Foliar condensate absorption capacity of four typical plant species and their physiological responses to water in the Mu Us Sandy Land of northwestern China

  Objective  In this study, we examined Agriophyllum squarrosum, Corispermum puberulum, Chenopodium aristatum, and Sophora alopecuroides in the Mu Us Desert of northwestern China to explore the ability of leaf condensate absorption and their physiological responses to water.

  Method  We determined whether the condensate can be absorbed by the leaves of four plant species, and whether the absorbed water can be transported to the root and rhizosphere soil by dew covered experiments and stable isotope tracer technology to contrast the δ²H values of samples in the leaves, roots and rhizosphere soil from the treatment and control. Meanwhile, we measured leaf water potential (Ψ_L), leaf water content (w_L), and stomatal conductance (Gs) before and after dew treatment by dew point water potential meter, electronic balance and plant porometer in order to evaluate the effects of foliar condensate absorption on the species.

  Result  (1) After the deuterium labelled condensate treatment, the δ²H values in samples of leaves (20‰−100‰) in the treatment group of four plant species were significantly higher than control (−25‰− −15‰); the δ²H values in samples of root(−45‰ − −30‰) and rhizosphere soil (−50‰ − −40‰) in the treatment group did not change significantly compared with control. (2) After the dew treatment, Ψ_L, w_L of A. squarrosum increased by 23.81%, 2.49%, and Gs of it decreased by 57.40%, respectively; w_L of C. puberulum increased by 2.45%, but the Ψ_L and Gs were not change significantly; Ψ_L of C. aristatum increased by 21.95%, but the w_Land Gs were not change obviously; for S. alopecuroides, there were no significant differences in Ψ_L, w_L and Gs.

  Conclusion  We find that all of the four plant species can absorb condensate through leaves, but the water cannot be transported to the root and rhizosphere soil. Agriophyllum squarrosum, Corispermum puberulum and Chenopodium aristatum could improve their water physiological state through water absorption. It may be an important water use strategy for them to adapt to drought environment, for this helps the plants to survive. However, Sophora alopecuroides does not significantly respond to foliar condensate absorption and also could not improve its water physiological state through this process.