摘要
沙米(Agriophyllum squarrosum)是生长在流动沙地上的植物,主要分布在中亚干旱、半干旱地区。以室内生长3个月的沙米幼苗为材料,经0~400mmol·L^(-1) NaCl溶液胁迫处理7d,检测植株的含水量及主要矿质离子在根茎叶的分布、积累和运输特征。结果表明:随着盐浓度的增加,沙米幼苗的含水量持续降低;体内Na^+、Cl^-的含量不断升高,K^+在根茎中先升高后降低,Ca^(2+)在各组织均呈下降趋势;此外,茎与叶的盐离子选择吸收系数SK,Na先升高后降低,根与茎SK,Na先降低后升高,并且均在200mmol·L^(-1)时达到临界值。盐浓度在0~200mmol·L^(-1)时,沙米根部的Na^+吸收持续增加,能够有效地抑制Na^+向地上部分的运输和积累;在盐浓度大于300mmol·L^(-1)时,Na+主要通过区隔化作用积累在茎部,即在高盐胁迫下茎部是沙米截留盐分避免其向上运输的主要部位。
Agriophyllum squarrosumis an annual desert plant adapted to mobile sand dunes in arid and semi-arid regions of Central Asia.In this study the A.squarrosumseedlings of three months were subjected to salt stress by soaked in 0-400 mmol·L-1 NaCl solutions（in 1/2 MS medium）for 7 days separately.We examined their water contents and main mineral ion contents in their roots,stems and leaves during salt stress.The experiment results indicated that the water content of A.squarrosumseedlings reduced gradually as NaCl concentration increased,but the Na＋and Cl-content kept roes observably,the K＋content increased in the beginning and the Ca^（2＋） content cut down in root,stem and leaf.In addition,the salt ion-selective absorption coefficient SK,Naof stem and leave increased at the beginning and then decreased,the SK,Naof root and stem is just showed on the opposite result,and both of them reaching a critical value at 200 mmol·L^（-1）.Which indicated that A.squarrosumcould effectively inhibit the absorption and accumulation of Na~＋in stem and leaf at0-200 mmol·L^（-1）,and Na＋accumulated in the stem mainly through compartmentalization function when the NaCl concentration was greater than 300 mmol·L^（-1）.Thus stem is the major tissue of A.squarrosumresponse to high salt stress because of its ability to preventing Na~＋carrying from root to leaf.
出处
《中国沙漠》
CSCD
北大核心
2016年第3期702-707,共6页
Journal of Desert Research
基金
国家重点基础研究发展计划项目(2013CB429904)
国家自然科学基金项目(41201048)
