不同氮素水平对棉花不同部位—铃叶系统生理特性及铃重空间分布的影响

Physiological Characteristics of Boll-Leaf System and Boll Weight Space Distributing of Cotton Under Different Nitrogen Levels

【目的】研究氮素营养对棉株主要源库关系的调节作用。【方法】以转基因抗虫杂交棉中棉所29(CCRI29)为材料,在田间进行不同氮肥水平(高氮:225.0kg·ha-1;中氮:112.5kg·ha-1;低氮:0kg·ha-1)试验,较为系统地研究了CCRI29中、下部铃-叶系统生理特性及铃重的空间分布。【结果】(1)与中氮、低氮相比,高氮促进了中部果枝叶生长后期叶绿素的合成,延长了叶片功能期。(2)氮肥水平对棉花器官中碳水化合物代谢有重要影响,低氮促进了果枝叶中碳水化合物的积累,中氮水平下碳水化合物代谢较为协调。(3)施入氮肥可以增加POD、SOD酶活性。不同部位棉铃对位叶的SOD、POD酶活性变化趋势一致,下部棉铃对位叶中各处理间比较为:中氮>高氮>低氮,而中部棉铃对位叶各处理间顺序为高氮>中氮>低氮。【结论】不同氮肥水平对棉花的生长发育有一定调节效应。中氮水平可以改善棉花的早衰现象,源库关系较为协调,从而促进了铃重的增加。

[ Objective ] The experiment was conducted in order to study the rules of Nitrogen on the cotton＂ source and sink＂ system. [Method] Using Bt-transgenic hybrid cotton variety CCRI29 as material, we studied the effects by applying different level of nitrogen fertilizer （225.0 kg-hal, high; 112.5 kg·ha^-1, medium; 0 kg·ha^-1, low） in the field in the years of 2002-2003. The plant density employed was about 53 336 per hectare. [Result] （1） Compared to mid-nitrogen and low-nitrogen, high-nitrogen promoted chlorophyll accumulating in leaf growth anaphase on fruit branch, which extended the leaf function period. The dissoluble protein content of leaf was the lowest under the treatment of low-nitrogen, and the chlorophyll content decreased rapidly in leaf growth anaphase, which accelerated the leaf＇s senescence. （2） Different nitrogen levels affected the carbohydrate metabolism in various organs of cotton plants. The carbohydrate synthesis was inhibited under high-nitrogen levels, but low-nitrogen level promoted carbohydrate accumulation in leaf on reproductive branch. Different nitrogen levels had no significant effect on carbohydrate concentration in seed cotton. （3） Nitrogen can enhance activity of SOD and POD to some extent. The order of their activity of leaf on the lower branch was mid-nitrogen〉high-nitrogen〉low-nitrogen, but the order of leaf activity on the middle branch was high-nitrogen〉mid-nitrogen〉 low-nitrogen. [ Conclusion ] Changed nitrogen application amount had some effects on cotton growth and development. The premature senescence in cotton would be improved under middle nitrogen condition.