Abstract |
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Salinity is a major environmental problem in the dry Mediterranean regions, affecting rangeland production. This study investigated the effects of salinity on P. equisetiforme an herbal medicine plant used in the treatment of sore throat, cold and cough and in the disinfection of wounds. The impacts of salinity on physiological and anatomical parameters were investigated with various levels of salinity (0, 100, 200, 300, and 400 mM NaCl). Biomass production, stomatal conductance (GS), transpiration (E) and intercellular CO2 concentration (Ci), chlorophylls (a and b) and the carotenoid decreased in parallel with salt stress degree. In contrast, net photosynthetic rate (PN) and the leaf relative water content was declined only at high salt stress (300-400 mM NaCl). The leaf anatomy showed an increase in upper and lower epidermal thickness with salinity and the leaf lamina and mesophyll became thicker at 200-300 mM NaCl maintaining water haemostasis in the leaves. The vascular bundle area was enhanced under salinity whereas thicker-walled xylem vessels with higher density were produced at high salinity. Our results indicated also that P. equisetiforme is relatively high salt tolerant plant surviving up to 200 mM NaCl without any lethal effects. Nonetheless, detailed field experiments with varying salinity regimes are needed to confirm these conclusions. |