摘要
对两种生长于相同沙丘生境中植物的内源生长调节物质 ,叶绿体膜脂肪酸组成及膜脂抗氧化系统酶类的季节变化的研究 ,结果证明 :具极强耐旱性的泡泡刺比具较强耐旱性的沙拐枣体内脱落酸 (ABA )含量高 4.7倍 (5月 )和 3.5倍 (7月 )。而两种植物的 ABA含量高峰出现在 7月 ,可能是受发育及环境高温的影响。玉米素核苷 (ZRS)的季节变化与植物开花关系密切 ;叶绿体膜脂肪酸以亚麻酸 (18:3)、亚油酸 (18:2 )和棕榈酸 (16 :0 )为主。5月和 9月 ,叶绿体膜脂的不饱和脂肪酸指数 (IUFA)较高 ,而 7月由于亚麻酸、亚油酸含量下降 ,棕榈酸、肉豆蔻酸 (14:0 )含量上升 ,膜脂的 IUFA值较低。分析 IU FA值的高低是对环境干旱和高温的响应。ABA对 7月叶绿体膜脂的 IU FA值下降可能具有直接作用 ;超氧化物歧化酶 (SOD)活性在 3个生长季节均较高 ,而过氧化氢酶 (CAT)、过氧化物酶(POD)活性除 9月较高外 ,5～ 7月活力很低 ,出现酶活力失衡现象。文中还对上述结果与环境条件间的相关性及沙漠植物的环境适应机理作了深入探讨。
The levels of abscisic acid (ABA)and zeatin riboside (ZR s) were determined for the assimilating tissue of the desert plants Calligonum mongolicum and Nitraria sphaerocarpa growing in the same dune habitat throughout an entire growing season.Fatty acid composition in chloroplasts and the activity of superoxide dismutase(SOD),catalase (CAT)and peroxidase (POD)relating to membrane lipids antioxidation were also investigated.The results showed that the levels of ABA in N. sphaerocarpa were 4.7 fold(May)and 3.5 fold(July)that in C. mongolicum.The highest ABA contents occurred in July,which could be related to both plant development and environmental high temperatures.Increase of ZR S contents coincided with the blooming period of (C. mongolicum and N. sphaerocarpa).The fatty acids in chloroplast membranes of the two plants were composed mainly of linolenic acid(18∶3),linoleic acid (18∶2)and palmitic acid (16∶0),but their proportions were markedly different in different seasons.In May and September,the index of unsaturated fatty acid (IUFA)of chloroplast membranes increased,but decreased in July.They may have resulted from drought (in May and September)and high temperatures(in July).During July,increased ABA contents may have played a direct role on the decrease of IUFA in chloroplast membranes.The activity of SOD remained high throughout the plants growing season(May July September),but that of CAT and POD decreased in May and July.The enzyme activity of the antioxidation system appeared to be in an unbalanced state.The correlations of these results to environmental adaptations in desert plants are discussed.
出处
《植物生态学报》
CSCD
北大核心
2000年第1期96-101,共6页
Chinese Journal of Plant Ecology
基金
国家自然科学基金!(批准号 :2 92 70 12 9)
