低温胁迫对紫花苜蓿生理特性影响的研究

The Effect of Chilling Stress on Physiological Characters of Medicago sativa

苜蓿作为优良的牧草,研究其在低温胁迫下时的生理生化特性的变化,对以后研究苜蓿转基因,提高其抗寒性有重要意义.通过对低温胁迫下紫花苜蓿叶片SOD、脯氨酸和电导率等生理生化指标的测定,确定其抗寒生理特性,研究结果表明,在4℃冷处理12h内,叶片的SOD活性呈上升趋势,随后呈下降趋势,24h后保持稳定;脯氨酸含量随冷处理时间呈增加趋势;在高于-3℃低温胁迫时,叶片的电导率呈缓慢增加,而在低于-4℃时,由于质膜受到损伤电导率呈明显增加,表明该紫花苜蓿可以耐受-3℃的低温.

Medicago sativa is excellent forage, so it is important to study its physiological and biochemical character in the condition of cold stress for transgenetic plants and improving cold-resistance. The characteristic on M. sativa cold-resistance was ascertained by measuring indexes about superoxide dismutase(SOD), proline (Pro) and electric conductivity. The result showed that with 4℃ treatment, the activity of SOD increased early, then decreased in 12h. At last it kept stabilization after 24h; Pro content increased during chilling treatment; The electric conductivity increased slowly with chilling treatment above -3℃, but increased significantly below -4℃ due to injury of plasma membrane. It was shown that M.sativa could endure the temperature of -3℃.