盐分条件下棉花相关生理特性的变化及水分胁迫指数模型的构建

Changes of Related Physiological Characteristics of Cotton Under Salinity Condition and the Construction of the Cotton Water Stress Index

【目的】构建盐土棉田棉花水分胁迫指数模型,以确定适宜的棉花水分运筹方式,为提高盐碱地棉花产量和品质提供理论依据。【方法】试验于2008—2009年在江苏南京(118°50′E,32°02′N)南京农业大学牌楼试验站进行,以耐盐品种中棉所44和盐敏感性品种苏棉12号为材料,将碳酸钠、重碳酸钠、氯化钠、氯化钙、氯化镁、硫酸镁、硫酸钠7种盐类等摩尔混合,按盐土比掺入基础土壤中,形成5种不同含盐水平的土壤(0:1.25dS·m-1;0.35%:5.80 dS·m-1;0.60%:9.61 dS·m-1;0.85%:13.23 dS·m-1;1.00%:14.65 dS·m-1),研究土壤盐分对棉花功能叶含水量和温度的影响,明确棉花叶气温差与空气饱和气压差的定量关系。【结果】随土壤盐分水平的升高,棉花功能叶的蒸腾速率、含水量和净光合速率均下降,叶片温度升高。以1.25 dS·m-1盐分处理作为充分灌水(即无水分胁迫)建立了棉花水分胁迫指数模型下基线方程,以此构建了不同土壤盐分下棉花水分胁迫指数模型。【结论】综合分析不同土壤盐分水平下棉花水分胁迫指数与叶片含水量和净光合速率的关系,认为棉花水分胁迫指数模型可以很好地反映盐分条件下棉花的受胁迫程度。用棉花CWSI实时监测盐分条件下棉花的水分胁迫状况,可为盐碱地确定适宜的棉花水分运筹提供理论依据。

[ Objective ] To construct the cotton water stress index （CWSI） and determine the suitable water logistics approach, in order to provide theoretical basis for improving cotton yield and quality under salinity field. [Method] The two-year experiments were conducted with Sumian 12 （salinity-sensitivity） and CCRI-44 （salinity-tolerance） at Pailou experimental station of Nanjing Agricultural University. Seven kinds of salts （NaCl, Na2CO3, NaHCO3, CaCl2, MgCl2, MgSO4, and Na2SO4）, were mixed into natural dried, sieved soils at an even molar ratio, forming soils with five levels of salinity, namely, CK （1.25 dS＇m^-1）, 0.35% （5.80 dS-m^-1）, 0.60% （ 9.61 dS.m-1）, 0.85% （13.23 dS.m-1）, and 1.00% （14.65 dS.m-1）, respectively. The effects of soil salinity rates on the water contents and temperature of cotton functional leaves were studied and quantitative relationships between leaf-air temperature difference and vapor pressure difference was determined. [ Result ] As the soil salinity rates increasing, the transpiration rate, water content and net photosynthetic rate of functional cotton leaves decreased and the leaf temperature increased. The lower equation of the cotton water stress index was set up in 1.25 dS.m1 salinity rate （well watered）, and the cotton water stress index based on theabove lower equation under different salinity rates was constructed. [ Conclusion ] Comprehensive analysis the relationship between cotton water stress index and leaf water content and net photosynthetic rate under different soil salinity rates, and found that the cotton water stress index is a good indicator to detect cotton water stress in salinity field. So, it could be applied to monitor cotton water stress using cotton water stress index, in order to provide theoretical basis for determine suitable water logistics approach under salinity field.