Changes in foliar epicuticular wax and photosynthesis metabolism in evergreen woody species under different soil water availability

Abstract

Epicuticular waxes (EW) are important for plant physiology as a protective barrier against water loss. Thus, the main goal of this study was to evaluate the ecophysiological performance of Cynophalla flexuosa, an evergreen woody species, under different foliar EW contents. The study was conducted during three periods throughout the year in a seasonally dry tropical forest area. The xylem water potential decreased to 70% at midday. The main EW components were n-alkane chains, effective in keeping the cuticle impermeability. We analyzed intact leaves and leaves with EW removed. C. flexuosa did not alter its photosynthetic performance throughout the day in leaves where EW was removed, except under the lowest soil water balance. Furthermore, foliar biochemical metabolism activity also was maintained. Thus, photochemical and gas-exchange values showed a high resilience, although soil water availability decreased. These findings highlight that this evergreen woody species performed under semiarid conditions with high foliar dynamic traits.