新疆塔里木河下游生态输水与胡杨叶片的生理及形态响应

选择塔里木河下游3个典型断面的15个研究样地,分析和测定了塔里木河下游2000￣2002年生态输水前后不同研究样地的地下水位、地下水含盐量和胡杨(Populus　euphratica　Oliv.)叶片中脯氨酸、可溶性糖、植物内源激素脱落酸和细胞分裂素的含量以及胡杨叶片的形态结构变化,研究了塔里木河下游主要建群种胡杨对生态输水的生理与形态的响应和适应性。结果表明,塔里木河下游胡杨生长已受到不同程度的干旱胁迫;输水后各样地地下水位均有所上升,胡杨对浅层地下水位的变化表现出明显响应,胡杨受到的生理胁迫降低,胡杨叶片角质层厚度、维管束导管官腔直径及管壁厚度皆随地下水位的上升而减少;随着地下水位的上升,地下水含盐量分别提高1.76　￣　2.47倍,输水效果由于盐对植物的生理胁迫作用的增加而有所减弱;在塔里木河下游极端干旱环境下,胡杨林保育恢复的合适地下水位埋深为3.15　￣　4.12　m,地下水含盐量为67.15　￣　72.65　mm。

Physiological Response of Populus euphratica to Artificial Water-recharge of the Lower Reaches of Tarim River

Physiological and xeromorphic responses and adaptation of Populus euphratica Oliv. to artificial water-recharge of the lower reaches of Tarim River in Xinjiang Uygur Autonomous Region were investigated. Measurements were made of groundwater table, salt concentration in groundwater, as well as the contents of proline, soluble sugars, plant endogenous hormone (abscisic acid, ABA and cytokinin, CTK), and anatomic structure in P. euphratica leaves along 15 transects in three areas before and after the water-recharge. Results showed that, following the events of water-recharge, the groundwater table raised, which reduced the physiological stresses of P. euphratica. With the rising groundwater table, the groundwater salinity increased by 1.76 to 2.47 folds; the thickness of cuticular of epidermis cell, the vessel diameter and wall thickness of vascular bundle of mesophyll cell in P. euphratica leaves were reduced; but the developmental state of palisade tissue of leaves were not affected. The effect of water-recharge was at the optimum to the recovery and restoration of ecological environment in this region when groundwa- ter table was raised to a range from ? 3.15 to ? 4.12 m below soil surface, and salt concentration of groundwater maintained in a range from 67.15 to 72.65 mmol/L.