Chin J Plant Ecol ›› 2011, Vol. 35 ›› Issue (10): 1029-1037.DOI: 10.3724/SP.J.1258.2011.01029

Special Issue: 稳定同位素生态学

• Research Articles • Previous Articles     Next Articles

Seasonal variation of water sources for plants growing on continuous rock outcrops in limestone area of Southwest China

NIE Yun-Peng1,2,3, CHEN Hong-Song1,2,*(), WANG Ke-Lin1,2   

  1. 1Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
    2Huanjiang Observation and Research Station for Karst Ecosystems, Chinese Academy of Sciences, Huanjiang, Guangxi 547200, China
    3Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2010-10-29 Accepted:2011-03-11 Online:2011-10-29 Published:2011-11-07
  • Contact: CHEN Hong-Song

Abstract:

Aims Woody plants in karst regions often grow on the continuous rock outcrops. However, the source of water for these plants is unclear. This study aimed at investigating the seasonal variation of water sources for plants growing on continuous limestone outcrops in southwestern China.
Methods Stable isotope techniques were used to access plant water uptake patterns for five different species in both wet and dry seasons. Then the IsoSource model was used to determine the probable contribution of each potential water source to total plant water uptake.
Important findings In the wet season, an average of >80% of water for four of the five species came from rainwater received in the previous 15 days and stored in fissures in shallow layers. Water accessed by the other species came mostly from recent rainwater; however, the species simultaneously absorbed water from fissures in deep layers that had been recharged from previous precipitation. In the dry season, all five species utilized both recent and previous rainwater, and the two tree species and one large evergreen shrub species used more previous rainwater (>50%).

Key words: continuous rock outcrops, IsoSource model, limestone, stable isotope, water sources of plants