Abstract: [Objective] This paper aimed to comprehensively evaluate the adaptability of transgenic Populus×euramericana cv. ‘74/76’ with multiple genes (Abbreviation:Transgenic poplar 107) under salt stress through measurements of growth traits, membrane permeability and photosynthesis and other physiological parameters of the transgenic polar 107 under different salt stresses, as well as of the change in the accumulation amount of exogenous gene expression products.[Method] The transgenic polar 107 was used as test material, which had been verified successful transformation. The transgenic materials were propagated by tissue culture, and then the obtained seedlings were transplanted in pots when their heights were up to 10 cm. The seedlings were cultured in growth chamber and treated with NaCl solutions which concentrations were 0, 3, and 6 g·L^-1, with the nontransgenic poplar 107 served as the control (CK). The growth indexes and physiological parameters, as well as accumulation of betaine and Bt toxin proteins of two lines were measured in 25 days after treatment.[Result] The results showed that under low salt concentration treatment, the height of transgenic poplar 107 was significantly higher than that of poplar 107, and the diameter of the transgenic lines was greater than that of poplar 107. Under high salt concentration, the height and the ground diameter of the seedlings of the two lines all were significantly affected by salt stress. Under low salt concentration, membrane permeability of transgenic poplar 107 was significantly lower than that of polar 107, chlorophyll content increased more greatly, and both net photosynthetic rate and transpiration rate increased and were significantly higher than that of polar 107. The actual photosynthetic efficiency Y(Ⅱ) of photosystem Ⅱ decreased slightly, but significantly higher than that of the control, indicating that photosystem Ⅱ was able to maintain higher electron transfer rate. F_v/F_m had a relatively greater increase, suggesting increased photosynthetic capacity. Under high salt concentration, the chlorophyll content of transgenic lines decreased slightly. However, both the plasmalemma permeability and net photosynthetic rate decreased significantly, F_v/F_m and Y(Ⅱ) had a sharp decline, electron transfer rate of photosystem Ⅱ was affected greatly and photosynthetic capacity decreased. The all change trends were the same as that of control, and the seedlings of two lines suffered to a great degree salt damage. The accumulation amount of exogenous genes expression in transgenic lines, detected by ELISA, showed that with the salt concentration increasing, the contents of Cry1Ac toxin protein, Cry3A toxin protein and betaine all had an increasing trend. The accumulation of exogenous genes products significantly increased under the stress of high salt concentration.[Conclusion] Transgenic polar 107 displayed strong adaptability under low concentration salt stress, and its salt tolerance was stronger than the polar 107. Both transgenic polar 107 with multiple genes and control polar 107 were to a great degree impacted under high concentration salt stress, and transgenic line did not show any advantage. Salt stress induced an expression enhancement of the exogenous Bt gene and BADH gene, suggesting that the transgenic poplar 107 would show a good salt tolerance and insect resistance potential under salt stress.

Key words: transgenic with multiple genes, Populus×euramericana cv. ‘74/76’, salt tolerance, BADH gene, Bt gene