Study on the membrane lipid peroxidation of the leaves of Kandelia candel seedlings to long-term and short-term salinity
[中文文摘]对长时间和短时间盐胁迫下红树植物秋茄（Ｋａｎｄｅｌｉｎ ｃａｎｄｅｌ）叶片膜脂过氧化作用、叶绿素含量、电解质渗透率、叶片肉质化程度等与盐胁迫强度之间的关系进行了对比研究．结果表明，短时间盐胁迫和长时间盐胁迫下秋茄叶片超氧化物歧化酶（ＳＯＤ）活性、丙二醛（ＭＤＡ）含量、叶片肉质化程度等随盐胁迫强度的提高而有不同的变化规律．在短时间盐胁迫下，随基质盐度的提高，ＳＯＤ活性（ｆｗ）变化呈“Ｕ”型，在盐度１５～２０处叶片ＳＯＤ活性最低，ＭＤＡ含量变化不明显，电解质渗透率和叶片肉质化程度先升高而后下降，在盐度２０处最高；在长时间盐胁迫下，ＳＯＤ活性先随盐度的提高而提高，当盐度高于１０时又随盐度的提高而下降，而ＭＤＡ含量随盐胁迫程度的提高而下降，电解质渗透率和肉质化程度却上升，不同盐胁迫时间下红树植物秋茄具有不同的耐盐机制。膜脂过氧化不是盐胁迫下秋茄叶片膜损伤的主要原因。[英文文摘] The membrane lipid peroxidation of the leaves of mangrove Kandelia candel seedling to long- and short-term salinity is dealt with. There were different trends in the SOD activity, MDA concentration and succulence of K. candel leaf with increasing salinity between long-term salt-stress (45 d) and short-term salt--stress(1 d). At short-term salt-stress with increasing salinity, SOD activity appeared in U-shaped, minimized at salinity 15 --20; MDA concentration did not change significantly, electrolyte leakage(% ) increased, and leaf succulence increased at first, maximized at salinity 20, then declined. While at long-term salt-stress with increasing salinity, SOD activity increased at low salinity and decreased at higher salinity, MDA concentration declined, electrolyte leakage and leaf succulence increased. There were differences in salt-tolerant mechanism between long-term saltstressed group and short-term salt-stressed group. Membrane lipid peroxidation was not the main reason for the destroy of K. candel leaves under salt stress.