汞胁迫对白骨壤(Avicennia marina)幼苗生理生态的影响  

Impacts of mercury stress on Avicennia marina seedlings eco-physiology

作　　者：袁彦婷[1] 丁振华[1] 张玲[1] 

机构地区：[1]厦门大学生命科学学院,福建厦门361005

出　　处：《生态学杂志》2011年第5期1013-1017,共5页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(40676064)资助

摘　　要：为了解红树植物的重金属抗性机制,对白骨壤(Avicennia marina)幼苗进行不同浓度Hg2+(1、5、10、50、100 mg.L-1)的胁迫实验,测定并分析了Hg2+胁迫对白骨壤幼苗叶片的光合作用和抗氧化酶活性的影响。结果表明:叶片净光合速率随着胁迫时间的延长而降低,高浓度(≥50 mg.L-1)Hg2+胁迫下叶片的净光合速率低于中低浓度胁迫,且高浓度胁迫的叶片净光合速率在48 h后快速下降;叶片净光合速率与胞间二氧化碳浓度呈极显著负相关,叶绿素含量随Hg2+浓度的增加而降低。气孔导度在不同浓度胁迫下反应不同,低浓度Hg2+对白骨壤幼苗光合的影响可能是气孔因素,中高浓度Hg2+对白骨壤幼苗光合作用的抑制主要是非气孔因素。低浓度Hg2+胁迫,白骨壤幼苗叶片SOD、POD活性升高,表现了一定的抗逆性,而高浓度表现为抑制作用,基本在100 mg.L-1Hg2+胁迫下活性达到最低值。说明Hg2+可以抑制白骨壤叶片的光合活性,高浓度Hg2+胁迫削弱了白骨壤的活性氧清除能力,植物极易受到伤害。In order to understand the heavy metals resistance mechanism of mangrove,a stress experiment with the seedlings of mangrove species Avicennia marina from Fujian Province was conducted to study the impacts of different concentration（1,5,10,50,and 100 mg·L-1） mercury（Hg2＋） on the seedlings leaf photosynthesis and antioxydase activities.With the increase of added Hg2＋ concentration and exposure time,the seedlings leaf net photosynthetic rate（Pn） and chlorophyll content decreased.Under the stress of high concentration Hg2＋（≥50 mg·L-1）,the decrement of Pn was higher than that under the stress of low concentration Hg2＋,and the Pn decreased rapidly after 48 h.There was a significantly negative correlation between Pn and extracellular carbon dioxide concentration（Ci）.The chlorophyll content decreased with increasing Hg2＋ concentration.The stomatal conductance（Gs） had different responses to the stress of different Hg2＋ concentration.At low Hg2＋ concentration,stomatal factors could limit the photosynthesis;while at high Hg2＋ concentration,non-stomatal factors could be the main causes inhibiting photosynthesis.Low Hg2＋ concentration promoted the activities of superoxide dismutase and peroxidase,while high Hg2＋ concentration inhibited the activities of the two enzymes,being the lowest under the stress of 100 mg Hg2＋·L-1.All the results implied that Hg2＋ could inhibit the leaf photosynthesis of A.marina,and high concentration Hg2＋ impaired the active oxygen elimination capability of A.marina,making the plants easily to be damaged.

关 键 词：汞 白骨壤 净光合速率 气孔导度 抗氧化酶活性 

分 类 号：X173[环境科学与工程—环境科学]