Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical c...Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical composition of the plant, and this change may affect the role soil fauna plays in decomposition of Bt plants. A 3 months litterbag field study, consisting of four treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under ambient and elevated CO2 levels, was conducted to investigate the abundance and community structure of soil Collembola that developed on the decaying leaf material. A total of 4,884 collembolans, including 13 genera of five families, were extracted in the present study. These results suggest that collembolan distribution was relatively uniform among the Bt cotton, elevated concentration of CO2 and control treatments, except for a significant difference in the densities of Onychiurus and Folsomides. No significant effects were detected in the decomposition rate between the two cotton varieties and two CO2 treatments. These findings indicated that transgenic Bt cotton plants and elevated CO2 do not have any adverse effect on the soil collembolans through the decomposition way in soil ecosystem.展开更多
Genetic engineering has created many genetically modified （GM） crop varieties that express the cry toxin from the bacterium Bacillus thuringiensis （Bt）. The cry toxin, synthesized during plant growth, has insectic...Genetic engineering has created many genetically modified （GM） crop varieties that express the cry toxin from the bacterium Bacillus thuringiensis （Bt）. The cry toxin, synthesized during plant growth, has insecticidal properties, and can be expressed anywhere in the plant. This study aimed to ascertain the richness and species diversity of edaphic Formicidae and Coleoptera in GM cotton fields compared with the conventional non-transformed cotton crop. We analyzed data from commercial cotton fields located in the municipality of Maracaju, Mato Grosso do Sul, Brazil. The experiment was conducted during the reproductive period of cotton, employed two treatments： Bt cotton and non-Bt cotton. Samples were collected with pitfall traps. Formicidae species richness in the Bt area was lower than in the non-Bt area, but species composition did not differ between the two treatments. Species composition of Coleoptera communities also differed between the treatments because some species were more abundant in the Bt cotton area. On the other hand, the species richness of this group was similar in both areas.展开更多
The effect of transgenic double genes, Cry1A + CpTI cotton and Cry1Ac toxinon the parasitoid, Campoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Huebner),was investigated in the laboratory. Helicov...The effect of transgenic double genes, Cry1A + CpTI cotton and Cry1Ac toxinon the parasitoid, Campoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Huebner),was investigated in the laboratory. Helicoverpa armigera larvae when in the first, second and thirdinstar could not survive if fed on transgenic cotton leaves. Consequently, C. chlorideae larvaecould not complete their development if parasitizing on such hosts. After H. armigera larvae werereared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C.chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for12-48 h. The present results showed that the body weight of larvae of the parasitoids weresignificantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fedon traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal andadult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaveslonger than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgeniccotton leaves in each treatment was not significantly different from those of controls. Thelongevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was notsignificantly different with that of the control.展开更多
文摘Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical composition of the plant, and this change may affect the role soil fauna plays in decomposition of Bt plants. A 3 months litterbag field study, consisting of four treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under ambient and elevated CO2 levels, was conducted to investigate the abundance and community structure of soil Collembola that developed on the decaying leaf material. A total of 4,884 collembolans, including 13 genera of five families, were extracted in the present study. These results suggest that collembolan distribution was relatively uniform among the Bt cotton, elevated concentration of CO2 and control treatments, except for a significant difference in the densities of Onychiurus and Folsomides. No significant effects were detected in the decomposition rate between the two cotton varieties and two CO2 treatments. These findings indicated that transgenic Bt cotton plants and elevated CO2 do not have any adverse effect on the soil collembolans through the decomposition way in soil ecosystem.
文摘Genetic engineering has created many genetically modified （GM） crop varieties that express the cry toxin from the bacterium Bacillus thuringiensis （Bt）. The cry toxin, synthesized during plant growth, has insecticidal properties, and can be expressed anywhere in the plant. This study aimed to ascertain the richness and species diversity of edaphic Formicidae and Coleoptera in GM cotton fields compared with the conventional non-transformed cotton crop. We analyzed data from commercial cotton fields located in the municipality of Maracaju, Mato Grosso do Sul, Brazil. The experiment was conducted during the reproductive period of cotton, employed two treatments： Bt cotton and non-Bt cotton. Samples were collected with pitfall traps. Formicidae species richness in the Bt area was lower than in the non-Bt area, but species composition did not differ between the two treatments. Species composition of Coleoptera communities also differed between the treatments because some species were more abundant in the Bt cotton area. On the other hand, the species richness of this group was similar in both areas.
文摘The effect of transgenic double genes, Cry1A + CpTI cotton and Cry1Ac toxinon the parasitoid, Campoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Huebner),was investigated in the laboratory. Helicoverpa armigera larvae when in the first, second and thirdinstar could not survive if fed on transgenic cotton leaves. Consequently, C. chlorideae larvaecould not complete their development if parasitizing on such hosts. After H. armigera larvae werereared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C.chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for12-48 h. The present results showed that the body weight of larvae of the parasitoids weresignificantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fedon traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal andadult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaveslonger than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgeniccotton leaves in each treatment was not significantly different from those of controls. Thelongevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was notsignificantly different with that of the control.
