Physiology Indexes Detection And Salt-tolerance Analysis On Transgenic (betA Gene) Plants Of Populus Simonii×P Nigra Under NaCl Stress

As a nonpoisonous osmotic regulator and biomolecular protective substance ,Betaine has an important role in plant stress tolerance physiology We transformed beta gene into genome of populus simoniiXP nigra through genetic engineering way. The betA gene coding choline dehydrogenase (CDH) which can synthesize betaine from choline in one step. In the base of previous the transgenic plants, we did this experiment. Under different salt concentration and stressed time, we determined several indexes of nine transgenic plants (T1~T9) and one control plant(TO). These indexes include that the content of betaine and proline , the activity of superoxide dismutase(SOD) and peroxidase(POD) and the salt-harm index and growth rate ,the relationship of these index were assay ed also .The results as follows:The betaine contents in transformed lines are higher than it in the control line of cuttage, and it both in the transformed and the control increased along with the promoting the content of salt solution and prolonging the treatment period.The difference of betaine contents between the transformed and the contort is remarkable and the sequence of contents from high to low in different lines as follow: T3>T9>T2>T7>T8> T4>T6>T5>T1>T0.The POD activity in transformed lines is higher than it in the control line, and the activity increased along with the promoting the contents of salt of solution and prolonging the treatment period , The sequence of average POD activities from high to low as follow :T4>T1 >T6>T5> TO.There is a positive correlation between the activity of POD and the contents of betaine in different lines, and the coefficient is 0.97.The contents of proline are increasing slowly after treatment with salt-stress . Apart from transformed line T1 with control, and T1 with T5, there have not differentiae between the other lines. In this experiment, synthesis pathways are not interfered by the transformed gene (betA) is confirmed.The activity of SOD is decreased after treatment with salt solution and dose not relate with the concentration of salt solution. Apart from Tl with control TO, there have not differentiae between the control with other transformed lines. In this experiment, the SOD activity dose not relate with the content of betaine and the transformed gene (betA) is confirmed.The salt-harm indexes of the transformed and the control lines was investigated and calculatedunder different concentrations of salt solutions. The salt-harm indexes of all lines were increasing along with the enhancing the concentration of salt solution. When the salt content up to 170mmol L-1 ,the salt-harm index is 1, which proved that it close to the high-point of salt tolerance of transformed line. The salt-harm indexes of all lines were calculated after treatment for 40 days, and the result is that, the T0 line is more sensitive to salt environment and then the T2, T4, T7, T8, T9, T1, T3, T6 and T5 later.The result, which educed from the investigation of growth rate, shows that the growth rates of transformed lines T2, T3 and T4 were not decreased, but increased in some sort. The growth rates of other transformed lines are decreased in turn.The heights of seedlings of T5, T6 and T1 were up to 2m ,and are more resistant to salt-stress than the control.The height and ground diameter of transformed lines were investigated after growth in field for 3 mouths ,and the result shows that the height and ground diameter of T1,T5,T6,T8 and T3 are greater than that of other transformed lines .The transformed lines T1, T3, T5, T6 and T8 are more suitable for forestation in salt-alkaline area than the other transformed lines and the contort ,after analysis of the physiologic index, height of seedling ,salt-harm index and growth rate of seedling under the salt-stress environment.