7种不同树种凋落叶对模拟酸雨缓冲性能的研究

Study of Buffering Capacity of Simulating Acid Rain in Seven Different Trees' Litter

采用浸提法,研究杉木、火力楠、木荷、楠木、马尾松、格氏栲和闽粤栲7种树种凋落叶对模拟酸雨的缓冲性能。结果表明:各树种凋落叶对模拟酸雨的缓冲能力中,火力楠凋落叶最强;楠木、木荷、杉木和马尾松凋落叶的缓冲能力相仿,处于中间的位置;格氏栲和闽粤栲凋落叶的缓冲能力最弱。在pH 2.7和pH3.5的模拟酸雨中,7种树种凋落叶均提高模拟酸雨溶液的pH值;在pH 5.0的模拟酸雨中,除火力楠外,其余6种树种凋落叶均未能提高模拟酸雨溶液的pH值。7种树种凋落叶在模拟酸雨作用下溶液pH值的上升幅度随着模拟酸雨酸度的增加而增加。除了pH 2.7模拟酸雨中格氏栲凋落叶盐基离子浸提总量大于木荷外,3个酸度梯度模拟酸雨盐基离子浸提总量的关系均是火力楠>闽粤栲>木荷>格氏栲>楠木>杉木>马尾松。7种树种除火力楠和木荷凋落叶外,各树种凋落叶盐基离子浸提总量均随着模拟酸雨酸度的增加而增加;各盐基离子的浸提量则随模拟酸雨酸度变化呈现出不同的变化趋势。通过综合分析得知,7种不同树种凋落叶对模拟酸雨的缓冲能力与凋落叶的pH值密切相关;盐基离子的淋溶虽然对缓冲模拟酸雨产生了重要作用,但是凋落叶对酸雨的缓冲性能是凋落叶与酸雨通过多种途径综合作用的结果。

The buffering capacity of leaf litter of Cunninghamia lanceolata, Michelia macelurei, Schima superba , Phoeba bournei , Pinus massoniana , Castanopsis kawakamii , Castanopsis fissa was studied through soaking extract method. The results were as follows： The litter of Michelia macelurei had the largest buffering capacity of simulating acid rain, buffering capacity of litter of Phoeba bournei, Schima superba, Cunninghamia lanceolata, Pinus massoniana was close to each other and the value was next to that of Michelia macelurei, the leaf litters of Castanopsis kawakamii and Castanopsis fissa had the lowest buffering capacity. When pH of simulating acid rain was 2.7 and 3.5, the pH of simulating acid rain of seven different species all improved. However,only the litter of Michelia macelurei improved the pH when pH of simulating acid rain was 5.0. As the pH values of simulating acid rain decreased, the pH of simulating acid rain with the aforesaid tree leaf litter went up. The total amount of base cations of simulating acid rain was in the order： Michelia macelurei 〉 Castanopsis fissa 〉Schima superb 〉Castanopsis kawakamii 〉 Phoeba bournei 〉Cunninghamia lanceolata 〉Pinus massoniana, except the condition that the pH of simulating acid rain was 2.7, in which the total amount of base cations of Castanopsis kawakamii ＇ s leaf litter was larger than the counterpart of Schima superba. Among the seven kinds of leaf litter, the total amount of base cations of five kinds （excluded Michelia macelurei and Schima superba） increased as pH of simulating acid rain rose. However, the amount of each kind of base cations had different trends as pH of simulating acid rain increased. The comprehensive analysis of buffering capacity of seven different trees＇ litter suggestedthat. （1）Buffering capacity was closely related to the pH of leaf litter. （2）Although base cations played an important role in buffering capacity of simulating acid rain, buffering capacity of leaf litter depended on the interplay between leaf litter and acid rain through multiple avenues.