【摘要】 以苜蓿为试验材料,分析了甘氨酸处理对幼苗镉(Cd)毒害缓解的生理机制。Cd毒害降低了苜蓿幼苗超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,导致幼苗出现氧化伤害,如丙二醛(MDA)含量升高,伊文斯蓝(Evans blue)染色加深。甘氨酸处理提高了苜蓿幼苗SOD和CAT活性,降低了MDA的累积,减少了氧化伤害。Cd毒害还降低了幼苗硝酸还原酶(NR)活性,外源甘氨酸处理则显著提高其NR活性。施用NR抑制剂钨酸钠降低了苜蓿幼苗的NR活性,同时抵消了甘氨酸对Cd胁迫幼苗的生长缓解作用。表明甘氨酸通过提高苜蓿幼苗的抗氧化能力和NR活性,从而提高幼苗对Cd胁迫的耐受性。更多还原

【Abstract】 Protective effects of Gly against Cd toxicity in alfalfa seedlings were investigated.Cd toxicity reduces the activity of SOD and CAT,resulting in oxidative damage such as high MDA content and Evans blue uptake by alfalfa seedling root.Supplementation of Cd with Gly increases SOD and CAT activity and decreases MDA accumulation,thereby reducing oxidative damage in alfalfa seedlings.Cd treatment also reduces NR activity while Gly enhances NR activity in Cd-treated alfalfa seedlings.On the other hand,tungstate (NR inhibitor) supply reverses the effect of Gly by decreasing NR activity and inhibiting seedling growth.The results suggest that enhanced Cd tolerance by Gly treatment is correlated with increasing activities of antioxidative enzymes and NR in alfalfa seedlings.更多还原