艾比湖流域盐碱尘沉降对棉花叶片的危害

Harmful effect of salt dust on cotton leaves in Aibi Lake basin,Northwest China

通过野外定位监测实验,研究了艾比湖流域盐碱尘对棉花叶片光合特性、盐分含量以及叶片细胞生理功能的影响。结果表明:盐碱尘沉降对棉花叶片的盐分离子含量造成影响,导致叶片Na+、Cl-和SO42-等有害离子含量增多,K+等营养元素含量减少,影响棉花叶片营养吸收,造成叶片遭受盐分离子毒害;盐碱尘沉降显著阻塞棉花叶片气孔,影响叶片净光合速率、呼吸速率、光能利用率、水分利用率、蒸腾作用和叶片温度;盐碱尘沉降造成棉花叶片细胞丙二醛含量增加,叶绿素、类胡萝卜含量减少;棉花叶片通过增加可溶性糖、脯氨酸含量来调节细胞溶剂的损失,通过增强抗氧化系统酶的活性来清除活性氧等有害物质,减少损伤,维持正常的生理功能。

Using a field monitoring experiment, we analyzed the hazard effects of salt dust depo- sition on the photosynthetic characteristics, salt ion contents, and cell physiological functions of cotton leaves in Aibi Lake basin. The results showed that salt dust deposition led to increases in Na^＋, Cl^-, and SO4^2- contents and a decrease in K^＋ content in cotton leaves, which influenced the absorption of nutrition elements by cotton leaves and made the leaves suffering from salt ion poisoning. Salt dust deposition significantly blocked the cotton leaf stomata and affected the photosynthetic indexes such as net photosynthetic rate, respiratory rate, light use efficiency, water use efficiency, transpiration, and the temperature of cotton leaves. Moreover, the salt dust deposition significantly increased the malondialdehyde content but decreased the chlorophyll and carotenoid contents in cotton leaves. Cotton leaves adjusted the loss of cell solvent by increasing the contents of the soluble sugar and proline and by increasing the activities of enzymes in antioxidant system to remove the harmful matters such as the reactive oxygen species, thereby reducing the damage caused by salt dust deposition and maintaining normal physiological functions of leaves.