Relationships between xylem embolism and eco-physiological indices in eight woody plants in situ (II): The relationship with photosynthetic eco-physiological indices

Abstract

The relationship between xylem embolism and eco-physiology indices (i.e. photosynthetic available radiation, temperature, relative humidity, photosynthetic rate, transpiration rate, stomatal conductance and water use efficiency) in eight tree species was investigated in situ. The species studied, Robinia pseudoacacia L., Acer truncatum Bge., Hippophae rhamnoides L., Ulmus pumila L., Pinus tabulaeformis Carr., Pinus bungeana Zucc.ex Endl., Ligustrum lucidum Ait., and Salix matsudana Koidz. f. pendula Schneid, grow well on the Xilin campus of Northwest A&F University. Results indicated that photosynthetic available radiation, air temperature and relative humidity can affect xylem embolism by daily adjustment of stomatal conductance, transpiration rate and water relations of a tree. Embolism was a common case in the daily growth of the plants, and there was some correlation between xylem embolism and photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency. Embolism may thus be an adaptive mechanism by some tree species to water stress.