N in spinach, Xiaoyan 54(wheat), Jing 411 (wheat) were 40.7%, 29.9%, 23.4% ; 45.5%, 16.1%, 7.7% and 32.5%, 12.4%, 4.7%, respectively, when nitrate-N was labeled in 10-20, 40-50, 70-80 cm soil layers. Between crops, the recovery of labeled nitrate-N in different soil layers by spinach was significantly higher than that of wheat. And between varieties, Xiaoyan 54 was significantly higher than that of Jing 411. Significant positive correlation was observed between crop root length density in corresponding soil layers and the recovery of labeled nitrate-N. In general, the distribution of nitrate-N in soil profile after harvest in column with spinach was lower than that with wheat, and Xiaoyan 54 was lower than Jing 411. After harvest, the peak of labeled nitrate-N in 10-20 cm layer was moved down to 40-50 cm, while that labeled in 40-50 cm layer did not move downward clearly and that labeled in 70-80 cm layer had the tendency to move upward and accumulated at 60 cm. No significant difference was observed on the moving distance of labeled nitrate-N in different layers between spinach and wheat and between two varieties of wheat.

A Study on Physical and Chemical Properties of Several Fly Ashes and Their Agrochemical Behaviors of Silicon and Phosphorus

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Scientia Agricultura Sinica. 2005, 38(02): 341-349 .

Abstract ( 944 )

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The physical and chemical properties and silicon releasing pattern and phosphate adsorption-desorption of fly ashes derived from six power stations in Hunan province were studied. The results showed that fly ashes could be used as soil amendments because the fly ashes were mostly composed by sand（1-0.05 mm）and coarse silt particle（0.05-0.01mm）accounting for 16.13 %- 85.68 % and 13.03 %-49.64 %, respectively. The bulk density of fly ashes was 2- to 3-fold lower than that of soils. The fly ashes generally have high alkalinity (pH 10.3-12.1, 1︰2.5 in H2O extract) except that the fly ashes of Changsha power factory derived from high sulfur coal have low acidity（pH 7.5, 1︰2.5 in H2O extract）. No obvious difference in contents of water-soluble and available silicon between fly ashes and soils was observed, so fly ashes can not be used directly as Si fertilizer. The contents of total potassium in fly ashes were approximately the same as in soils, but the contents of free iron oxide in fly ashes were 3- to 4-fold lower than those in soils. The releasing processes of Si in fly ashes and soils could be well described with Elovich equation and Freundlich equation ,in which the parameter b value and k value could express the releasing capacity of Si in fly ashes and soils .The larger the b and k values, the more the Si will be released from the fly ashes. The b value and k value in 5 fly ashes derived from various locations in order of magnitude is Xiangtan power factory (1539.3，2139.3)and Yueyang paper factory (1602.4，1274.0)＞Huaneng power factory (1325.7，1181.6)＞Changsha power factory(1250.6，915.9)＞Dongting nitrogenous fertilizer factory (751.9，565.6)＞Zhuzhou power factory (555.5，454.4). The fly ashes can supply certain Si nutrition for crop growth because the amount of silicon released in fly ashes were 3.0-25.0 times higher within 100 hours than those in the soils, thus the fly ashes can be a kind of Si fertilizer additive when manufacturing Si fertilizer. Furthermore, the fly ashes derived from Xiangtan power factory and Yueyang paper factory are fairly good Si fertilizer additives. The contents of total P and available P in fly ashes were generally higher than those in soils. The adsorption capacity of P in fly ashes increased with increasing P added，but the rates of P adsorbed in fly ashes decreased with increasing P added. The rates of P adsorbed in fly ashes were higher than those in soils, but the rates of P desorbed in fly ashes were lower than those in soils. The sorption processes of P in fly ashes could be also well described with Langmuir equation and Freundlich equation and Temkin equation, in which parameter Xm value and a value and k2 value can be used as a comprehensive index to characterize the potential phosphate sorptivity of fly ashes. The phosphate adsorption in fly ashes were mainly specific adsorption and chemical precipitation, thus it is suggested that the fixation of P must be considered when fly ash is used as soil amendments or filling substances of compound fertilizers.

A Study of Agricultural Tridimension Pollution and Discussion On Its Control

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Scientia Agricultura Sinica. 2005, 38(02): 350-357 .

Abstract ( 1089 )

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The new scientific concept of "Agricultural Tridimension Pollution" (ATriP) and its control theory were brought forward for the first time in this paper since the increasing pollution of unsuitable agriculture production measures within hydrosphere, pedosphere, biosphere and air-sphere. It was summarized that the development proceeding, tendency and key research fields of the control on the ATriP in the paper. It was also put forward that the necessary measures are needed to accelerate the technology development of control on the ATriP.

Development of Potato Industry and Food Security in China

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Scientia Agricultura Sinica. 2005, 38(02): 358-362 .

Abstract ( 1321 )

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Under the pressures of population increase, arable land decrease, water shortage, planting area reduction of three major grain crops (rice, wheat and maize) in recent years, there is a potential crisis in food security in China. As an all-purpose crop with high water utilization efficiency and long industrial chain, the potato planting area has been increased year by year. Compared with the three major grain crops, potato planting area can be further increased by using the winter fallow fields and its yield can be further increased as well. With the development of potato industry, potato will play more and more important roles in alleviating the problem of food security in China.

Development and Evaluation of Core Collection of Japanese Apricot Germplasms in China

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Scientia Agricultura Sinica. 2005, 38(02): 363-368 .

Abstract ( 747 )

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Cluster analysis was used to study the relationship of Japanese apricot originated from China. First, three groups were classified according to the color of the fruits: group for white mei, red mei and green mei. Then, clustered according to 27 characteristics with SAS program. The data of isozyme, RAPD and SSR were also taken into account. Finally, 20 Japanese apricot germplasms were screened as core collection from 197 Japanese apricot germplasms. The reliability of core collection was identified.

Effect of Light Quality on Photosynthesis and Chlorophyll Fluorescence in Strawberry Leaves

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Scientia Agricultura Sinica. 2005, 38(02): 369-375 .

Abstract ( 1194 )

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Chlorophyll contents, maximal photochemical efficiency of PSII (Fv/Fm) , Fm/Fo, amount of inactive PSⅡreaction centers (Fi-Fo) and rate of QA reduction were correlated with red/blue ratios positively, but chlorophyll (a/b) ratios were correlated with red/blue ratios negatively. Carotenoid contents were in the order: blue film >green film> red film, white film and yellow film, which were correlated with red/far-red ratios negatively. The apparent quantum efficiency (AQY), photorespiratory rate（Pr）and carboxylation efficiency (CE) also were strongly affected by light quality. The net photosynthetic rate（Pn）of strawberry leaves under green film was significantly lower than that of under all other film treatments.

Physiological Mechanism of Metabolism of Carbohydrate, Phenols, Free Amino Acid and Endogenous Hormones in Middle Scales of Lilium davidii var. unicolor Bulbs Stored at Low Temperature for Dormancy Release

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Scientia Agricultura Sinica. 2005, 38(02): 376-382 .

Abstract ( 1056 )

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Changes in carbohydrate, phenols, free amino acids and endogenous hormones in middle scales of Lilium davidii var. unicolor bulbs stored in moist sawdust for 101 days at 2℃, 6℃ and 10℃, respectively, were studied. Results indicated that starch content and ABA level decreased markedly along with decline of storage temperature and prolonging of duration, and total soluble sugar content，phenols content, GA3 and IAA concentration increased sharply. Notable changes of above substances occurred at earlier phase (34 d). Correlation analysis revealed that increase of amylase activity and PAL activity conduced to increase of total soluble sugar content and phenols content, respectively. As a general tendency, free amino acid content decreased, and arginine content was the highest and its changes were dramatic among all kinds of free amino acids. According to results of stepwise regression analysis and path analysis, it is concluded preliminarily that the metabolism in middle scales may be regulated mainly by endogenous GA3.

Effects of GA3 on Postharvest Lignification of Green Asparagus

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Scientia Agricultura Sinica. 2005, 38(02): 383-387 .

Abstract ( 1022 )

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Excised green asparagus（Asparagus officinalis L.） were treated with gibberellic acid（GA3）at 24℃±1℃. The results indicated the levels of lignin, total phenol and active oxygen in asparagus treated with GA3 were significantly lower than those of in the control. Activities of the enzymes related lignin synthesis，including phenylalanine deaminase, polyphenol oxidase, cinnamyl alcohol dehydrogenase and peroxidase were also reduced by GA3 treatment. Degradation of protein，DNA and RNA in the asparagus were significantly inhibited by GA3 treatment. The results suggested that GA3 treatment could improve the postharvest quality of green asparagus.

Membrane Lipid Peroxidation Mediated by Mechanical Wounding and Jasmonic Acid in Pea Seedlings

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Scientia Agricultura Sinica. 2005, 38(02): 388-393 .

Abstract ( 1286 )

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The effects of wounding and exogenous-applied jasmonic acid (JA) on the membrane lipid peroxidation were investigated in pea seedlings (Pisum sativum L.). The results showed that the activities of both phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) significantly increased by wounding and application of JA. The metabolism of reaction oxidative species (ROS) was enhanced, especially O2-·and H2O2 increased rapidly. The antioxidant enzymes such as supiroxide dismutase (SOD), catalase (CAT), ascrobate peroxidase (APX) and peroxidase (POD) were also activated. Pretreatment of JA of 1-10 μmol·L-1 could effectively induce plant defense response, and thus decrease the level of cell membrane lipid peroxidation. However, high concentration of JA (100 μmol·L-1) resulted in unbalance of metabolism of ROS and promote lipid peroxidation. It is concluded that JA, under the suitable concentration, can induce pea seedlings defense response to wounding.

Detection of cDNA of Avian Influenza Virus by DNA Microarray

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Scientia Agricultura Sinica. 2005, 38(02): 394-398 .

Abstract ( 1345 )

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A rapid microarray-based assay for the reliable detection of H5, H7 and H9 subtypes of avian influenza virus (AIV) was developed. The strains used in the experiment were A/Turkey/England/N28/73（H5N2），A/African starling/983/79（H7N1）and A/Turkey/Wiscosin/1/66（H9N2）. The cDNAs clone which encode approximately 500bp avian influenza virus gene fragments were obtained by reverse transcription PCR technique, the DNA fragments, which were reamplified from recombinant plasmids, were spotted on a glass-bound microarray. Cy5-labeled fluorescent probes were hybridized to these samples cDNAs, which generated from vRNA during reverse transcription. These samples cDNAs contained multiple fragments of AIV including the hemagglutinin gene and matrix gene. The type of AIV were detected with the matrix gene，and the subtypes of AIV were differentiated with hemagglutinin gene. The arrays were scanned to determine the probe binding sites. The hybridization pattern agreed approximately with the known grid location of each target. The results showed that DNA microarray technology could provide a useful diagnostic method for AIV.

Detection of Beta-lactamase and Extended-spectrum Beta-lactamase and Antibiotic Susceptibility Test Analysis of Pathogens Isolated from Pig and Chicken

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Scientia Agricultura Sinica. 2005, 38(02): 399-404 .

Abstract ( 1223 )

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The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase-producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with two-fold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta-lactamases(ESBLs).The results revealed that most of the 43 clinically isolated strains could produce beta-lactamase and 3 strains of Shigella isolated from chicken samples produced ESBLs. Ａll of the 30 lactamase-producing strains isolated and only one of the 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamase-producing isolates decreased by 10-40 and 10-20 times, respectively, when it was conbined with sulbactam at ratio of 1∶2 and 1∶4. All clinical isolates were susceptible to third-generation cephalosporins.The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased by 2-4 times when they were conbined with sulbactam.

The Apoptosis and Dynamic Expression of Bax and Bcl-2 in Lymphocytes of Bursa of SPF Chickens Infected with SNJ93 Strain

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Scientia Agricultura Sinica. 2005, 38(02): 405-409 .

Abstract ( 851 )

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Apoptosis and dynamic expression of their regulatory genes Bcl-2 and Bax in lymphocytes of bursa of 21-day -old SPF chickens infected with SNJ93 strain from the first to fourteenth day post infection were investigated. Apoptosis was observed by electron microscope and apoptosis rate was assessed by TUNEL method. The expression of Bcl-2, Bax was investigated by immunohistochemical ABC method. The apoptosis of lymphocytes in bursa of chickens infected with SNJ93 strain from the first to seventh day post infection significantly increased compared with that of normal SPF chickens (P<0.01).The expression of BCL-2 significantly increased in lymphocytes of bursa of SPF chickens infected with SNJ93 strain from the first to nineth day post infection compared with those of normal chickens (P<0.01). The expression of Bax significantly increased from the first to seventh day post infection (P<0.01 or P<0.05).The ratio of bcl-2 and Bax significantly decreased from the first to fifth day post infection (P<0.05 or P<0.01). A great deal of disappearance of lymphocytes of bursa of SPF chickens infected with SNJ93 strain from the first to seventh day was related to apoptosis .The ratio of Bcl-2 and Bax could precisely reflect the degree of apoptosis of lymphocytes of bursa.

Studies on Hemodynamics and Hemorheology Character of Different Tongue Complexion in Mule

Scientia Agricultura Sinica. 2005, 38(02): 410-414 .

Abstract ( 717 )

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To determine the relationship between hemodynamics and hemorheology and tongue complexion of animals. The Hemodynamics and hemorheology parameters were measured by using noninvasion technic in 83 mule with intestinal obstruction. It was found that as tongue complexion changed from normal to pink, red and crimson, the parameters PR, CO, CI, EWK, HOI, BLK and blood viscosity increased gradually (P<0.05, or P<0.001), while MRT, MST, FEK and VER decreased gradually (P<0.05, or P<0.001).The parameter PR, CO, CI, EWK, HOI, BLK, , MRT, MST, FEK and VER were much different in mule with normal, pink, red and crimson tongue complexion. This study suggested that there are different changes in cardiovascular function as tongue complexion changed from normal to pink, red and crimson in mule.

Identification and Marker-assisted Selection of HMW-Glutenin 1Dx5 Gene in Wheat

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Scientia Agricultura Sinica. 2005, 38(02): 415-419 .

Abstract ( 1222 )

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Wheat bread-making quality is associated with allelic pairs at the Glu-D1 complex locus, designated 1Dx5-1Dy10 and 1Dx2-1Dy12, respectively. The specific PCR marker of 1Dx5 was applied to detect the presence of the HMW-glutenin 1Dx5 gene in 49 wheat varieties. The results showed that the PCR marker could amplify a 450bp fragment in 17 varieties and the positive control, Cheyenne, comprising the 1Dx5 gene, while other 32 varieties and the negative control did not show the specific product. The results suggested that this PCR marker of 1Dx5 could identify the presence of the HMW-glutenin 1Dx5 gene. The low proportion containing the HMW-glutenin 1Dx5 gene in the 49 wheat varieties implied that the application of the good bread wheat varieties or elite HMW-glutenin subunits in breeding program should be improved. Also the results corresponding to those by protein SDS-PAGE indicated that this marker was reliable and effective. Six BC1F1 populations derived from backcrosses of common wheat lines were screened by this molecular marker and individual plants with the HMW-glutenin 1Dx5 gene were identified.

Effect of Nitrogen Application Rate on Noodle-making Quality of Wheat

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Scientia Agricultura Sinica. 2005, 38(02): 420-424 .

Abstract ( 824 )

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A nitrogen fertilization trial was conducted at the Experimental Station of Shandong Agricultural University. The objective of this study was to investigate the influence of nitrogen application rate on noodle making quality of two winter wheat (Triticum aestivum L.) cultivars, Yannong15 (YN15) and Jimai19 (JM19), which are extensively used for making Chinese fresh- and dry- noodles. The results suggested that the protein content and SDS sedimentation value of flour were, to some extent, increased by nitrogen fertilization, resulting in the obvious improvement of noodle-making quality. The effect of nitrogen application on fresh-noodle making quality was significantly more than that on dry-noodle making quality. The response of JM19 was detected much stronger than that of YN15 in noodle making quality. As compared with control, the total scores of fresh-noodle and dry-noodle in YN15 increased by 10.8% and 9.1% respectively due to nitrogen application, and those in JM19 increased by 12.5% and 11.0%， respectively. A close relationship existed between noodle making quality and flour protein content. Also, SDS sedimentation value was positively associated with noodle making quality. The role of nitrogen application on noodle making quality was through the improvement of noodle elasticity, viscosity, palate, and appearance.

Establishment and Application of Detection of Prune Dwarf Virus (PDV) by RT-PCR

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Scientia Agricultura Sinica. 2005, 38(02): 425-427 .

Abstract ( 1139 )

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A pair of primers was synthesized based on the nucleotide sequence of the coat protein gene of prune dwarf virus (PDV).The expected size 172bp was amplified by RT-PCR from the infected samples, while no amplified products from the healthy samples.The amplified products were cloned and sequenced. The result showed that the detection system was stable.Thus a rapid, sensitive and accurate method for PDV identification and detection by RT-PCR has been built up and were used to detect whether some fruit trees in orchards were infected by PDV or not.

Effect of Soil Se Level on Selenium Uptake and Transformation by Two Spring Soybean Cultivars

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Scientia Agricultura Sinica. 2005, 38(02): 428-432 .

Abstract ( 748 )

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A pot experiment of Se uptake by two spring soybean cultivars with different Se affinities and using two soils with different Se levels was conducted. The Se translocation and transformation in plant organs was studied after harvest. In soils with high Se level, there was no significant difference in Se accumulation in grains between the two cultivars. However, a stronger Se translocation and accumulation, and higher ratio of organic Se to inorganic Se in grains were found in the cultivars of higher Se affinity than that of low Se affinity although Se translocation in grains was significantly lower in the soils with low Se level. This study indicates that both genotypic and soil affect Se translocation and organic Se synthesis by soybean cultivars, and also shows that difference in organic synthesis under different soil Se level. Higher Se bio-availability in soybean grains can be expected from exotic Se amendments. These may be fundamental for high-Se soybean production and processing for Se nutrition regulation both for animals and human.

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