Biodiv Sci ›› 2018, Vol. 26 ›› Issue (6): 564-571.DOI: 10.17520/biods.2017342

• Original Papers • Previous Articles     Next Articles

Water utilization sources of Populus euphratica trees of different ages in the lower reaches of Tarim River

Jiang Zhang1, Guifang Li1, Yaling He2, Yudi Mu3, Li Zhuang1,*(), Hongling Liu4,*()   

  1. 1 Key Laboratory of Xinjiang Phytomedicine Resource Utilization of Ministry of Education, College of Life Sciences, Shihezi University, Shihezi, Xinjiang 832003
    2 Faculty of Medicine, Shihezi University, Shihezi, Xinjiang 832003
    3 College of Life Sciences, East China Normal University, Shanghai 200241
    4 College of Chemistry and Life Science, Chengdu Normal University, Chengdu 610101
  • Received:2017-12-31 Accepted:2018-05-03 Online:2018-06-20 Published:2018-09-11
  • Contact: Zhuang Li,Liu Hongling
  • About author:

    # Co-first authors

Abstract:

Water availability is one of the most important factors affecting the growth and reproduction of terrestrial plants, particularly in arid regions. Understanding the strategies of desert riparian plants to circulate and utilize water can reveal the scientific basis for ecological water conveyance engineering and contribute to planning ecological restoration of similar areas. In this study, we examined whether Populus euphratica trees of different ages in the lower reaches of Tarim River differed in their water sources by using the stable hydrogen and oxygen isotope technology. Specifically, for P. euphratica of different ages in the same habitat, we measured hydrogen and oxygen stable isotope ratios (δD and δ18O) values of xylem water and potential water sources (soil moisture and ground water). Then, we used multi-isotope mass balance analysis (IsoSource) to calculate the possible contributions of potential water sources to the total water content in plants. We found significant differences of δ18O value for soil moisture at different soil depths. Also, the δ18O values of young wood (-7.83 ± 0.07‰), mature wood (-8.53 ± 0.11‰) and over-mature wood (-9.36 ± 0.21‰), which were significantly different, while δD values did not differ statistically among the forest types. Furthermore, δ18O values of P. euphratica in three kinds of forest age became lower while the distance was deeper from soil surface and gradually approached to ground water on the whole. The shallow soil water in 0-60 cm was significantly affected by evaporation. The isotopic composition of soil water had experienced a strong evaporation and fractionation process. And soil water content was small, while δ18O values were large. Finally, our results showed that water utilization of P. euphratica of different ages came from different sources. The young wood of P. euphratica used an average of 16.2% of its water from 80-140 cm of the soil, 21.4% from 140-220 cm, and 24.6% from 220-340 cm and the average utilization ratio of ground water was 24.5%. In comparison, mature wood of P. euphratica mainly utilized the water from 220-340 cm of the soil and the ground water, with the utilization rate being 36.9% and 42.3%, respectively. Over-mature wood had water utilization ratios of 32.8% from 140-340 cm of soil and 49.3% of ground water.

Key words: stable oxygen and hydrogen isotopes, water utilization sources, soil water, forest age, Populus euphratica, ground water