Foliar water uptake of four shrub species in a semi-arid desert

Abstract

Dew water plays an important role in supporting biological processes in desert ecosystems. Although some mechanisms underlying how plants survive in water-limited environments have been investigated, the water-use strategies of most desert plants remain unclear. We investigated whether foliar uptake of dew water occurs in four dominant shrub species (Artemisia ordosica, Hedysarum mongolicum, Salix psammophila, and Caragana korshinskii), in the Mu Us Desert of northern China. A fluorescent tracing experiment indicated that all four species absorbed water via leaf trichomes and cuticles, and A. ordosica also absorbed water via the stomata. A dew water exposure experiment and isotopic tracing revealed that water entered the leaves and stems of the four species, thereby enhancing their water potential. The relative contribution of dew water to the total water in the leaves of A. ordosica, H. mongolicum, S. psammophila, and C. korshinskii was 20.0 ± 7.0%, 8.4 ± 6.4%, 7.8 ± 1.9%, 3.1 ± 2.3%, respectively. The results demonstrated that all four species had the capacity to absorb water by their leaves, and the absorbed water could be transported to the stems. Our findings suggest that foliar water uptake may be one of the survival mechanisms by shrubs in the desert environment.