Scientia Agricultura Sinica

Pyramiding Two Bacterial Blight Resistance Genes into a CMS Line R106A in Rice

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Scientia Agricultura Sinica. 2005, 38(11): 2157-2164 .

Abstract ( 1396 )

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Most of the male sterile lines have no resistance to bacterial blight (BB) and the cultivars with a single BB resistance gene will break-down easily. Two resistance genes，Xa21 and Xa23 were pyramided into a male sterile line through crossing, backcrossing and selfing to improve its resistance. The PGMS line 3418S（carrying Xa21）was crossed with CBB23 (carrying Xa23). The F1 was backcrossed with 3418S to get BC1F1, then, selfing for 3 times to pyramid the two genes and bred a new line R106 with homozygous resistance by inoculation and MAS. The new line R106 was also as a recipient for developing a cytoplasmic genetic male sterility (CMS) line R106A by the back-crossing procedure. The line R106A was highly resistant to 7 Chinese pathotypes of Xanthomonas oryzae pv. oryzae (Xoo) and showing overall resistance, which might maintain durability. The methods including backcrossing times, selecting generation were also discussed.

Variation and Stability Analysis of Wheat Dough Stability Time

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Scientia Agricultura Sinica. 2005, 38(11): 2165-2172 .

Abstract ( 1570 )

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Farinograph dough stability time is an important index for classifying wheat, and it often indicates the most appropriate end use for wheat cultivars. This research was directed at the problem of large fluctuations in dough stability time that occurs during commercial wheat production. The variations in dough stability time and its consistency across locations and years were analyzed using 12 principal high-quality wheat cultivars (varieties) from China's Shandong Province, which were grown at nine different locations for three successive years. The results indicated that the coefficient of variation for dough stability time ranged from 24.29% to 49.60% across different varieties, locations, and years. Additive main effects and multiplicative interaction (AMMI) analysis indicated that there were significant interactions in dough stability time among varieties, growth locations, and years. The genotypic effect was the most noticeable, followed by the interaction between genotype and environment. The environmental effect was the least significant. The interactions between variety and locations differ greatly, however. Each cultivar (variety) apparently has a specific adaptability to growth location. Therefore, for the successful commercial scale production of high-quality wheat, we should select both proper cultivars and their most suitable growth locations should be selected to meet the requirements for dough mixing stability time.

Distribution of Puroindoline Alleles in Chinese Winter Wheats and Its Effect on Solvent Retention Capacity

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Scientia Agricultura Sinica. 2005, 38(11): 2173-2181 .

Abstract ( 1538 )

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In total, 244 varieties and advanced lines from four Chinese winter wheat regions were used to investigate the variation of kernel hardness, flour particle size, puroindoline type and solvent retention capacity. The results indicated that five puroindoline alleles including Pina-D1a/Pinb-D1a (wild type), Pina-D1b/ Pinb-D1a, Pina-D1a/Pinb-D1b, Pina-D1a/Pinb-D1d and Pina-D1a/Pinb-D1p were observed in Chinese winter wheats, and Pina-D1a/Pinb-D1b was the most prevalent type with a frequency of 81.2% in hard wheats. Pina-D1a/Pinb-D1p was only present in Chinese wheats up to now. Significant correlations were observed between kernel hardness and four kinds of SRC (solvent retention capacity) and the coefficients of correlation between WSRC (water solvent retention capacity) and hardness by SKCS (single kernel characterization system) and NIR (near infrared spectroscpy) were 0.73 and 0.64, respectively. Means of WSRC and SCSRC (sodium carbonate solvent retention capacity) in varieties with Pina-D1b/Pinb-D1a allele were significantly higher than that of Pina-D1a/Pinb-D1b. In addition, wheats in different regions have different hardness types and solvent retention capacity. The average of WSRC in Northern China Plain winter wheats was significantly different from that of Southwestern winter wheat region, and the average of SCSRC in Northern China Plain winter wheats was significantly different from that of the middle and lower reaches of the Yangtze River winter wheat region. This study has provided useful information for improving Chinese wheat hardness and in the application of solvent retention capacity at early generation selection in wheat breeding program.

Chromosomal Location of the Genes Associated with Photosynthesis of Lophopyrum elongatum (Host) A.L?ve in Chinese Spring Background

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Scientia Agricultura Sinica. 2005, 38(11): 2182-2188 .

Abstract ( 1399 )

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Researches on the relationship between photosynthesis and wheat yield have attracted the attention of both domestic and overseas scholars. There is no report about the study on the effects of exogenous chromosomes on photosynthesis using the substitution series as materials. In this research, Triticum aestivum cv. Chinese Spring- Lophopyrum elongatum (Host) A.L?ve disomic substitutions series were used as materials and flag leaves as the measuring position. And the CI-310 Portable Photosynthesis System made by CID Co. in USA was used to measure the net rate of photosynthesis of flag leaves in different developing stages and the correlations between photosynthesis and yield. The result showed that the line of DS2Ee (2A) has the highest photosynthetic rate in the whole developing stage when it is in the anthesis, it can be used in improving process of the character of kernel number. The flag leaves of DS4Ee (4A, 4B, 4D) lines can remain certain high net photosynthetic rate from heading to grain filling stage. It can be used in research of promoting the yield index like 1000-grain weight through improving the photosynthetic rate at grain filling stage.

The Impacts of US and CGIAR's Germplasm on Maize Production in China

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Scientia Agricultura Sinica. 2005, 38(11): 2189-2197 .

Abstract ( 1288 )

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Wide adoption of a few of homogeneous germplasm would reduce crops' genetic diversity, increase crop vulnerability stresses, and reduce the stability of crop production. The introduction and utilization of exotic germplasm is a sustainable solution for broadening the genetic diversity and promoting periodical replacement of varieties. The genetic contribution and economic impacts of exotic genetic resources (particularly that of US and CG resources) on China's maize production were evaluated on the basis of analysis of varieties' pedigree information from 20 major maize-producing provinces in China from 1982 to 1997. The results indicated that the contribution of US and CG germplasm resources to the continuous increase of China's maize production, particularly CG gerplasm resources, has shown a rapid increase trend since the 1990s. The genetic contribution of US germplasm resources increase by 1%, per unit maize yield will increase by 0.2% (0.01 t·ha-1). If the contribution of CG germplsam resources, which has greater potential yield, increase by 1%, maize yield will increase by 0.025 t·ha-1. One policy should be implemented for the government is encouraging breeders to focus more attentions on the use and improvement of CG germplasm resources. The US germplasm resources have been utilized extensively in China so that they can offer germplasm resources for maize breeding and maize production.

Development and Superior Performance of High Oil Yielding Canola Hybrid Zhongyouza No.8

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Scientia Agricultura Sinica. 2005, 38(11): 2198-2204 .

Abstract ( 1360 )

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High oil yield resulted from the combination of high grain yield and high oil content is a prerequisite for the development of high efficient oilseed rape production. Using irradiation induced mutation，sexual hybridization combined with paired test cross, the fertility, yield and oil content of the three lines of cytoplasmic male sterility were improved and a new hybrid variety Zhongyouza No.8 with high oil yield was developed. The yield of Zhongyouza No.8 was significantly higher than that of the control variety Zhongyou 821 with 9.82% and 10.64% increase in Hubei provincial and nationwide trials, respectively. The oil content and oil yield of Zhongyouza No.8 was the highest among all the lines in Hubei provincial trials, being 42.77% and 1 051.05 kg·ha-1 with 3% and 161.25 kg·ha-1 increase compared to the control Zhongyou 821, respectively. The genetic basis for the strong heterosis, factors contributing to the yield and oil content increase of Zhongyouza No.8 as well as the strategy for high oil yielding variety improvement through the increase of seed size are discussed in this paper.

Photosynthetic Efficiency of a New Plant Type of Rice Developed by the International Rice Research Institute

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Scientia Agricultura Sinica. 2005, 38(11): 2204-2210 .

Abstract ( 1656 )

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The net photosynthetic rate of the NPT of rice is distinctly lower than that of conventional indica rice. According to chlorophyll fluorescence analysis, the primary photochemical efficiency of the NPT of rice is remarkably higher than that of conventional indica rice. In contrast, the practical light use efficiency of the NPT of rice, expressed whether as saturated net photosynthetic rate per unit chlorophyll or as photochemical quenching of chlorophyll fluorescence, is lower, indicating that non-photochemical processes are the major limiting factor to photosynthesis. The physiological improvement of the NPT of rice is discussed in terms of light use efficiency.

Photosynthetic Properties of CMS-Based Hybrid Cotton (Gossypium hirsutum L.) with Okra Leaf

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Scientia Agricultura Sinica. 2005, 38(11): 2211-2218 .

Abstract ( 1442 )

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Twenty-four CMS-based hybrids with five leaf types in upland cotton were made among super Okra leaf, Okra leaf and normal leaf parents by NCⅡ mating design to compare photosynthetic properties of different leaf type hybrids and to study their relationships with yield and fiber properties. Compared with Zhongza29 (CK hybrid), yields of super okra leaf and okra leaf hybrids were obviously lower, but semi-Okra leaf hybrids was 1.16% higher in yield of seed cotton and 2.06% in yield of lint cotton, and 10 days earlier in maturation. Semi-Okra leaf cotton hybrid, CLA 17 × ZR4, which was made by super Okra leaf sterile line and Zheda strong restorer line, had a 13 % higher yield over CK. For fiber properties, semi-Okra leaf hybrids had better quality in fiber length and micronaire value than CK with normal leaf. For photosynthetic indexes at different development stages of plant, semi-Okra leaf hybrids showed higher Pn (net photosynthetic rate), Gs (stomatal conductance ) and Tr (transpiration rate) than normal leaf hybrids at all stages except the harvesting stage, especially Pn was the highest in the flowering stage, but Ci was lower than normal leaf hybrids. There were positive correlation coefficients between Pn and yield-relatied traits at different development stages, of them, yield of seed cotton was the most significant relationship with Pn, boll number and bolls weight were in middle, fruiting branche was the smallest. Investigation of photosynthetic indexes in upper, middle and lower layer leaves of hybrid plants at the boll-setting stage showed that light intensity, light transmittance, Pn and Gs of super Okra leaf and Okra leaf hybrids were higher in the lower layer leaves than those of other leaf hybrids, especially those of super Okra leaf hybrids was the highest values in light transmittance and Pn, increased by 94.12% and 45.54% over CK respectively, but Pn was lower in the upper and middle leaves. Pn and Gs of semi-Okra leaf hybrids were higher in the top, middle and lower layer leaves than those of normal leaf hybrids, such as Pn, increased by 8.06% for the upper layer, 1.7% for the middle layer and 30.77% for the lower layer leaves than CK, respectively. The study indicates that semi-Okra leaf hybrids has better photosynthetic properties which are of benefits to expression of heterosis of yield and fiber properties.

Studies on the Dynamic Changes of Soluble Sugar Contents in Leaf, Stem and Grain in Different Winter Wheats and the Relationship with Grain Starch Contents

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Scientia Agricultura Sinica. 2005, 38(11): 2219-2226 .

Abstract ( 1025 )

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Three wheat cultivars differing in grain protein content, Zhengmai 9023(strong-gluten wheat), Wenmai 4 (medium- gluten wheat)and Yumai 50 (weak-gluten wheat) were used in an experiment to study the dynamic changes of total sugar content and sucrose content in the flag leaf, stem, sheath and grain and the starch content in grain. Result showed that, the total soluble sugar and sucrose content in flag leaf in Wenmai 4 and Yumai 50 were higher than that in Zhengmai 9023, and the activities of sucrose(SS) and sucrose-phosphate (SPS) activity in flag leaf showed the same dynamic trend during filling stage.The time that the maximum of SS and SPS activity occurred was earlier than that of total soluble sugar content and sucrose content. Twelve days after anthesis the total soluble sugar content in grain of Yumai 50 was highest but that was lowest in Zhengmai 9023. During the filling stage the starch content in grain of Yumai 50 was highest among the three wheat cultivars, and the activity of adenosine diphosphorate glucose pyrophrylase (ADPP) showed the same trend during the later fiiling stage. The correlation analysis showed that there was a negative correlation between the total soluble sugar content in stem and the starch content in grain, and there was also a positive correlation between the total soluble sugar content in leaf, the sucrose content in leaf, total soluble sugar content in grain and the starch accumulating rate in grain after eighteen days after anthesis. The quantity and contribution to grain starch yield of remobilized total soluble sugar from top of 2nd and 3rd nodes of wheat stem in Yumai 50 and Zhengmai 9023 were the highest, but the quantity and contribution to grain starch yield of remobilized total soluble sugar from top of 4th and 5th nodes of wheat stem of Wenmai 4 were the highest.

Application of the Candidate Resistance Genes to Genetic Diversity in Rice

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Scientia Agricultura Sinica. 2005, 38(11): 2227-2232 .

Abstract ( 1234 )

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The homologues of 24 rice cultivars were analyzed using 19 candidate resistance gene (CRG) probes from rice and barley with NBS-LRR structure, while the resistance of the cultivars was tested by inoculating 26 isolates of Magnaporthe grisea in this study. The results showed that the 24 cultivars had 127 loci totally, each probe had 6.7 loci averagely. Except for Qitougu, Babaogu and Zinuo, indica cultivars had more loci and higher blast resistance than japonica ones in field and artificial inoculation, implying the positive correlation between the DNA band numbers and blast resistance. The clustering analysis classified the 24 cultivars into 2 groups and 5 subgroups, which respectively corresponded to indica-japonica differentiation and known rice heterotic groups based on pedigree information and blast reaction. The results demonstrated that CRG markers could be used to investigate genetic relationships among rice cultivars, and to control rice blast by inter-planting different cultivars and thus providing rice resistance breeding with parent genetic background.

Cloning and Sequence Analysis of a cDNA Encoding Chemosensory Protein in Helicoverpa armigera

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Scientia Agricultura Sinica. 2005, 38(11): 2233-2239 .

Abstract ( 1350 )

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A full-length cDNA, CSPHarm, was cloned from antennae of Helicoverpa armigera. The open reading-fragment of CSPHarm was 381bp, encoding 127 amino acid residues. This deduced amino acid sequence shared some common structural features with chemosensory proteins in insects. It also shared high identity with chemosensory proteins from other insects. Therefore, CSPHarm was a cDNA encoding chemosensory protein of H.armigera. CSPHarm displayed a strong hydrophilicity all along the molecular, except for the hydrophobic domain between residues 20-30, which was likely binding domain of hydrophobic compounds. Semi-quantitative RT-PCR analysis showed that CSPHarm was highly expressed in head, thorax, abdomen, leg, wing and antenna of H. armigera. No obrious difference at expressed level of CSPHarm among these tissues. CSPHarm was also expressed in egg, larva, pupae and adult and relatively low expressed in egg and highly expressed in adult.

Histopathological Effects of the Protein Toxin from Xenorhabdus nematophila on the Midgut of Helicoverpa armigera

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Scientia Agricultura Sinica. 2005, 38(11): 2240-2245 .

Abstract ( 1219 )

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Xenorhabdus nematophila HB310 is highly virulent to many insects, and it is symbiotic with Steinernema carpocapsae HB310. ToxinⅡwas obtained by salting out and native-PAGE from the cells of X. nematophila HB310. The histopathology of toxinⅡto Helicoverpa armigera larvae was studied by dissecting and olefin slice of the midgut. The symptoms showed that the histopathology of the H. armigera midgut was similar to that of other novel midgut-active toxins such as the δ-endotoxins from Bacillus thuringiensis, as well as Tca from Photorhabdus luminescens W14. The midgut tissues of H. armigera fouth-instar larvae began to change after taken the toxinⅡorally in 6 hours. The foreport of peritrophic membrane began fracture and the cells extended. The epithelium was decomposed gradually and the midgut tissues were loose or disordered at last. The peritrophic membrane disappeared after 12 hours but appeared again after 72 hours following transient or sublethal exposure to the toxin. The toxinⅡalso directly destroyed the excised peritrophic membrane of H. armigera.

HPLC Analysis on Formation of the Multi-Bioinsecticidal-Toxin BtA

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Scientia Agricultura Sinica. 2005, 38(11): 2246-2253 .

Abstract ( 942 )

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Based on the theory of multi-bioinsecticidal toxin and the technique of bioconjugation, The multi-bioinsecticidal- toxin BtA was worked out in order to provide a new idea and a new method for development of a new type of biocide. The bioconjugation procedure of BtA included: decomposing Bacillus thuringiensis (B.t.) crystal by DTT into the protoxin with an end amino group; activation and derivation of abamectin to form abamectin-COONa with a carboxylic group; final bioconjugation by using amino-carboxylic conjugator EDC to achieve the substance combination of two biotoxins. In the detecting program, the experiments were carried out with HPLC (High Pressure Liquid Chromatogram) on measuring BtA bioconjugation system at different reaction times to identify the occurrence of bioconjugation reaction, on comparing BtA bioconjugate system with the three reactants and three two-reactant combinations to distinguish bioconjugated product BtA, and on a qualitative analysis of the bioconjugated product BtA. The results proved that a new bioconjugated substance was confirmed to present in BtA bioconjugation system, which was named as multi-bioinsecticidal- toxin BtA.

Determination of Abamectin and Its Toxicological Metabolite in Vegetables and Fruits by HPLC with Pre-column Fluorescent Derivatization

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Scientia Agricultura Sinica. 2005, 38(11): 2254-2260 .

Abstract ( 1731 )

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A rapid HPLC method for simultaneous determination of abamectin and its toxicological metabolite in vegetables and fruits with fluorescent detector after pre-column derivatization was developed. After extracted by acetonitrile, overleaping cleaned-up step,the target compounds in samples was directly pre-column derivatised by TFAA-NMIM-CAN system. The results suggested that the fortified recovery and variation coefficient of added compouds in samples were 84.2%～110.8% and 1.9%～12.8%, respectively, the limited level of detection is 1μg·kg-1.

Recovery of Labeled Nitrate-N in Different Soil Layers by Wheat in Different Growth Stages

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Scientia Agricultura Sinica. 2005, 38(11): 2261-2267 .

Abstract ( 905 )

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Recoveries of labeled nitrate-N in different soil layers by wheat at different growth stages were investigated with soil column experiment under the controlled irrigation condition. The results showed that recovery and uptake of labeled nitrate-N by wheat at any stage decreased with the increase of depth of labeled-N in the soil profile. The recovery of labeled nitrate-N in 10-20 cm, 40-50 cm, 70-80 cm soil layer were 15.7%, 3.4% and 1.2% at shooting stage, respectively, and the corresponding recovery were 30.6%, 10.7% and 3.9% at earring stage, 33.1%, 13.1% and 5.1% at flowering stage; and 32.5%, 12.4% and 4.7% at maturing stage. Uptake of labeled nitrate-N in 10-20 cm soil layer by wheat almost maximized at earring stage, but the maximum uptake of 40-50 cm and 70-80 cm layers occurred at flowering stage. Recoveries of labeled nitrate-N in different soil layers by wheat were significantly correlated with the root density and its dry weight in corresponding layers.

Correlation Between Corn Leaf Spectral Reflectance and Leaf Total Nitrogen and Chlorophyll Content Under Different Nitrogen Level

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Scientia Agricultura Sinica. 2005, 38(11): 2268-2276 .

Abstract ( 1427 )

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The correlation between the corn leaf chlorophyll content, total nitrogen content, moisture content and leaf spectral reflectance was studied in a patted experiment under different N treatments. Results showed that shooting stage and trumpet stage were sensitive stages for diagnosis of nitrogen in corn. The precision of inferring leaf nitrogen and chlorophyll concentration by leaves maximal spectral reflectance at green waveband was: trumpet stage > shooting stage > anthesis-silking stage. Different wavebands should be chosed for diagnosis of corn leaf nitrogen and chlorophyll concentration in different development stages. It was proved that the reliability of using visible spectral reflectance was preferable than other wavebands at shooting stage and trumpet, but near infrared spectral reflectance was more reliable at anthesis-silking stage. The combination spectra variables of two wave bands were better than single wave band to estimate the content of leaf total nitrogen and chlorophyll.

Distribution and Remobilization of Nitrate in Two Cultivars of Pakchoi Plant

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Scientia Agricultura Sinica. 2005, 38(11): 2277-2282 .

Abstract ( 894 )

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Studies on the distribution and remobilization of nitrate in vegetable plants are important theoretical bases for decreasing nitrate content in vegetables and increasing nitrate use efficiency by plants. Hydroponic experiments and plant electro-physiological methods were used to determine tissue nitrate content and vacuolar nitrate activity of different organs of two pakchoi cultivars, which were significantly different in nitrate accumulation. Results obtained were as follows: Vacuolar nitrate activities of leaf blades, petioles and roots were 4.6, 2.0 and 7.4 times of tissue nitrate content respectively, inferring that nitrate activity in vacuoles was much higher than in cytosol. Nitrate contents in leaf blades, petioles and roots of Liangbaiye 1 were 2.4, 1.9 and 3.6 times of those of Shanghaiqing. Tissue nitrate contents in different organs of pakchoi were in the decreasing order of petiole > leaf blade > root, but no significant difference was found among these three organs. After pakchoi plants were transferred to the solution without nitrate, both the tissue nitrate contents and vacuolar nitrate activity significantly decreased, while cytosolic nitrate activity and NRA in leaf blades maintained relatively unchanged. Nitrate was predominantly stored in vacuole and could be reused by plants. Tissue nitrate stored in roots and petioles could be remobilized by leaf blades, and vacuolar nitrate could be released into cytosol to maintain a steady cytosolic nitrate concentration, and thus the nitrate reductase activity was kept in normal level. Liangbaiye l, a high nitrate accumulating cultivar, had a high vacuolar nitrate activity, and its tissue nitrate contents decreased more slowly than Shanghaiqing after transferring to the solution without nitrogen, which probably was caused by its low NRA.

Dynamic Characteristics of Potassium Release from Controlled Release Fertilizer by Using Ion Exchange Resin Membrane

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Scientia Agricultura Sinica. 2005, 38(11): 2283-2289 .

Abstract ( 1249 )

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The characteristics of potassium release dynamics of multi-longevity controlled release fertilizers (CRFs) were investigated by using ion exchange resin membrane (IERM) adsorption method in a soil-column leaching experiment. The results showed that the accumulated net K2O adsorbed by IERM was in the order of FT1>FT4>FT2=FT7>FT5>FT6=FT3 among the treatments. There wasa significant correlation between the net amounts of K2O adsorbed and the amount of K2O in leaching solution every week during early stages of the experiment. However, there was no significant correlation between the net amount of K2O adsorbed and K2O in leaching solution of every fortnight in late stage of the experiment. The accumulated net amount of K2O adsorbed by IERM was greater at the third and the seventh times of extraction. Results also indicated that the value of M in Richards equation was no significant difference among treatments and bigger than that measured. The value of k was in a larger range of 0.1130 to 0.2722 which was able to reflect the difference of K2O release from the CRFs accurately. Nevertheless, the value of M in Logistic equation varied among treatments and smaller than that measured. The value of k was in a narrow range of 0.5066 to 0.6006 which could hardly to reflect the difference of K2O release from the CRFs accurately. It is concluded that Richards equation is better than Logistic one to describe and forecast nutrient release dynamic properties of the multi-longevity CRFs by using ion exchange resin membrane.

Effects of Local Irrigation on Absorption and Use of Nitrogen from Different Root Zones of Maize

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Scientia Agricultura Sinica. 2005, 38(11): 2290-2295 .

Abstract ( 1037 )

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Effects of local irrigation in root zones on absorption and use of nitrogen from different root zones were studied on maize grown in split-root containers. Maize was irrigated in both halves of the pot (control, C) or water was continuously supplied to the one-half of the pot and the other half kept dry (fixed partial root zone irrigation treatment, F), or water was alternatively supplied to two halves of the pot (alternative partial root zone irrigation treatment, A). (15NH4)2SO4 was applied to one of the two root zones and (14NH4)2SO4 to another root zone. The results was as follows: For A treatment, during the first five days when irrigation water was supplied or re-supplied to one half-root zone, the nitrogen inflow of the root system in the irrigated zone was significantly increased as compared with that of the control and other root zones, suggesting that A stimulated the compensation of nitrogen uptake again and again. Take a long view, the amount of N absorption from two root zones of A almost equalized, and the use and residue and also lose efficiency of N fertilizer applied to two zones was close to each other. As for F treatment, the N in plant was mainly from the irrigated root zone. The use and lose efficiency of N fertilizer applied to the irrigated zone increased obviously as compared with the non-irrigated zone, while the residue efficiency was the contrary. The use efficiency of N fertilizer for A was higher than that of the non-irrigated zone of F, and lower than the irrigated zone. As compared with C, both F and A increased the N use efficiency of maize.

Analysis of the Changes of Calcium Content of Several Apple Cultivars in Developing Season

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Scientia Agricultura Sinica. 2005, 38(11): 2296-2300 .

Abstract ( 1232 )

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Changes of calcium concentration and accumulation in 8 apple cultivars were investigated. The results showed that the calcium concentration in leaves and shoots increased with the development of growth. The calcium content displayed a little difference at early stage in the season, and a significant difference at later stage, especially in shoots. The highest content of Ca of 19638.6 mg·kg-1 was observed in Starkrimson and the lowest of 8751.3 mg·kg-1 in Fuji fruits. The concentration of peduncle showed the increasing tendency with the development of fruit and accorded with the accumulation of calcium in fruit. With the development of fruit, the calcium concentration decreased rapidly from the highest in young fruit. There were significant differences in decrease of Ca content among cultivars. The young fruits of Starkrimson contained the highest calcium concentration of 506.52 mg·kg-1. Pink Lady was the next, while Red Fuji was only 66.27% of Starkrimson. The order of concentration of calcium in mature fruit were as follows: Starkrimson>Sansa>Pink Lady>Senshu>Gala>Red Fuji>Red General >New Century. After analysis showed that 8 cultivars could accumulate calcium in the whole development period, and the highest of 35%－46% of total calcium was accumulated in young fruits, the amount of accumulated Ca was lower in June. Some early cultivars, i.e. Gala, Sansa, Starkrimson, accumulated nearly 30% of total calcium in rapid growing stage. Fuji and Pink Lady had consistent accumulation of calcium, i.e. 22.6%, 19.9% and 26.7%, 24.6%, respectively, in July and August, total accumulation exceeded early stage of fruit development because they had longer growing stage. There was little accumulation after physiological maturity.

Analysis of DNA Methylation in Navel Oranges Based on MSAP Marker

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Scientia Agricultura Sinica. 2005, 38(11): 2301-2307 .

Abstract ( 1663 )

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The extent and pattern of cytosine methylation in 24 navel orange cultivars，genomes were assessed by using the technique of methylation-sensitive amplified polymorphism (MSAP). 4.7%-15.0% DNA methylation events were detected in the CCGG sequence of navel orange genomes. In all, 639 fragments were amplified using 18 pairs of selective primers, and 10 of the 18 primers showed 43 DNA methylation polymorphisms. The average proportion of polymorphism（P）was 6.7%. The results demonstrate DNA methylation events occur frequently in navel oranges；methylation patterns vary among the cultivars, and the external cytosine methylation of the CCGG sequence（15.0%） is more than internal one (4.7%). This paper is the first time to analyse cytosine methylation in navel oranges using MSAP, indicating MSAP technique is efficient for detection of cytosine methylation in navel orange genomes.

Assessment of the Genetic Diversity of Pummelo Germplasms Using AFLP and SSR Markers

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Scientia Agricultura Sinica. 2005, 38(11): 2308-2315 .

Abstract ( 1236 )

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Genetic diversity of 110 pummelo germplasm and 12 its relatives were analyzed by SSR and AFLP. Approximately 99.1% of the 335 SSR were polymorphic, and 9.85 alleles per SSR loci were identified. Gene diversity values changed from 0.1939 to 0.9073, and 46 SSR polymorphic bands were scored. 72% of the 343 AFLP were polymorphic, and 82 polymorphic loci per AFLP were identified. Heterozygosity changed from 0.21863 to 0.28445, and 44 AFLP polymorphic bands were scored. The UPGMA result showed that 122 accessions of pummelo and their relatives were divided into eight groups, in which the pummelo genotypes mainly be composed of Shatian pummelo varieties group, Wendan pummelo varieties group and many hybrid pummelo groups. The classified result is beneficial for us to use various target varieties to widen the genetic background of pummelo.

Changes of Polyphenols in Tobacco Leaves During the Flue-Curing Process and Relative Analysis of Some Chemical Components

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Scientia Agricultura Sinica. 2005, 38(11): 2316-2320 .

Abstract ( 985 )

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Changes of polyphenols in tobacco leaves during the flue-curing process and relation analysis with some chemical componets were studied. Leaf samples were taken from different tobacco producing regions of Henan Province. The results indicated that the content of total phenols increased during 0-24 hours of curing and then decreased. It reached the lowest point at 72 hours of curing and increased quickly after 72 hours of curing. The content of chlorogenic acid also showed the trend of raising during 0-24 hours of curing. But the lowest point tended at 24 or 36 hours of curing and then it slowly increased until curing process ended. The content of rutin generally increased with the proceeding of curing and showed little fluctuation; But the changes of PPO and POD activities were on the contrary. The highly significant positive correlations were observed between rutin and total sugar（r=0.822**）, and the significant negative correlations with starch, nicontine and protein, respectively.

Extraction of Anthocyanin from Sweetpotato by Macroporous Resin and Its Bacteriostatic Mechanism

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Scientia Agricultura Sinica. 2005, 38(11): 2321-2326 .

Abstract ( 1171 )

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The extraction technology by using adsorption of macroporous resin and the bacteriostatic mechanism of anthocyanin from sweetpotato were studied in an experiment. The results showed that the maximum extraction rate of anthocyanin from sweetpotato 3.81 mg·g-1 was gained on the optimal extractive conditions of 0.8% citric acid, the material to solvent ratio of 1: 200, 60oC homothermal bainmarie, 2 hours extraction time. The high purity extracts with 225.1E colour value ( E1%1cm532nm ) was obtained through purification by using AB-8 macroporous resin's adsorption, which was six times as the crude extracts. The inhibitory effects of anthocyanin from sweetpotato on growth of E.coli, S.aureus and P.aeruginos were discovered, and showed a positive correlation with the concentration of anthocyanin from sweetpotato. Observation under transmission electron microscope, SDS-PAGE analysis and comparing growth curves of normal E.coli affected by anthocyanin from sweetpotato indicated that the bacteriostatic mechanism was the combination of anthocyanin from sweetpotato with protein or enzyme in the cell and inhibiting cell division, then cell died caused the concentration and disintegration of cytoplasm. The anthocyanin from sweetpotato possesses two functions of pigment and bacteriostatis and it is a perfect natural pigment.

SNP Detection in Tibetan Chicken and Recessive Chicken GH Gene and Its Associations with Growth Traits

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Scientia Agricultura Sinica. 2005, 38(11): 2327-2332 .

Abstract ( 1487 )

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SNP of growth hormone (GH) gene Intron4 of Tibetan chicken and recessive white chicken were detected by using modified allele specific PCR (M-ASP), PCR-RFLP and sequencing reaction and its associations with growth traits of Tibetan chicken was done. The results indicated that there were M-ASP and SacI-RFLP polymorphisms in Intron4 of GH gene and there was a C/G mutation by DNA sequencing and resulted in 3 genotypes CC, CG and GG. The distributions of three genotypes and two alleles between two chicken breeds were very similar and the frequencies of genotype CC and allele C were highest among them. The results χ2 showed that there were not significant differences in the frequencies of genotypes or alleles between the two chicken breeds (P＞0.05), however, there were significant differences within each of the two chicken breeds (P＜0.05), respectively. The results of analysis of variance showed that genotypes had significant effect on twelve growth traits of Tibetan chicken at 0.05 or 0.01 levels, and there was a positive relationship between genotype CC and body weight of Tibetan chicken at the age of 7 weeks (P＜0.05). It implies that GH gene is the major gene affecting growth traits of Tibetan chicken or it links with the major gene, and the mutation could be used as the molecular genetic marker to select Tibetan chicken for high body weight at the age of 7 weeks.

Relationship Between Polymorphisms of CSN3, CSN1S2 and β-lg Genes and Litter Sizes of Xinong Saanen Dairy Goat

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Scientia Agricultura Sinica. 2005, 38(11): 2333-2338 .

Abstract ( 1195 )

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In this paper, PCR-RFLP technique was firstly adopted to analyze the association of polymorphisms of CSN3, CSN1S2 and beta-lactoglobulin genes with litter sizes of 69 Xinong Saanen dairy goats. The results revealed that there was a statistical significant relationship between CSN3-TaqI locus and litter sizes (P < 0.05). For example, the first birth litter size of individuals with genotype TC were more than those of individuals with genotype CC (P < 0.01), while the second birth litter size of individuals with genotype CC were more than those of individuals with genotype TC (P < 0.05). Moreover, the results showed that no statistical significant difference between CSN3-HindIII locus and litter sizes was found (P > 0.05). However, there was significant relationship between CSN1S2-Alw26I locus and litter sizes. For instance, the first birth litter sizes of individuals with genotype NF more than those of genotype NN (P < 0.05), while the fourth birth litter sizes of individuals with genotype NF was less than those of genotype NN (P < 0.01). No significant correlation between beta-lactoglobulin gene and litter sizes was observed in this experiment. Based on these results, it was indicated that CSN3 and CSN1S2 gene had significant positive effects on litter sizes of dairy goats. So it is primitively presumed that casein gene such as CSN3, CSN1S2 gene and FecB gene probably might be linked, which would well explain the gene effects of CSN3 and CSN1S2 gene on litter sizes. Additionally，CSN3 and CSN1S2 gene can be regarded as effective molecular markers on MAS program for litter size of dairy goat.

Effects of Diethylstilbestrol on Adult Hamster Testes Spermatogenesis

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Scientia Agricultura Sinica. 2005, 38(11): 2339-2343 .

Abstract ( 938 )

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To explore the effects of diethylstilbestrol (DES) an environment endocrine disruptor, on the spermatogenesis of adult hamster, 10 adult hamsters were treated with DES (1mg·kg-1 body weight) daily by subcutaneous injection for one week. Morphological changes on adult hamster testis and spermatogenetic cells were observed by light and transmission electron microscope. Apoptotic spermatogenetic cells were detected by TUNEL staining and methyl green-pyronin staining. The results showed that the testis weight and seminiferous tubule area decreased significantly (P<0.01). Germ cells distributed disorderly in seminiferous tubule. Few long spermatids were found in almost all of the tubular lumen. Testis regression was associated with an important increase of apoptosis, especially in spermatocytes and spermatids. A lot of flocculent dense bodies or vacuole structures were observed in the cytoplasm of degenerating spermatocytes and spermatids by transmission electron microscope. In conclusion, this study indicates that DES has induced spermatogenetic cell apoptosis and it is an important cause of the abnormal spermatogenesis of adult hamster testis.

Cloning and Expression of VPg2 Gene Fragment of Foot-and-Mouth Disease Virus and the Evaluation of VPg2-ELISA for Antibody Detection

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Scientia Agricultura Sinica. 2005, 38(11): 2344-2348 .

Abstract ( 1393 )

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VPg2 gene fragment was successfully subcloned from 3ABC gene of the foot-and-mouth disease virus（FMDV）TaiBao strain and constructed VPg2 expressing plasmid by inserting the target gene fragment into pGEX-4T-1 vector. The expressed protein was analysed by Western blotting. The result showed strong reaction with FMDV positive serum. VPg2 protein ELISA was evaluated through testing sera of 4 cattle groups i.e. control group, vaccinated group, infected group and infected after vaccination group. Negative results were obtained for the control group and the vaccinated group. On the contrary, positive results were obtained for the infected group and part of the infected after vaccination group. In the infected group and infected after vaccination group, the duration of the antibody against VPg2 lasted for at least 90 days. The earliest detecting time of VPg2 antibody was 10th day after infection. The duration of the antibody against VPg2 was the same with the antibody against 3ABC tested previously. 2170 negative sera were tested using indirect VPg2-ELISA and 3ABC-ELISA. The results showed that the false positive rates were 0.55% in VPg2 ELISA assay and were 2.21% in 3ABC-ELISA assay.

Study on Serotype and Apx Toxins Type of Actinobacillus pleuropneumoniae Strains Isolated from Shandong Province

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Scientia Agricultura Sinica. 2005, 38(11): 2349-2354 .

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Twenty field strains of Actinobacillus pleuropneumoniae (APP) were isolated from lung, tonsils and trachea in 85 pigs with sever pleuropneumonia in different districts of Shandong Province. Slide agglutination test and PCR were used to determine their serotype and Apx toxins type, respectively. The results of slideagglutination test indicated that there were 5 serotypes among the 20 field strains, serotype 7(6/20) and serotype 5 (5/20) were the dominant, the other serotypes were serotype 3(4/20), serotype 4(3/20) and serotype 8(2/20). The PCR results indicated that there were four kinds of Apx toxins in the 20 field strains，among them，serotype 3, 4, 8 contain ApxⅡ, ApxⅢ and ApxⅣ，serotype 5 contains ApxⅠ, ApxⅡand ApxⅣ, serotype 7 contains ApxⅡ and ApxⅣ, ApxⅡ and ApxⅣ existed in all the 20 field strains. The results of Apx sequence analysis indicated that the homogeneity of Apx gene was 99.5%－100% in different serotype APP if they had the same type of Apx. The pathogenicity was different when mice inoculated with APP which contain different Apx, serotype 5 APP was very virulent, for it contains ApxI and ApxⅡ. This study has established the foundation for control Porcine infectious pleuropneumonia in immune prevention, subunit vaccine and PCR diagnosis based on ApxⅣ gene.

Isolation and Characterization of Mutants with High Inorganic Phosphorus in Seeds of Soybean

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Scientia Agricultura Sinica. 2005, 38(11): 2355-2359 .

Abstract ( 1228 )

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In soybean seed, about 60%-80% phosphorous (P) is stored as phytic acid, which is believed as an important anti-nutrition factor to human being and non-ruminant livestock. In this study, two soybean mutant lines, LPA-4297 and LPA-1216, with high inorganic P in seeds, were induced and isolated for the first time from Chinese soybean germplasm by using 60Co gamma rays irradiation. Preliminary observations on agronomic characters of the mutants in parallel with their parents were also made. Based on the changes of P composition in mutant seeds, and according to similar findings in already known low phytate mutants in crops including soybean, it is considered that the mutation in LPA-4297 is similar to the type1 low phytate mutation (lpa1), and that in LPA-1216 is similar to type 2 mutation (lpa2).

Risk Analysis of Alien Invasive Western Flower Thrips, Frankliniella occidentalis (Pergande), in China

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Scientia Agricultura Sinica. 2005, 38(11): 2360-2364 .

Abstract ( 1291 )

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Based on the rule of pest risk analysis (PRA) of international standards for pest measurements (ISPM) and the relevant model of PRA, this paper delt with the quantitative and qualitative analysis of the risk level of Frankliniella occidentalis (Pergande) on five aspects - the distribution, potential damaged degree, economical value of damaged host plants, spreading possibility and risk management difficulty in China. The value of the synthetic index of the pest risk is 2.33, which has reached the level of the quarantine pest in China. Based on this result two strategies for the better risk management were proposed and evaluated in order to reduce the risk to an acceptable level.

The Effects of Organic Materials on Absorption Dynamic Parameter of 32P of M. hupehensis Rehd. Root System

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Scientia Agricultura Sinica. 2005, 38(11): 2365-2371 .

Abstract ( 1525 )

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The uptake of phosphorus in three different types of roots system (absorbing roots，growing roots and brown roots) of M. hupehensis Rehd. was affected by three kinds of organic materials and was in accordance with Michelis-Menten equation. Treatment with various kinds of organic materials changed the uptake kinetics parameters of 32P to different extent. The addition of organic materials increased Imax and decreased Km as compared with the control. The value of Imax of three kinds of roots was in the following orders: treatment with chicken manure > sheep manure > peanut straws in summer, and treatment with sheep manure> chicken manure > peanut straws in autumn (value of Km was in the opposite order). Imax and Km of the three types of roots were determined and it was found that Imax of absorbing roots was 7.4 to 8.7 times that of brown roots, and Imax of growing roots 4.7 to 5.8 time as large as that of brown roots. Km of brown roots was 1.1 to 1.5 times and 1.0 to 1.2 times those of absorbing roots and growing roots. This means that the potential P uptake efficiency and affinity in absorbing and growing root was greater than that of brown roots. The Imax was positively correlated with plant biomass in summer while showed no great significance in autumn.

Interspecific Somatic Hybrids Between Brassica oleracea var. botrytis and Ogura Type CMS Brassica napus via Asymmetric Protoplast Fusion

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Scientia Agricultura Sinica. 2005, 38(11): 2372- .

Abstract ( 1051 )

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Abstract: Asymmetric protoplast fusion beween hypocotyl protoplasts of Brassica oleracea var. botrytis and leaf protoplasts of Ogura type CMS Brassica napus was performed by PEG method. Leaf protoplasts from donor plant were treated with UV light at a dose of 0.0250、0.0750、0.3150、0.4680 and 0.9600 J·cm-2 respectively. 68 plants regenerated in the dose range from 0.0250 to 0.4680 J·cm-2,and none at the dose of 0.9600 J·cm-2. Results of chromosome counts、flow cytometry、isozyme analysis、RAPD and specific amplification of Ogura-CMS-associated mitochondrial gene orf138 revealed that 32 somatic hybrid plants were obtained and the CMS-associated mitochondrial gene orf138 had been introduced into the receptor genotype of Brassica oleracea var.botrytis.

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