NaCl胁迫对3种榆树幼苗生理特性的影响

为给盐碱地区引种栽培提供理论依据,以木栓榆(Ulmus thomasiiSarg.)、厚叶榆(U.crassifolia)和白榆(U.pumila)的1年生盆栽苗为研究对象,测定其在不同浓度NaCl胁迫下的叶片相对电导率(RC)、叶绿素(Chl)、丙二醛(MDA)、脯氨酸(Pro)、可溶性糖(SS)含量等项指标,结果表明:随着NaCl浓度增加和胁迫时间的延长,各种幼苗的Pro含量均逐渐增加,初期上升不明显,中后期增加显著,但木栓榆和厚叶榆Pro增幅比白榆小;白榆叶片RC上升最大,木栓榆最小;白榆的MDA增加最明显,厚叶榆也很明显,但增幅不大,木栓榆MDA增幅最小,膜系统最稳定。3种榆树幼苗初、中期的SS含量均迅速增加,后期均先升后降,再回落到各自的最低点;3种幼苗Chla/Chlb值呈上升趋势,白榆Chl总量下降明显,木栓榆和厚叶榆降幅不很明显。综合各项指标,木栓榆、厚叶榆抗盐能力较强,白榆抗盐能力较弱,属中等耐盐树种。

Effect of NaCl stress on physiological characteristics of three elm species seedlings

By studying one-year potted seedlings of Ulmus thomasii Sarg.,U.crassifolia and U.pumila as subjects,we determined their growing status quo,leaf relative conductivity(RC),chlorophyll(chl),Pro,MDA,soluble sugar(SS) content under NaCl stress with different concentration to disclose its salt-tolerance and lay theoretic foundation for introduction and cultivation of three tree species in saline-alkali area.Results showed that(1) with increase of NaCl concentration and lengthening of stress time Pro content of all kinds of elm seedlings gradually increased,inconspicuous at the initial stage but remarkable in the middle and final stages;the increase of Pro content of U.thomasii and U.Crassifolia was smaller than that of U.pumila;MDA of U.pumila significantly improved,meanwhile the increase of leaf MDA in U.thomasii was the smallest among them,and stability of U.thomasii membrane system was best;leaf RC of U.pumila increased most obviously while that of U.thomasii rose the least;at premegaphase stage SS content of various elms rapidly increased,then increased more,but then decreased,and finally returned to its own lowest point;the ratio of chla & chlb presented an increasing trend but leaf total chl content decreased.Proline,soluable sugar,MDA of U.thomasii and U.Crassifolia had an inconspicuously decreasing trend.Ultimately through overall assessment,it was concluded that salt-tolerance of U.thomasii and U.Crassifolia was higher,and that of U.pumila was lower,belonging to the middling salt-tolerant tree species.