%A TANG Ting, ZHENG Guo-Wei, LI Wei-Qi %T Adaptation to Extremely High Temperature in an Alpine Environment: Systemic Thermotolerance in Arabis paniculata %0 Journal Article %D 2014 %J Plant Diversity %R 10.7677/ynzwyj201414047 %P 683-697 %V 36 %N 06 %U {https://journal.kib.ac.cn/CN/abstract/article_33362.shtml} %8 2014-11-25 %X
Alpine ecosystems are characterised by frequent fluctuations between high and low temperatures. The resistance of alpine plants to low temperatures has received considerable attention, but little is known about their adaptation 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 chlorophyll fluorescence data suggest that under heat shock conditions, Apaniculata has a thermostable photosystem II (PSII) and that efficient nonphotochemical 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 Apaniculata than in Athaliana. The degree of unsaturation and fatty acid chain length was closely correlated with membrane fluidity. Compared with Athaliana, Apaniculata 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 Apaniculata compared with Athaliana, might correlate with better protection against high temperature in Apaniculata than in Athaliana. Our findings suggest that the alpine plant Apaniculata uses all of these physiological and biochemical adjustments to adapt to high temperature, and that similar to lowland tropical species, Apaniculata exhibits systemic thermotolerance. Accordingly, Apaniculata might be a useful model plant to study the molecular and physiological mechanisms that contribute to thermotolerance in plants.