磷酸中和缓解Na_2CO_3对星星草的胁迫作用

Relaxation of Na_2CO_3 stress on Puccinellia tenuiflora (Griseb)Scribn. et Merr.plants by neutralizing with H_3PO_4

对星星草施加用磷酸中和至不同ｐＨ的１００ｍｍｏｌ／ＬＮａ＿２ＣＯ＿３胁迫处理，并测定其胁变指标。结果表明：中和至ｐＨ６～９均可缓解１００ｍｍｏｌ／ＬＮａ＿２ＣＯ＿３对星星革的胁迫作用，其中以ｐＨ８效果最佳。中和至ｐＨ８可使茎叶和根的相对生长率分别比未中和的提高了５８％和８８％；明显促进根生长，使根冠比提高；使茎叶中的脯氨酸含量降至未被胁迫的对照（ＣＫ）水平，柠蒙酸含量明显下降；使根中Ｋ￣＋含量上升、Ｎａ￣＋含量下降；茎叶中Ｋ￣＋含量上升、Ｎａ￣＋含量下降的幅度最大；使叶片电解质外渗率降至ＣＫ水平。实验结果进一步证明了高ｐＨ是Ｎａ＿２ＣＯ＿３胁迫作用的主要因素之一。用磷酸等酸性物质中和可望成为治理碱地的一种有效措施。

Puccinellia tenuiflora plants were stressed with 100mmol/L Na2CO3 which were neutralized to various pHsby adding H3PO4.Some strain indexes in the plants were determined.The treatment of neutralizing to pH8achieved the best result in relaxing Na2CO3 stress on Puccinellia tenuiflora plants.In the pH8 treatment,therelative growth rates of shoot and root were respectively more than 58%and 88%of without neutralizedone;the root growth was obviously promoted,which made an increase in root /shoot ratio; the prolinecontent in shoot dropped to the level of no stressed contrast;the citric acid content in shoot had a drop belowthe level of the contrast;the K+ content increased and the Na+ content decreased in roots,the degrees of theincrease in K + and the decrease in Na + were the greatest in shoots;the leakage rate of electrolyte in leavesdropped nearly to the level of the contrast.The experimental results supported that the high pH was themain factor of Na2CO3 stress. It can be expected to neutralize with H3PO4 or other acidic substances as aneffective method to recover alkaline soil.