苏打盐碱胁迫对长穗冰草幼苗生长和K^+、Na^+含量的影响

Effect of Saline-Sodic Stress on Seedling Growth and Content of K^+ and Na^+ of Agropyron elongatum

在人工模拟不同pH梯度的苏打盐碱土上种植长穗冰草,旨在探讨长穗冰草苗期耐碱性和盐碱胁迫下K+、Na+含量的变化及其生理响应。结果表明,长穗冰草是一种耐碱性较强的植物,在土壤pH≤10.5的苏打盐碱土上可以出苗和生长。与对照(pH7.5)相比,pH≤8.5的土壤对长穗冰草出苗有促进作用,pH>10.5时对出苗产生严重抑制,长穗冰草出苗最适宜的pH为8.5。长穗冰草的株高随土壤pH值的升高而下降(r=-0.9406**),地上部干重和分蘖数随土壤pH值的升高而增加(r=0.8834**和r=0.9787**)。苏打盐碱胁迫抑制长穗冰草顶端生长优势的同时,促进了幼苗地上部干重与分蘖数的增加。分蘖数可以作为衡量长穗冰草耐碱性强弱的生长指标。随着苏打盐碱胁迫的增强,长穗冰草地上部K+含量不断降低,Na+含量显著升高,K+/Na+比值减小,表明Na+含量的升高和K+/Na+比值的降低可能是抑制长穗冰草生长的主要原因之一。K+、Na+的含量变化对维持长穗冰草植物细胞的离子平衡起到了积极的调节作用。

In order to understand the tolerance of Agropyron elongatum seedling to saline-sodic stress,the seedling emergence and growth of Agropyron elongatum under saline-sodic stress were investigated.The results showed that Agropyron elongatum was a grass which adapted to high pH sodic soil.It can emerge and grow in the sodic soil of pH≤10.5,increased pH of soil accelerated Agropyron elongatum seedling emergence when pH≤8.5.Seedling emergence would be reduced obviously when pH>10.5.pH 8.5 is approperiate for the seedling emergence of Agropyron elongatum.With increasing of soil pH,the height of Agropyron elongatum seedlings decreased(r=-0.9406^(**)),the dry weight of shoot and number of tillerings of Agropyron elongatum increased(r=0.8834^(**) and r=0.9787^(**)),but they would be decreased if pH of soil was higher than 9.9.Number of tillerings can be used as a parameter for sodicity tolerance screening for Agropyron elongatum.With saline-sodic stress increasing,the content of K^+ reduced and the content of Na^+ increased in the shoot of Agropyron elongatum,the ratio of K^+/Na^+ also reduced.Higher Na^+ and lower K^+/Na^+ is a part of regime of height reductiong for Agropyron elongatum under saline-sodic stress.The variation of K^+、Na^+ contents played a regulation role in ions equilibrium in cells.