Trichomes: a means for foliar water uptake (FWU) (Plant J)

Foliar water uptake (FWU); water uptake through the leaf surface, is observed in several species and helps in drought conditions through water uptake from fog, snow, dew and rain. In this paper, Schreel et al. showed trichomes as a major source of FWU in beech (Fagus sylvatica L.) plants. Trichomes are large epidermal hairy projections on the leaf surface. Using water soluble fluorescent tracers, the authors observed a strong fluorescence in trichomes, a weak signal in epidermal and collenchyma cells, and an absence of signal in substomatal cavities, indicating trichomes as a major means of surface absorption. This is further supported by the evidence that trichomes lack the cuticle and their cell walls are rich in pectin molecules, amenable for water absorption. Beech leaves subjected to 3.5 hours dehydration showed the empty trichomes, of which 75% were filled with water after 4 hours of rehydration. Thus, this work shows trichome-absorption and to a lesser extent cuticular-absorption as means for FWU in beech plants. (Summary by Vijaya Batthula @Vijaya_Batthula) Plant J. 10.1111/tpj.14770