摘要
高山生态系统的主要气候特征是温度变化幅度较大,目前研究主要集中于高山植物的抗冻机制,而很少关注其对极端高温(高于45℃)的适应性。本研究发现高山物种圆锥南芥跟拟南芥比,具有更强的基础耐热性和获得性耐热性。通过叶绿素荧光检测发现在极端高温下,圆锥南芥具有更稳定的光系统II和更有效的能量耗散机制来维持更高水平的光合效率。通过电导率和丙二醛含量的检测发现圆锥南芥的膜伤害更小,膜流动性与脂肪酸链的长度和不饱和度紧密相关,圆锥南芥脂肪酸具有更低的16∶3含量,更长的碳链,不饱和度没有明显的变化,这些可能有助于维持膜的稳定。另外,更高表达量的HSP101和HSP70可能为圆锥南芥提供了更好的保护作用。以上结果表明,圆锥南芥能利用生理生化活动的调整来适应高山环境中的极端高温,这种耐热策略与低地耐热植物相似,因此圆锥南芥具有系统性耐热能力,可以作为研究植物耐热分子机制的模式物种。
Alpine ecosystems are characterised by frequent fluctuations between high and low temperatures. The re- sistance of alpine plants to low temperatures has received considerable attention, but little is known about their adap- tation to extremely high temperatures （ 〉45 ℃ ）. In this study, the alpine species Arabis paniculata was shown to display superior basal thermotolerance and acquired thermotolerance than its relative Arabidopsis thaliana. Our chlo- rophyll fluorescence data suggest that under heat shock conditions, A. paniculata has a thermostable photosystem II （PSII） and that efficient non-photochemical quenching maintains a high level of photosynthetic efficiency. Assays of ion leakage and malondialdehyde （MDA） content revealed that membrane damage caused by high temperatures was less severe in A. paniculata than in A. thaliana. The degree of unsaturation and fatty acid chain length was closely cor- related with membrane fluidity. Compared with A. thaliana, A. paniculata had a lower 16：3 （roughanic acid） content, longer fatty acid chain length and no major alterations in the level of unsaturation of membrane fatty acids ; this might enable the maintenance of stable membrane fluidity. Furthermore, more extensive accumulation of heat shock proteins （HSPs）, such as HSP101 and HSP70 in A. paniculata compared with A. thaliana, might correlate with better protec- tion against high temperature in A.paniculata than in A. thaliana. Our findings suggest that the alpine plant A. paniculata uses all of these physiological and biochemical adjustments to adapt to high temperature, and that similar to lowland tropical species, A. paniculata exhibits systemic thermotolerance. Accordingly, A. paniculata might be a useful model plant to study the molecular and physiological mechanisms that contribute to thermotolerance in plants.
出处
《植物分类与资源学报》
CAS
CSCD
北大核心
2014年第6期683-697,共15页
Plant Diversity
基金
NSFC (31300251)
XiBuZhiGuang Project
关键词
高山植物
圆锥南芥
耐热能力
光系统
脂肪酸
热激蛋白
Alpine plants
Arabis paniculata
Thermotolerance
Photosystem
Fatty acids
Heat shock proteins
