不同盐胁迫时间下秋茄幼苗叶片膜脂过氧化作用的研究

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.

Study on the membrane lipid peroxidation of the leaves of Kandelia candel seedlings to long-term and short-term salinity

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.