Establishment of the Exogenous Gene Expression System Based on Atropabelladonna Hairy Roots Establishment of the Exogenous Gene Expression System Based on Atropabelladonna Hairy Roots Exogenous Gene Expression on Transgenic Populus×euramericana cv. ‘74/76‘ Carrying Bivalent Insect-Resistant Genes Characteristics of Pollen from Transgenic Lines of Apple Carrying Exogenous CpTI Gene