铬诱导下薄荷的氧化胁迫响应和铬分布

Response of Mentha haplocalyx Briq. to Chromium-Induced Oxidative Stress and Chromium Distribution

为探讨薄荷（Mentha haplocalyx Briq.）耐受和富集重金属铬的生理机制,采用盆栽法研究不同质量浓度、不同处理时间Cr6＋对薄荷不同器官中抗氧化酶（SOD,POD,CAT）活性、铬含量和亚细胞组分中铬分布的影响.结果表明：随着Cr6＋质量浓度的增加,SOD,POD,CAT 3种酶活性呈先升后降的趋势,在Cr6＋质量浓度为40 mg/L时,3种酶活性均出现峰值;在50 d内,3种酶活性整体上呈增长趋势.在亚细胞水平上,铬在根中的亚细胞分布从大到小依次为细胞壁、质体、细胞核、线粒体、可溶部分;铬在叶片中的亚细胞分布从大到小依次为可溶部分、细胞壁、叶绿体、细胞核、线粒体.在器官水平上,根中铬含量占整个植株铬含量的80%~93%,为器官中最高.研究表明薄荷体内的抗氧化酶,根中的细胞壁和叶片中的液泡在铬耐受和解毒中起到重要作用.

A pot culture experiment was carried out to investigate the effects of chromium on antioxidant enzyme activities,subcellular distribution and chromium accumulation of Mentha haplocalyx Briq.It was observed that with increasing chromium concentrations and time in the first 50 days,the activities of antioxidant enzymes（SOD,POD and CAT） first increased and then decreased,with a peak occurring at 40 mg/L of chromium.At the subcellular level,chromium content was distributed in cell wall plastid nucleus mitochondrion soluble fraction of the root cells and in soluble fraction cell wall chloroplast nucleus mitochondrion of the leaf cells.At the organ level,chromium accumulation in different organs increased continuously,and the chromic content of the roots accounted for 80%～93% of the total.These results suggested that antioxidant enzymes,the cell wall of the root and the vacuoles of the leaf played important roles in the major mechanism for M.haplocalyx Briq.accumulating chromium and its resistance to chromium toxicity.