Absorção de orvalho em folhas de Combretum leprosum Mart. (Combretaceae) no semiárido

Abstract

The morphological and functional characters of the leaves which help absorption of water and adjustment of the water potential aid to maintain hydration of the plant tissues. Experiments with apoplastic tracer showed the peltate trichomes of Combretum leprosum absorb water and this reaches the mesophyll cells. Measurements of water potential after simulation of dew on the leaves resulted in increased water potential of them. The occurrence of pectic substances in the ordinary cell walls, peltate trichomes and polysaccharide in the mesophyll cells was demonstrated by ruthenium red. The leaf ability to absorb dew and the occurrence of the hydrophilic polysaccharides in trichomes and in the mesophyll cells improved hydric status leaves. In the caatinga dew can be an alternative water source for plants and possibly affect the phenology.