The Influence Of Acid Rain Stress On Chlorophyll Fluorescence Parameters Of The4Tree Species In Zhejiang Province

The impact of acid rain on terrestrial ecosystems has become a global environmental problem，theharm of acid rain to the trees, and the trees’ adaptive mechanism are the hotpots of forestry study. Bytaking2evergreen broadleaved species Quercus glauca and Eleocarpus glabripetalu, and2economictree species Camellia sinensis and Myrica rubra seedlings as the research object, improving experimentmethods, we design3different treatments: foliar spray, entire drench and soil drench. In addition,we setsevere acid rain(pH2.5), moderate acid rain(pH4.0)and weak acidic acid rain(pH5.6)for eachtreatment,and add one blank control group as a comparison. We measured relative chlorophyll contentand chlorophyll fluorescence parameters of the4tree species, and then we carried systematical analysisand statistical test, so as to reveal the direct effect,indirect effect,comprehensive effect of acid rain toseedlings and their differences, so we can elucidate the seedlings’ response mechanism to acid rain onmorphology, physiology and nutrition, which will provide some referential theoretical basis forselecting anti-acid rain tree species,forest restoration,evaluating and preventing the damage of acid rainto forest.The results show that:(1) From the aspect of3concentration gradients of simulated acid rain, we draw the followingconclusions. In the same treatment,the leaf relative chlorophyll content (SPADR), light energytransformation efficiency of PSⅡ(Fv/Fm), activity potential of PSⅡ(Fv/F0) and actual photochemicalefficiency of PSⅡ(Yield) of the4species all came to the minimum in winter, while photochemicalquenching (qP) came to the minimum in summer, it indicated that SPAD, Fv/Fm, Fv/F0and Yield ismore sensitive to low temperature, while qP is more sensitive to hard light; The severe acid raininhibited chlorophyll content and chlorophyll fluorescence parameters(Fv/Fm, Fv/Fo, Yield and qP)ofQuercus glauca, however it promoted the parameters of Eleocarpus glabripetalu, and that the lower thepH of acid rain was, the more significant the changes were; Under moderate acid rain, SPAD, Fv/Fm,Fv/F0,Yield and qP of Camellia sinensis and Myrica rubra rised, Under heavy acid rain, the chlorophyllcontent and chlorophyll fluorescence parameters of them declined.(2) From the aspect of3treatments of simulated acid rain stress, we draw the followingconclusions. Compared with the control group, the three treatment all inhibited the chlorophyll contentand chlorophyll fluorescence parameters(Fv/Fm, Fv/Fo, Yield and qP)of Quercus glauca, however theypromoted the parameters of Eleocarpus glabripetalu, the order of the effect was entire drench＞soildrench＞foliar spray; Soil drench increased the chlorophyll content and chlorophyll fluorescenceparameters(Fv/Fm, Fv/Fo, Yield and qP)of Camellia sinensis and Myrica rubra, while entire drenchinhibited the chlorophyll content and chlorophyll fluorescence parameters; In a certain period of time,Soil drench had the greatest positive influence on the chlorophyll content and chlorophyll fluorescenceparameters of Camellia sinensis and Myrica rubra, foliar spray was the next, entire drench was the last.Over the certain time, foliar spray had the greatest positive influence, soil drench was the next, entiredrench was still the last. (3) Comparing the acids resistance of the4tree species, we can concluded: the acids resistance ofQuercus glauca was extremely weak, while the acids resistance of Eleocarpus glabripetalu was strong,the2economic species Quercus glauca and Eleocarpus glabripetalu has certain resistance to acid, it hasa damage threshold between pH4.0and pH2.5.