中文摘要：

【目的】分析不同pH值及处理方式的酸雨对秃瓣杜英幼苗的生物量和生理指标的影响,为酸雨胁迫下秃瓣杜英幼苗的响应机制提供科学依据。【方法】采用盆栽受控试验,设置2个酸雨梯度（pH2.5和pH5.6）、3种酸雨处理方式（地上处理：仅对幼苗地上部分进行酸雨喷淋,酸雨不进入土壤;地下处理：仅对幼苗土壤进行酸雨喷淋,地上部分不接触酸雨;全淋处理：酸雨喷淋全株后进入土壤）以及p H7.0蒸馏水为对照处理,测定幼苗生物量积累和叶、茎、根生物量分配,叶绿素含量和叶绿素荧光特性,丙二醛含量和膜透性,以及抗氧化酶活性等指标。【结果】1）在pH2.5酸雨浓度梯度下,3种处理方式对秃瓣杜英幼苗生长均有不同程度的抑制作用,差异显著,与对照相比,地上处理的总生物量、株高增长量、地径增长量分别降低了16.7%,28.1%和25.7%,地下处理分别降低了10.9%,4.7%和17.5%,全淋处理分别降低了18.5%,5.2%和27.5%;同时,地下处理提高了幼苗叶片生物量占总生物量的比例,降低了茎和根生物量的比例;3种处理的叶绿素a含量、总叶绿素含量、叶绿素a/b均显著低于对照;地上处理的PSⅡ原初光能转化效率（Fv/Fm）和PSⅡ潜在活性（Fv/ Fo）显著低于对照,全淋处理的Fv/ Fo和PSⅡ实际光化学效率（ΦP（SⅡ））显著低于对照,而地下处理的Fv/Fm,Fv/ Fo和ΦP（SⅡ）值与对照没有显著差异;3种处理的膜透性、丙二醛含量和抗氧化酶活性均显著高于对照,其中地下处理高于其他2种酸雨处理。2）在p H5.6的酸雨浓度作用下,与对照相比,3种处理对秃瓣杜英幼苗生物量没有显著影响,而叶绿素a含量、总叶绿素含量和叶绿素a/b均显著降低,膜透性、丙二醛含量、过氧化物酶活性和过氧化氢酶活性均显著增加,但低于pH2.5酸雨浓度的影响;地上和全淋处理的Fv/ Fo和ΦP（SⅡ）值显著降低。【结论】地下酸雨处?

英文摘要：

【Objective 】Comparisons of direct,indirect and composition effects of acid rain treatments on biomass allocation and physiological characteristics in Elaeocarpus glabripetalus seedlings were carried out in order to provide a scientific basis to study the mechanism of E. glabripetalus seedlings responding to simulated acid rain. 【Method】Potted plants were used to establish the experiment,treatments included 2 different p H values of acid rain（ pH2. 5 and p H5. 6）and 4 different models of exposure to acid rain,including 1） aboveground exposure： only the aboveground of seedlings were exposed to acid rain; 2） soil exposure： only the soil around seedlings was exposed to acid rain; 3） whole exposure：the seedlings and soil were both exposed to acid rain; 4） Control： exposed to distilled water with pH7. 0. Biomass accumulation and allocation,chlorophyll content and chlorophyll fluorescence characteristics,malondialdehyde（ MDA）content and membrane permeability,the activity of antioxidant enzymes were measured. 【Result 】1） The growth ofseedlings were inhabited to different extents when exposed to acid rain at pH2. 5 level,and significant differences were found among the 3 models of exposure to acid rain. Compared with the control,total biomass,height increment,diameter increment of seedlings for the model of aboveground exposure decreased by 16. 7%,28. 1% and 25. 7% respectively;those of soil exposure decreased by 10. 9%,4. 7% and 17. 5% respectively; those of whole exposure decreased by 18. 5%,5. 2% and 27. 5% respectively. For the underground exposure,the ratio of leaf biomass to total biomass increased,and those of stem and root biomass decreased. The chlorophyll a（ Chla） content,total chlorophyll（ total Chl）content,chlorophyll a / b（ Chla / b） were significantly lower than those of the control. For the aboveground exposure,primary photochemical efficiency of PS Ⅱ（ Fv/ Fm） and potential activity of PSⅡ（ Fv/ Fo） were significantly lower than those for the cont