棉花幼铃脱落过程中IAA、ABA、MDA含量及SOD、POD活性的变化

经去柱头阻止受精或去叶处理即将脱落的棉幼铃，随脱落进程加快，其内在生理变化均伴随膜脂过氧化加剧、ABA含量增加、POD活性提高，在脱落前达到最大值，而正常幼铃的变化平稳；IAA含量则逐渐减少，并明显低于正常幼铃的；SOD活性在开花后的前3天呈上升趋势，并明显高于正常铃的，以后又逐渐下降。超氧自由基（O2）的积累及其引起的膜脂过氧化伤害可能是影响幼铃内源激素平衡，导致幼铃脱落的重要原因之一。

Changes of IAA,ABA and MDA Contents and Activities of SOD and POD in the Courseof Abscission of Young Cotton Bolls

During the abscission of the young cotton bolls by removing the opposite leaf or removing stigma to prevent fertilized treatment,the content of ABA,MDA and the activity of SOD increased gradually and reached its maximum just prior to abscission of the young boll,while these indexes varied gently in the normal one(Figs.1,2B and 3C);but the content of IAA decreased gradually;which was obviously lower than the normal one(Fig.2A);SOD activity tend to rise and abviously higher than the normal one during the early 3 days after bloom,thereafter that decreased gradully(Fig.3A).Accumulation of superoxide radical and membrane-lipid peroxidation damage caused by it disturbed the balance between endogenous hormones,which was probable one of the important factors to lead the abscission of young cotton bolls.