模拟酸雨对耐冬山茶生理生态学特征的影响

Effects of Simulated Acid Rain on the Ecophysiological characteristics of Camellia japonica(NaiDong)

以野生耐冬山茶[Camellia japonica(NaiDong)]一年生幼苗为研究对象开展温室控制试验,试验设置3个模拟酸雨酸度(pH5.6、pH4.0和pH3.0)以及3个模拟酸沉降添加频率(6 d一次为高添加频率、12 d一次为中添加频率、18 d一次为低添加频率),测定了耐冬山茶幼苗的生长指标、生物量指标、叶形态特征、气体交换参数和叶绿素含量,以探究不同酸沉降条件下耐冬山茶幼苗的生理生态响应。结果表明:随着模拟酸雨pH的降低,净光合速率及气孔限制值降低,比叶面积及细胞间隙CO_(2)浓度呈增加趋势。冠面积和比叶面积随着模拟酸雨添加频率的增加,呈现先上升后下降的趋势,在中添加频率处理下达到最大值。总叶绿素含量受到模拟酸雨pH和添加频率交互作用的影响,在高频添加处理下,总叶绿素含量随着模拟酸雨pH的降低而升高。耐冬山茶对短期模拟酸雨胁迫具有较强抗性与忍耐力,其总生物量未受模拟酸雨酸度、添加频率及二者交互作用的影响。

In this study,wild Camellia japonica(NaiDong)seedlings were selected as the research object in a greenhouse control experiment.Three simulated acid rain acidities(pH5.6,pH4.0 and pH3.0)and three simulated acid precipitation adding frequencies high adding frequency(every six days),moderate adding frequency(every twelve days)and low adding frequency(every eighteen days)were set up.The growth parameters,biomass,leaf morphological characteristics,gas exchange parameters and chlorophyll content of C.japonica(NaiDong)seedlings were measured to explore the physiological and ecological responses of C.japonica(NaiDong)seedlings to different simulated acid deposition patterns.The results showed that with the decrease of pH,the net photosynthetic rate and stomatal limitation of C.japonica(NaiDong)seedlings decreased whereas the specific leaf area and intercellular carbon dioxide concentration increased.The crown area and specific leaf area of C.japonica(NaiDong)seedlings increased and then decreased with the increase of addition frequency,reaching their maximum values at moderate addition frequency.The total chlorophyll content of C.japonica(NaiDong)seedlings was affected by the interaction between acidity and addition frequency.Under high addition frequency condition,the total chlorophyll content increased with the decrease of pH.In summary the Camellia japonica(NaiDong)generally possesses relatively strong resistance and tolerance to short term simulated acid rain,maintaining its biomass unchanged under different simulated acid precipitation adding frequencies and simulated acid rain acidities.