东北碱化草地的主要盐分Na_2CO_3对羊草危害因素分析

An Analysis of a Main Salt of Alkalizing Meadow Steppe Na_2CO_3—Harming Factors to Leymus Chinensis

通过生态模拟实验,分析了造成东北草地盐碱化盐分Na_2CO_3危害羊草的诸因素,旨在探讨Na_2CO_3对羊草危害作用的实质及其解决途径。分别对水培下的羊草苗施加10mmol/L Na_2CO_3,与其相应因素等强度的渗透、pH、Na^+等单因素,以及Na_2CO_3加磷酸中和等不同的胁迫处理。7天后,测定日相对生长率、脯氨酸积累量,细胞相对透性、叶绿素含量及Na^+、K^+含量等胁变指标。通过比较不同处理下羊草的受害程度,分析各因素在Na_2CO_3危害作用中的地位及其相互关系。结果表明,由Na_2CO_3所造成的高pH 是羊草的最大受害因素,其次才是钠离子效应,与前两者相比,渗透效应非常微弱,甚至可以忽略。用磷酸中和降低Na_2CO_3的高pH,可以明显抵消Na_2CO_3对羊草的危害作用。

Using ecological simulated experiment,the harming factors of Na_2CO_3,which is a main salt of causingthe saline—alkali condition of meadow steppe in Northeast China,to Leymus chinensis have been analysed.The purpose is to expose the action of Na_2CO_3—harming to Leymns chinensis and to seek a way to solve it.Leymus chinensis seedlings grown in nutrient solution were respectively treated with 10mmol/L Na_2CO_3,thesingle factors as osmosis,pH,and Na^+ of equal strength to the corresponding factor of 10 mmol/LNa_2CO_3,and neutralized Na_2CO_3 by adding phosphatidic acid.Some strain indexes,including relativegrowth rate,the contents of accumulative proline and chlorophyll,relative permeability,and the contentsof K^+ and Na^+,were determined after 7 d treated.The role of every factor in the Na_2CO_3—harming and their interrelation were analysed by comparingthe harmed degrees under different treatments.The results showed that high pH caused by Na_2CO_3 was thefirst harming factor to Leymus chinensis,the ionic effects of Na^+ were the second,the osmotic effects werenegligible comparing with the two formers.The harming action of Na_2CO_3 to Leymus chinensis can be obviously relaxed by neutralizing withphosphatidic acid to reduce the high pH of Na_2CO_3.