Studies On Mechanism And Ecological Safety Assessment Of Transgenic Hybrid Poplar 741 With Two Insect-resistant Genes

Using leaves with different insect resistance from strains Pb 11, Pb29, Pb3, Pbl2, Pbl7of transgenic hybrid poplar741 as experimental materials and the normal poplar741 as CK to feed the larvae of Lymantria dispar L., Clostera anachoreta (Fabricius) and Hyphantria cunea (Drury) indoors through individual and colony feeding methods, the resistant efficiency and regularity of the transgenic hybrid poplar741 against those insects was systematically studied in this research. The arthropods communities in both high-resistant and medium-resistant strains of the transgenic hybrid poplar741 were being investigated in the experimental cultivating fields. In order to provide scientific foundations for the persisting and rational utilization of the transgenic hybrid poplar741, its possible ecological risk imposed on the arthropod community after its releasing into the environment, was assessed from community biological aspect. The main results are as follows:(1) The influence of the transgenic hybrid poplar741 on the death and growth of the target pest.Indoors , the colony and individual of the Lymantria dispar L. , Clostera anachoreta (Fabricius) and Hyphantria cunea (Drury) were being fed separately, the poplar's killing efficiency and influence on those larvae were observed, and the results show that: The hybrid poplar741 transformed double insect-resistant genes had resistance on all pests tested, the resistance on Lymantria dispar L. is strongest, the resistance on Clostera anachoreta (Fabricius) took the second place and the resistance on Hyphantria cunea (Drury) was weaker. The main appearances of the poplar's resistance are as follows: it has poisoning effect on lower instars larvae and obvious inhibiting effect on,the survival higher instars larvae's growth; the larvae's development period was postponed; the growth speed, the weight increasing rate and the quantity of frass were decreased; and all the effects led to badness development or even to death. The result indicated that the persisting insect-resistance of the transgenic hybrid poplar 741, which could delay the growth of the next generation larvae and even influence the outbreak and development of the future population, has achieved a good insect-resistant effect. The insect-resistant effect of the poplar varied under different temperatures. The mortality and development speed of larvae increased along with the rising temperature.(2) The spatiotemporal dynamic state of the poplar's insect-killing activity and the measurement of the poplar's content of the Bt toxin protein.Leaves collected in different burgeoning time and from different parts of the branches, wereused to feed the larvae of the Clostera anachoreta (Fabricius) indoors. With the recorded larvae mortality and the calculated ecdysis index, the results indicated that: leaves collected in different burgeoning time have the different insect resistance; leaves from different parts of the branches also have the different insect resistance against the larvae of Clostera anachoreta (Fabricius) . Through enzymatic combination immunology quantification method, it was proved that: the correlation between the content of the Bt toxin protein in the transgenic poplar 741 leaves and the biological measurement results was very good. The resistant strains of Pb3 had the highest content of the Bt toxin protein, and the Pb11,Pb12 had the lower contents in turn. The longer the burgeoning time the leaves had, the higher quantity the Bt toxin protein they contented. The results of the indoors biological determining and measurement of the contents of the Bt toxin protein were unanimous.(3) The transgenic hybrid poplar741 's effect on the enzyme in the pest larvae's body. Accompanied with the insect-resistant experiment, the larvae of the Lymantria dispar L. ..Clostera anachoreta (Fabricius) were fed with leaves from different resistant strains of the transgenic hybrid poplar741. using the larvae of 4~6 instars as the enzymatic extracting materials, the activities of carboxzlesterase, glutathione-S-aryl...