Abstract:

【Objective】 The objective of this experiment is to study the effect of simulated acid rain at different pH levels on the physiological and ecological characters of camellia. 【Method】 With pot experiments,this paper studied the effect of simulated acid rain that included 4 different pH values (2.0, 3.0, 4.0, 5.6) on the membrane damage and antioxidant enzyme activity, chlorophyll (Chl) content, and gas exchange parameters of camellia (Camellia sasanqua) seedlings leaves. 【Result】 The results showed that under simulated acid rain of different values stress, the membrane permeability and malondialdehyde (MDA) content of camellia leaves gradually increased, and there was a significant correlation between them. The dismutase (SOD), catalase (CAT) and peroxidase (POD) activities were showed a single-peak curve which was firstly increased and then decreased, and the maximum of SOD and CAT appeared at the pH4.0 point and POD at the pH 3.0. Chl content a gradually decreased with decreasing pH value, and then increased significantly at pH 2.0. The net photosynthetic (Pn), intercellular CO2 concentration (Ci), stomatal conductance (Gs), and transpiration rate (Tr) all showed a trend of increase first and then decrease. The stomatal limitation value (Ls) showed an trend of gradual increase. 【Conclusion】 Results show that camellia has strong resistance to acid rain, pH 3.0 can be used as an invisible critical point of acid rain damage to its leaves. Therefore, camellia can be considered as one of the landscaping and vegetation constructing plants in the acid rain-hit area.

Key words: simulated acid rain, Camellia sasanqua, resistance, antioxidant enzymes, physiology and ecology