棉花的缺水伤害和抗伤害机理

On the Mechanism of Cotton Plant Damaged by Water Deficit and Its Resistance

水分亏缺可以在棉花的器官、组织、细胞、细胞器和分子水平上造成伤害，名括气孔和非气孔限制等引起的光合降低，活性氧代谢失调造成的膜伤害和由此引起的呼吸异常、Ｎ代谢紊乱、激素平衡破坏等，在器官水平上表现出生育不良和减产。但棉株体内存在完整的抗缺水伤害系统，主要表现在缺水时通过可溶性糖和脯氨酸积累调节渗透压和保护大分子物质，通过结合态ＩＡＡ转化为游离ＩＡＡ，稳定游离ＩＡＡ的水平，通过保护酶系的协同作用稳定膜系统等。

Water deficit could cause damages to cotton in organ, tissue, cell, sub-cell and molecule levels. Stomatal and non-stomatal factors result in reduction of photosynthesis. Oxygen activation damages cell membrane, which results in abnormal respiration, N metabolic disorder and disorder of hormonal balance, of the final results being bad growth and yield decrease of cotton. However, there exists a complete resistant system to water deficit in cotton plant, such as accumulation of sugar and proline for regulating osmotic po- tet.tial. and maintenance of the stability of free IAA and membrane by the transformation of conjugated IAA into free IAA and coordinated action of enzymes respectively.