模拟酸雨对水稻叶片质膜H~+-ATPase活性与矿质元素含量的影响

采用水培法研究模拟酸雨(p H=5.0、3.5、2.5)对水稻叶片质膜H+-ATPase活性与矿质元素含量的影响.结果显示:与对照(CK)相比,酸雨处理5 d(胁迫期)后,p H=5.0组质膜H+-ATPase活性与活化能、K+、Ca2+、Mg2+含量均无显著变化,仅细胞渗透势下降.p H=3.5酸雨导致细胞渗透势、K+含量下降,质膜H+-ATPase活性、H+-ATPase活化能、Ca2+含量明显上升,Mg2+含量无显著变化.p H=2.5组H+-ATPase活性、细胞渗透势和K+、Mg2+含量明显下降,H+-ATPase活化能和Ca2+含量上升,表明矿质元素含量不仅受H+-ATPase活性的调控,还与酸雨强度和离子价态有关.经5 d恢复(恢复期)后,p H=5.0组各指标均恢复到CK水平,p H=3.5组除细胞渗透势外均恢复至CK水平,p H=2.5处理组各指标虽未达到CK水平,但较胁迫期有所恢复.表明K+、Ca2+、Mg2+含量受H+-ATPase活性的调节,且恢复效果受酸雨强度影响.

Effect of simulated acid rain on plasma membrane H+-ATPase activity and mineral elements contents in rice leaves

We studied the effect of simulated acid rain on plasma membrane H⁺-ATPase activity and mineral elements contents in rice leaves by hydroponic in a greenhouse. The results showed that plasma membrane H⁺-ATPase activity and activation energy,and contents of mineral elements (K⁺,Ca²⁺ and Mg²⁺) in leaves treated with simulated acid rain at pH 5.0 had no significant difference from those of the control (p <0.05),with an exception of lower osmotic potential than that of the control (p <0.05). When rice leaves were exposed to simulated acid rain at pH 3.5,osmotic potential and the contents of K⁺ decreased whereas H⁺-ATPase activity,H⁺-ATPase activation energy and the contents of Ca²⁺ increased. However,the contents of Mg²⁺ had no significant difference from that of the control (p <0.05). When rice leaves were exposed to acid rain at pH 2.5,H⁺-ATPase activity,osmotic potential as well as contents of K⁺ and Mg²⁺ decreased whereas H⁺-ATPase activation energy and the contents of Ca²⁺ were higher than those of the control (p <0.05). The results indicated that mineral elements contents (K⁺,Ca²⁺ and Mg²⁺) were not only regulated by the activity of H⁺-ATPase,but also related with the intensity of acid rain and ion valence. During the recovery period,all parameters in leaves treated with simulated acid rain at pH 5.0 were close to the control. Similarly,all parameters in leaves treated with simulated acid rain at pH 3.5 were close to the control except osmotic potential. For pH 2.5 simulated acid rain treatment,all parameters were better than those measured during the stress period. The results showed that plasma membrane H⁺-ATPase could adjust contents of K⁺,Ca²⁺ and Mg²⁺. Moreover,the regulation effect was dependent on the intensity of acid rain.