Role of mucilage during achene germination and sprout growth of the endangered Tibetan medicinal herb Mirabilis himalaica (Nyctaginaceae) exposed to abiotic stresses  

作　　者：Yuzhen Chen Lu Zhang Xiao Lu Xiaozhong Lan Man Shen Cunfu Lu 

机构地区：[1]Beijing Advanced Innovation Center for Tree Breeding by Molecular Design,College of Biological Sciences and Biotechnology,National Engineering Laboratory for Tree Breeding,Beijing Forestry University,Qinhua East Road 35,Haidian District,Beijing 100083,China [2]Agricultural and Animal Husbandry College,Tibet University,Yucai West Road 100,Linzhi,Tibet 860000,China [3]College of Plant Science and Technology,Beijing University of Agriculture,Beunong Road 7,Beijing 102206,China

出　　处：《Journal of Plant Ecology》2018年第2期328-337,共10页植物生态学报（英文版）

基　　金：This work was financially supported by the National Science Technology Support Program(2011BAI13B06);the National Natural Science Foundation of China(31270737);Beijing Municipal Natural Science Foundation(KZ20150020021,6112016);111 Project(B13007)and Program for Changjiang Scholars and Innovative Research Team in University(IRT13047).

摘　　要：Aim Mirabilis himalaica(Nyctaginaceae)is an endangered medicinal plant mainly distributed in the plateau region of northern Tibet,China.The outer surface of M.himalaica achenes is covered by a pectinaceous mucilaginous layer upon hydration.However,the role of the achene mucilage is poorly understood.in this study,we inves-tigated the effects of mucilage on achene germination and sprout growth under abiotic stress to explain how M.himalaica survive the alpine environment.Methods We investigated the effect of mucilage on achenes germination by contrast the capacity of water absorption,dehydration and respira-tion of intact achene and the achene with mucilage removal.We performed abiotic stresses experiments including drought stress,salt stress,cold stress and high temperature stress,and quantified the effects of mucilage removal on achene germination rate,root and shoot lengths of seedlings.Important Findings Mucilage is extremely hydrophilic,and the mass of intact achenes can be 9-fold greater than that of demucilaged achenes.The removal of the mucilaginous layer did not significantly change final germination percentages under ideal conditions,but intact achenes(i.e.with muci-lage)took longer to germinate.The mucilage significantly decreased seed respiration rates by acting as a physical barrier that prevented oxygen diffusion.Germination rates,shoot and root growth of intact achenes were higher than those of demucilaged ones during exposures to cold,heat,osmotic and salt stresses.Achene mucilage presumably plays an ecologically important role in the life cycle of M.himalaica by aiding the critical achene germination and early seedling growth in the stressful habitats of the plateau region of northern Tibet.

关 键 词：Mirabilis himalaica achenes mucilage GERMINATION abiotic stresses 

分 类 号：Q94[生物学—植物学]