模拟不同类型酸雨胁迫对山核桃生理特征的影响

随着经济的发展，中国酸雨污染类型由硫酸型向硫酸、硝酸复合型转变，为了解转变对我国陆地植物生态系统的影响，以山核桃（Carya cathayensis）为试验对象，研究模拟硫酸型酸雨（SAR）、硝酸型酸雨（NAR）及混合型酸雨（MAR）对山核桃的生理特征影响。试验测定了山核桃在不同酸雨类型下，生长量，叶绿素含量和光合反应参数在pH值为5.6，4.0，2.5时的数据。结果表明：SAR处理下，山核桃的株高、基径在pH 5.6时高于另两个梯度，NAR处理下，生长量的大小为pH 5.6处理MAR>SAR，有显著差异，但三种酸雨类型各梯度间的叶绿素含量差异不显著；三种酸雨对山核桃的光合作用都产生抑制，净光合速率在pH 2.5处理下小于pH 56处理，对表观量子效率（AQE）、最大净光合速率（Pnmax）、光饱和点（LSP）都表现为MAR

Effect of simulated different types of acid rain on physiological characteristics in Carya cathayensis

With economic development， the type of acid rain pollution in China changed from the sulfuric acid to sulfuric acid and nitric acid complex， due to the increase of nitrogen content in the acid rain， which may lead to the change of terrestrial plant ecosystem. In this paper， Carya cathayensis was used as the experimental material to study the effect of simulated sulfuric acid rain （SAR）， nitric acid rain （NAR） and the mixed acid rain （MAR） on physiological characteristics in Carya cathayensis. In experimental design， in addition to three types of acid rain， three gradients of pH value as pH 2.5 （severe acid rain stress）， pH 4.0 （moderately acid rain stress）， pH 5.6 （acid rain control treatment） were also designed. The growth parameters， chlorophyll content and photosynthetic reaction parameters of Carya cathayensis under three pH values and three types of acid rain were experimentally determined. The experimental results showed that: under SAR， plant height， basal diameter of Carya cathayensis in pH 5.6 was higher than the other two gradients. In the NAR treatment， the growth performance showed as pH 5.6 MAR> SAR， and there are significant differences in chlorophyll content among different types of acid rain but not among different pH values in the same acid rain treatment. Three types of acid rain showed inhibitive effect on photosynthesis characteristics of Carya cathayensis， the net photosynthetic rate under pH 2.5 was less than pH 5.6. The apparent quantum efficiency （AQE）， maximum net photosynthetic rate （Pnmax）， light saturation point （LSP） was lower in MAR treatment than NAR. The results showed that NAR and MAR showed more complex influence on plant physiological characteristics of Carya cathayensis than SAR， the plant height and chlorophyll content in mixed acid rain treatment was greater than sulfuric acid rain.