Percy K E, Baker E A
Department of Agricultural Sciences, University of Bristol, AFRC Institute of Arable Crops Research, Long Ashton Research Station, Bristol, BS18 9AF, UK.
New Phytol. 1988 Jan;108(1):75-82. doi: 10.1111/j.1469-8137.1988.tb00206.x.
Leaves of Phaseolus vulgaris L., Vicia faba L., Pisum sativum L. and Brassica napus L. were exposed from emergence to full expansion to seven treatments of simulated acid rain at pH values between 5.6 and 2.6. Droplet leaf contact angles in all species decreased on leaves exposed to simulated acid rain at pH <4.6 relative to those exposed at pH 5.6. Retention of rain containing fluorescein increased on P. vulgaris leaves exposed to simulated acid rain at pH 4.6 and at pH < 3.8. Retention by B. napus leaves was increased at pH < 4.6. Uptake of the three ions studied was in the order Rb ≤ SO ≤ Ni . Uptake of Rb increased into B. napus leaves and decreased into P. vulgaris leaves exposed at pH ≤ 3.4. Uptake of SO and Ni by B. napus leaves increased after exposure to simulated acid ruin at pH 2.6 but it was unaffected in P. vulgaris. Up to 7%, of applied SO , was found in the epicuticular wax layer on B. napus leaves 48 h after application, most being found after exposure at pH 2.6. The order of lateral movement of ions within leaves paralleled the order of uptake. Movement of all three ions was increased in B. napus leaves exposed previously to simulated acid rain at pH 2.6. The increased retention of fluorescein on leaves exposed to simulated acid rain and the reduced contact angles for water are attributed to decreases in surface roughness. The altered ion uptake pattern could also be related to changes in surface wax structure or could be associated with observed changes in properties of cuticular membranes. These results demonstrate that the interaction of plants with their atmospheric environment could possibly be affected by pre-exposure to acid rain in amounts and at pH values that occur in ambient rainfall.
菜豆、蚕豆、豌豆和甘蓝型油菜的叶片从出土到完全展开期间，接受了pH值介于5.6至2.6之间的七种模拟酸雨处理。相对于pH值为5.6时暴露的叶片，所有物种中，pH值<4.6的模拟酸雨处理下叶片上的液滴叶接触角均减小。在pH值为4.6和<3.8的模拟酸雨处理下，菜豆叶片上含荧光素雨水的滞留量增加。甘蓝型油菜叶片在pH值<4.6时滞留量增加。所研究的三种离子的吸收顺序为铷≤硫酸根≤镍。在pH值≤3.4时暴露的甘蓝型油菜叶片中铷的吸收增加，而菜豆叶片中铷的吸收减少。甘蓝型油菜叶片在pH值为2.6的模拟酸雨处理后，硫酸根和镍的吸收增加，但菜豆不受影响。施用于甘蓝型油菜叶片的硫酸根中，高达7%在施用48小时后出现在表皮蜡层中，大部分是在pH值为2.6的处理后发现的。离子在叶片内横向移动的顺序与吸收顺序一致。在先前pH值为2.6的模拟酸雨处理下的甘蓝型油菜叶片中，所有三种离子的移动均增加。暴露于模拟酸雨的叶片上荧光素滞留量的增加以及水接触角的减小归因于表面粗糙度的降低。离子吸收模式的改变也可能与表面蜡结构的变化有关，或者可能与角质膜性质的观察变化有关。这些结果表明，植物与大气环境的相互作用可能会受到环境降雨中出现的酸雨数量和pH值的预先暴露的影响。
