中文摘要：

在重度酸雨（pH 2.5）、中度酸雨（pH 4.0）和轻度酸雨（pH 5.6） 3个酸雨梯度下，研究全淋处理、土壤处理和地上处理3种酸雨胁迫方式对杨梅（Myrica rubra）幼苗叶绿素荧光参数的影响。结果表明：胁迫6个月时间内，杨梅相对叶绿素含量（SPAD）、PSⅡ原初光能转化效率（Fv/Fm）、PSⅡ潜在活性（Fv/Fo）、PSⅡ实际光化学量子产量（Yield）表现为：土壤处理〉地上处理〉全淋处理，当胁迫6个月以上，表现为地上处理〉土壤处理〉全淋处理，可见全淋处理抑制作用最强，土壤处理和地上处理具有阶段性，前期地上处理抑制作用较强，后期土壤处理抑制作用较强。重度酸雨胁迫下，各处理叶绿素荧光参数值均低于对照组，中度和轻度酸雨胁迫下除全淋处理外，则高于对照组，表现出杨梅对酸雨有较强的耐受性，一定浓度的酸雨能增加杨梅叶绿素荧光参数指标。夏季和秋季的Fv/Fm、Fv/Fo、Yield值较高，冬季和春季的值较低；土壤处理、地上处理、全淋处理的Fv/Fm和Fv/Fo存在显著差异。

英文摘要：

At three simulated acid rainfall intensities with pH values of 2.5 （severe）, 4.0 （medium） and 5.6 （light）, the responses of chlorophyll fluorescence parameters of Myrica rubra seedlings were studied in three stress ways, i.e. only the aboveground part of seedlings exposed to acid rain （T1）, both of the seedlings and soil exposed to acid rain （T2）, only the soil exposed to acid rain （T3） compared with blank control （CK）. The relative chlorophyll content （SPAD）, PS Ⅱ maximal photochemical efficiency （Fv/Fm）, PS Ⅱ potential activity （Fv/Fo）, and PS actual photochemical quantum yield （Yield） under each stress showed T3〉T1〉T2 within six months, and T1〉T3〉T2 after six months. It indicated that T2 had the strongest inhibition on seeding. T1 had the stronger inhibition at the early stage while T3 showed the stronger inhibition at the later stage. All chlorophyll fluorescence parameters in the three stress ways were lower than those in the CK group under the severe acid rainfall intensity, while T1 and T3 had higher values than the CK group under the medium and light acid rainfall intensities. It indicated that M. rubra seedlings had strong tolerance ability to acid rain. Acid rainfall at certain intensities could increase the values of chlorophyll fluorescence parameters of M. rubra. The values of Fv/Fm, Fv/Fo and Yield were higher in summer and autumn than in winter and spring. Significant differences in the values of Fv/Fm and Fv/Fo were found among T1, T2 and T3.