剪穗处理下小麦叶片逆向衰老的生理表现

研究剪3/4穗处理下，小麦功能叶片叶绿素和可溶性糖含量、过氧化氢酶（CAT）活性和丙二醛（MDA）质量摩尔浓度变化，揭示小麦叶片逆向衰老的生理表现。结果表明，小麦品种随剪穗处理时间的延长，旗叶叶绿素含量和CAT活性均低于倒二叶，而MDA质量摩尔浓度变化高于倒二叶，与各自对照相比，倒二叶与倒三叶的叶绿素含量及CAT活性在灌浆后期都保持较高水平，旗叶则降速较快。另外，剪穗处理导致小麦功能叶片可溶性糖大量积累。出现旗叶衰老早于倒二叶的现象。说明剪穗处理下，叶片同化物的过度积累可能是导致小麦叶片逆向衰老的主要原因。

Physiological Performance of Leaf-inverted Senescence in Ear-partial-removed Wheat

The treatment of 3/4 ear removal from the topmost portion of each ear at the flowering stage caused leaf-color inversion of functional leaves(top 3 leaves ) of wheat. The physiological performance of leaf-color inversion of functional leaves of wheat under ear removal treatment were explored by measuring the chlorophyll content, soluble sugar content, catalase (CAT) activity and molality of solute of malonaldehyde MDA. The results showed that the chlorophyll content and CAT activity of flag leaf were lower than those of top 2nd leaf with the time extension of ear removal. However, the molality of solute of MDA was higher than that of top 2nd leaf with the time extension of ear removal. Compared with the respective control, the chlorophyll content and CAT activity of top 2nd leaf and top 3nd leaf maintained higher level in the late of grain filling stage. However, the chlorophyll content and CAT activity of flag leaf decreased rapidly. In addition, the ear removal treatment leaded to the excessive accumulation of soluble sugar in wheat functional leaves. The experiments demonstrated that removal of 3/4 ear accelerated the senescence of flag leaf, and at the same time delayed the senescence of the 2nd leaf from the top. Thus, the earlier senescence of the flag leaf of 3/4 ear removal might be related to the excessive accumulation of assimilates.