镧对铜胁迫下玉米幼苗叶片抗氧化系统的影响

Effects of Lathanum on antioxidant system in leaf of Zea mays L. seedlings under copper stress

为探讨La促进作物生长、增强抗逆性的生理基础,以玉米(Zea mays L.)幼苗叶片为材料,研究了Cu2+胁迫下La3+对玉米幼苗抗氧化系统的影响。结果表明:0.5 mmol/L Cu2+处理促进了脯氨酸(Pro)、可溶性糖和丙二醛(MDA)的积累,显著提高了细胞质膜透性(RMP)及POD和CAT的活性;随着La3+浓度的升高,Pro、可溶性糖和MDA含量先下降后上升,保护酶POD和CAT活性呈下降-上升-下降趋势。说明适宜浓度的La3+降低了细胞内Cu2+胁迫诱导的膜脂过氧化产物和渗透物质的积累,延缓膜透性的增加,缓解了活性氧自由基的产生,从而缓解Cu2+对玉米幼苗的伤害,La3+最佳作用浓度为80 mg/L,La3+浓度160 mg/L及以上则与Cu2+协同作用加剧对玉米幼苗的伤害。

To explore the role of La in promoting crop growth and enhancing the physiological basis of resistance, the effects of La on antioxidant system of Zea mays L. seedlings under copper stress were investigated. The results showed that 0.5 mmol/L Cu^2＋could promote the synthesis of Pro, soluble sugars and MDA, enhance the level of POD and CAT activity, cause RMP increased significantly. With the increase of La^3＋ concentration, contents of Pro, soluble sugars and MDA in maize seedlings decreased firstly and then increased, while the activities of protective enzymes POD and CAT had the trend of decrease-increase-decrease. The results indicated that the optimum concentration of La^3＋ deleted MDA, soluble sugars and Pro accumulation, reduced the relative membrane permeability, and decreased the active oxygen of the maize seedlings under copper stress. The optimum La^3＋ concentration was 80 mg/L. When the concentration of La^3＋ reached 160 mg/L, it had a cooperative effect with copper, which aggravated the damage to seedlings of Z. mays L..