白玉兰光合生理特性对锑矿区土壤复合重金属胁迫的响应

Response of Photosynthetic Physiological Characteristics of Magnolia denudata to Soil Stress Polluted by Compound Heavy Metals in Antimony Mine Area

为了解锑矿区土壤复合重金属污染对白玉兰光合生理特性的影响,分重度污染、轻度污染和无污染土壤栽培白玉兰苗木进行盆栽试验,并采用LI-6400光合测定系统对重金属胁迫处理的白玉兰进行了光合生理特性日变化研究。结果表明:在白玉兰盆栽试验中,联盟和对照的Pn日变化呈"单峰型"曲线,峰值都出现在12:30左右,长龙界的Pn日变化无规律,3个处理的光合能力为联盟>对照>长龙界,重金属胁迫对植物的光合有抑制作用。Gs与Tr在日变化过程中具有显著性正相关(联盟0.981**,长龙界0.829*,对照0.87*),Tr在很大程度上决定于气孔的活动状态。白玉兰光合速率控制因子为非气孔限制。重金属污染越严重,白玉兰对环境条件的适应能力越弱(对照>联盟>长龙界)。

With pot experiments, which were treated with heavily pollution, slightly one polluted by compound heavy metals and non-pollution one （CK）, and using Li-6400 portable photosynthesis system, the diurnal variation of photosynthesis of Magnolia denudate seedlings was studied to explore the effect of soil stress polluted by compound heavy metals on photosynthetic physiological characteristics in antimony mine area. The results were as following： The diurnal variation of net photosynthetic rate （Pn）of Lianmeng and CK presented a single-peak curve, and the maximum value occurred at about 12：30, While the diurnal variation of Pn of Changlongjie showed irregular. The order of photosynthetic capacity of three treatments was Lianmeng 〉 Duizhao〉 Changlongjie, heavy metals stress had an inhibitory effect on photosynthesis of plant; There was a significant positive correlation between stomatal conductance（Cs） and transpiration rate （Tr） during the diurnal variation（Lianmeng 0.981＊＊,Changlongjie 0.829＊, Duizhao 0.87＊）. The transpiration rate （Tr） was determined by the status of stomatal activity to a great extent. So the controlling factor of photosynthetic rate was non-stomatal limitation. It was also found that the heavier the metal pollution the weaker is the ability of Magnolia denudate to adapt to environmental conditions （Duizhao 〉Lianmeng〉 Changlongjie）.