高温胁迫对观赏凤梨叶片抗氧化系统和渗透调节物质积累的影响

采用盆栽试验,研究了40℃高温胁迫处理对观赏凤梨叶片抗氧化系统及渗透调节物质积累的影响。结果表明,与25℃对照相比,高温胁迫8 h内,观赏凤梨叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著升高,脯氨酸(Pro)和热激蛋白(HSP)含量显著增加,同时叶片超氧阴离子(O2-·)产生速率、过氧化氢(H2O2)和丙二醛(MDA)含量、电解质外渗率、叶绿素含量与对照相比均无显著变化,植株生长也无明显伤害,表明SOD、POD、CAT活性的提高以及HSP、Pro含量的增加有利于缓解短期高温胁迫对观赏凤梨的氧化伤害。之后随胁迫时间的延长,叶片SOD、POD、CAT活性逐渐下降至对照以下,HSP和Pro含量降低,同时叶片O2-·产生速率加快,H2O2和MDA含量升高,电解质外渗率增加,可溶性蛋白含量降低,游离氨基酸含量增加,叶绿素和类胡萝卜素含量下降,气孔逐渐关闭,观赏凤梨植株幼叶、成熟叶受伤害症状逐渐加重。

Effects of High Temperature Stress on Antioxidant System and Accumulation of Osmotic Adjustment Substance of Bromeliaceae

The effects of high temperature （40℃） on antioxidant system and the accumulation of osmotic adjustment substance of Bromeliaceae seedlings were studied. The results showed that compared to the control, during the early 8 hour of treatment, the activities of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） and the contents of proline （Pro） and heat-shock proteins （HSP） increased significantly. The generation rate of the superoxide free radical （O2-？）, hydrogen peroxide （H2O2） and malondialdehyde （MDA） contents, electrolytic leakage, chlorophyll contents changed slightly. No obvious injury was observed in plant growth. The results indicated that the heat tolerance of Bromeliaceae was improved by enhancing the activities of SOD, POD and CAT and the contents of Pro and HSP. With stress time lasting, the activities of SOD, POD and CAT and the contents of Pro, HSP, protein, chlorophyll and carotenoid decreased, but the generation rate of O2-？, H2O2 and MDA contents, electrolytic leakage, free amino acids contents increased significantly. Leaf stomata closed gradually. Young and mature leaves of Bromeliaceae seedlings suffer injury gradually.