Effect of Different LED Light Qualities on Bt Toxic Protein Content and Chlorophyll Fluorescence of Transgenic Poplar Leaves Insect Resistance Selectivity of Transgenic Hybrid Poplar 741 Life Table of Population of Target Insect in the Stands of Transgenic Hybrid Poplar 741 SELECTION AND INSECT RESISTANCE OF TRANSGENIC HYBRID POPLAR 741 CARRYING TWO INSECT-RESISTANT GENES Influence of temperature on insect-resistance of transgenic hybrid poplar 741. Researches on the insect-resistant effect of transgenic hybrid poplar 741 with two insect-resistant genes