Chin J Plan Ecolo ›› 2015, Vol. 39 ›› Issue (12): 1176-1187.DOI: 10.17521/cjpe.2015.0114

• Orginal Article • Previous Articles     Next Articles

Sap flow characteristics and its responses to precipitation in Robinia pseudoacacia and Platycladus orientalis plantations

WU Xu1, CHEN Yun-Ming2,3,*(), TANG Ya-Kun2,3   

  1. 1Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
    2State Key Laboratory of Soil Erosion and Dry-land Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
    and 3Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
  • Online:2015-12-01 Published:2015-12-31
  • Contact: Yun-Ming CHEN
  • About author:

    # Co-first authors


Aim In the loess hilly region, drought stress frequently occurs during the late spring and early summer as a result of insufficient water supply and asynchronous changes between temperature and precipitation. Our objective was to quantify the characteristics of water-consumption through transpirations and their responses to precipitation in the dominant plantations in this region. Methods Thermal dissipation probe (TDP) was used to measure the sap flow density (Fd) of Robinia pseudoacacia and Platycladus orientalis from April through October in 2009 in Ansai National Ecological Experimental Station. Environmental variables, including meteorological factors and soil water content, were simultaneously measured. Important findings The diurnal variation of Fd exhibited a single-peak curve during the growing season of R. pseudoacacia and P. orientalis. The maximum Fd was three times greater in R. pseudoacacia (0.12068 m3·m-2·h-1) than that in P. orientalis (0.03737 m3·m-2·h-1). Except in the rapid-growth season (July to August), the Fd of these two species during the post-precipitation period were significantly higher than that during the pre-precipitation period. The Fd of P. orientalis and R. pseudoacacia was well fitted with transpiration (VT), an integrated index calculated from both vapor pressure deficit (VPD) and solar radiation (Rs), using an exponential saturation function. Generally, Fd increased in response to rising VT, while these values tended to be stable when VT reached about 50 kPa (W·m-2)1/2. Furthermore, R. pseudoacacia showed more sensitive to precipitation (p < 0.001) than P. orientalis, according to different hydraulic conductance model coefficients (fitting parameter b) between pre- and post-precipitation periods. Therefore, R. pseudoacacia could be considered as a precipitation-sensitive species, while P. orientalisasa precipitation-insensitive species. Through analyzing the different responses of plantation species to precipitation in the loess hilly region, this study provides a scientific basis for the local plantation management from the aspect of tree water use during ecological restoration.

Key words: Robinia pseudoacacia, Platycladus orientalis, sap flow, environmental parameters, water use