不同配置模式下油蒿和柠条对降雨变化的生理生态响应及调节机制

Eco-physiological responses and related adjustment mechanisms of Artemisia ordosica and Caragana korshinskii under different configuration modes to precipitation variation

研究了沙坡头地区固沙植物油蒿和柠条在1m×1m和2m×2m配置模式下的群落学特征,以及在自然和控制降雨条件下的水分关系、气体交换及其调节机制.结果表明:随着土壤含水量的变化,油蒿和柠条的生理耗水和生长特性不同,油蒿的气孔导度、水势、蒸腾速率、光合速率和快速生长均呈现明显的波动性,并且对土壤水分的消耗量高于柠条;柠条的上述指标变化相对低缓而恒定,光合生长速率较低,多年累积生物量却很高.两种植物对水分胁迫的响应过程和调节机制不同,油蒿主要为保水机制,柠条主要为节水机制.在极端干旱年份,柠条的节水、抗逆特性更强.固沙植物种的选择应既利于防风固沙和节约用水,又利于固沙林的稳定.

This paper studied the community characteristics of two sand-fixing plants （Artemisia ordosica and Caragana korshinskii） under different configuration modes （ 1 m×1 m and 2 m×2 m） in the Shapotou region of Northwest China as well as the water relation, gas exchange, and their adjustment mechanisms of the plants under natural and artificial precipitation conditions. With the variation of soil water content, the physiological water consumption and growth characteristics of A. ordosica differed from those of C. korshinskii. A. ordosica presented obvious fluctuation in the stomatal conductance, water potential, transpiration rate, photosynthetic rate, and rapid growth, and had higher water consumption than C. korshinskii. However, the variations of the above-mentioned indices of C. korshinskii were relatively slow and more constant. The C. korshinskii had a lower photosynthetic rate but a very high accumulated biomass over years than A. ordosica. The response procedures and adjustment mechanisms of the two plants under water stress differed, with a water- conserving mechanism for A. ordosica and a water-saving mechanism for C. korshinskii. In extremely drought years, the C. korshinskii had stronger capabilities of water-saving and stress tolerance than A. ordosica. It was suggested that the selection of sand-fixing plants should have a view to the benefits in water saving and sand fixation, and also, to the stability of sand-fixing forest.