花铃期缺水对棉花干物质积累和用水效率的影响

Effects of Water Deficiency on Dry Matter Accumulation and Water Use Efficiency in Cotton During the Flowering and Fruiting Stages

花铃期缺水对棉花干物质积累和用水效率影响的大小,随缺水的时期早晚、时间长短和轻重程度而不同,整个花铃期缺水对其影响的程度>盛花期缺水>初花期缺水。此期缺水对棉株地上部分干物重的影响大于根系,从而根干重占总干重的比例增加。就地上部分而言,轻度缺水时茎秆干重的下降幅度>子棉干重;严重缺水时结果相反。在严重缺水条件下,虽棉株用水效率提高,但子棉产量明显降低。初花期轻度缺水,能适应控制营养生长,促时同化产物向子棉中运输,达到节约用水,使棉花产量和用水效率同步提高。

Effects of water deficiency during the flowering and fruiting stages on dry matteraccumulation(DWA)and water use efficiency(WUE)varied with the early and late pe-riod,length and degrees of water deficiency.The effects of water deficiency on themwere more severe during the whole flowering and bolling stages than during mid and lateperiod and the early flowering period.During this period,the effect of water stress ondry weight(DW)of plant parts above the ground was more severe than that of root DMthereby the percentage of root DMamong total DM increased.As far as the plant partsabove the ground are concerned,the effects of slight water eficiency on stem DM werelarger than that on seed cotton DW.The result of serious water deficiency was justopposite.Although WUE of cotton plants was increased,the yield of seed cotton obvi-Ously decreased under severe water stress.Slight water deficiency during the early periodcould properly control vegetalion growth and promote transportation of assimilationproducts into seed cotton so as to achieve water-saving use and raise cotton yield andWUE synchronously.