Seasonal and microclimatic influences on the ecophysiology of Mediterranean coastal dune plants

Abstract

Coastal dune environment, due to the complex coast-to-inland gradient, contributes greatly to plant biodiversity. The ability of plants to withstand the harsh conditions of this habitat leads to a peculiar vegetation profile which may be affected by the natural and artificial degradation of the coast. Given that these disturbances are bound to increase in the future, there is a great interest in the deepening of knowledge of resistance mechanisms allowing plants to colonize this stressful environment. Our focus was on physiological stress markers that could be early signals of changes before ecological disturbances become evident. Three representative species of the different dune zones, Achillea maritima, Ammophila arenaria and Helichrysum stoechas were studied during the four seasons. Winter and summer were confirmed as the most critical seasons with different levels of stress depending on the coast profile where plants grew. The shoreline-inland gradient of stress conditions was evident only for A. arenaria, whose physiology was negatively affected in foredune during summer and for this reason this species could be a useful indicator of increasingly harsh environmental conditions. Physiological performances of the studied species changed across the seasons and the occupied niches, in accordance with the respective strategies of resistance.

Field comparison of ecophysiological traits between an invader and a native species in a Mediterranean coastal dune

“…Respecting maximum photochemical efficiency, and considering the optimum values between 0.75-0.85 in normal plants (Bolhàr-Nordenkampf andÖquist, 1993, Maxwell andJohnson, 2000), the Fv/Fm values in A. maritima denote that the native species, with values through the year higher to 0.760, was not under particularly stressing conditions. These data agree with those recorded by Scorce et al (2019) in the same species in a coastal dune system in Italy. In contrast, ΦPSII was affected by the meteorological conditions, pointing out the species underwent certain dynamic photoinhibition, especially in winter when the lowest values were recorded.…”

“…photosynthetic rate increased during summer Scorce et al (2019). also studying A maritima, recorded summer values of Ψmd as low as -2 MPa, Thus the Ψmd values registered in this study are moderately high.…”

Floral traits and reproductive success variation among inflorescence orders in Eryngium maritimum

“…Although this species is restricted to sandy dunes, where the sand volume is highly mobile (Isermann & Rooney, 2014), plants can also be found hundreds of meters inland (Gil, 1994), displaying a gradient from the coast to inland areas (Sorce et al . 2019). This means that species along the dune are exposed to different environmental and microclimate conditions (Sorce et al .…”

“…This means that species along the dune are exposed to different environmental and microclimate conditions (Sorce et al . 2019), which could influence reproductive behaviour of the plants, involving morphometric or phenological changes. However, the specific effect of location on the investment in reproductive structures has not been sufficiently analysed in the western Mediterranean, which could be critical to understanding differences between the inner and outer coastal subpopulations.…”

Effect of Zinc Priming on Salt Response of Wheat Seedlings: Relieving or Worsening?

“…The concentrations of pigments were expressed as mg g −1 FW. Nineteen days after imbibition, before the collection of seedlings, photosynthetic efficiency was determined by analysing chlorophyll a fluorescence by a portable fluorometer (MINI-PAM Walz, Effeltrich, Germany), according to Sorce et al [59]. Eight records per pot, each one on a distinct plant, were taken on leaves dark adapted for 30 min by dark leaf clips (Walz) before the measurement of Fo, Fm, and Fv/Fm; the latter is an expression of the maximum PSII quantum yield [60].…”