天津盐渍化生境54种植物钙晶体与钙组分特征

Features of calcium crystals and calcium components in 54 plant species in salinized habitats of Tianjin

植物钙包括游离态的Ca2+和结合态易溶、微溶和难溶于水的钙盐,而难溶于水的钙盐常会形成钙晶体.为了解盐渍化生境中不同生长型植物体内的钙状况,本文对天津市54种植物进行了钙晶体的镜检和钙组分的测定.结果表明:在盐渍化生境中的54种植物体内,有38种植物体内镜检到较多的钙晶体,其中37种植物体内为以簇晶和方晶为主的草酸钙晶体,只在桑科的无花果叶片中观察到内含碳酸钙晶体的钟乳体.按生长型统计,落叶乔、灌木体内的草酸钙晶体较多,藤本植物体内的草酸钙晶体较少,而草本植物和常绿乔木体内未镜检到草酸钙晶体.同时,从乔木、灌木、藤本到草本,植物体内盐酸溶性钙含量逐渐减少而水溶性钙含量逐渐增多,且草本植物体内的水溶性钙含量显著高于乔木和灌木.在盐渍化生境中,植物体内的钙晶体和钙组分因生长型不同而有所差异,草酸钙在落叶乔、灌木抵御盐分胁迫中发挥着重要作用.

Plantcalcium（Ca）is composed of dissociated Ca2＋ and and hard soluble combined Ca salts.The hard soluble Ca salts can understand the Ca status in different form plants in salinized easily soluble,slightly soluble,often engender Ca crystals.To habitats,54 plant species were sampled from the salinized habitats in Tianjin,with the Ca crystals examined by microscoPe and the Ca components determined by sequential fraction ation procedure.More Ca crystalswerefoundin38ofthe54plantspecies.In37ofthe38plantspecies.drusyandprismaticCaoxalatecrystals domi-nated,whereas the cystolith of Ca carbonate crystal only appeared in the leaves of Ficus carica of Moraceae.The statistics according to growth form suggested that deciduous arbors and shrubs had more Ca oxalate crystal,1ianahad lesser Ca oxalate crystal,and herbs and evergreen arbors had no Ca oxalate crystal.Fromarbor,shrub,lianatoherb,the concentration of HCl-soluble Ca decreased gradually,while that of water soluble Ca was in adverse.The concentration of water solu.ble Ca in herbs was significantly higher than tha t in arbors and shrubs.This study showed that in salinized habitats,plant Ca crystals and Ca components differed with plant growth form,and the Ca oxalate in deciduous arbors and shrubs played an important role in withstanding salt stress.