种植密度和EDTA对短季棉活性氧代谢及铃重的影响

Effect of Plant Density and EDTA on the Metabolism of Active Oxygen and Boll Weight of Short-season Cotton

采用裂区设计，研究了种植密度和ＥＤＴＡ对短季棉活性氧代谢和铃重的影响。结果表明，随密度上升，短季棉功能叶中ＳＯＤ活性、ＭＤＡ含量分别呈显著下降和增高趋势，幼蕾、花中ＳＯＤ、ＰＯＤ活性呈下降趋势。但密度在６万～９万株·ｈｍ－２范围内，随密度增加并不会导致幼蕾、花中ＳＯＤ、ＰＯＤ活性的显著下降。ＥＤＴＡ减缓了功能叶中ＳＯＤ活性下降和脂质过氧化产物的积累，提高叶绿素和蛋白质含量，延缓叶片衰老；增强幼蕾、花中ＳＯＤ和ＰＯＤ活性，具增铃增铃重的效果。同时，密度在９万株·ｈｍ－２时，ＥＤＴＡ的增铃重效应较佳。

The experiment was conducted with the split plot design to study the effects of plant density and EDTA on the metabolism of active oxygen and boll weight of short-season cotton. The results showed that rise in MDA content was associated with reduction in SOD activity in functional leaves when plant density was increased from 60,000￣120,000 plants·hm -2 . In addition, reductions in activities of SOD and POD in squares and flowers were significant or not signficant when plant density was increased from 90,000￣120,000 plants·hm -2 or from 60,000￣90,000 plants·hm -2 , respectively. The foliar sprays of EDTA at flowering stage could significantly increase leaf chlorophyll and protein contents, delay the degradation of SOD activity, and reduce the accumulation of MDA, and thereafter, the leaf longevity was prolonged. It the meanwhile, EDTA could also promoted the activities of SOD and POD in squares and flowers, and therefore, both the total ball number and boll weight were increased significantly. Furthermore, better results were observed in plants treated with EDTA under the density of 90,000 plants·hm -2 .