新疆滴灌棉花花铃期干旱复水对叶片光合特性及产量的影响

Effects of Rewatering after Drought Stress on Photosynthesis and Yield during Flowering and Boll-Setting Stage of Cotton Under-Mulch-Drip Irrigation in Xinjiang

在新疆气候生态条件下，采用膜下滴灌植棉技术，控制花铃期0-60cm土壤滴水下限分别为田间持水量的45％（中度干旱）、60％（轻度干旱）和75％（正常供水，对照），滴水上限均为田间持水量，研究不同程度干旱复水对棉花叶片光合特性及产量形成的影响。结果表明，干旱降低了叶片净光合速率（Pn）和气孔导度（Gs），中度干旱下叶片光化学猝灭系数（qp）、PSⅡ电子传递量子产量（φpsⅡ）降低，非光化学猝灭系数（NPQ）升高。复水后3d内Pn和Gs恢复，以轻度干旱恢复最快；φpsⅡ和qP与Pn的变化相似：NPQ复水后1-2d显著降低。从初花期至盛铃前期，轻度干旱复水后光合物质累积量与对照无明显差异，盛铃后期至吐絮期低于对照，籽棉产量较低；中度干旱复水后光合物质累积量及籽棉产量均最低。

In order to develop water saving irrigation stratagem and increase cotton yield in Xinjiang, we did the irrigation experiment in the field, controlled the lower limit of soil relative moisture content in layer of 0-60 cm at 45%, 60%, and 75% （the control） respectively of field water-holding capacity, which was the upper irrigation limit, and studied the effects of rewatering after drought on photosynthesis and yield during flowering-boll stage of cotton under-mulch-drip irrigation. The result showed that drought reduced the parameters of gas exchange. Photochemical quenching coefficient （qp） and PS Ⅱ photochemical quantum yield （φpsⅡ） were reduced but non-photochemical quenching coefficient （NPQ） was increased significantly under moderate drought. Net photosynthetic rate （Pn） and stomatal conductance （Gs） of three water treatments could be rapidly recovered within three days after rewatering, and the recovery of mild drought treatment was the most rapid. The recovery of φpsⅡ and qp in three water treatments was similar to that of Pn which achieved the maximum in 2-3 days after rewatering. The NPQ of three water treatments decreased significantly in 1-2 days after rewatering. From early flowering stage to early full boll stage, accumulation of single plant photosynthate was not much different from that of mild drought treatment after rewatering and the control, but the accumulation of single plant photosynthate was decreased significantly from later full boll stage to boll opening stage that let the seed cotton yield in mild drought treatment after rewatering be lower than that in control. Accumulation of single plant photosyn-thate and seed cotton yield in moderate drought treatment after rewatering was always lower than that in mild drought treatment and control.