镉胁迫下紫苏低分子量有机酸及镉含量变化

Changes of low molecular weight organic acids and cadmium in Perilla frutescens under cadmium stress

分析了不同镉浓度水培处理紫苏根茎叶的有机酸组成、镉含量及其相关性.结果表明,利用HPLC可分离并同时定量分析出9种低分子量有机酸.在不同处理紫苏的根茎叶中均检测到其中的8种有机酸,包括:草酸、酒石酸、丙酮酸、抗坏血酸、乙酸、柠檬酸、富马酸和琥珀酸.草酸、酒石酸、乙酸、柠檬酸、富马酸和琥珀酸占有机酸总量的95%以上.有机酸含量平均值在紫苏各器官间存在显著差异(P<0.05),茎(13 530.2μg·g^(-1))>叶(9 963.7μg·g^(-1))>根(8 676.7μg·g^(-1)).紫苏各器官的有机酸含量随着镉胁迫时间的延长和处理浓度的增大而显著升高,不同处理间差异显著(P<0.05).紫苏各器官的镉平均含量高低顺序为:根(753.1 mg·kg^(-1))>茎(135.6 mg·kg^(-1))>叶(24.3 mg·kg^(-1)),镉含量随时间的延长和浓度的增大显著升高,不同处理间差异显著(P<0.05).相关分析表明,紫苏有机酸总量与根、茎的镉含量显著正相关,与叶片镉含量显著负相关.紫苏根的镉含量与草酸、酒石酸含量显著正相关;茎的镉含量与酒石酸、丙酮酸、抗坏血酸、柠檬酸及琥珀酸含量显著正相关;叶的镉含量与抗坏血酸、乙酸含量显著正相关,与草酸及柠檬酸含量显著负相关.

The contents of organic acids and cadmium in roots and stems of Perilla frutescens under different concentrations of cadmium and their correlation were analyzed.The results showed that 9 low molecular weight organic acids could be separated and simultaneously quantified by HPLC.8 kinds of organic acids were detected in the rhizome and leaves of P.frutescens,including oxalic acid,tartaric-acid,pyruvic acid,ascorbic acid,acetic acid,citric acid,fumaric acid and succinic acid.Oxalic acid,tartaric acid,acetic acid,citric acid,fumaric acid and succinic acid accounted for more than 95%of the total organic acid.The average value of organic acid content was significantly different among the organs of P.frutescens(P<0.05),stem(13 530.2μg.g 1)>leaf(9 963.7μg.g 1)>root(8 676.7μg.g').The contents of organic acids in different organs of P.frutescens increased significantly with the increase of cadmium stress and treatment concentration,and the difference w-as significant betw-een different treatments(P<0.05).The average cadmium content in various organs of P.frutescens was:root(753.1 mg.kg)>stem(135.6 mg.kg 1)>leaf(24.3 mg.kg 1).The content of cadmium increased significantly with time and concentration,and the difference between different treatments was significant(P<0.05).Correlation analysis show-ed that total amount of organic acids in P.frutescens was positively correlated with cadmium content in roots and stems,and negatively correlated with cadmium content in leaves.The cadmium content of P.frutescens root was significantly correlated with the content of oxalic acid and tartaric acid;the content of cadmium in stem was positively correlated with tartaric acid,pyruvic acid,ascorbic acid,citric acid and succinic acid;the content of cadmium in leaves was positively correlated with ascorbic acid and acetic acid content,and significantly negatively correlated with the content of oxalic acid and citric acid.