【摘要】：In this study,Bt-Cry1Aa gene was transformed to Populus deltoides × P.euramericana cv'Nanlin895' using Agrobacterium-mediated method.Leaves of four transgenic clones B1,B4,B17,and B21 were exposed to the larvae of Micromelalopha troglodyta to assess the insecticidal activity of Bt poplar under laboratory and field conditions.The results showed that these clones had certain insecticidal activity.The clone B21 had a corrected mortality up to 95.3% during 12 days.The corrected mortality of these clones was between 39.0-68.8% in August and 46.5-95.3% in September under field conditions.The pupation ratio of M.troglodyta feeding on Bt poplar leaves was 4.0-53.3%,which was significantly different from the 83.8-96.0% of the control.These Bt poplars had highly inhibitory effect on the growth of M.troglodyte larvae.Their intake and weight growth was significantly lower than those of the control.The impact of Bt transgenic poplars on microorganisms in rhizosphere soil was also studied with the primary result indicating that there were no significant differences of bacteria,fungi,and actinomycete in the rhizosphere microorganisms between the transgenic poplars and the control,suggesting no negative influence on the soil microorganism system.Therefore,these results suggested that Bt transgenic clone B21 could be potentially used for poplar plantation and a germplasm for the breeding of poplar with insect-resistance.