| Bt Transgenic Cotton, transferred to gene of the high production, high quality, strong resistance andother excellent characteristics based on human needs, showing the huge social and economic benefits byimproving cotton production, reduce pesticide use and saving labor since the commercial cultivation in1996. However, the debate on genetically modified biological safety is warming in pace with vigorousdevelopment of transgenic plants in the global, scientists worry that the species boundaries will break withlarge number of distantly related species gene reorganization, affect the course of evolution of natural; theGMOs with new characters may affect the biological community structure and ecosystem function, thelessons in this respect is a lot, such as the famous British Pusztai event, Cornell University Danaidae event,"super weeds" event in Canada, Mexico corn events and Bt cotton damage to the environment events. Inaddition, the extensive use of antibiotic marker genes in genetically engineered may be transferred to somepathogens and caused prevalence of the disease into the environment, thus affecting human health. All ofthese are for us in the research and application of genetically modified organisms sounded the alarm.The soil is an important place for material circulation and energy conversion in the ecosystem, the Bttoxin of Bt transgenic crops into the soil ecosystem through the various secretions of roots and crop stubble,etc., soil active granular appearance rapid adsorption of Bt toxin, and then closely combined and avoiddegradation organism, and maintain the insecticidal activity; Collembolans are the advantages ofarthropods in the soil ecosystem, plays an important role in reduce heavy metal polution, Bt toxin proteinresidue accumulation and organic toxicity, but also indicative of the ecological, such as judgments on soilquality and indicative of the detection of soil pollution, but also as a biological indicator of soilenvironment.Three kinds of Collembola as experimental subjects in this paper, transgenic cotton Bt toxin onnon-target Collembola insect in the impact of the differences of community structure, growth anddevelopment and enzyme activity was studied, provide a theoretical basis for the safety assessment ofgenetically modified organisms; whiLe the DNA bar code technology of several kinds of Collembola usingCO1gene for species identification. The specific results are as follows:(1) The impact on community dynamics of Collembola insect investigated on the community structure of the insects in transgenic cotton fields, Collembola was investigated by the trematode apparatus methodand Tullgren method, the analysis of it focused on species richness, community diversity index, evennessindex, dominant concentration index. The results showed that: whether it is bivalent transgenic cotton fieldsor transgenic insect-resistant species richness, community diversity, evenness index, dominantconcentration compared to control fields, overall trend remains consistent.(2) Collembola feeded on Bt cotton after different time, which were measured the mortality, bodylength, fecundity, hatching days and hatchability. The results showed that: Compared with CK, the Btcotton has a certain impact on Orchesella cincta of the fecundity and mortality, However, nothing more; Nosignificant impact on Sinells curiseta and Ceratophysella dentiaulata.(3) Fed Collembolans with three different concentrations of Bt cotton leaf content in the laboratory,the protection and detoxifying enzymes change was measured at different feeding time. The results showedthat: feeding10%concentrations of Bt transgenic cotton after2h,4h,8h,24h, each enzyme activity didnot change significantly; concentration of30%, the superoxide dismutase(SOD) of feeding insect-resistantcotton+yeast and the peroxisome (POD) of feeding transgenic herbicide-resistant+yeast had significanteffect on the activity of three species Collembola, there was no significant difference at the0.01level;concentration of50%, the SOD activity of Sinells curiseta was a significant change in the feeding oftransgenic herbicide-resistant+yeast after2h,4h,8h,24h, but there was no obvious change compared withthe control in the0.01level, there were no evident differences on the other two species insect;concentration of50%of transgenic cotton feeded the first and second generations of the three springtails,its various enzyme activity were no obvious difference compared with the control.(4) The kinds of Collembolans was classified by DNA barcoding Determination of nine kinds of theCollembolans DNA CO1gene sequence comparative analysis of the genetic distance collembolans species,NJ phylogenetic tree was constructed. The results showed that: the contents of A+T (61.5%) obviouslyhigher than that of C+G (38.6%), which is suitabLe to serve as the important basis of DNA barcodetechnology. This study not only to the classification of species identification, and the results further showthat CO1gene can accurate springtails for species identification.In summary, the Bt toxic protein of insect-resistant cotton on Collembolan species richness,community diversity, evenness index, dominant concentration and enzyme activity were not significant difference effect, but there may have a certain impact on the growth and development. Therefore we canconsider that: the toxic protein of Bt cotton are for springtails security, and safety to the environment in ashort period of time. |
PDF Full Text Request