滨海沙地植物厚藤叶片生理特征的季节变化

Seasonal changes of leaf physiological characteristics of Ipomoea pes-caprae in coastal sand

关键词:  厚藤, 叶片, 生理指标, 季节变化, 适应性

Key words:  Ipomoea pes-caprae, leaf, physiological index, seasonal changes, adaptability

摘要:

滨海沙地条件恶劣,季节气候环境差异较大,植物生存困难。厚藤是南方滨海沙地广泛分布的重要固沙植物。为探究厚藤对不同季节环境变化的适应机制,研究其叶片生理性状的季节变化,该文以广西滨海沙地自然生长的厚藤为实验材料,分别测定了不同季节厚藤叶片的叶绿素含量、渗透物质含量、抗氧化酶活性、叶绿素荧光参数等生理指标,并进行相关性分析和主成分分析。结果表明:(1)叶绿素含量随季节变化的趋势一致,春季均显著大于其他三个季节,但叶绿素a/b在各季节间无显著变化。(2)叶绿素荧光参数的F_v/F_m和F_v/F_o具有相同的变化趋势,整体表现为夏冬季显著高于春秋季。(3)脯氨酸含量随季节逐渐增大,冬季时含量最高; 可溶性糖含量冬季显著高于其他三个季节; 丙二醛(MDA)含量各季节间差异不显著。(4)春季的超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性显著高于其他季节,夏秋冬季节间无显著差异; 过氧化物酶(POD)活性在各季节间差异不显著。(5)相关性分析和主成分分析显示,各生理指标与气候因子间存在一定的关联。温度和日照数显著影响可溶性糖含量; 叶绿素含量和抗氧化酶活性能够较好地反映厚藤对季节气候变化的响应。综上可知,厚藤可通过调节叶绿素a与叶绿素b含量使叶绿素a/b保持稳定,同时提高渗透调节物质含量和抗氧化酶活性以适应季节变化,其中光合作用和抗氧化酶系统是影响其季节性适应能力的关键。

Abstract:

Poor conditions, and quite differences in seasonal climate environment in coastal sandy land makes it difficult for plants to survive. Ipomoea pes-caprae is an important sand-fixing plant widely distributed in southern coastal sandy land. In order to explore the adaptation mechanism of I. pes-caprae to environmental changes in different seasons, the seasonal changes of its leaf physiological traits were studied. In this paper, I. pes-caprae grown up naturally in coastal sand of Guangxi was taken as experimental material, and the physiological indexes such as the contents of chlorophyll, the contents of osmotic substance, antioxidant enzyme activities and chlorophyll fluorescence parameters of the I. pes-caprae leaves in different seasons were measured, and the correlation analysis and principal component analysis were also carried out. The results were as follows:(1)Chlorophyll contents had the same trend with season changes, which was significantly higher in spring than those in other three seasons, but chlorophyll a/b had no significant change among seasons.(2)F_v/F_m and F_v/F_o of chlorophyll fluorescence parameters also had the same change trends, which were significantly higher in summer and winter than those in spring and autumn.(3)Proline content increased gradually with seasons, and reached the highest level in winter. Soluble sugar content in winter was significantly higher than those in other three seasons. There was no significant differences in malondialdehyde(MDA)contents among seasons.(4)The activities of superoxide dismutase(SOD)and catalase(CAT)in spring were significantly higher than those in other seasons, but there was no significant differences among summer, autumn and winter. There was no significant differences in peroxidase(POD)activities among seasons.(5)There was a certain correlation between physiological indexes and climate factors by correlation analysis and principal component analysis. Temperature and sunshine duration significantly affected the contents of soluble sugar. Chlorophyll contents and antioxidant enzyme activities could better reflect the response of I. pes-caprae leaves to seasonal climate change. To sum up, the chlorophyll a/b can be kept stable by adjusting the contents of chlorophyll a and chlorophyll b, and meanwhile, the contents of osmotic adjustment substances and the activities of antioxidant enzymes can improve it to adapt to seasonal changes, among which photosynthesis and antioxidant enzymes system are the key factors affecting its seasonal adaptability.