野外模拟增温对亚热带杉木叶片膜脂过氧化及保护酶活性的影响

Effects of simulated warming outdoor on lipid peroxidation and protective enzyme activities in the subtropical species Cunninghamia lanceolata

温度通常被认为是植物生长和生产的重要限制因子,全球变暖严重影响生态系统,但全球变暖对亚热带杉木(Cunninghamia lanceolata)叶片膜脂过氧化及保护酶活性的影响并不甚清楚。该研究在野外利用电缆对土壤增温,设置对照和增温2种处理,每个处理5个重复。通过测定渗透调节物质、内在水分利用效率、保护酶活性及丙二醛等指标,探究增温对杉木生理生化特征的影响。研究表明:1)增温提高渗透调节能力,但对杉木叶片膜脂过氧化作用不明显;2)增温显著提高杉木的水分利用效率和固碳效益,即降低了固碳耗水成本;3)增温降低超氧化物歧化酶活性和过氧化物酶活性,却显著提高过氧化氢酶活性和抗坏血酸过氧化酶活性。由此可见,杉木主要通过提高保护酶(特别是过氧化氢酶和抗坏血酸过氧化酶)活性以减轻高温胁迫伤害,这有助于维持杉木细胞代谢稳定。因此,该区域在未来全球变化背景下的温度升高效应值得长期而深入的探讨。

Aims Temperature is often considered as an important limiting factor for plant growth and production. Ecosystems are often affected by the global warming. However, there is little known about the effects of the global climate change to the lipid peroxidation and protective enzyme activities of Cunninghamia lanceolata in subtropical zones. Methods Heating cables were used to generate a warmed environment in the wild. Two treatments--control and warming （with five replicates each）, were used in the study. We sampled fresh leaves of the C. lanceolata to ex- amine the osmotic adjustment substances, inter water use efficiency, protective enzyme activities, and malondial- dehvde content.Important findings 1） Warming improved osmotic ability, whereas its effect on lipid peroxidation of C. lanceo- lata was not obvious; 2） Warming significantly improved inter water use efficiency and carbon sequestration ben- efits, which indicated that warming decreased the water consumption costs of carbon sequestration; 3） Warming decreased the activity of superoxide dismutase and peroxidase, but significantly increased the activity of catalase and ascorbate peroxidase. These results suggest that warming could protect itself from high temperature through protective enzyme activities （especially catalase and ascorbate peroxidase） of C. lanceolata, which is beneficial to stable cell metabolism. Therefore, more studies are needed about how temperature affects the C. lanceolata under global change in this region.