采用盆栽试验,研究3种砷浓度下(0、10和100 mg·kg-)老芒麦(Elymus sibiricus)和香根草(Vetiveria zizanioides)生长特征及根、茎、叶三部位砷含量变化及其细胞膜透性、抗氧化酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)]响应特征.结果表明,低浓度砷对老芒麦和香根草株高和生物量抑制不明显,高浓度下抑制显著(P＜0.05),二者相比香根草对重金属砷有更好的抗性.除老芒麦叶片变化不显著外,两种植物其余部位的砷含量均随着浓度的增加而显著增加;老芒麦地上部的砷积累量随浓度的增加显著降低,香根草则表现出随浓度的增加显著升高,高浓度条件下香根草地上部的砷积累量要高于老芒麦.老芒麦根、茎、叶三部位的细胞膜透性均表现出随砷浓度增加显著升高,香根草根、叶部位表现出相同的变化趋势,但茎部的差异不显著(P＞0.05).砷胁迫引起了老芒麦根、茎、叶三部位CAT、SOD和APX活性的显著增加,而香根草这3种酶的活性能够在10和100 mg·kg-1间维持.POD活性有所不同,表现为砷胁迫引起两种植物茎、叶部位降低,根系增加.综合而言,香根草对于重金属砷有更好的抗性、更强的富集能力,并且SOD与POD可能在其抗氧化体系中起关键作用.%The effect of arsenic (As) stress (10,100 mg · kg-1) on the activity of catalase (CAT),peroxidase (POD),superoxide dismutase (SOD),and ascorbate peroxidase (APX),as well as cell membrane permeability and arsenic content in three parts (roots,stems,leaves) of Elymus sibiricus and Vetiveria zizanioides were evaluated by pot experiments.The results showed that low concentrations of arsenic had no significant inhibition on plant height and biomass of E.sibiricus and V.zizanioides,but they were significantly inhibited at high concentrations (P＜0.05).Compared with E.sibiricus,V.zizanioides exhibited better resistance to arsenic stress.The contents of arsenic in both plants increased significantly with the increase of the concentration of arsenic applied,except for that in the leaves of E.sibiricus.The accumulation of arsenic in the aerial parts of E.sibiricus decreased significantly with the increase of its concentration,whereas that of the V.zizanioides showed the opposite trend;overall,the accumulation of arsenic in the aerial parts of V.zizanioides was higher than that of E.sibiricus at high concentrations.The membrane permeability of roots,stems,and leaves of E.sibiricus all showed a significant increase with the increase of arsenic concentration,and the roots and leaves of V.zizanioides showed the same trend,although the stems of V.zizanioides did not exhibit a significant difference.Arsenic stress caused a significant increase in CAT,SOD,and APX activity in roots,stems,and leaves of E.sibiricus,whereas the activities of three enzymes in V.zizanioides could be maintained between As10 and As 100,but the arsenic stress caused the POD activity in stems and leaves to decrease and to increase in the root system.Taken together,V.zizanioides had better resistance and greater enrichment capacity to the heavy metal arsenic.SOD and POD may play important roles in the antioxidative system.
展开▼
