叶型超补偿下棉花叶中保护酶活性的变化

研究了棉花在叶片损失后产生的超补偿现象和超补偿下棉叶中的保护酶活性的变化。在棉花盛蕾期，用剪刀剪除棉花标准叶面积的25%和50%，模拟田间害虫的食叶危害程度，结果显示：50%去叶处理可使棉花成铃数增加24.4%, 产生超补偿现象。25%去叶处理在短时间内对棉花的株高和叶中蛋白质含量都没有影响，植株株型亦无大的变化，表明25%叶面积属于生长冗余范畴。但25%去叶处理的植株叶中蛋白质含量最高点比对照推迟一周出现。50%去叶处理可增加单株棉花的冠叶面积，在处理后2周时使棉花株高减低14.5%，蛋白质含量增加7.7%，过氧化物酶活性增加14.1%。在处理后3天，不论是过氧化物酶比活力还是多酚氧化酶比活力，都是50%去叶处理的值较大。保护酶活性发生变化是棉花发生超补偿的前奏。而在处理后2周时过氧化物酶和多酚氧化酶的比活力，50%去叶处理的与对照最为接近，表明 50%去叶处理属于超补偿范畴。

Changes in the protective enzyme activities of cotton plants under overcompensation for leaf removal

The occurrence of overcompensation response of cotton plants after leaf loss and the changes in their protective enzyme system were studied. The 25% leaf removal and 50% leaf removal in standard were imposed on cotton plants respectively with scissors to simulate the process of field pest herbivory. The results showed that the 50% leaf removal could increase the yield of sound boll by 24.4% that suggested the happening of overcompensation. The 25% leaf removal had no influence on cotton plant height and protein content in leaves, suggesting the 25% leaf removal in standard falling into the category of growth redundancy, but the climax in protein content in cotton leaves postponed about one week. The 50% leaf removal could increase the total area of plant canopy, decrease cotton plant height by 14.5% in two weeks after treatment, increasing protein content by 7.7%, acquiring 14.1% higher peroxidases activity than the control (CK). Three days after 50% leaf removal treatment, both peroxidases specific activity and in polyphenoloxidases specific activity increased. At the time of two weeks after 50% leaf removal treatment, the specific activities of peroxidases and polyphenoloxidases were more similar to that of CK. All these indicated that the treatment of the 50% leaf removal in standard fell into the category of overcompensation.