柠檬香蜂草对铜的耐性及其积累特征研究

Tolerance and Accumulation Characteristics of Copper in Melissa officinalis

以柠檬香蜂草(Melissa officinalis)幼苗为材料,设置不同浓度Cu^(2+)胁迫(CK、200、400、800和1 000mg·kg^(-1))盆栽实验,测定胁迫0、7、14、21、28d后植物生物量、叶绿素含量、抗氧化酶活性、可溶性蛋白含量、丙二醛(MDA)含量以及植物体内Cu含量等指标,探讨柠檬香蜂草对Cu^(2+)的耐受性及其积累特征。结果表明:(1)相同处理时间下,柠檬香蜂草除MDA含量外其他所有指标均随着Cu^(2+)胁迫处理浓度的增加呈低浓度促进、高浓度抑制的变化趋势,且高浓度组(800和1 000mg·kg^(-1))与低浓度组(200和400mg·kg^(-1))之间差异显著(P<0.05);MDA含量在1 000mg·kg^(-1)浓度下持续增长至第14天后开始下降。(2)柠檬香蜂草体内Cu的积累量随Cu胁迫浓度的升高呈先增加后减少的趋势,并在浓度为400mg·kg^(-1)时达到最高值(0.71mg/盆)。(3)在整个胁迫过程中,柠檬香蜂草植株的铜富集系数及其耐性系数均随Cu浓度的增加而减小,各处理浓度对Cu的耐性系数均大于0.5,富集系数均大于1。研究发现,柠檬香蜂草对Cu胁迫具有一定耐受性和富集能力,具有成为铜污染土壤修复植物的潜力。

In this study, Cu tolerance and accumulation characteristics in Melissa officinalis were investigated by some indexes, such as biomass, chlorophyll contents, antioxidant enzyme activities, soluble protein （SP）, malondialdehyde （MDA） and Cu contents in plants under different concentrations of Cu2＋ （0, 200, 400, 800, 1 000 mg·kg-1） through pot experiments was measured after 0, 7, 14, 21 and 28 days. The results show that： （1） at the same treatment time, there was a similar trend that a significant increase at low doses （200 and 400 mg·kg-1）, while an inhibitory at high doses （800 and 1 000 mg·kg-1） in most of indexes except MDA content. Furthermore, the statistical results showed that differences were significant between high doses group （800 and 1 000 mg·kg-1） and those of low dose groups （200 and 400 mg·kg-1） （P〈0. 05）. Unlike these changes of other indexes, the variation trend of index MDA was growing 14 days ago and decreasing at 1 000 mg·kg-1 Cu2＋ concentration. （2） As the Cu2＋ dose increasing, the total Cu concentration in plants reached up peak at 400 mg·kg-1 （0.71 mg each pot） then declined. （3） Throughout the experiments, these indexes of tolerance and the bio concentration factors of M. officinalis were more than 0.5 and 1, respectively. Both the index of tolerance and the bio concentration factor decreased with the Cu2＋ concentration increasing after 28 days, which explored that M. officinalis has some certain of tolerance ability and accumulation capacity for Cu. The results suggested that M. officinalis has the potential to be a promising plant for phytoremediation in Cu contaminated soil.