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PCR identification of the wheat polymers with high quality subunit and powdery mildew resistance Pm4a gene LIU Yongan1，2，PAN Binrong1，2，YUE Gaohong1，2，MEI Xixue2，XU Likui1，2，*，ZHANG Zongchen1，2，ZHOU Zhihui1，2 2016, 28(4):  545.  Abstract ( 403 )   HTML ( 68 )   PDF (995KB) ( 1484 )    In order to improve the quality， yield and disease resistance of wheat lines （varieties）， Ningchun 4， and Yangmai 19 which have 1Dx5+1Dy10 subunit and Pm4a powdery mildew resistance gene were used as parents in present study， respectively. Genomic DNA was extracted from the 1/31/2 grain endosperm of their F2 individuals. PCR identification was conducted with the specific markers of 1Dx5 subunit and Pm4a genes. The results showed that 51 seeds were identified as 1Dx5 subunit and Pm4a gene polymers among 100 F2 individuals. PCR identification used in present study could overcome the time consuming and being easy to confuse the subunits with similar migration rate of SDSPAGE electrophoresis， get rid of the restrictions of climate and farming season of field and greenhouse identification， and improve the efficiency and accuracy of identification greatly. With further evaluation of the selected polymers， the lines with good agronomic traits， high yield and quality， resistance to powdery mildew would be hopefully developed. Related Articles | Metrics

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Identification and analysis of salt stressresponsive transcription factor in leaf of southern type alfalfa PEI Cuiming， ZHANG Zhenya， MA Jin* 2016, 28(4):  550.  Abstract ( 356 )   HTML ( 1 )   PDF (1032KB) ( 1416 )   Illumina RNAsequencing was performed in two alfalfa samples of control （WT_CK2） and NaCltreated samples（WT_N2）in order to estimate a broad spectrum of transcription factor genes affected by salt stress，and the realtime fluorescent qRTPCR technique was used to verify the expression characteristics of random selected 4 genes. These results indicated that 7 497 of them showed two fold higher or lower difference under NaCl stress from the control， including 474 transcription factors （TFs） belonging to 46 transcription family， among which 242 genes were upregulated and 232 were downregulated. Transcription factor families including bHLH，NAC，WRKY and C2H2， among which more than 70% genes were upregulated. Expression patterns of random selected 4 genes confirmed the results of the digital gene expression profile. In addition， this study also identified a large number of candidate functional transcription factor genes such as MsERF110， MsERF071， Ms bHLH36， MsZFP， MsHSFB3， MsMYB， MsNAC， MsWRKY and so on， which appeared to be constitutively involved in the response to salt stress. This study revealed that many transcription factor family were involved in response to salt stress in leaf of southern type alfalfa. Related Articles | Metrics

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Isolation， identification and capsule serotyping of Pasteurella multocida originated from swine LIN Xingyu1，2， HU Ling1， WANG Yin1，2，*， YANG Zexiao1， YAO Xueping1， XIAOLu1， REN Meishen1， ZENG Xiangjie1 2016, 28(4):  558.  Abstract ( 443 )   HTML ( 3 )   PDF (1243KB) ( 1361 )   To investigate the serotypes of Pasteurella multocida in Sichuan， Chongqing and Yunnan， a total of 125 tissue samples were collected from intensive piggery during 2013 to 2014. PCR was performed to identify the isolated Pasteurella multocida and separate their capsular serotyping. It was shown that 11 strains of Pasteurella multocida were isolated from the lung tissues of swine. PCR typing assay indicated that 7 strains were serotype A （63.6%）， 3 strains were serotype D （27.3%）， 1 strain was serotype F （9.1%）， the serotype B and serotype E were not found. It suggested that swine lung plague was mainly caused by serotype A Pasteurella multocida in these areas. In addition， a rare serotype F was isolated from the collected swine lung tissues. These results would provide scientific basis for the prevention and treatment of Pasteurella multocida in above areas. Related Articles | Metrics

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Seroepidemiological investigation and analysis on duck Tembusu virus antibody level in Zhejiang Province LI Jianqiu1， ZHOU Caiqin2,YU Bin3,WU Xuejun2， ZHAO Lingyan 2， ZHOU Lei2， ZHANG Cun3， XU Hui2，* 2016, 28(4):  563.  Abstract ( 382 )   HTML ( 1 )   PDF (485KB) ( 1323 )   In the present study， seroepidemiological investigation on duck Tembusu virus （TMUV） antibody level was carried out. A total of 4 989 sera samples were collected from duck， goose and chicken during 2010-2014 in Zhejiang Province. The TMUV antibody levels of collected samples were detected by ELISA method. It was shown that the positive rates of TMUV antibody in duck， goose and chicken samples were 27.33%， 694% and 111%， respectively. By yearly analysis， TMUV antibody positive rate was 54.83% in the infected duck flocks in 2010-2011 during epidemic period. Goose and chicken sera samples were not collected in that period. TMUV positive rates in the infected duck and goose flock were 3388% and 20.00%， respectively， in 2012， and positive serum sample was not found in chicken flocks. TMUV positive rates in the infected duck， goose and chicken flock were 49.68%， 10.00% and 28.00%， respectively in 2013. TMUV positive rates in the infected duck and goose flock were 39.19% and 6.67%， respectively， in 2014， and no positive serum sample was found in the chicken flocks. In conclusion， the highest TMUV antibody level was found in the year of 2010-2011 during the epidemic period， and duck was the main TMUV infected poultry. Related Articles | Metrics

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Present situation of Eriocheir sinensis resources and protection countermeasures in Jiangxi and Anhui reaches of Yangtze River#br# WANG Haihua1，2，3， ZHUANG Ping1，2，*， FENG Guangpeng1， GAO Yu1， ZHAO Feng1 2016, 28(4):  567.  Abstract ( 327 )   HTML ( 1 )   PDF (1572KB) ( 1306 )   In 2008-2014， the changes of adult mitten crab Eriocheir sinensis resources were investigated in Jiangxi， Anhui reaches of Yangtze River by field survey， ship monitoring， interviews with fishermen and fishery administrations. It was shown that the crab fishing season and fishing period has changed in both Jiangxi and Anhui reaches of Yangtze River. In midstream， fishing period increased by 20 to 30 d， while， fishing period decreased by 7 to 12 d in downstream. Statistics showed that the average individual weight of crab reached the big crab standard， and the mean fatness value exceeded the standard level of crab. During 2008 to 2014， the quantity of crab captured increased first and then decreased as the “∧” shaped curve a significant negative correlation with the total pollutant of Yangtze River water. On this basis， for the protection of mitten crab in Yangtze River， suggestions were proposed as follows: strengthening the control of pollutant discharge in Yangtze River; establishing protected areas of crab in Yangtze River Estuary; strengthening fishery management in Yangtze River; smoothing crab migration routes; enhancing propagation and releasing of crab; exploring ecological scheduling and so on. Related Articles | Metrics

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Analysis on genetic diversity of Wanzai black rabbit based on microsatellite markers HUANG Jiangnan， LIU Linxiu， JI Huayuan， XIE Jinfang， ZHOU Quanyong， XIONG Ligen， WEI Qipeng* 2016, 28(4):  574.  Abstract ( 333 )   HTML ( 1 )   PDF (705KB) ( 1495 )    Genetic diversities of Wanzai black rabbit， Wanxi Angora rabbit and Belgian rabbit were studied using 13 microsatellite markers. The genetic diversity was disclosed by calculating the allele frequency， heterozygosity （Ho）， expected heterozygosity （He）， F value and genetic distance. It was shown that there were 3 imbalance locus in each of the above mentioned rabbit populations， indicating a rich genetic diversity. The average polymorphism information contents （PIC） of Wanzai black rabbit， Wanxi Angora rabbit and Belgian rabbit were 0.35， 0.48， 0.31， respectively. The average He were 0.40， 0.54， 0.37， respectively， and the average Ho were 0.39， 0.51， 0.35， respectively. The average genetic differentiation coefficient （Fst） value among populations was 0.120 1. The observed closest genetic distance was 0.145 2 between Wanzai black rabbit and Belgian rabbit， and the observed farthest genetic distance was 0.200 0 between Wanzai black rabbit and Wanxi Angora rabbit. Related Articles | Metrics

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Study on the resistance induced by BABA and BTH against powdery mildew in tomato LI Huijia,ZHU Lulu，LI Shuai，YANG Huanhuan，ZHANG Dongye，WANG Qiang, WU Mingchen, LI Jingfu* 2016, 28(4):  580.  Abstract ( 434 )   HTML ( 1 )   PDF (915KB) ( 1351 )   The tomato seedlings were treated with 500 mg·L-1 BABA and 50 mg·L-1 BTH respectively， then inoculated with powdery mildew fungus on 1， 2， 3， 5， 8 and 15 d after treatment. The duration of action， optimal processing mode and diseaserelated mechanisms of two inducers were investigated by measuring disease index， relative control effect, H2O2 and NO content and powdery mildew resistance related gene expression levels. The results showed that the best time of BABA was the second day and the effective duration was about 10 days， the best time of BTH was the first， third and fifth day and the effective duration was up to 15 days. The contents of H2O2 and NO were significantly increased. The expression patterns of CHI3， GLUCA， GLUCB， PR1A genes all showed similar trend， but had differences at different treatment time in different materials. In conclusion， BABA and BTH could be used to improve the disease resistance of tomato to tomato powdery mildew. Related Articles | Metrics

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Physiological responses of Citrus maxima cv. ‘Dongshizao’ to different waterretention measures and comprehensive evaluation YUAN Huifang1， XIAO Rongcai1， HUANG Jing1， LI Yueying2， YUE Hai1， TIAN Yaohua1，* 2016, 28(4):  586.  Abstract ( 373 )   HTML ( 2 )   PDF (883KB) ( 1327 )   Citrus maxima cv. ‘Dongshizao’ was selected as the experimental material to evaluate the effects of different droughtresistant measures on its physiological characteristics during the key phenological phases. Four droughtresistant measures （black plastic， white plastic， weeds and water retention agent） with a control treatment were carried out in field. The results showed that soil moisture content （SMC） was increased in the treatments of mulching with black plastic， white plastic and weeds or adding water retention agent. The content of soluble protein （SP）， proline （Pro）， soluble sugar （SS） and sucrose （Suc） in pomelo leaves all changed in different extents. Malondialdehyde （MDA） content and relative conductivity （REC） in all treatments were lower than that of the control， and especially for black plastic， white plastic and weed mulch， MDA and REC showed the lowest values. During the different phenological phases of pomelo， the SP of white plastic and control treatment were the highest in mature period （September）， the SP， SS， Suc， Pro and REC of other treatments had the highest values in budding period （January）， and the SP， SS， Suc and Pro of all treatments had relatively high values when pomelo was close to mature period， while they had very low values during other phenological periods. This suggested that pomelo started the corresponding resistance to stress to maintain metabolic balance by adjusting the content of osmotic regulation substances. Membership function of fuzzy mathematics method was used for comprehensive evaluation of different soil conservation measures. Using the mean value of each index membership degree in each treatment as the comprehensive appraisal standard， the effects of all the soil moisture conservation measures from high to low in order were showed as: black plastic mulch>weeds coverage>white plastic mulch>water retention agent>control. Related Articles | Metrics

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Effects of exogenous nitric oxide on growth and polysaccharide accumulation of protocormlike bodies from Dendrobium officinale LI Qiaozi1，GAO Suping2，*，ZHANG Keyan1，CHEN Feng1，DUAN Jingjing1，CAI Xinyi1 2016, 28(4):  595.  Abstract ( 352 )   HTML ( 4 )   PDF (717KB) ( 1420 )   Sodium nitroprusside（SNP） was used as nitric oxide（NO） donor， the effects of different concentrations of exogenous NO on the protocormlike bodies（PLBs） from Dendrobium officinale， including the growth， chlorophyll content， the activity of sucrose synthase （SS） and the accumulation of polysaccharide were studied. The results showed that a low level of SNP was beneficial for the growth of protocormlike bodies， but the high level of SNP could promote the synthesis of polysaccharide. The dry weight of PLBs cultured in 0.50 mmol·L-1 SNP medium was 36.9% more than its control on the 28th day， and the total chlorophyll content on the 14th day was 1.33 times of the control. The polysaccharide content in the treatment of 1.00 mmol·L-1 SNP was 1.59 times of the control， while the activity of sucrose synthetase significantly increased. Taken together， 0.50 mmol·L-1 SNP showed the best effect， which could promote the dry weight， chlorophyll content， sucrose synthetase activity and the content of polysaccharide， and the above indexes were significantly higher than other treatments. While cPTIO， nitric oxide scavenger， was added， the growth of PLBs， sucrose synthase activity and polysaccharide accumulation were all inhibited. Related Articles | Metrics

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Effects of heavy metals and salt stress on physiological characteristics of Syngonium podophyllum Schott ZHANG Jiayang 2016, 28(4):  601.  Abstract ( 621 )   HTML ( 1 )   PDF (1392KB) ( 1384 )   The influence of two heavy metals （Pb2+ ， Cd2+） ， salt stress （NaCl） and their mixed solutions on the photosynthetic system，membrane system and antioxidant system of Syngonium podophyllum Schott were investigated. The results showed that with the increasing concentration of single and mixed solution treatment， chlorophyll， carotenoids， soluble protein and soluble sugar content and POD activity in Syngonium podophyllum Schott were all inhibited. The content of free proline and CAT activity increased first and then decreased with the increasing concentration of stress， MDA content and relative conductivity increased with increasing concentration of stress. SOD activtly decreased with the increasing concentration of heavy metals, but increased first and then decreased with the increasing concentration of NaCl. This study suggested that， chlorophyll content， membrane system and antioxidant system of Syngonium podophyllum Schott were sensitive to the stress of heavy metals and salt. These parameters could be taken as indicators in evaluating the damage of heavy metals and salt stress on Syngonium podophyllum Schott. Related Articles | Metrics

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Characterization of transcriptome reveals pathway of flavonoids in Ephedra sinica Stapf MA Jing 1， CHENG Tielong 1， 2， *， SUN Canyue 3， DENG Nan 1， SHI Shengqing 1， JIANG Zeping 1 2016, 28(4):  609.  Abstract ( 477 )   HTML ( 2 )   PDF (1895KB) ( 1511 )   Ephedra sinica Stapf is not only an important medicinal plant rich in flavonoids and alkaloids， but also an important sandfixing plant in the desert environment. In this study， the transcriptome of E. sinica from SRA database in GenBank was further analyzed by bioinformatics method. 7 947 954 clean reads and 13 389 unigenes were acquired after de novo assembly; 10 481 annotations were acquired from Nr database， 4 533 from KOG database， 7 121 from GO database， 5 833 from KEGG database， 8 039 from SwissProt database after function annotation against five databases. We also discovered a series of unigenes which were associated with flavonoids biosynthesis by KEGG pathway analysis， which benefits the cloning of related genes and biosynthesis of related components in flavonoids pathway. This study could provide references for understanding the resistance mechanism of E. sinica and utilization of its medicinal value in the future studies. Related Articles | Metrics

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Construction of kiwifruit AFLP analysis system and dynamic monitoring of tissue culture variation of subculture seedling LYU Tianwen1， LI Wangwei1， ZHANG Taikui1， LIU Huimin1， LI Kun2,* 2016, 28(4):  618.  Abstract ( 321 )   HTML ( 1 )   PDF (1283KB) ( 1369 )   In order to decrease the loss of variant seedlings in tissue culture， the variant rate of sub cultured seedlings of ‘Hort 16A’ was dynamically monitored by AFLPs in the study. The AFLP analysis system was set up and optimized， and the genetic diversity of 75 samples of R7R11’s generations was studied too. The experiments showed that using 1 U restriction enzyme to digest 300 ng genomic DNA at 37 ℃ for 4 h in dual enzymes restriction could achieve the best effect. 1U T4 DNA ligase， 15 μL adpter and 2 μL ATP could get the best adpter ligation. The best dosage of preamplification primer was 08 μL （100 μmol·L-1） and that of the selective amplification of Taq polymerase was 025 （83 350 nkat·mL-1） μL. 8 pairs of primer whose number of amplified bands were the richest were selected. A total of 494 bands were amplified using these 8 pairs of primer， out of which 310 were polymorphic bands， and the polymorphic rate was 627%. The results showed that kiwis tissue subculture seedlings could maintain their genetic stability until the ninth generations. But from the tenth generation， the variant rate of sub cultured seedlings had an upward tendency. Related Articles | Metrics

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Effects of fenaminosulf on the yields and benefits of singleharvesting Zizania latifolia Turcz. ex Stapf ZHOU Jinlian 1， CHEN Jianming 2， *， WANG Lailiang 3， ZHANG Juefeng 2， MA Yamin 3， WANG Bin 4， ZHONG Haiying 2 2016, 28(4):  624.  Abstract ( 1319 )   HTML ( 19 )   PDF (1563KB) ( 1661 )   In view of the nonstandard usage of fenaminosulf on singleharvesting Z.latifolia， the effects of different spraying periods， different concentrations and spraying times on yield and value of singleharvesting Z.latifolia were studied. The results show that in some regions where singleharvesting Z.latifolia could be harvested twice per year， fenaminosulf could significantly promote forming swollen gall， advance the harvest time for about 50 d. Fenaminosulf with 0.5 g·L-1 （a.i.） should be used at 150， 160 and 175 d after transplanting of Z.latifolia last year. In normal singleharvesting Z.latifolia growing regions， once application of fenaminosulf could obviously advance harvest time and improve yield and benefit， but with more frequency of use， yield and benefit of Z.latifolia decreased more significantly. In conclusion， fenaminosulf with 10 g·L-1 （a.i.） should be used only once at 4060 d after transplanting of Z.latifolia. Related Articles | Metrics

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Infection， spread and distribution of pathogens of twig blight disease on bayberry REN Haiying1， LIANG Senmiao1， ZHENG Xiliang1， QI Xingjiang1，*， ZHU Xiaoting2， YAN Liju2 2016, 28(4):  630.  Abstract ( 365 )   HTML ( 2 )   PDF (1614KB) ( 1462 )   In order to develop the effective technologies to prevent and control the twig blight disease of bayberry， it was studied that how conidia infected and disseminated， how the twig blight disease occured and spread in the whole year， and how the fungi distributed in bayberry plants. The conidia solution with concentrations of 2×101 to 2×106 mL-1 could infect bayberry mainly through the orifice and wound on the young shoots. The conidia had two peaks of infection， the whole May， the mid of June to the mid of July， respectively. The conidia could be captured throughout the year. There were 2 captured peaks， the mid of May to the mid of June， the end of August to the mid of October， respectively. The bayberry trees had new diseased shoots throughout the year， and the peak incidence was in the middle of September to the early of November. The twig blight disease had the centers， and the trees in the low altitude， water erosion serious position were infected firstly. The isolated fungal strains and DNA copy numbers of the diseased were 2-6 times of the healthy in a whole year. The pathogens could survive in the bayberry plants in the whole year with the most quantity in young shoots， but without obvious time peaks. Related Articles | Metrics

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Cloning and heterologous expression in Lactococcus lactis of phosphatidylinositolspecific phospholipase C gene from Bacillus cereus TANG Xianze1， LIU Wei2， PI Xionge2， YIN Yeshi2， WANG Xin2， LIU Xinli1，* 2016, 28(4):  640.  Abstract ( 351 )   HTML ( 1 )   PDF (979KB) ( 1439 )   Based on the codon bias of Lactococcus lactis， phosphatidylinositolspecific phospholipase C gene from Bacillus cereus was optimized and then synthesized for protein expression. The cloned gene was inserted into Escherichia coliLactococcus lactis shuttle vector pAMJ399， and then transformed to L. lactis cells by electroporation to induce expression. The result of SDSPAGE showed that the recombinant protein was secreted extracellular in the form of soluble proteins， and its molecular weight was about 35 ku， which was consistent with the expected protein size. Meanwhile， the recombinant protein showed significant enzyme activity on PIListeria chromogenic plate. The results indicated that phosphatidylinositolspecific phospholipase C （PIPLC） was successfully expressed in L. lactis. The growth condition was optimized as follows: 2% inoculation amount; GM17 medium with 1% erythromycin; 32 ℃. After 24 h static culture under above condition， it could produce 1.092 μg·mL-1 PIPLC in the supernatant of culture medium. Related Articles | Metrics

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Degradation behavior of sulfonamides in aquaculture sediments and its influencing factors LIU Jinghua，ZHANG Fen， GUO Xia， HUANG Xueling， SUN Jianhua， SUN Zhenzhong 2016, 28(4):  647.  Abstract ( 384 )   HTML ( 2 )   PDF (1038KB) ( 1383 )   To evaluate the degradation of sulfonamides in aquaculture sediments， sulfadiazine （SD）， sulfamethazine （SM2） and sulfamethoxazole （SMZ） which exhibited relatively high detection rates in aquaculture sediments were chosen as the research objects. Through laboratory simulation degradation experiment， a series of environment factors including temperature， microorganism， illumination and initial concentrations in sediments were tested to determine their impacts on degradation of SD， SM2 and SMZ. It was shown that raising temperature could effectively promote the degradation of SD， SM2 and SMZ in sediments， and these sulfonamides exhibited e a higher degradation rate under 25 ℃ and 35 ℃ than that under 5 ℃. SD and SM2 degradation in sediments were mainly attributed to abiotic degradation， and microbial degradation was complementary. SMZ in sediments was significantly influenced by microbial degradation， and the contribution rate of microbial degradation reached 55%. Illumination had no significant effect on the degradation of the three kinds of sulfa drugs in sediments. With the increase of the initial concentrations， the degradation efficiency of SD， SM2 and SMZ declined gradually， and the halflife period of degradation was extended. Under the condition of the lower concentration as 0.01 and 0.1 mg·kg-1， the halflife period of SD， SM2 and SMZ was short. Within the initial concentration of 1～50 mg·kg-1， the halflife period of SD， SM2 and SMZ was 11.13～128.36 d. Related Articles | Metrics

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Safety evaluation of new fungicide fluxapyroxadpyraclostrobin to mulberry and silkworm XIE Daoyan， YANG Zhenguo， ZHOU Chuntao， CHAI Jianping， DA Aisi， NI Jing， JIANG Xiujun， LUO Yanjie* 2016, 28(4):  654.  Abstract ( 498 )   HTML ( 1 )   PDF (645KB) ( 1382 )   The aims were to investigate the safety of 42.4% fluxapyroxadpyraclostrobin SC on mulberry and silkworm. The harm to mulberry and residual toxicities to silkworm of different concentration of 42.4% fluxapyroxadpyraclostrobin SC were evaluated. The results showed that all treatments were not phytotoxic to mulberry. At 20 d after spraying， the developmental duration of 2 instar of Bombyx mori showed no difference among the groups feeding on mulberry leaf treated with 141 and 212 mg·L-1 fluxapyroxadpyraclostrobin SC and the water control， but the development period of 3， 4， and 5 instar larvae were delayed. The development periods of silkworms were delayed and body weights of tetramolter were reduced after feeding on mulberry leaf treated with 283 and 565 mg·L-1 fluxapyroxadpyraclostrobin SC. After feeding mulberry leaf treated with 141 and 212 mg·L-1 fluxapyroxadpyraclostrobin SC， the economic characters of silkworm showed no significant difference compared with the water control and 10% difenoconazole WDG group， while feeding 283 and 565 mg·L-1 processing mulberry leaf， its cocoon weight， cocoon shell， cocoon shell rate and pupa weight were significantly lower than those of the water control. Therefore， 42.4% fluxapyroxadpyraclostrobin SC was unfavorable in mulberry field and surrounding farmland during the sericulture， and its safety interval period for silkworm was longer than 20 d. Related Articles | Metrics

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Comparison of storage factors and evaluation of storage methods for purple pepper fruit HU Nengbing， SUI Yihu， HE Keqin， WANG Mimi， ZHANG Ruonan， HU Xiaoxiao 2016, 28(4):  659.  Abstract ( 438 )   HTML ( 1 )   PDF (608KB) ( 1384 )   Effects of 5 storage methods on freshkeeping of purple pepper 9007 × 9049Ⅱ were studied at room temperature and low temperature of 7 ℃, respectively. The results showed that temperature was the main factor influencing purple pepper storage， decay rate rose to 75% at room temperature after 15 d， while storage time could be extended to 50 d at low temperature， and the optimum method for its storage was treated with 15 min UV and packed with PE at low temperature of 7 ℃. Related Articles | Metrics

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Analysis of volatile components in petitgrain oil by GC/MS combined with retention index LI Yuandong， LIU Xiuming， DANG Lizhi， JIANG Juxing， WANG Wenyuan， MAO Deshou， DUAN Yanqing* 2016, 28(4):  665.  Abstract ( 343 )   HTML ( 3 )   PDF (512KB) ( 1359 )   The volatile components of petitgrain oil were analyzed by GC/MS， and the peak area normalization method was used to calculate the relative content of each component. With the mass spectrometry library search， 56 compounds which accounted for 97.471% in the volatile components of petitgrain oil， were confirmed using retention index comparison. Linalyl acetate （30.685%）， linalool（22.166%）， alphaterpineol（9.040%）， geranyl acetate（5.696%）， myrcene（3.716%）， neryl acetate（3.573%）， limonene（3.263%）， betapinene（2.943%）， nerol（2.314%）， （E）betaocimene（1.941%）， betacaryophyllene（1.851%）， gammaterpineol（1.557%）， alphapinene，（1.332%）， （Z）betaocimene（1.300%） were the main components. The cis（trans）isomers were confirmed by retention index， and the accuracy of compound qualitative analysis in natural flavor was improved. These results provided the technical support for the development and application of petitgrain oil. Related Articles | Metrics

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Isolation and identification of an aromaproducing strain and optimization of its fermentation condition YU Xiang1， LI Yuanshi2， LIU Dong3, WANG Ruiting2， TIE Jinxin1, MA Lin1，* 2016, 28(4):  670.  Abstract ( 339 )   HTML ( 1 )   PDF (1094KB) ( 1460 )   An aromaproducing strain GXY35 was isolated from 14 kinds of tobacco leaves， and the aroma components were analyzed by gas chromatographymass spectrometry （GC/MS）. The strain was identified as Klebsiella sp. from physiological and biochemical characteristics and 16S rDNA. The content of 4vinylgualacol in fermentation broth was the highest. On the basis of single factor test， the fermentation condition of strain was optimized by orthogonal experiment. The optimal fermentation condition was as follows: the solidliquid ratio of 1∶20， the inoculums size of 12%， the fermentation temperature of 37 ℃， the fermentation time of 72 h， and the initial pH of 7.0. Under the optimal fermentation condition， the content of the characteristic favoring substance of 4vinylgualacol was 0.725 mg·mL-1. Related Articles | Metrics

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Study on analysis method of storage time of Huangshanmaofeng tea by electronic nose YANG Chunlan， XUE Dawei*， BAO Junhong 2016, 28(4):  676.  Abstract ( 372 )   HTML ( 1 )   PDF (820KB) ( 1534 )   Five levels of Huangshanmaofeng tea with 6 varied storage time were detected by electronic nose. Firstly， the original feature vectors presenting the tea odor were acquired. Then， the first 5 principal components were extracted as the principal feature vectors by principal component analysis （PCA）. With the principal feature vectors used as BPNN input， a new model called PCABPNN for storage time analysis of Huangshanmaofeng tea was built. After experimental test， it was shown that for the tea of 0 d storage， the maximum prediction error （MPE） was 11 d， and the samples of prediction error exceeding 10 d was 5 （6.67%）; for the tea of 60 d storage， MPE was 13 d， and the samples of prediction error exceeding 10 d was 4 （5.33%）; for the tea of 120 d storage， MPE was 16 d， and the samples of prediction error exceeding 10 d was 7 （9.33%）; for the tea of 180 d storage， MPE was 19 d， and the samples of prediction error exceeding 10 d was 8 （10.67%）; for the tea of 240 d storage， MPE was 21 d， and the samples of prediction error exceeding 10 d was 8 （10.67%）; for the tea of 300 d storage， MPE was 14 d， and the samples of prediction error exceeding 10 d was 6 （8.00%）. In conclusion， PCABPNN model could be used to analyze the storage time of Huangshanmaofeng tea， and the proposed model was better than BPNN， which used original feature vectors as the input. Related Articles | Metrics

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Determination of storage time of watermelon based on acoustic impulse method LU Yong 1， 2， LI Zhenfeng 1， 2， *， PU Hongjie 1， 2， WANG Disong 1， 2 2016, 28(4):  682.  Abstract ( 349 )   HTML ( 2 )   PDF (960KB) ( 1379 )   In order to study the effects of storage time on acoustic properties of watermelons， the changes of vibration response frequency of watermelon were studied by the way of percussion with the vibration detection system designed by our lab. The results showed that the first response fundamental frequency had a good correlation with storage time， and then a nonlinear function model was established， the correlation coefficient was 0.919 1. By selecting multiple vibration eigenvalues， a multiple linear regression model was established to describe storage time. Test analysis of the watermelon samples showed that it could get the best measurement model when placing the excitation and receiving points at the watermelons stem and stalk， respectively. The correlation coefficient and standard estimation error of this model was 0.931 3 and 1.8120， respectively. It provided a reference for the storage and sale of watermelon after picking. Related Articles | Metrics

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Test and analysis of axial compressive mechanical properties for ramie stalk SHEN Cheng， CHEN Qiaomin， LI Xianwang， ZHANG Bin*， HUANG Jicheng， TIAN Kunpeng 2016, 28(4):  688.  Abstract ( 334 )   HTML ( 1 )   PDF (726KB) ( 1384 )    In this paper， elastic parameter test method of composite material mechanics was applied and WDW10 microcomputer control universal testing machines was used to study the characteristics of axial compressive mechanics on the xylem of ramie and the whole stalk. It was shown that the average axial compressive elasticity modulus of the whole stalk of ramie xylem of Zhongzhu No.1 was 241.93 MPa， and the average maximum stiffness was 12.61 MPa， while the average axial compressive elasticity modulus of stalk was 304.85 MPa， and its average maximum stiffness was 12.58 MPa. There was no significant difference in elasticity modulus and compressive strength between the elasticity modulus of xylem and stalk. In the stalk composition， xylem and phloem bond on the surface upon their adhesion strength which can not prevent the phloem slipping from the surface of xylem. In the compressive test， it mostly showed the loadbearing function of xylem. Related Articles | Metrics

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Prediction of fatigue life for screw of adjustment mechanism of seedling box of adjustable spacing transplanter ZHU Dequan1， YAO Yafang1， WU Liquan2， JIANG Rui1， XIONG Wei1 2016, 28(4):  693.  Abstract ( 307 )   HTML ( 2 )   PDF (1465KB) ( 1336 )   To predict fatigue life for sliding screw of adjustment mechanism of seedling box， the calculation formula of fatigue life was derived by the related theory and method. The rigid coupling model of adjustment mechanism was built with Adams and Ansys software. The real working condition of adjustment mechanism of seedling box was imitated and the axial load of screw was gained. The maximum Von Mises stress of thread was 188 MPa， which was analyzed by the finite element method based on Ansys software. The maximum Von Mises stress was less than strength limit of the material. Based on the initial conditions， fatigue life of thread was analyzed with Ansys/fesafe software. The results showed that the working life of sliding screw was 3 598 h and met the requirements of rice transplanter. Related Articles | Metrics

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Design of a rice transplanter used to synchronously transplant parental seedlings for hybrid rice seed production XIONG Wei1， ZHU Dequan1， 2，*， ZHU Dewen3， WU Liquan2， WANG Chaoxian1， WU Zuolong4 2016, 28(4):  699.  Abstract ( 328 )   HTML ( 1 )   PDF (2076KB) ( 1347 )   At present， planting the parental seedlings for hybrid rice seed production was carried out artificially， which had a lot of problems such as large labor intensity， low production efficiency， high cost， etc. A kind of rice transplanter was developed to plant the parental seedlings synchronously as two lines of paternal seedlings and ten lines of maternal seedlings. The machine was developed based on 2ZT9358 riding rice transplanter， according to the requirements of seed production of hybrid rice. The key structure parameters were determined， and the design of parental seedling transplanting mechanisms， the screw shaft of the boxtransferring mechanism and other key components were determined. Field test showed that the operating performance of the designed transplanter was pretty good.Its productivity was 0.35 hm2·h-1， the paternal and maternal damaged seedling rate were 2.7%， 2.4%， respectively， the floating seedling rate were 2.2%， 2.0%， respectively， the miss planting hill rate were 3.1%， 3.2%， respectively， the laid seedling hill rate were 2.5%， 2.1%， respectively， the percent of pass of planting depth were both 94%， and the percent of paternal pass of relative uniformity were 90.5%， 91.8%， respectively， which were all in line with the national standard for rice transplanter （GB/T 208642007）. In conclusion， the designed rice transplanter could meet the actual requirements for hybrid rice seed production. Related Articles | Metrics

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Costbenefit assessment for greenhouse gas mitigation in ricebased agriculture MI Songhua1， HUANG Zuhui2，*， ZHU Qibiao1， HUANG HExiao1, LI Baozhi1 2016, 28(4):  707.  Abstract ( 360 )   HTML ( 3 )   PDF (1116KB) ( 1462 )   This study presented a modeling tool to assess emission of greenhouse gases（GHGs）from ricebased agricultural system as affected by different mitigation technologies， as well as mitigation potential of single technology according to technical coefficients recommended by intergovernmental panel on climate change （IPCC）. As there were a range of technically feasible measures to reduce agricultural GHG emissions， the present study also developed a marginal abatement cost curve （MACC） to assess their costeffectiveness and mitigation potential in the field. It was shown that with the current farmers practice in China， soilborne emissions were the major source of GHGs， followed by nitrogen fertilizer application both onand offfarm. Through improvement in water management， inorganic/organic N supply， rotation and straw returning， GHG emission could be reduced by 1.52% to 40.17% during the whole cropping cycle. A significant reduction of global warming potential （GWP） could be achieved by modification of water management. The present study then assessed GHG emissions and economic returns under different mitigation technologies in rice growing region. Taking Huangyan District， Taizhou City as an example， the shadow price would be 1.63 to 9.79 yuan·kg-1 CO2 equivalent （CE） when baseline technology （continuous flooding， urea fertilization， burning of rice straw） was converted to preferable options， and the technology combinations including continuous flooding， urea fertilization and straw used as construction material exhibited the highest costeffectiveness. Related Articles | Metrics