花铃期高温胁迫对海岛棉不同部位果枝成铃质量的影响

Effect of Heat Stress on the Boll Setting Quality of Island Cotton on Different Fruiting Branches

以耐热差异明显的海岛棉品种‘新海43号’(XH43)和‘新海49号’(XH49)为材料,于盛花期在田间搭设塑料棚进行为期3d(H3)、6d(H6)和9d(H9)的增温处理,增温结束后立即恢复自然温度,以田间不搭棚的自然温度为对照(CK),研究不同天数高温处理对海岛棉净光合速率、成铃率及不同部位果枝产量和品质的影响。结果表明:(1)高温胁迫降低了XH43和XH49的产量及产量构成因素,其中H6、H9处理均达到显著水平;高温胁迫显著降低了中部果枝的铃数、单铃重、衣分和籽棉产量,但显著增加了上部果枝铃数,促进了上部果枝产量的提高。(2)高温胁迫对XH43和XH49的纤维品质无显著影响,但导致两品种中部果枝棉铃上半部平均长度、整齐度指数和断裂比强度显著降低。而高温胁迫显著提高了上部果枝棉铃的断裂比强度,其中H6、H9处理均达到显著水平,较对照分别增加2.19%~5.12%和4.48%~7.59%。(3)高温胁迫下XH49各部位产量和品质变化幅度均大于XH43,表明高温胁迫对XH49影响更为严重。(4)花铃期短期高温胁迫,导致中部果枝棉铃大量脱落及发育受阻。在生殖生长后期,H6、H9处理后的棉株净光合速率显著高于对照,增温处理增强了棉株后期光合生产能力,进而提高了上部果枝的铃数、产量和断裂比强度。

In order to study the effects of net photosynthetic rate, boll setting rate, yield and quality of island cotton on different fruiting branches under different warming days, the warming experiment on island cotton with plastic shed was conducted under the flowering period, taking two cotton varieties(XH43 and XH49)with different heat tolerances as material, and 3 different warming days treatments were designed: H3(3 days shading), H6(6 days shading), H9(9 days shading). The natural temperature in the field was used as the control(CK). The results showed that heat stress reduces the yield and yield components of XH43 and XH49. Among them, H6 and H9 treatments reached significant levels. Heat stress significantly decreased the boll number, boll weight, lint percentage and seed cotton yield of the middle fruit branch, but significantly increased the boll number of the upper fruit branch and promoted the yield of the upper fruit branch. Heat stress had no significant effect on the fiber quality of XH43 and XH49, but resulted in a significant decrease in the upper half mean length, uniformity index and breaking tenacity of the upper fruit branch. However, heat stress significantly increased the breaking tenacity of upper fruit branches, in which H6 and H9 treatments reached a significant level, which increased by 2.19%-5.12% and 4.48%-7.59%, respectively, compared with the control. The changes of yield and quality of different fruit branches of XH49 were greater than those of XH43 under heat stress. The results showed that the effect of heat stress on XH49 was more serious. Short-term heat stress will lead to a large number of bolls shedding and development hindering of cotton bolls in the middle fruit branches during the boll stage. The net photosynthetic rate of cotton treated with H6 and H9 was significantly higher than that of the control, which enhanced the photosynthetic capacity of cotton in the later stage, and then increased the boll number, yield and breaking tenacity of upper fruit branches.