U（Ⅵ）胁迫下碎米莎草体内抗氧化系统响应特征

The Responses Characteristics of the Antioxidant System of Cyperus iria L. to Uranium Stress

采用水培方式研究了铀尾矿库土著优势植物——碎米莎草不同生长期各部位在不同质量浓度铀〔U（Ⅵ）,记为U〕溶液胁迫下w（SP）（SP为可溶性蛋白）、CMDA（丙二醛含量）以及SOD（superoxide dismutase,超氧化物歧化酶）、POD（peroxidase,过氧化物酶）、CAT（catalase,过氧化氢酶）、ATPase（三磷酸腺苷酶）活性的变化.结果表明,ρ（U）≤250 mg/L时,碎米莎草各部位SOD、POD、CAT活性在整个生长阶段均受到显著诱导（P〈0.05）,而CMDA、ATPase活性与对照组相比无显著差异（P〉0.05）;ρ（U）≥750 mg/L时,SOD、POD和CAT活性与对照组相比显著降低（P〈0.05）;ρ（U）达到1 000 mg/L以上时,与对照组相比,降低趋势更显著（P〈0.01）,而ATPase活性受到显著诱导（P〈0.05）,CMDA在幼苗期显著增加（P〈0.05）,膜脂过氧化损伤程度严重.表明碎米莎草对铀胁迫的生理响应中,以根系SOD、CMDA的响应最为敏感.

The effects of the contents of soluble protein and malondialdehyde （MDA） and the activities of superoxide dismutase （SOD） , catalase （CAT） , peroxidase （POD） and adenosine triphosphatase （ATPase） induced by uranium toxicity to Cyperus iria L. at different growth stages and positions were investigated. The results indicated that the activities of SOD, POD and CAT increased significantly （P 〈 0. 05 ） , but there was no significant difference in the content of MDA and the activities of ATPase between the control group and the group treated by low concentration of uranium （≤ 250 mg/L ）. However, the activities of SOD, POD and CAT decreased significantly （P 〈 0.05 ） as the concentration of the uranium reached up to 750 mg/L, while the activities of ATPase, the contents of MDA and soluble protein increased, which indicated serious increases of lipid peroxidation as the concentration of uranium reached 1000 mg/L （P 〈 0. 05 ）. Thus, the activities of SOD and the contents of MDA of the root part could characterize the toxicity response of C. iria to uranium.