棉花源库比对中、下部果枝叶生理活性及铃重的影响

以转基因抗虫杂交棉中棉所29(CCRI29)为材料，通过去叶和去蕾处理，研究改变源库比对大田棉花中、下部果枝叶生理活性的影响。结果表明：减库处理可以提高中、下部果枝叶片中蛋白质的含量，促进后期果枝叶中叶绿素的合成，延长叶片功能期。减源处理促进中、下部果枝叶生长前期果枝叶中叶绿素含量，表现出暂时性的超补偿效应，但是在果枝叶生长后期，叶绿素含量快速下降；并且减源处理不利于叶片中蛋白质的合成。提高源/库比、降低源/库比均降低了中、下部果枝叶中SOD和POD活性，对MDA含量的影响为：减源＞CK＞减库。源库比例的改变影响叶片的寿命和功能，改变棉花源库比，打破了源库平衡，其叶片的生理活性也会发生相应变化。受源器官生理特性变化的影响，不同处理单铃重差异较大，表现为：减库＞CK＞减源。

Effects of Source/Sink Ratio on Boll Weight and Physiological Activities of Leaves at Middle and Lower Fruiting Branches in Cotton

Cotton is one of important cash crops, but so far, few studies on the boll and leaf system at the same node position in cotton were reported. In this study, the effects of source/sink ratio on growth and development and physiological characteristics in cotton were evaluated using CCRI29, a BT-transgenic hybrid cotton cultivar. Three treatments were designed in the experiment: picking off buds on the fruit branch at 8 d after anthesis for leaving two or three leaves to support one boll (PB), picking off some leaves on the fruit branch at 8 d after anthesis for leaving one leaf to support two bolls (PL), and normal training managements (CK). The results indicated that in PB treatment, the content of soluble protein increased and the chlorophyll content in the later growth stage boosted in middle and lower fruit branch leaves, prolonging the function period of the leaves. In PL treatment, the chlorophyll content of leaves was promoted in the earlier growth stage, and decreased sharply in the later growth stage, and the soluble protein content of leaves was the lowest among the three treatments, suggesting that there was a temporarily physiological compensation effect in fruit branch leaves, but the leaf senescence was accelerated by cutting leaves at late growth stage. Altered the ratio of source/sink also affected the SOD and POD activities and MDA content in fruit branch leaves, showing a tendency that both increasing and decreasing source/sink ratio could reduce the activities of SOD and POD. The MDA content of leaf under different treatments was ranked as PL>CK>PB. The results of statistic analysis indicated that there were a significant, positive correlation between SOD activity and POD activity ( r = 0.845**, P < 0.01) in CK treatment, but no correlation between SOD and POD activities after changing the source/sink ratio, indicating that the ratio of source/sink affected the physiological characteristics and function period of fruit branch leaves in cotton. As a result of changing source/sink ratio, the ringle boll weigh was PB>CK>PL.