Abstract:

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 groundwater 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.

Key words: Populus euphratica , Tarim River, physiological response, xeromorphic, water-recharge