Arid Zone Research ›› 2023, Vol. 40 ›› Issue (3): 436-444.doi: 10.13866/j.azr.2023.03.10

• Plant Ecology • Previous Articles     Next Articles

Water source of spruce (Picea schrenkiana) at different altitudes in the Tianshan Mountains during the growing season

TIAN Shengchuan1,2,3(),ZHAO Shanchao4,ZHENG Xinjun1,2,3(),WANG Yugang1,2,LI Yan1,2   

  1. 1. State Key laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, China
    2. Fukang Station of Desert Ecology, Chinese Academy of Sciences, Fukang 831505, Xinjiang, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
    4. Natural Forest Protection Center of Xinjiang Uygur Autonomous Region, Urumqi 830001, Xinjiang, China
  • Received:2022-09-15 Revised:2022-11-09 Online:2023-03-15 Published:2023-03-31

Abstract:

Picea schrenkiana is a typical constructive species in the Chinese Tianshan forest ecosystem with important ecological values. In this study, P. schrenkiana at three altitude gradients were selected to study its water sources during the growing season (June to September) in the natural forest conservation area of the northern slope of Tianshan Mountains. The hydrogen-oxygen stable isotope technique was used to determine the δ18O values of xylem water and soil water levels. In addition, the relationships between xylem water or soil water δ18O values and altitude were analyzed, and the IsoSource model was used to quantify the water sources of P. schrenkiana at different altitudes. The results showed that: (1) the δ18O of soil water at the three elevations were depleted in April and enriched from May to September. The δ18O values of stem water at 1450 m elevation showed the greatest variation between months, while the δ18O of stem water was gradually enriched at the three elevations from June to September; (2) the 0-0.2 m soil water contributed more than half of the P. schrenkiana water requirement at the three elevations during the growing season, with the surface soil water average contribution rates of 61.37%, 51.35%, and 58.42% in the high, middle, and low elevations, respectively. In May and June, P. schrenkiana tended to use soil water in all layers equally, and no significant shift in the plant water uptake was observed during the growing season. In addition, the water absorption of P. schrenkiana mainly occurred at 0-0.2 m soil water level, suggesting that it could rapidly absorb rainfall water, which can improve soil hydrology and reduce the damage caused by extreme rainfall. Therefore, strengthening the protection management of P. schrenkiana forests can effectively improve the water conservation capacity of forests and enhance their ecological benefits.

Key words: Picea schrenkiana, stable isotopes, IsoSource model, water source