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25 February 2015, Volume 27 Issue 2 Previous Issue    Next Issue

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Construction and functional verification of a plant expression vector containing both herbicide resistant gene CP4\|EPSPS and stress tolerance related transcription factor GmGT\|2A LI Yan\|jie1，2， ZHU Dan\|hua1， FENG Xiao\|feng3， GAO Sha3， YANG Qing\|hua1， DONG De\|kun1，* 2015, 27(2):  133.  Abstract ( 402 )   PDF (1860KB) ( 1298 )   An efficient and easy\|to\|use plant expression vector plays an important role in the research of gene functions. In this study， the glyphosate resistant gene CP4\|EPSPS was cloned to replace the original selective marker Bar gene of plant expression vector pBA002. The new plant expression vector was named as pES002. A Trihelix transcription factor GmGT\|2A was subsequently ligated into pES002 to form a new plant expression vector, namely pES002\|GmGT\|2A. This vector was transformed into Arabidopsis by floral dipping method to verify the functions of both CP4\|EPSPS and GmGT\|2A genes. Results showed that the transgenic lines greatly improved the tolerance to both glyphosate and high salinity stress， indicating that both the new selective marker gene and the target gene worked well. Thus， this vector was successfully constructed and could be further used in transgenic related research. Related Articles | Metrics

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Heterosis and combining ability of plant height and its components of barley LI Hong\|tao， WANG Jun， ZHANG Can\|hong， CHI Ming， WANG Duo\|ming， HU Bing 2015, 27(2):  141.  Abstract ( 360 )   PDF (578KB) ( 1269 )   The objective of this study was to determine the relationship between heterosis and combining ability of beer barley， traits were measured in a complete diallel cross （Griffing П mating design） involving 21 hybrids and 7 parents during 2011-2012. The main results were as follows. there was great variation in the heterosis of height and its components， the average heterosis of internodes length was negative except for the first internode; the third and fourth internode had the larger average heterosis. Plant height and its components were controlled by both additive and dominant genetic effects， and the additive effect was the main factor. The general combining abilities of plant height and each internode length of Supi 3 and Gangpi 2 showed negative effect， and they could be used as parents in improving the structure of the plant height. The general combining ability of spike length of Lian 0719 showed positive effect， so it could be used as the parents in improving spike length. Except for the fifth internode, the specific combining ability of the other internode length in the three crosses involving Yangnongpi 5×Suyinmai 2, Gangpi 1×Supi 3， Suyinmai 2×Supi 3 showed negative effect， and the specific combining ability of spike length showed positive effect. They could be considered as the fine combinations in dwarfing breeding. The heritabilities of the plant height and its components were so high that these traits were suitable for early generation selection. Related Articles | Metrics

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Effects of different irrigation methods on the growth and yield of double\|harvest Zizania latifolia Turcz. ex Stapf CHEN Jian\|ming1， PANG Ying\|hua2， ZHANG Jue\|feng1， ZHU Xu\|yan2， HUANG Xi\|zhi2， FENG Fan1， ZHU Jian\|jie2 2015, 27(2):  148.  Abstract ( 424 )   PDF (813KB) ( 1394 )   In order to explore water\|saving cultivation method for double\|harvest Zizania latifolia， effects of four different irrigation treatments on the growth and yield of Z. latifolia were conducted. The treatments were set as combinations of different growth stages with different water depth of irrigation （WDI）. The WDI of treatment Ⅰ， Ⅱ， Ⅲ， Ⅳ was 4-5， 4-5， 8-9， 14-15 cm， respectively， at earlier and middle tiller stage， 1-2， 4-5， 4-5， 8-9 cm， respectively， at later tiller stage， 8-9， 14-15， 14-15， 19-20 cm， respectively， at stem swelling stage， and 1-2， 4-5， 4-5， 8-9 cm， respectively， at harvest stage. It was shown that plant height of treatment Ⅰ， Ⅱ and Ⅲ was shorter than that of treatment Ⅳ， while tiller numbers of formers were larger than the latter， and no significant difference was found among the former three treatments. Weights of vaginated Zizania shoot and bald Zizania shoot showed no significant difference among four treatments， while the length and width of bald Zizania shoot of treatment Ⅰ， Ⅱ and Ⅲ were bigger than treatment Ⅳ. The yield of treatment Ⅱ and Ⅲ increased by 079% and 387% than treatment Ⅳ， while the yield of treatment Ⅰ was a little lower than that of treatment Ⅳ. The present results indicated that compared with traditional irrigation method （treatment Ⅳ）， a cut down of 30%-50% irrigation quantity in the tiller， stem swelling and harvest stage， respectively， could reduce the height of Zizania plants， while increase the tiller number， and finally increase the yield obviously. It was concluded that the water\|saving cultivation of Z. latifolia was feasible， and quantity of water could be reduced by 30%-50%. Related Articles | Metrics

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Clone and expression of ISG15 gene from MDCK cell and analysis of its antiviral activity LIU Ai\|ling1， PAN Jie1， PANG Yun\|qian3， YU Ke\|xiang2， MA Xiu\|li2， SONG Min\|xun2，* 2015, 27(2):  154.  Abstract ( 413 )   PDF (1020KB) ( 1231 )   ISG15 gene was cloned from MDCK cells using RT\|PCR， and the alignment of ISG15 with the reported sequence （GenPept databank: XM_0036390532） revealed 99 % nucleotide sequence identities. The ISG15 was cloned into expression vector pET\|28a to construct the expression plasmid p28a\|M15， and was expressed in Escherichia coli. The protein expression in E. coli induced by IPTG was secreted in the supernatant with a recombinant protein of about 22 kD. The recombinant protein was purified using Ni\|chelate affinity chromatography and then added into MDCK cells quantitatively with and without AIV H9N2 subtype infection. The results showed that ISG15 protein could inhibit AIV replication in normal MDCK cells， however， it could promote AIV replication in MDCK cells infected by AIV H9N2 subtype. This study will provide theoretical basis for ISG15 antiviral function in vitro. Related Articles | Metrics

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The relations of Eimeria perforans and Cyniclomyces guttulatus to diarrhea of rabbit SHI Tuan\|yuan1， WEI Wei1，2， FU Yuan1， BAO Guo\|lian1， SUO Xun3， HAO Li\|li2 2015, 27(2):  160.  Abstract ( 573 )   PDF (992KB) ( 1232 )   In order to study the relations of Eimeria perforans and Cyniclomyces guttulatus to diarrhea of rabbit. C. guttulatus and E. perforans isolated by our research team were used to infect experimental rabbits， respectively. Between 4 to 6 days after the inoculation with E. perforans， drinking， food intake and feaces excretion were obviously decreased in the inoculated rabbits. And diarrhea and death were found between 12 to 14 days after the inoculation in the third group， the diarrhea and death rate were 50% and 25%， respectively. After the inoculation with C. guttulatus， neither diarrhea nor death was found. Thus， E. perforans is pathogenic and one of important pathogenies to the diarrhea of rabbit， and C. guttulatus is non\|pathogenic to the diarrhea of rabbit. Related Articles | Metrics

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Effects of linolenic acid on buffalo oocyte maturation and early embryo development in vitro ZHENG Hai\|ying， YANG Chun\|yan， ZHANG Xiu\|fang， HUANG Fen\|xiang， LIANG Xian\|wei， SHANG Jiang\|hua*， ZHENG Wei* 2015, 27(2):  165.  Abstract ( 363 )   PDF (570KB) ( 1254 )   This study was conducted to investigate the effect of different linolenic acid （ALA） concentrations （0， 10， 50， 100 and 200 μmol·L-1） during in vitro oocyte maturation （IVM） and in vitro embryo culture （IVC） on the maturation of oocytes and developmental competence of preimplantation embryo in buffalo. The oocytes from abattoir ovaries were matured and fertilized， and presumptive zygotes were cultured in the medium， then the maturation rate cleavage and blastocyst development rate were examined， respectively. The results showed that the maturation rate of oocytes treated with 50 μmol·L-1ALA was significantly increased （74.18%） compared with the control and other supplemental groups （P＜0.05）， and the blastocyst development rate of oocytes treated with 50 μmol·L-1ALA （33.24%） was significantly higher than those of the control and 10 μmol·L-1 ALA supplemental groups（P＜0.05）. The presence of 50 μmol·L-1 ALA in IVC resulted in a significantly higher blastocyst development rate （34.52%） compared to the control and 100 μmol·L-1 ALA supplemental groups （P＜0.05）; The ALA with different concentrations were added to both IVM and IVC， cleavage rates in the group of 200 μmol·L-1 ALA was significantly higher than that of the control （P＜0.05）， while blastocyst development rate and percentage of Day 7 blastocysts showed no difference. In conclusion， addition of 50 μmol·L-1 ALA to either IVM or IVC in vitro can promote the maturation rate of buffalo oocytes and blastocyst development. Related Articles | Metrics

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The polymorphisms of five functional genes in Chunan spotted pig LI Qing\|hai1，ZHU Rong2，LOU Li\|feng1，LIU Rong\|ping2，WANG Huan\|huan1，XIA Zhou\|wu2，ZHANG Xue\|dong1，* 2015, 27(2):  171.  Abstract ( 413 )   PDF (766KB) ( 1199 )   This study aimed to explore the germplasm characteristics of Chunan spotted pig. By PCR\|RFLP method， estrogen receptor （ESR） gene， β subunit of follicle stimulating hormone （FSHβ） gene， growth hormone （GH） gene， melanocortin receptor 4 （MC4R） gene and ryanodine receptor 1（RYR1） gene were detected. The results showed that MC4R and RYR1 gene had only one kind of genotype， AA or BB respectively. ESR， GH gene had two kinds of genotypes， AB and BB. Genotype distributions of all genes conformed to Hardy\|Weinberg equilibrium in Chunan spotted pig populations（P>0.05）. The findings indicated that Chunan spotted pig has genetic characteristics such as better reproductive performance， lower lean meat rate， longer growing period and better stress\|tolerant. Related Articles | Metrics

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Comprehensive evaluation on heat tolerance of various lettuce seedlings SONG Yun\|peng， LIU Kai\|ge， GONG Fan\|rong* 2015, 27(2):  176.  Abstract ( 396 )   PDF (663KB) ( 1285 )   To detect the adaptability difference under high temperature of different lettuce cultivars， leaf segments of seven lettuce cultivars （A\|G） were used to study the heat tolerance by electrical conductivity method and antioxidant enzyme indexes. The results showed that with the rise of treated temperature， cells injured rate of leaf segments from A to G were increased with trends of slow\|fast\|slow， showed typical S\|type curve， the significance test of which was fit Logistic equation. The heat resistance of the seven lettuce cultivars followed the order: C>D>F>B>G>E>A， respectively. Meanwhile， treating with high temperature for 6 d increased the superoxidase （SOD）， peroxidase （POD）， catalase （CAT） activities and the malondisldehyde （MDA） contents of various lettuce cultivars. The relationship between semi\|lethal high temperature and antioxidant enzyme indexes was significant. The above results showed that semi\|lethal high temperature could be considered as the index of lettuce heat resistance. Related Articles | Metrics

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Relationship between mechanical strength and morphological index of inflorescence stem of herbaceous peony（Paeonia lactiflora Pall.） LI Cheng\|zhong1， SUN Yan1， ZHAO Da\|qiu2， TAO Jun2，* 2015, 27(2):  182.  Abstract ( 345 )   PDF (656KB) ( 1224 )   Mechanical strength of inflorescence stems within seventy\|six herbaceous peony（Paeonia lactiflora Pall.） varieties were measured by mechanical strength tester determinator of plant stem， and the varieties were divided into three categories by stem mechanical strength using the method of dynamic clustering in this study， namely high mechanical strength， medium mechanical strength and low mechanical strength， and the variation range of the categories was11.9～21.3，8.5～14.2，2.8～9.7 N， respectively， the number was 14，40，22， respectively， conforming to normal distribution. The difference in stem diameter and stem weight were extremely significant among each type. The difference in flower weight was significant， but the difference in stem length was not significant. Correlation analysis showed that the stem mechanical strength was significantly positive correlated with stem diameter and stem weight， and the flower weight of low mechanical strength cultivars was significantly negative correlated with the stem mechanical strength. Related Articles | Metrics

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Effect of low temperature stress on the physiological mechanism of kidney bean varities with different chilling tolerance LIU Ri\|lin， ZHANG Yu\|ting， PAN Ling\|jie， YU Chao， AI Jian\|guo， ZHU Zhu\|jun， WANG Hua\|sen* 2015, 27(2):  189.  Abstract ( 316 )   PDF (616KB) ( 1289 )   The chilling tolerance of 32 genotypes of kidney bean（Phaseolus vulgaris L.） seedlings were preliminary identified， and a variety with higher chilling tolerance named as Chaojijiulibai， a variety with lower chilling tolerance named as Dajiang\|106\|jiadouwang were screened out， and the variety named as Jiadouwang No.1， whose chilling tolerance was between the former two， was selected as the control. These three varieties were taken as the materials treated under low temperature stress in order to study the physiological indexes and the chilling resistance mechanisms. The results were as follows: Under low temperature stress at 5℃， the chilling injury index and electrolytic leakage of leaves of Chaojijiulibai were distinctly lower than those of the other two. The SOD， POD activity of three varieties all increased at first， then decreased， but the enzyme activity of Chaojijiulibai were always higher than that of Dajiang\|106\|jiadouwang. The enzyme activity of the control was always between two varieties and higher than that of Dajiang\|106\|jiadouwang. During the recovery period after low temperature stress， Pn and ΦPSⅡ of Dajiang\|106\|jiadouwang were distinctly lower than those of the control， but Pn and ΦPSⅡ of Chaojijiulibai were distinctly higher than those of the control. In conclusion， Chaojijiulibai has a better chilling tolerance than that of Dajiang\|106\|jiadouwang and the control. Related Articles | Metrics

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Effect of drought stress and rewatering on growth and physiological indexes of silver edge ivy ZHANG Xue\|ping1， WANG Xue\|juan2， ZHANG Jin\|yun3， LIU Ai\|rong1，*， ZHOU Yu\|li1 2015, 27(2):  194.  Abstract ( 303 )   PDF (709KB) ( 1228 )   In order to explore the effect of drought and rewatering on growth and drought resistance of silver edge ivy， the changes of growth and some physiological indexes were studied. The results showed: comparing with the control， the growth rate of the longest caulis and increment rate of leaf in each treatment decreased in varying degrees， the relative plasma membrane permeability and proline content increased in varying degrees. The chlorophyll content and root activity under the severe stress significantly increased compared with the control， but there was no difference in chlorophyll content and root activity among other treatments. After rewatering， chlorophyll content， the relative plasma membrane permeability and proline content of the treatments were decreased to the normal level， but root activity was higher than the control. The results indicated that the survival of silver edge ivy was not threatened under drought stress condition in this experiment. Related Articles | Metrics

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Effects of composite SNP cold\|resistant agent on cold tolerance in cucumber seedlings LI Yang， ZHANG Peng， ZHANG Xiao\|qian， LIAO Xiao\|li， CUI Jin\|xia* 2015, 27(2):  200.  Abstract ( 513 )   PDF (1429KB) ( 1273 )   Based on SNP， a kind of cold\|resistant agent was formulated. Cucumber cv. Jinyan No. 4 was used as material to study the biochemical and physiological indexes related to the ability of cold\|resistance under low temperature. The results showed that, compared with SNP treatment， SNP+mixture A treatment was more effective to increase soluble protein content， antioxidant enzymes SOD， POD， APX activity and root activity of cucumber seedlings under low temperature stress， and could alleviate the oxidative damage caused by low temperature stress on cucumber seedlings， and increase the cold resistance. Related Articles | Metrics

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Effects of mating status on the development and oviposition in female mealybugs （Phenacoccus solenopsis） ZHANG Ge\|wei1，2， ZHU Yi\|yong2， ZHANG Peng\|jun2， HUANG Fang2， LU Yao\|bin1，2，* 2015, 27(2):  206.  Abstract ( 416 )   PDF (1010KB) ( 1242 )   To study the effects of mating status on development and oviposition in female mealybugs， Phenacoccus solenopsis.We compared the longevity， ovarian development and number of eggs laid in Phenacoccus solenopsis under different mating status. The results showed that in Phenacoccus solenopsis， mating stimulated ovarian development and oviposition. Mated Phenacoccus solenopsis females had higher total number of eggs laid， duration of gestation， duration of reproduction and number of eggs laid in the first clutch compared to delay\|mated females. When grown into oviposition period， unmated females could not develop into the embryonic phase and laid few eggs. Delay\|mated females could make a trade\|off between maintenance and reproduction by a nutritional rearrangement， which indicated that females would resorb the resources from eggs for a longer survival when they couldnt get mated. Once mated， females would lay eggs， and their physiological state got reset， but the number of eggs laid was lower than mated females. Related Articles | Metrics

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Study on the biological characteristics of Fusarium oxysporum Schl. f. sp. Nelumbicola （Nis. & Wat.） Booth ZHOU Xiao\|jun1,*， HE Xiao\|chan1， ZHENG Zhai\|sheng1， ZHANG Shang\|fa1， SUN Yu\|jian1， LOU Bing\|gan2 2015, 27(2):  211.  Abstract ( 459 )   PDF (727KB) ( 1273 )   The effects of culture medium， photoperiod， temperature， pH degree， carbon and nitrogen source on the biological characteristics of Fusarium oxysporum Schl. f. sp. Nelumbicola （Nis. & Wat.） Booth， pathogen of Rhizome rot of lotus root Nelumbo nucifera Gaertn， were studied. The results showed that the mycelia could grow well on four tested culture mediums under 20～30℃， and the optimum temperature was 28℃. Different photoperiods had no significant influences on the growth of mycelium. It was found that the range of pH was 4～13 and the optimum was 7. The optimal carbon source was maltose， sucrose and fructose， and the optimal nitrogen source was yeast extract powder. Related Articles | Metrics

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Optimization of fermentation medium for endophytic actinomycete CR20 from citrus HU Xiu\|rong，HUANG Zhen\|dong，PU Zhan\|xu，DU Dan\|chao，CHEN Guo\|qing，LU Lian\|ming* 2015, 27(2):  215.  Abstract ( 338 )   PDF (809KB) ( 1257 )   Endophytic actinomycete CR20 with antagonistic effect on many plant pathogens was isolated from the root of citrus，it was identified as Streptomyces sp. In order to improve the antibiotic producing ability of CR20，the fermentation medium was optimized using one\|factor\|at\|a\|time and orthogonal test. The results showed that culture medium containing 1.5% glucose， 1% soluble starch， 3% peanut powder， 1% （NH4）2SO4， 0.4% NaCl， 0.2% CaCO3， 0.1% FeSO4·7H2O and 0.1% KH2PO4 was the best， and the inhibition rate of Colletotrichum gloeosporioides from citrus reached to 84.66% and was 1.3 times higher than of that before optimization. Based on the optimized medium，the optimum fermentation time of the strain CR20 is 96 h in 5 L automatic fermentor. Related Articles | Metrics

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Optimization of fermentation conditions of the endophytic strain Lysobacter enzymogenes R\|2\|1 for microbicide production YING Chen， RUAN Chuan\|fen， TANG Yi\|fei， ZHANG Hua\|wei* 2015, 27(2):  220.  Abstract ( 412 )   PDF (1132KB) ( 1238 )   An endophytic strain R\|2\|1， Lysobacter enzymogenes， was firstly isolated from traditional Chinese medicine Artemisia annua Linn. Bioassay indicated that the ethyl acetate extract of fermentation broth of this strain had a broad spectrum of antimicrobial activities. The present work focused on optimization of its fermentation conditions using orthogonal experiment and response surface analysis （RSA）. The former was used to optimize the LB liquid medium. The best medium included the following components: corn flour 20 g·L-1， peanut meal 20 g·L-1， bean pulp 20 g·L-1， yeast extract 2 g·L-1， tryptone 4 g·L-1， （NH4）2SO4 6 g·L-1，K2HPO4 6 g·L-1， MgSO4·7H2O 4.8 g·L-1， MnSO4·H2O 0.02 g·L-1， FeSO4·7H2O 0.01 g·L-1， CaCl2·2H2O 0.12 g·L-1， NaCl 2.4 g·L-1， riboflavin 3.0 g·L-1， thiamine 1.2 g·L-1， vitamin B6 0.01 g·L-1， biotin 0.1 g·L-1， and the number of living microbe of strain R\|2\|1 reached 694×108 cfu·mL-1 under the optimal condition after 24 h. The fermentation condition of L. enzymogenes was optimized by RSA with statistical software Design Expert 7.00. Under the optimum conditions （fermentation time 87.2 h， initial pH 7.55， fermentation volume 204 mL， inoculation volume 7.90 mL）， the yield reached （0.518±0.050） g·200 mL-1. The yield could be raised to （0.523±0.023） g·200 mL-1 at 210 r·min-1 and 30℃ conditions. These results could provide references to scale up production of biobactericide of L. enzymogenes R\|2\|1. Related Articles | Metrics

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Characteristics of Ougan fruit in relation to postharvest granulation JIN Wei\|wei*，GAO Ai\|ling，CHEN Gong\|kai，WU Zhen\|wang 2015, 27(2):  229.  Abstract ( 341 )   PDF (816KB) ( 1268 )   Ougan fruit， which was traditional and characteristic to Wenzhou， was used to study the postharvest granulation occurred at room temperature. Exterior quality， size, flesh plumpness and flesh color were tested. Results showed that the contents of total soluble solids， titratable acid and vitamin C in Ougan fruit were decreased during postharvest storage. Granulation was observed during 80-90 d in storage of Ougan fruit， and the peels of granulation fruits were seemed normal as or even better than those of normal fruit， while the flesh plumpness was worse than that of normal fruit. Granulation fruit appeared yellow and shriveled while the normal fruit appeared red and well\|stacked. The differences of h， L， b value and flesh weight percentage between granulation fruit and normal fruit were significant. The differences of diameters between the two were also significant， and granulation was easier to occur on the fruit with bigger size. According to this paper， Ougan fruit could be scaled with diameter for proper storage time to reduce postharvest loss. Related Articles | Metrics

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ISSR analysis of genetic variation to Sargassum fusiformis wild and breeding strains in Wenzhou NAN Chun\|rong1， ZHANG Peng2， LIN Shao\|zhen2， WU Chao\|yi1， ZHANG Li\|ning2，* 2015, 27(2):  234.  Abstract ( 513 )   PDF (967KB) ( 1251 )   The inter\|simple sequence repeat （ISSR） molecular marker technique was used to investigate genetic diversity， genetic variation to 2 wild stocks and 3 breeding strains in Hizikia fusiformis of south Zhejiang. The results showed that: a total of 76 loci and 56 polymorphic loci were obtained from 6 primers which had been screened and P% （the percentage of polymorphic loci） was 74.67%. Neis gene diversity was 0.1823. Shannons information index was 0.2712. The values were higher than the individual level. Population within and between populations Neis genetic diversity calculation level of genetic differentiation （Gst） was 0.5529， the genetic differentiation between populations was greater than the population differentiation. Gene exchange between the populations （Nm） was 03341; Shannons information index showed that the genetic variability and genetic diversity of wild populations were generally higher than breeding populations. Results also showed that after breeding， the traits of each breeding strains tends to be stable. Clustering figure showed that three breeding strains were separated from two wild populations and they presented significant difference after breeding. Related Articles | Metrics

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Effects of salinity and soil moisture on microbial composition and community diversity in a coastal saline soil ZHENG Zhi1，2，LIU Chen2，FU Qing\|lin2，*，GUO Bin2，LIN Yi\|cheng2，DING Neng\|fei2 2015, 27(2):  240.  Abstract ( 349 )   PDF (1221KB) ( 1243 )   To assess the response of microbial community to salinity and soil moisture by denaturing gradient gel electrophoresis （DGGE） and phospholipid fatty acids （PLFA） analysis， we carried out an incubation experiment under different salinity and soil moisture gradients by adding varying amounts of salt and water to a coastal saline soil. Treatments included a concentration of four salinity levels: 1.90， 9.41， 19.76 and 26.92 g NaCl·kg-1 soil， corresponding to an electrical conductivity of 0.68， 3.55， 7.49 and 10.22 dS·m-1 and three moisture contents: 20%， 30% and 40%. The results showed that soil moisture did not significantly affect soil bacterial and fungal diversity， but soil salinity significantly decreased soil bacterial and fungal diversity. The bacterial and fungal diversity indices and richness indices in the soil salinity treatments of 19.76 and 26.92 g NaCl·kg-1 soil were lower than those in the other two treatments， of which the lowest diversity index and richness index appeared in the treatment with soil salinity of 26.92 g NaCl·kg-1 soil and soil moisture content of 40%. Soil moisture did not significantly affect bacterial biomass， but significantly reduced fungal biomass. The fungal biomass in the soil moisture treatment of 20% was significantly higher than those in the soil moisture treatments of 30% and 40%. Related Articles | Metrics

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Assessment on soil heavy metals contamination by matter\|element model LIU Wei\|ming1，3， WANG Xiao\|fei2，*， WEI Meng\|meng2， LI Xuan\|hai1 2015, 27(2):  249.  Abstract ( 343 )   PDF (501KB) ( 1260 )   The traditional evaluation model for soil heavy metal pollution consisted diverse indexes and the result exhibited uncertainty. Based on the matter element theory and dependency function in the extension theory， an evaluation model for soil heavy metal pollution was established. In the present study， the established model was used to assess the heavy metal contamination in a sugarcane soil in Guangxi. It was shown that the pollution level of the sugarcane soil was between clean and good， and the evaluation result was comparable to the result made by the Nemerow index method， which proved the feasibility of this established evaluation method. Related Articles | Metrics

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Soil and water conservation mechanism of conservation tillage and its promotion suggestions in the black soil zone of Northeast China WU Cai\|wu， XIA Jian\|xin* 2015, 27(2):  254.  Abstract ( 431 )   PDF (776KB) ( 1309 )   Black soil is well known for its fertile qualities and high levels of organic matter. The black soil zone in Northeast China is one of three major black soil regions in the world. In recent years， the natural factors and human activity weakened the quality of black soil， resulting in the loss of water and soil seriously. Therefore， protection of soil and water resources is not only related to the development in Northeast China， but also important to support the sustainable development of agriculture. In the present paper， both domestic and foreign achievements about conservation tillage were summarized to clarify the characteristics of conservation tillage and possible mechanism of conservation tillage in reducing soil erosion. Considering the conflicting results about the real effect of conservation tillage on water and soil conservation， this paper specifically addressed the importance of long\|term study. Finally， the difficulties encountered in the implication of conservation tillage in Northeast China were pointed out， and corresponding suggestions were made to provide references for the promotion of conservation tillage. Related Articles | Metrics

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Numerical simulation of mixing process of fertilizer particles in continuous mixer of variable rate fertilizer applicator JIN Li\|li1，2，JI Chang\|ying1，2，*，FANG Hui\|min1，2， TAN Ying1，2 2015, 27(2):  261.  Abstract ( 341 )   PDF (547KB) ( 1306 )   Continuous mixer is an important part of variable rate fertilizer applicator. The mixing process of fertilizer particle is an important factor for the precision ratio of various fertilizer compositions. To investigate the mixing characteristic of particles， the discrete element model was adopted to track the movement of each fertilizer particle. The mathematical model was established based on Hertz theory and Newtons second law. Variation coefficients were taken as mixing index to analyze the degree of mixing. The internal structure of mixing device and the speed of spindle were put emphasis upon to discuss the mixing characteristics of fertilizer particle. It is found that with the increase of the number of spreading plate and blocking material barrel， the fertilizer particle tended to uniform mixing. With the increase of spindle speed， the fertilizer particle mixing uniformity was improved obviously. The simulation results provided a reference for the design of mixing device. Related Articles | Metrics

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Study on environmental protection in the ecologically sensitive town along Taihu Lake： The case of Guangfu Town， Wuzhong District in Suzhou ZHU Xian\|ting，LI Xin，DING Jin\|hua*，SHEN Yi\|ting 2015, 27(2):  266.  Abstract ( 495 )   PDF (722KB) ( 1253 )   Under the background that Suzhou is going to explore the ecologically sensitive areas along the Taihu Lake in the south， we took Guangfu Town， Wuzhong District， Suzhou City for example and built up the ecological sensitivity evaluation system by combining theoretical analysis and frequency analysis with AHP. It was concluded that its ecological sensitivity level was extremely high， water source protection areas and nature reserves were extremely sensitive， the possibility of encountering water， droughts and other disasters and historical sites were highly sensitive， and that important shoreline protection zone， cultivation in the freshwater and mineral resource development were moderately sensitive. In the future， it is necessary to protect these ecologically sensitive areas and sensitive factors based on their sensitivity level according to the spatial heterogeneity of ecosystem services law so as to achieve regional ecological environmental protection and sustainable resource development in the harmony and sustainability. Related Articles | Metrics

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Evaluation on freshness of Penaeus vannamei by color and texture WANG Wei，CHAI Chun\|xiang*， LU Xiao\|xiang，PENG Deng\|feng 2015, 27(2):  271.  Abstract ( 391 )   PDF (814KB) ( 1306 )   Penaeus vannamei was selected to study the correlation between the freshness of shrimp and its color and texture. The color and texture of Penaeus vannamei at different storage time under 4 ℃and-3 ℃ were tested， and total volatile basic nitrogen （TVBN）， sensory evaluation were measured at the same time. Data was analysed by Fisher linear discriminant， and a color difference model， a texture model and a comprehensive model were established for assessing shrimp freshness. The results showed that the accuracy of the color difference model and texture model was 87.1% and 92.9%， respectively， and the accuracy of the comprehensive model was 98.4%. Thus， the accuracy of the comprehensive model was higher than the others. Related Articles | Metrics

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Optimization of extraction technology of total flavonoids in Parochetus communis and the antioxidative effects YANG Shen\|ming1， WANG Bo1， WANG Zhen\|ji1，2，*， LIU Qiang1 2015, 27(2):  278.  Abstract ( 371 )   PDF (779KB) ( 1274 )   In this study， the content of total flavonoids in Parochetus communis was determined using Al(NO3)3\|NaNO2 method. The extraction technology of total flavonoids was optimized through L9 (34) orthogonal experiment. The effect of total flavonoids on scavenging of hydroxyl radicals and DPPH radicals in Parochetus communis was also studied. The results showed that the optimum extraction parameters were as follows: The volume fraction of ethanol was 75%， extraction temperature was 75℃， ratio of solid to liquid was 1∶40 (g·mL-1)， and extraction time was 150 min. Under such condition， the average content of total flavonoids was 1.543 mg·g-1， and the scavenging effect of total flavonoids on ·OH and DPPH· were 42.59% and 60.40% respectively， implying such material can effectively scavenge ·OH and DPPH·. Related Articles | Metrics

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Study on traceability management of modern agricultural facilities： based on the analysis of image recognition of solar cells SHI Tie，SUO Xue\|song*，ZHOU Jing\|ren，HAN Chang\|xing，GAO Li\|ai 2015, 27(2):  285.  Abstract ( 417 )   PDF (1372KB) ( 1194 )   In order to solve the problem of remote mountainous rural new energy， realize agricultural modernization， the solar panels traceability management system was established. The study designed prints bar codes in a silicon ingot side lasers， and proposed the traceability information management system which combined solar cells made from silicon ingot to link each step lamination with barcode. And for the image processing and recognition of the cell side of barcode cut into the thickness of micron grade， this study firstly used the digital image processing， then the method of scan pixels was applied to judge article black and white and code word segmentation， and the barcode image edge was smooth and could be identified， which could promote structure of agricultural facilities， and provide some technical supports for the development of modern agriculture， energy saving， environmental protection， etc. Related Articles | Metrics

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System design of solar greenhouses combined with ground source heat pump SU Wei，MU Qing，DONG Ji\|xian，WANG Bin\|quan 2015, 27(2):  290.  Abstract ( 354 )   PDF (599KB) ( 1305 )   Greenhouse is an irreplaceable technology in modern agriculture， but it was easily affected by weather. The combination of solar energy\|ground source heat pump system can make full use of the complementary advantages of both of them. It confirmed the stable operation of greenhouses all year round. Therefore， a solar greenhouse combined with ground source heat pump system and the PLC control circuit of the system were designed， and the brief analysis on the feasibility was carried out. It also provides certain reference and suggestion about subsequent application of the greenhouses combined with solar energy and ground source heat pump system. Related Articles | Metrics

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Study on factors affecting rural labors non\|farm participation: based on survey data from five provinces in China QIU Yuan1， YE Chun\|hui1，*， ZHU Qi\|biao2， MI Song\|hua2， HUANG Li\|li2 2015, 27(2):  295.  Abstract ( 386 )   PDF (631KB) ( 1239 )   In this paper， a large national sample data of 101 villages from five provinces in China was applied to study factors that influence rural labors work transfer from agriculture to non\|agriculture industry. Rural labors work was divided into three types， which were farming only， non\|farm only， and both. Then a multinomial logistic model was used to do empirical analysis. The results showed that personal characteristics， household characteristics， community characteristics， land transfer status， evaluation of public services and regions were important factors affecting their non\|farm participation. In order to transfer rural labors work from agriculture to non\|agricultural sectors， and effectively improve the income of farmers and promote rural development， basic education， training and guidance in rural areas should be strengthened， and non\|farm industries， road and other related infrastructural construction in rural area are supposed to be improved. Related Articles | Metrics

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Analysis on some primary experiences and thoughts to promote system innovation of regional agricultural production and operation—Based on the survey of Chongzhou model in Sichuan Province ZHANG She\|mei， RAN Rui\|ping* 2015, 27(2):  301.  Abstract ( 393 )   PDF (818KB) ( 1241 )   This paper analyzed the incentives， conducts and experiences of agricultural production in system innovation in Chongzhou， Sichuan Province. It was presented that Chongzhous conduct was a valuable exploration in solving contradiction between grain production and farmers revenue increment， and in controlling disadvantages of mighty capital and weak farmers in traditional industrialization. It also does help in effectively cultivating new professional farmers， as well as in promoting demand\|supply connection of agricultural technology. The Chongzhou model was of theoretical and practical significance in impelling system innovation of regional agricultural production and operation. Related Articles | Metrics

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Evaluating the supply efficiency of the rural productive public goods： A case of Hubei Province LUO Fang， MA Wei\|min， ZHOU Ye\|wang， WANG Qing 2015, 27(2):  307.  Abstract ( 418 )   PDF (981KB) ( 1201 )   As China entering the period of industry nurturing agriculture， financial funds for agriculture have grown substantially， and then improving efficiency of funds service is important as well as increasing fiscal input. Evaluating the supply efficiency of rural public goods in Hubei Province, a big agricultural province, is the premise of improving service efficiency of fiscal input. Based on the non\|parameter DEA model， the supply efficiency of rural productive public goods in Hubei Province in the past 20 years was evaluated and the relative efficiency to the other fellow provinces was estimated. It was concluded that Hubei Province had the trend of supply efficiency of rural productive public goods decreasing and relative efficiency was low among the 13 granary provinces. Related Articles | Metrics

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Research progress of the application of glucagon\|like peptide\|2 on piglets and its half\|time prolongation strategy WU Jie1，2， QI Ke\|ke2， XU Zi\|wei1，2，*， WAN Jing1，2 2015, 27(2):  315.  Abstract ( 421 )   PDF (567KB) ( 1190 )   The injury of intestinal morphology and configuration induced by the weaning stress will cause diarrhea and growth cessation， which do harm to the health of piglets. Glucagon\|like peptide\|2 is an incretin gastrointestinal hormone， plays an important role in growth and restoration of intestines. This review summarized glucagon\|like peptide\|2 from anabolism， the therapeutic effects on intestinal injure of piglets and the half\|time prolongation strategy. The purpose of this paper is to provide references for further application of glucagon\|like peptide\|2 in weaning piglets. Related Articles | Metrics