[ Objective] The study was aimed to determine the biological characteristics of Rhabditis （Oscheius） sp. isolated from a rhizosphere soil of alfalfa field in Hailar City, Hulunbuir League, Inner Mongolia Autonomous ...[ Objective] The study was aimed to determine the biological characteristics of Rhabditis （Oscheius） sp. isolated from a rhizosphere soil of alfalfa field in Hailar City, Hulunbuir League, Inner Mongolia Autonomous Region. [ Method] The last instar larvae of Galleria mellonella and Tenebrio molitor were used as insect hosts. The infectivity of nematode was determined, and its heat tolerance ability was measured by using water bath method. [Result] The infectivity of the nematodes was lower at the dosages of 10, 20 and 40 IJs/larva, but higher at the dosages of 80,160, 32.0 and 640 IJs/larva. The corrected mortality （CM） of G. mellonella at 96 h and T. molitor at 120 h were both above 90%. The nematode infectivity was highest at the dosage of 80 IJs/larva when the hosts＇ CM reached 100% after 120 h. About 25% nematode individuals could survive in 36℃ water bath for 2 d in the densities of 1 000 -5 000 IJ/ml, after 6 d, there were still 3% -9% individuals survived, until 9 d the nematodes died totally. A hundred percent of the nematode individuals died in 38℃ and 40 ~C water bath after 6 h and 2 h, respectively. [Conclusion] Rhabditis （ O. ） sp. has a higher potential to cause the host mortality and represents heat tolerance up to 36℃.展开更多
[Objective] This study aimed to reveal the effects of Aphelenchoides besseyi infection on different rice varieties（lines）.[Method] By field observation and indoor phenotypic investigation,four conventional japonica ...[Objective] This study aimed to reveal the effects of Aphelenchoides besseyi infection on different rice varieties（lines）.[Method] By field observation and indoor phenotypic investigation,four conventional japonica rice varieties（lines） and japonica rice restorer line R161 under natural onset conditions were observed and analyzed.[Result] After being infected by A.besseyi,different rice varieties（lines）exhibited various symptoms.Specifically,Ning 1707,Ning 1818,Zhendao 88 and Nanjing 9108 had withered leaf tips and exhibited the symptoms of ＂small grains and erect panicles＂;japonica rice restorer line R161 only had withered leaf tips without symptoms of ＂small grains and erect panicles＂,and the withering symptoms occurred in flag leaf tip,whole flag leaf and top second leaf,respectively.After being infected by A.besseyi,all the experimental materials could sprout normally,but their plant height,panicle length,seed-setting rate and 1 000-grain weight were affected to varying degrees.In addition,after being infected by A.besseyi,various symptomatic tissues of R161 exerted different effects on rice yield.Especially,panicles with withered and twisted whole flag leaf were most affected.[Conclusion] This study provided the basis for further exploration of the damages of A.besseyi infection to rice and development of corresponding control measures.展开更多
To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on ...To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tat Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tat Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.展开更多
基金Supported by Ministry of Science and Technology of China on 863 Program"Soil Technique of Nematode Repair Biological Pollution"(2006AA06Z354)Support Plan Program"Production Technology ofHigh Efficiency Standard on Main Fruit Trees"(2008BAD92B08)BeijingGovernment on Purchasing Technology Service Program(2007DAg03B03-07)~~
文摘[ Objective] The study was aimed to determine the biological characteristics of Rhabditis （Oscheius） sp. isolated from a rhizosphere soil of alfalfa field in Hailar City, Hulunbuir League, Inner Mongolia Autonomous Region. [ Method] The last instar larvae of Galleria mellonella and Tenebrio molitor were used as insect hosts. The infectivity of nematode was determined, and its heat tolerance ability was measured by using water bath method. [Result] The infectivity of the nematodes was lower at the dosages of 10, 20 and 40 IJs/larva, but higher at the dosages of 80,160, 32.0 and 640 IJs/larva. The corrected mortality （CM） of G. mellonella at 96 h and T. molitor at 120 h were both above 90%. The nematode infectivity was highest at the dosage of 80 IJs/larva when the hosts＇ CM reached 100% after 120 h. About 25% nematode individuals could survive in 36℃ water bath for 2 d in the densities of 1 000 -5 000 IJ/ml, after 6 d, there were still 3% -9% individuals survived, until 9 d the nematodes died totally. A hundred percent of the nematode individuals died in 38℃ and 40 ~C water bath after 6 h and 2 h, respectively. [Conclusion] Rhabditis （ O. ） sp. has a higher potential to cause the host mortality and represents heat tolerance up to 36℃.
文摘[Objective] This study aimed to reveal the effects of Aphelenchoides besseyi infection on different rice varieties（lines）.[Method] By field observation and indoor phenotypic investigation,four conventional japonica rice varieties（lines） and japonica rice restorer line R161 under natural onset conditions were observed and analyzed.[Result] After being infected by A.besseyi,different rice varieties（lines）exhibited various symptoms.Specifically,Ning 1707,Ning 1818,Zhendao 88 and Nanjing 9108 had withered leaf tips and exhibited the symptoms of ＂small grains and erect panicles＂;japonica rice restorer line R161 only had withered leaf tips without symptoms of ＂small grains and erect panicles＂,and the withering symptoms occurred in flag leaf tip,whole flag leaf and top second leaf,respectively.After being infected by A.besseyi,all the experimental materials could sprout normally,but their plant height,panicle length,seed-setting rate and 1 000-grain weight were affected to varying degrees.In addition,after being infected by A.besseyi,various symptomatic tissues of R161 exerted different effects on rice yield.Especially,panicles with withered and twisted whole flag leaf were most affected.[Conclusion] This study provided the basis for further exploration of the damages of A.besseyi infection to rice and development of corresponding control measures.
基金Supported by the Strategic Research Grant from City University of Hong Kong(No.7002500)the National Natural Science Foundation of China(Nos.41006081,40730847)the Fundamental Research Funds for Central Universities of the Ministry of Education of China from Ocean University of China(No.201013002)
文摘To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tat Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tat Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.
