We investigated whether there were consistent differences in the physiological and anatomical traits and phenotypic variability of an invasive (Prosopis juliflora (Sw.) DC.) and native species (Anadenanthera colubrina (Vell.) Brenan) in response to seasonality in a tropical dry forest. The water potential, organic solutes, gas exchange, enzymes of the antioxidant system, products of oxidative stress and anatomical parameters were evaluated in both species in response to seasonality. An analysis of physiological responses indicated that the invasive P. juliflora exhibited higher response in net photosynthetic rate to that of the native species between seasons. Higher values of water potential of the invasive species than those of the native species in the dry season indicate a more efficient mechanism for water regulation in the invasive species. The invasive species exhibits a thicker cuticle and trichomes, which can reduce transpiration. In combination, the increased epidermal thickness and the decreased thickness of the parenchyma in the dry season may contribute to water saving. Our data suggest a higher variability in anatomical traits in the invasive species as a response to seasonality, whereas physiological traits did not present a clear pattern of response.

No 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.

No abstract