Effect of high light and desiccation on photosystem Ⅱ in the seedlings and mature plants of tropical seagrass Enhalus acoroides during low tide  

作　　者：Xingkai CHE Hu LI Litao ZHANG Jianguo LIU 

机构地区：[1]CAS and Shandong Key Laboratory of Experimental Marine Biology,Center for Ocean Mega-Science,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China [2]Laboratory for Marine Biology and Biotechnology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China

出　　处：《Journal of Oceanology and Limnology》2023年第1期241-250,共10页海洋湖沼学报（英文）

基　　金：Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB42000000);the National Natural Science Foundation of China(No.32071577);the International Partnership Program of Chinese Academy of Sciences(No.GJHZ2039);the Shandong Provincial Natural Science Foundation(No.ZR201911130493);the Taishan Industrial Experts Program(No.Tscy20200102)。

摘　　要：During low tide,the intertidal seagrass Enhalus acoroides is often exposed to high light and desiccation,which can seriously threaten its survival,at least partly by inhibiting photosystem Ⅱ(PSⅡ)activity.The response of leaves of E.acoroides to high light and desiccation was compared for seedlings and mature plants.Results show that the resistance of seedling and mature leaves to high light was quite similar,but to desiccation was very different.Seedling leaves were more sensitive to desiccation than the mature plant leaves,but had better water retention.The damage of desiccation to seedling leaves was mainly caused by dehydration,whereas that to mature plant leaves was caused by hypersaline toxicity.The recovery rate of PSⅡ of seedling leaves was significantly slower than that of the mature plants after the stresses disappeared,which may at least partly contribute to seedling mortality in the wild.In addition,compared to high light,desiccation seriously inhibited the recovery rate of PSⅡ activities even if the leaves became fully rehydrated to their normal relative water content(RWC)in the following re-immersion.Desiccation inhibited the recovery rate of RC/CS_(M)(reaction center per cross section(at t=t_(Fm)))to decrease the production of assimilatory power,which maybe the cause of the slower PSⅡ recovery in desiccation treatments.This study demonstrates that desiccation particularly coupling with high light have a very negative ef fect on the PSⅡ of E.acoroides during low tide and the sensitivity of seedlings and mature plants to desiccation is significantly different,which have important reference significance to choose an appropriate transplanting depth where seedlings and mature plants of E.acoroides not only receive sufficient light for growth,but also that minimize desiccation stress during low tide.

关 键 词：Enhalus acoroides high light DESICCATION photosystemⅡ 

分 类 号：Q945[生物学—植物学]