胡杨生理指标对塔里木河下游生态输水的响应

Response of Physiological Indexes of Populus euphratica to Ecological Water Transport in the Lower Reaches of the Tarim River

根据塔里木河下游受生态输水影响的断面和未受输水影响断面的胡杨生理指标脯氨酸、脱落酸和叶片含水量的变化,就胡杨生理指标对生态输水的响应进行了初步分析。结果显示:①在受到生态输水影响的断面,胡杨叶相对含水量增加,脯氨酸、脱落酸因水分条件的好转而分解降低;在未受到生态输水影响的断面,因为干旱胁迫程度的加重,胡杨叶相对含水量减少,脯氨酸、脱落酸因积累而增加。②在生态输水前,胡杨生理指标总体上与地下水位变化相一致,即:随着地下水位的降低,胡杨脯氨酸和脱落酸水平增加;随地下水位的升高,脯氨酸和脱落酸水平有降低的趋势。③从个别数据的异常看,在塔里木河下游,当地下水位较低时,地下水位的升降仅是影响胡杨干旱胁迫的一个因子。因此,在塔里木河下游开展的生态输水工程,对该区胡杨生长的影响非常显著,它在一定程度上缓解了胡杨水分的亏缺,减轻了干旱胁迫程度。

According to the variation of proline (Pro),abscisic acid (ABA) and water content of Populus euphratica Oliver leaf in two sections that has and has not been affected by ecological water transport respectively,the response of physiological indexes of Populus euphratica to ecological water transport in the lower reaches of the Tarim river is preliminarily discussed.The results are as follows:① At the section affected by the ecological water transport,the Pro and ABA decompose and the relative water content of the leaf increases because P.euphratica can easily get water;at the section not affected by the ecological water transport,the Pro and ABA contents accumulate and the water content of the leaf decreases because the extent of drought stress subjected by P.euphratica reinforces;② By and large,the change characteristic of such three physiological indexes is consistent with the groundwater level change before ecological water transport.In other words,the content of Pro and ABA accumulates when the groundwater level declines and decomposes when the groundwater level rises;③ From the abnormality of some data,it is believed that the groundwater level is not the single factor affecting the extent of P.euphratica subjected to drought stress when it exceeds some depth.In a word,the effect of ecological water transport project on P.euphratica is very obvious in the lower reaches of the Tarim river,and it eases water deficit and drought stress to P.euphratica in certain extent.