铜胁迫对两种地衣植物生理生化特征的影响

以中国树花（Ramalina sinensis Jatta.）和亚花松萝（Usnea subfloridana Stint.）为材料,研究了铜胁迫对这两种地衣植物生理生化特性的影响。结果表明：在Cu2＋的作用下,中国树花和亚花松萝体内叶绿素质量分数和过氧化物酶（POD）活性发生一系列的变化,且表现出明显的剂量效应关系和时间效应关系。随着处理浓度的加大和处理时间的延长,中国树花体内叶绿素质量分数呈现先降后升再降。在处理的48 h,当Cu2＋质量浓度为0.1 mg.mL-1时中国树花体内叶绿素a质量分数下降为0 mg.mL-1时的16.34%,叶绿素总质量分数下降为42.54%,而当Cu2＋质量浓度为0.5 mg.mL-1时叶绿素a质量分数下降为22.95%,叶绿素总质量分数下降为60.39%,亚花松萝体内叶绿素质量分数呈现先升后降的趋势,当Cu2＋质量浓度为0.1 mg.mL-1时,处理48 h后的亚花松萝体内叶绿素质量分数比36 h下降18.82%;当Cu2＋质量浓度为0.5 mg.mL-1时,处理48 h后的亚花松萝体内叶绿素质量分数比36 h下降23.52%。随着处理浓度的加大和处理时间的延长,中国树花过氧化物酶活性呈现上升的趋势,当Cu2＋质量浓度为0.1 mg.mL-1时,处理24、36、48 h后过氧化物酶的活性分别增加为88.1%、64.83%和65.49%;当Cu2＋质量浓度为0.5 mg.mL-1时,分别增加为69.83%、82.05%和82.57%。而亚花松萝过氧化物酶活性呈现先下降后上升等波动性变化,Cu2＋质量浓度为0.1 mg.mL-1时,处理24、36、48 h后过氧化物酶的活性先下降62.56%,后增加7.93%,又下降42.28%;当Cu2＋质量浓度为0.5 mg.mL-1时,比对照组分别下降72.92%、33.49%和62.56%。对比两种地衣植物发现,中国树花体内生理指标的变化较亚花松萝的明显,说明中国树花对铜胁迫反应较敏感,有利于监测重金属铜污染。

Influence of copper stress on physiological and biochemical characteristics of two different lichens species

The influences of copper stress on physiological and biochemical characteristics of two lichen species,Ramalina sinensis Jatta.and Usnea subfloridana Stint.which were collected from the unpolluted August first tree farm area of Urumqi in Xinjiang,were studied in this paper.The results indicated that the changes related to chlorophyll content and protective enzymes activities of R.sinensis and U.subfloridana showed dosage effect and time-dependent effect evidently under different concentrations of copper treatment.With the increasing of copper concentration and processing time,chlorophyll in R.sinens is first decreased,then increased and finally decreased.Compared with 0 mg·mL-1 copper concentration,the chlorophyll A decreased 16.34% and the decrease of total chlorophyll was 42.54% at 0.1 mg·mL-1 copper concentration after 48h treatment;at 0.5 mg·mL-1 concentration,the decrease of the chlorophyll A was 22.95% and the decrease of total chlorophyll was 60.39%;but chlorophyll content of the another lichen U.subfloridana increased first,then decreased（comparing 48h copper treatment to 36 h at 0.1 mg·mL-1 and 0.5 mg·mL-1 two different concentrations,the decreases of the chlorophyll were 18.82% and 23.52% respectively）.The activity of peroxidase（POD） of R.sinensis increased（after 24 h、36 h、48 h treatment with 0.1 mg·mL-1 copper,the increase of POD activity were 88.1%、64.83%,65.49%;the increase of POD activity at 0.5 mg·mL-1 copper after 24 h、36 h、48 h treatment were 69.83%、82.05% and 82.57%）,but the activity of peroxidase（POD） of U.subfloridana fluctuated irregularly with the increasing of concentration and duration of copper stress（treated with 0.1 mg·mL-1 copper concentration,the POD activity decreased 62.56% after 24h,increased 7.93% after 36h and finally decreased 42.28% after 48h;at 0.5 mg·mL-1 concentration after 24h,36h and 48h treatment,the decrease of enzyme activities were 72.92%、33.49%,62.56% compared to the control group）.We can conclude from the results that the changes of physiological indexes of R.sinensis under different conditions of copper stress were more obvious than of U.subfloridana,meaning that R.sinensis might be more sensitive to the copper stress,and it could be used as a desirable indicator for the detection of copper pollution.