花铃期缺水对棉花生长发育及生理特性的影响

THE EFFECTS OF WATER DEFICIT ON THE DEVELOPMENT AND PHYSIOLOGICAL CHARACTERS OF COTTON DURING FLOWERING AND BOLL SETTING

花铃期土壤相对含水量在60％以下时,棉花主茎平均日生长量和果节出现速率比不缺水的对照降低30％以上;土壤水分低于40％时,生长基本停止。随土壤缺水程度加剧,棉叶的光合速率(Pr)、水势(ψ_1)和蒸腾强度(Tr)呈直线下降,气孔阻力(r_s)呈指数曲线型增加。此期土壤水分适宜时,棉株的Pr为22.0mg千重/dm^2·h,ψ_1在-15巴以上,Tr约9.4μg/cm^2·s,r_s约2.3s/cm;严重缺水时,Pr、ψ_1和Tr均降低50～53％,r_s增加约54％。

It was observed that the rates of main stem growth and fruiting site formation decreased by over 30% when soil relative water content (SRWC) was lower than 60% as against control plantsj growth virtually ceased when SRWC fell below 40%. There were linear decreases in the photosynthetic rate (Pr) , water potential (ψ1) ar.d transpiration rate (Tr) of cotton leaves and exponentia curve increases in stomatal resistance (rs) as soil moisture deficit increased, when soil moisture was suitable during this period, the average Pr was 22.0 mg DW/dm2. h2, ψ1 above -15 bar, Tr about 9.4 μg/cm2.s, rs about 2.3 S/cm; Pr, ψ1 and Tr all decreased by 50-53% and rs increased by about 54% under severe water deficit.