Studies On The Insect-Resistance Of Transgenic Haploid Populus Simonii Carr.×P.nigra L.Harboring Double Genes

The study was conducted for finding the insect-resistance of haploid Populus simonii Carr. XP. nigra L. with Bt+spider peptide gene and providing scientific foundations for the farther propagation and commercial production of the transformed insect-resistant-strains. The leaves of two transgenic clones TT1&TT3,which were served as experimental objects, and the non-transgenic Populus simonii Carr.XP nigra L., which was served as Ck, were fed to the larvae of three species, Lymantria dispar (Linnaeus), Malacosoma neustria testacea Motschulsky and Clostera anachoreta (Fabricius). And the resistance of the transgenic strains against these insects was determined through picked leaves feeding and web sack feeding methods.At the same time, the impact of the insecticidal protein in transgenic strains on midguts of larvae of Clostera anachoreta (Fabricius) was studied through olefin cutting mothed in this paper. The main results are as follows:(1) Transgenic plantlets could increase the the mortality of larvae.On the corrected mortality, the killing effect of TTl was stronger than that of TT3 to Lymantria dispar (Linnaeus) and it was evident in 20~24d . To Malacosoma neustria testacea Motschulsky the killing effect of TT3 was stronger than that of TTl and it was evident in 12~18d.To Clostera anachoreta (Fabricius) the killing effect of TT3 was also stronger and evident in 1-15d.(2) Transgenic plantlets could inhibit ecdysis of larvae and exhibit toxicity to a certian extent.To Lymantria dispar (Linnaeus) the TT3's toxicity was stronger than TT1's during the first 18d, but TTl's toxicity was stronger on the day of 24 . To Malacosoma neustria testacea Motschulsky and Clostera anachoreta (Fabricius) TT3's toxicity was stronger than TTl's during the whole experiment. The toxicity of TT1 and that of TT3 to three kinds of larvae fluctuated evidently and had not distinct regularity.(3) Transgenic plantlets could postpone the development of larvae, and the effect of TT3 was stronger than that of TT1 on the total developmental stage of larvae. The delay-time of TT1 and TT3 to the larvae of each instar of Lymantria dispar (Linnaeus) fluctuated with the change of instar. But to ones of Malacosoma neustria testacea Motschulsky and Clostera anachoreta (Fabricius) the delay-time of TT3 was longer than that of TT1.(4) Transgenic plantlets could restrain the increase of larvae's weight, generally speaking, the effect of them was more evident with the extension of time. On average weight of larvae, to Lymantria dispar (Linnaeus), the difference between the effect of TT1 and that of TT3 was negligible.To Malacosoma neustria testacea Motschulsky and Clostera anachoreta (Fabricius) the restraint effect of TT3 on average weight of larvae was significantly stronger than that of TT1.On the increasing quantity and the increasing speed of larvae's weight,to the larvae of Lymantria dispar (Linnaeus) and Malacosoma neustria testacea Motschulsky the restraint effect of TT1 and TT3 was that TT3 was better early and TT1 was better late.(5) Transgenic plantlets could decrease the quantity of food taken by larvae and thequantity of frass, the effect of TT3 was stronger than that of TT1.(6) Transgenic plantlets could affect the feeding behavior of larvae and make the dead larvae produce some symptoms. Most dead larvae of Malacosoma neustria testacea Motschulsky and Clostera anachoreta (Fabricius) were dark in cuticle and had straight and swelled bodies.(7) Transgenic plantlets could reduce the weight of pupae and deformed them. The pupae of larvae which fed on transgenic plantlets were apparently smaller than that of CK .The average weight of the former was evidently under that of the latter ,too. Deformed pupae were generated from the larvae of TT3.(8) Transgenic plantlets could damage the midguts of larvae. The arrangement of midgut cells of larvae which fed on the same transgenic plantlets was becoming loose With the extension of time. The regularity of these cells was reducing.They distorted and disaggregated gradually.The content of midgut was diminishing. The whole midgut even completely distorted at last, and there was no food in the cavity of midgut. Compared TT1and TT3, the damage to the midguts of TT3 was more serious than that of TT1.