复水对花铃期轻度干旱胁迫棉花形态特性和产量的解除效应研究

水资源匮乏是限制棉花可持续发展的主要因素之一，明确棉花干旱后的复水灌溉量、复水时间及其对生长发育的影响解除程度，可为制定有效抗旱减灾降损措施提供科学依据。采用精准水分模拟试验，研究了花铃期不同复水程度（50%、75%、100%灌溉量）对棉花轻度干旱胁迫（土壤湿度为50%-60%）形态特性、产量的解除效应。结果表明，干旱复水后，100%和75%复水量处理棉花蕾铃干物质、地上总干物质均高于或接近对照，干物质增加量与复水程度呈正比，而50%复水量处理始终低于对照，复水对干旱的解除效应不显著。复水过程中，棉田土壤湿度和植株叶片含水率的差异变化趋势一致，复水后第4d达到最高，随后逐渐下降；复水后第19天至30天，50%复水量叶片含水率显著低于对照，土壤已发展为重旱，而75%、100%复水量叶片含水率与对照间差异不显著，土壤为无旱状态，二者配合可快速监测棉田干旱状况。复水后株蕾铃数、单铃重、棉花纤维长度均低于对照，蕾铃脱落率增加，最终产量低于对照，但75%、100%复水量产量与对照差异不显著。50%复水量无法解除轻度干旱胁迫对棉花生长发育的影响，75%、100%复水量可有效解除干旱影响，且在复水后第19d内受旱棉花处于恢复生长的旺盛期，进行干旱复水灌溉时需考虑复水程度和时间差。

Study on the Relieve Effect of Rewatering on Morphology and Yield of Cotton at Flower and Boll Stage during Mild Drought Stress

The lack of water resources is one of the main factors of limiting the sustainable development of cotton. It is necessary to clarify the amount of rewatering irrigation, rewatering time and the degree of influence on growth and development of cotton after drought. It can provide scientific basis for the effective drought relief and loss reduction measures. Using precision water simulation test, the effects of different degrees of rewatering (50%, 75%, 100% irrigation) on the mild drought stress (50% -60%) in cotton at flower and boll stage were analyzed under membrane drip irrigation. The results showed that, the cotton buds and bolls dry matter, the total dry matter above ground of cotton of 100% and 75% rewatering treatments, were significantly higher than control after drought rewatering, and the increase of dry matter was proportional to the degree of rewatering. The dry matter of 50% rewatering treatments was lower than control, and the effect of rewatering on relieving drought is not significant. In the process of rewatering, the trend of soil moisture and water content of plant leaf reached the highest in the 4d after rewatering, and then decreased. The water content of plant leaf of 50% rewatering treatment was significantly lower than the control, and the soil has developed into severe drought. There was no significance of water content of plant leaf between 100% and 75% rewatering treatment and control, and the soil was no drought. The two indexes can quickly monitor the drought condition of cotton field. After rewatering, the number of bud bells, single bell weight and cotton fiber length were lower than the control, the bud bell shedding rate increased, and the final yield was lower than the control. The difference of yield was not significant between treatments of 75% and 100% reclaimed water and the control. The treatment of 50% reclaimed water cannot relieve the effect of mild drought stress on the growth and development of cotton. The effect of mild drought stress can be discharged in the treatments of 75% and 100% reclaimed water respectively. There was a vigorous period of recovery and growth of cotton within the 19 days after rewatering. The degree and time difference of rewatering should be considered for rewatering irrigation after drought.