中华金叶榆和水蜡对铅胁迫的生理生态响应

Physiological Ecological Responses of Ulmus pumila “Jinye”and Ligustrum obtusifoliumto Lead Stress

【目的】探究铅胁迫对两年生中华金叶榆(Ulmus pumila L.cv.jinye)和水蜡(Ligustrum obtusifolium)生理生态的影响,选择适生树种修复中国西部的铅污染地区。【方法】通过将外源铅(三水合乙酸铅)加入到土壤中的方式设置3个铅胁迫处理组T1,T2和T3并分别施加相当于土壤中铅质量分数为400,800和1 200mg·kg^(-1)外源铅;并设置1个不施加外源铅的对照组(CK)。考察铅胁迫对这两个树种的生长、生理、铅耐受能力及铅积累特征的影响。【结果】中华金叶榆和水蜡的株高、生物量、耐性指数、净光合速率随土壤中铅质量分数的增加而下降;中华金叶榆和水蜡体内的保护酶活性随土壤中铅质量分数的增加呈现先升高后降低的趋势;中华金叶榆和水蜡幼树根、茎、叶中铅质量分数随着土壤中铅质量分数的增加而相应增加,且均在各自的T3组中达到最大值。【结论】中华金叶榆在土壤中铅质量分数为800mg·kg^(-1)时对铅的耐受能力和转移能力较好,适合在中国西部表层铅污染严重地区推广应用。然而,水蜡在土壤中铅质量分数为400mg·kg^(-1)时虽然也具有较高的铅耐受能力,但相较于中华金叶榆而言,它的各部分富集和转移铅的能力较差。

[Purposes]In order to reveal the physiological ecological responses of two years old Ulmus pumila ＂Jinye＂and Ligustrum obtusifolium saplings to lead stress and provide reference for repair lead pollution in the western region of China.[Methods]Three different kinds of lead treatment were applied which include T1（400 mg·kg^-1）,T2（800 mg·kg^-1）,T3（1 200 mg·kg^-1）through adding exogenous lead to the soil;set up the control group CK（0 mg·kg^-1,control）no exogenous additions.The effects of growth,physiology,capacity of lead tolerance,characteristics lead accumulation of U.pumila ＂Jinye＂and L.obtusifolium seedlings was investigated under lead stress.[Findings]The plant height,biomass,tolerance index,net photosynthetic rate of U.pumila ＂Jinye＂and L.obtusifolium decreased with the lead mass fraction in soil raised.The activities of protective enzymes in leaves of U.pumila ＂Jinye＂and L.obtusifolium presented the same trends.Activities of superoxide dismutase,peroxidase,catalase,and ascorbate peroxidase raised at first,then decreased with the lead mass fraction in soil raised.Lead mass fraction of root,stem and leaf of U.pumila＂Jinye＂and L.obtusifoliumreached the peak at T3.[Conclusions]U.pumila ＂Jinye＂seedlings had a high capacity of growth adaptation,tolerance and translocation under 800 mg·kg^-1 lead stress,so U.pumila ＂Jinye＂had more considerable potential application to those lead contaminated areas in the western region of China.L.obtusifolium seedlings had a high capacity of growth adaptation,tolerance under 400 mg·kg^-1 lead stress,but had a worse capacity of lead accumulation and lead translocation contrast with U.pumila ＂Jinye＂.