铜胁迫对弯囊苔草（ Carex dispalata）生长和生理特性的影响

用水培方法研究了弯囊苔草在不同Cu^2＋浓度（1、5、25 mg·L^-1）胁迫下的生长特性和部分生理生化指标的变化。结果表明，不同Cu^2＋浓度胁迫下，弯囊苔草正常生长，但其生长特性表现出高浓度抑制的相关性, 高浓度下没有新生根。弯囊苔草叶片3种抗氧化酶活性都随胁迫时间的延长呈先上升再下降趋势。SOD在处理的第4 d达到峰值，且活性一直显著高于对照（P＜0.05），3种Cu^2＋浓度处理下的峰值大小顺序为5 mg·L^-1＞25 mg·L^-1＞1 mg·L^-1。POD和CAT活性在处理第7 d达到峰值，POD活性峰值大小顺序为5 mg·L^-1＞1 mg·L^-1＞25 mg·L^-1；CAT活性峰值大小顺序为25 mg·L^-1＞5 mg·L^-1＞1 mg·L^-1。丙二醛（MDA）和可溶性糖含量都是随着胁迫时间的延长而上升，处理结束时的丙二醛（MDA）（r=0.988 0）和可溶性糖含量（r=0.951 2）与Cu^2＋浓度表现出正相关性。脯氨酸（Pro）含量随胁迫时间的延长也呈先上升后下降趋势，1 mg· L^-1和5 mg·L^-1 Cu^2＋浓度处理下脯氨酸（Pro）含量在处理第4 d达到最大值，25 mg·L^-1高浓度处理下脯氨酸（Pro）含量在处理第7 d达到最大值。叶绿素在5、25 mg·L^-1 Cu^2＋浓度处理下随胁迫时间的延长呈先上升后下降的趋势，1mg·L^-1Cu^2＋处理下的叶绿素含量不断上升，实验结束时各处理下叶片的叶绿素含量与处理浓度呈负相关。结果表明弯囊苔草能通过调节体内抗氧化酶活性来增强其抗氧化胁迫能力，这为其作为铜污染水体的修复植物提供了可能。

Copper Stress on the Growth and Some Physiological Parameters of Carex dispalata

Effects of Cu^2＋ stress on the growth, activities of antioxidant enzymes, chlorophyll contents, membrane lipid peroxidation, soluble sugar and proline contents in the leaves of Carex dispalata were investigated experimentally with water culture method. The results showed that although Carex dispalata growed normally, the growth characteristics were correlated negatively with increasing Cu^2＋ concentrations, and roots did not regenerate under high Cu^2＋ concentrations. The activities of antioxidant enzymes increased in the beginning and then decreased with increasing stressing time. SOD activities of three treatments（ 1 mg· L^-1, 5 mg· L^-1 and 25 mg· L^-1 ） reached peak value in the 4th day and remained significantly higher than the control treatment（P〈0.05 ） throughout the experiment, and the activities were the highest at 5 mg· L^-1, followed by 25mg· L^-1 and 1 mg· L^-1, respectively. Both POD and CAT activities reached peaks in the 7th day. The peak value was highest at 5mg· L^-1, followed by 1mg· L^-1 and 25 mg· L^-1, respectively, for POD activities, whereas that of CAT was the highest at 25 mg· L^-1, followed by 5 mg· L^-1 and 1 mg· L^-1, respectively. MDA and soluble sugar contents increased with increasing stressing time and both were positively correlated with increasing Cu^2＋ concentrations when the experiment ended r=- 0.988 0 and 0.951 2 for MDA and soluble sugar, respectively. Proline contents also increased in the beginning and then decreased with increasing stressing time. Under 1 mg· L^-1 and 5 mg· L^-1Cu^2＋ concentrations, proline contents reached peak value after four-day treatment, while under 25 mg· L^-1 the peak value reached after seven-day treatment. Similarly, chlorophyll contents increased in the beginning and then decreased with increasing stressing time under 5 mg· L^-1and 25 mg· L^-1 Cu^2＋ concentrations as well, whereas that under 1 mg· L^-1 Cu^2＋ concentration increased continuously. The chlorophyll contents were allcorrelated negatively with Cu^2＋ concentration under each treatment when the experiment was completed. In summary, Carex dispalata can improve its tolerance to oxidative stress by regulating in vivo activities of antioxidant enzymes, suggesting that the plant species investigated is a potential plant for the restoration of copper-polluted water bodies.