Abstract:

In order to investigate the effects of exogenous SacB gene & BADH gene on Lespedeza formosa under drought stress, potted plants of ordinary and transgenic L. formosa were used as materials. All plants were cultured under the same conditions and then were treated with drought stress. The tolerance to drought was compared among the 3 types of plant materials (two transgenic and one ordinary). Proline, betaine, soluble sugar, superoxide dismutase (SOD), malonalohyde (MDA) and chlorophyll were measured when the 3 types of plant materials were subjected to drought stress. The results showed that there were no any significant differences in the aforementioned indexes among the 3 material types of plants before drought stress. With the decrease of soil relative water content, the transgenic plants accumulated higher levels of proline and soluble sugar than non-genetically modified control plants. The BADH-transgenic plants accumulated higher level of betaine than SacB-transgenic and control plants. There was no significant difference in SOD activity among 3 material types although they showed higher SOD activity with the increased severity of water deficit. The levels of MDA in plants expressing SacB gene or BADH gene were lower than non-genetically modified plants under drought condition. The levels of chlorophyll in transgenic plants were higher than non-genetically modified plants under water deficit condition. Response of the field plants to natural drought stress further validated that the transgenic L. formosa had higher tolerance to drought stress than non-genetically modified plants.

Key words: Lespedeza formosa, transgenic plants, drought stress, physiological indexes