【摘要】 对生长在青藏高原不同海拔自然生境下的多年生典型抗寒植物—矮嵩草 Kobresiahumilis 的抗氧化系统进行了比较研究.结果表明,矮嵩草的叶组织中,非酶抗氧化系统物质脯氨酸 Pro 和抗坏血酸 AsA ,随着海拔升高具有明显的增加趋势.在抗氧化酶系统中,过氧化物酶 POD 和过氧化氢酶 CAT 活性均随海拔的升高,而明显增强.但叶中的超氧化物歧化酶 SOD ,随着海拔的升高,其活性有下降趋势,三者变化趋势并不一致.高海拔矮嵩草的植株与低海拔的植株相比,叶细胞内的膜脂过氧化加剧,丙二醛 MDA 含量明显增加.细胞可溶性蛋白也随海拔升高显著增加.根中的抗氧化系统变化与叶中的有所不同.根中AsA含量随海拔而显著升高,且较叶中的增加明显,但Pro含量则有所减少.根中的CAT和POD活性变化与叶中的变化趋势基本一致,且随海拔高度的增加,根中的CAT活性较叶中的变化更为明显.而根中的SOD活性变化不如叶中明显,MDA含量随海拔增高,其变化趋势比叶中的小.可见,青藏高原典型抗寒植物矮嵩草体内的两类抗氧化系统,在不同海拔条件下可能存在互补协同的调节作用,这可能是矮嵩草适应或抵抗高原极端高寒低温和强UV-B辐射等环境胁迫的重要生理机制之一.更多还原

【Abstract】 The antioxidative system of perennial forage grass (Kobresia humilis) were studied at different altitudes outdoors in QinghaiTibet Plateau. The result showed that free proline and ascorbic acid (AsA) were increased obviously in leaves with the altitude ascended while superoxide dismutase (SOD) activity was slightly decreased. Activities of peroxidase (POD) and catalase (CAT) both were increased significantly with the increase in elevation, especially CAT. The changes of three main enzymes activity were not consistent with each other as altitude elevated. Membrane lipid peroxidation increased and led to high accumulation of malondialdehyde (MDA) in cell. On the other hand, the total soluble protein increased significantly. But antioxidative system in roots varied differently with leaves. AsA increased more obviously in roots as compared to the leaves while Pro tended to decline with the altitude increased. The changes of POD and CAT activity in roots were similar to the leaves and the later changed more clearly, but SOD activity appeared not clearly and MDA changed less than that in leaves. Hence, the two antioxidative systems probably existed acollaboration relationship to each other, which may play an important physiological mechanism for role in Kobresia humilis to adapt the plateau environmental stresses of extreme coll temperatures and high UVB radiation.更多还原