Abstract:

betA is a gene encoding choline dehydrogenase. In the previous work, 13 betA transgenic Populus simonii×P.nigra plants were obtained. In this experiment, 9 transgenic plants were chosen for salt tolerance test. Transgenic and untransformed control plants were treated with 0, 100, 140, 170, and 200 mmol·L^-1 NaCl for different period of time. After these plants were treated for 2, 7, 12, 17 and 22 days, the betaine content of transgenic plants and untransformed control plants were determined, respectively. After the transgenic and untransformed control plants were treated with salt for 60 days, plant height and index of salt damage were determined. The results of ANOVA and multiple comparisons showed that the betaine content between transgenic and untransformed control plants was statistically different. The betaine content in transgenic plants was 27.1% higher than that in untransformed control plants. The index of salt damage in transgenic plants was 15.8% lower than that in untransformed control plants. And the plant height of transgenic plants was 44.1% higher than that of untransformed control plants. Based on the growth rate and the salt tolerance, T1, T4, T5 and T6 transgenic lines were identified as plants with high salt tolerance and fast growth.

Key words: Populus simonii×, P. nigra, transgenic plant, betA, betaine, salt tolerance