关键词: 巴丹吉林沙漠, 植物水分状况, 水分传输, 水力特性

Abstract: We measured soil water potential, plant water potential, and hydraulic conductivity of four typical plant species, namely Zygophyllum xanthoxylon, Artemisia ordosica, Ferula bungeana, and Nitraria tangutorum, in different locations of high sandy mountains in the Badain Jaran Desert and at different distances from the lake, with the aim to uncover the mechanisms of water transport. The results showed that: (1) water potential values shared the same characteristics for all the four plant species, namely, root>stem>leaf. Among those species, the averagewater potential of various organs of the shrub N. tangutorum was the lowest, while that of the perennial herbaceous F. bungeana was the highest. In terms of location, the same species had the lowest water potential in the upper part of the sandy mountain, and the highest in the lower part of the sandy mountain. The lowest and highest water potential of each organ of N. Tangutorumwas obtained at 100 m and 20 m away from the lake, respectively. In terms of diurnal variation, water potential values of all species were the highest before dawn. (2) Soil water potential of all plots fluctuated and rose with increasing soil depth. (3) Among the four species, hydraulic conductivity was highest in Z. xanthoxylonand lowest in F. bungeana. In terms of location, hydraulic conductivity of all species on the sandy mountain shared the same characteristics, namely, upper part > middle part > lower part. The hydraulic conductivity of N. Tangutorum at different distances from the lake showed as 20 m away from the lake < 50 m away from the lake < 100 m away from the lake. In terms of diurnal variation, hydraulic conductivity of all species was the lowest at midday. Our results suggest that plant water potential and hydraulic conductivity were positively correlated and that there is an adaptive water transport strategy for plants to maintain their water balance and support their growth in special habitats.

Key words: Badain Jaran Desert, plant water status, water transport, hydraulic characteristics.