Seasonal variability in physiological and anatomical traits contributes to invasion success ofProsopis juliflorain tropical dry forest

Abstract

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.

Peer Review #1 of "Seed germination and early seedling survival of the invasive species Prosopis juliflora (Fabaceae) depend on habitat and seed dispersal mode in the Caatinga dry forest (v0.2)"

“…The higher nutrient availability in the flooding plain and terrace, along with the low aluminum content in the flooding plain, may also be important because excess of this element in the soil can impair the calcium, magnesium, phosphorous and potassium absorption by Prosopis plants, as reported for P. juliflora in the Caatinga (Jiménez et al, 2008;Oliveira et al, 2017).…”

“…Prosopis juliflora was introduced in the Caatinga at early 1940s as a food source for livestock and successfully spread across the region by invading and forming monospecific stands, particularly across former agricultural lands along river banks and flooding plains (Nascimento et al, 2014;Almeida et al, 2015;Santos and Diodato, 2015;Oliveira et al, 2017).…”

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

“…Observations and records of the material were performed under a Leica microscope model DM500 (Germany). Micromorphometric analyzes were performed from images: mesophyll thickness (and their parenchyma), abaxial and adaxial epidermis thickness, and total leaf thickness; stomata were counted to determine stomatal density by area (0.5 mm 2 ) as described in detail by Oliveira et al (2017).…”

“…Low water availability and high radiation, the typical semiarid abiotic factors, lead to changes in the foliar anatomy, reduced photochemical activity, and increased photoprotection mechanisms of photosynthetic machinery (Oliveira et al 2017). Thus, gas exchange is affected by reducing stomatal conductance and consequently the net CO2 assimilation (Chaves et al 2016).…”

“…Thus, gas exchange is affected by reducing stomatal conductance and consequently the net CO2 assimilation (Chaves et al 2016). Furthermore, one expects imbalance in leaf biochemical metabolism, especially of sugars (Oliveira et al 2017).…”