In order to determine the proper salt concentration of brackish water for irrigating cotton seedlings, this study used the pot experiment to examine the effects of brackish water under different NaCl concentrations on the physiological characteristics of cotton seedlings grown on seashore saline soil. The results showed that compared with CK, the germination rate of the cotton seeds treated by brackish water with 4 g/L NaCl decreased significantly by 26.09％, but the brackish water with 2 g/L and 3 g/L NaCl did not inhibit the germination rate of cotton seeds. Compared with CK, the fresh weight, plant height, root length and dry weight of cotton seedlings treated by brackish water with 4 g/L NaCl decreased significantly by 34.08％, 27.27％, 38.26％ and 35.29％, respectively. Brackish water decreased chlorophyll contents but increased antioxidant enzyme activities, superoxide anion production rate, H2O2content and MDA contents in cotton seedling leaves. The inhibition effect of brackish water with 4 g/L NaCl were the most significant, and some growth and physiological indexes of cotton seedlings treated by brackish water with 3 g/L NaCl were also decreased significantly. Nevertheless, the inhibition effects of brackish water with 2 g/L NaCl were not significant, which is the suitable concentration of brackish water for irrigating cotton seedlings in the yellow river delta.%为找出棉花苗期微咸水灌溉的适宜浓度,明确滨海盐土区微咸水在棉花苗期代替淡水灌溉的可行性.本研究在盆栽试验条件下,研究了浇灌不同NaCl浓度的微咸水对棉花幼苗生理特性的影响.结果表明:与CK相比,NaCl浓度为4 g/L的微咸水处理显著降低了棉籽发芽率,达26.09％,而NaCl浓度为2～3 g/L的微咸水处理与对照无显著差异.与CK相比,NaCl浓度为4 g/L的微咸水处理显著降低了棉花幼苗的鲜重、株高、根长和干重,降低幅度分别为34.08％、27.27％、38.26％ 和35.29％;显著降低了棉花幼苗叶绿素含量,提高了抗氧化酶活性、可溶性蛋白含量和游离脯氨酸含量;增加了棉花幼苗超氧阴离子的产生速率、H2O2含量及丙二醛积累量.NaCl浓度为3 g/L的微咸水处理对棉花幼苗的部分生长和生理指标也具有显著的抑制作用.NaCl浓度为2 g/L的微咸水处理对棉花幼苗的生长没有显著的抑制作用,可以在黄河三角洲地区棉花幼苗期代替淡水灌溉.
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