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选择茶(Camellia sinensis)幼苗为试验材料,在盆栽条件下采用受控模拟酸雨喷淋的试验方法,设置3个酸雨梯度p H 2.5、p H 4.0和p H5.6,每个梯度下分别设计地上处理、全淋处理和土壤处理,测定其叶绿素荧光和光合特性.结果表明:在p H 2.5酸雨胁迫下,全淋处理显著减少了茶幼苗相对叶绿素含量(SPAD)合成、降低PSⅡ原初光能转化效率(Fv/Fm)、潜在活性(Fv/F0)、实际光化学量子产量(Yield)、光化学淬灭系数(qP)以及净光合速率(Pn)、气孔导度(Cond)、蒸腾速率(Tr)等光合参数,提高了胞间二氧化碳浓度(Ci)、光补偿点(LCP)和暗呼吸速率(Rd),地上处理作用下茶幼苗受到抑制作用其次,土壤处理对茶幼苗的抑制作用最小;在p H 4.0酸雨胁迫下,除光饱和点(LSP)、光补偿点和暗呼吸速率其余各处理值均高于对照组(CK),并且土壤酸雨>地上酸雨>全淋酸雨处理>CK,而p H 5.6酸雨胁迫下,各参数变化为土壤酸雨>地上酸雨>CK>全淋酸雨处理.可见,在p H 2.5酸雨胁迫下,全淋酸雨处理对幼苗的抑制作用最强;p H 4.0和p H 5.6酸雨胁迫下,土壤酸雨处理对于幼苗的促进作用最强;处理方式和酸雨强度的交互作用下Fv/Fm、Amax、AQY、LSP、LCP和Rd都具有显著差异,而SPAD、Fv/F0、Yield、qP差异不显著.得出结论为:酸雨对植物的作用机理随酸雨浓度而定,重度酸雨胁迫下,直接和间接作用都有;而中、轻度酸雨胁迫下,主要是通过土壤酸化后对植物起间接作用.
Tea (Camellia sinensis) seedlings were selected as experimental materials, and controlled by simulated acid rain shower under pot experiment, three acid rain gradients p H 2.5, p H 4.0 and p H5.6 were set up, and each gradient was designed The soil chlorophyll fluorescence and photosynthetic characteristics of the seedlings were measured under the acid rain stress of p H 2.5, and the total leaching treatment significantly reduced the relative chlorophyll content (SPAD) synthesis of tea seedlings and decreased the light energy (Fv / Fm), potential activity (Fv / F0), actual photochemical quantum yield, qP, Pn, Tr (Ci), light compensation point (LCP) and dark respiration rate (Rd) were increased. The seedling of tea plant was inhibited by above-ground treatment. Secondly, soil treatment had the least inhibitory effect on tea seedling. Under the acid rain stress of p H 4.0, all treatment values except light saturation point (LSP), light compensation point and dark respiration rate were higher than CK (CK), and soil acid rain> acid rain on the ground> acid rain> CK, However, under the acid rain stress of p H 5.6, the parameters changed to soil Rain> acid rain on the ground> CK> total leaching acid rain treatment. It can be seen that under acid rain stress of p H 2.5, total acid rain treatment had the strongest inhibitory effect on seedlings. Under acid rain stress of p H 4.0 and p H 5.6, Fv / Fm, Amax, AQY, LSP, LCP and Rd under the interaction of treatment and acid rain intensity were significantly different, while the differences of SPAD, Fv / F0, Yield and qP were not significant. The mechanism of action of acid rain on plants depends on the concentration of acid rain. Under the severe acid rain stress, both the direct and indirect effects are present. However, under moderate and light acid rain stress, the plants act indirectly through soil acidification.