模拟酸雨对4种木本植物叶绿素荧光特性的影响

文中研究了不同pH（2.5、4.5）模拟酸雨对4种鼎湖山南亚热带森林优势树种:木荷（Schima superba）、黧蒴（Castanopsis fissa）、肖蒲桃（Acmena acuminatissima）、黄果厚壳桂（Cryptocarya concinna）叶片叶绿素荧光特性的影响，结果表明: 4种木本植物离体叶片经pH 4.5模拟酸雨处理7 d后未出现可见伤害， F_v/F_m与对照组相比无显著差异. 而在经pH 2.5 模拟酸雨处理7 d后，叶片均出现了明显的可见伤害，其中黄果厚壳桂的可见伤害程度和PSII受损程度较其他3种植物小. 经pH 2.5或pH 4.5的模拟酸雨处理后，黄果厚壳桂叶片光PSII电子传递速率（ETRII）大幅度降低，同时PSI环式电子流被激发，这可能是其提高自身抗酸能力的主动调节机制. 研究结果显示,黄果厚壳桂的抗酸雨胁迫的能力高于其他3种木本植物，酸沉降可能会提高南亚热带森林群落中黄果厚壳桂的相对优势地位.

Effect of Simulated Acid Rain on Chlorophyll Fluorescence in Leaves of Four Woody Plants

The effect of simulated acid rain pH(2.5, 4.5) on chlorophyll fluorescence was investigated with four woody plants which were collected from Dinghu Mountain (Schima superba, Castanopsis fissa, Acmena acuminatissima and Cryptocarya concinna). As the results indicated,no visible damage appearedon on detached leaves treated with pH 4.5 simulated acid rain for 7 d and their Fv/Fm did not change significantly; visible damage appeared on detached leaves treated with pH 2.5 simulated acid rain for 7 d, with the damage of Cryptocarya concinna leaves being less severe than that of the other three woody plants' leaves. The results of PSII F_v/F_m fluorescence imaging showed that PSII of Cryptocarya concinna was less severely damaged than that of the others. Meanwhile, ETRII of Cryptocarya concinna, treated with simulated acid rain of pH 2.5 and pH 4.5, was significantly reduced, and the cyclic electron flow of PSI was excited. The results indicated that Cryptocarya concinna had higher acid resistance than the other three woody plants, suggesting that the strong acid deposition might lead to the advantage of Cryptocarya concinna in the subtropical forest communities.