Agroecological valorization of Capparis spinosa L.: multi-dimensional salinity plasticity inverstigation and nutrient transport

Water scarcity and land degradation are increasingly constraining agricultural production, and phytotechnology is a promoted sustainable solution. This study investigated Capparis spinosa L. capacity in growing in a saline accentuated environment. The effects of different NaCl concentrations (0 to 200 mM) on growth, leaf physiology and ion selectivity and transport in a caper subspecies native to Tunisia (thorny caper) were evaluated, and plant salinity regulation and resistance mechanisms were characterised. The results showed significant differences in most quantitative morpho-physiological and growth indicators as well as ion accumulation and transport. Under salinity, plants showed some tolerance and physiological plasticity, with a notable development starting from root biomass increase (25%), length (27%), and extending to leaf biomass (18%), area (17%) and blade thickness (60%). Salinity causes a decrease in major cations absorption and a sharp increase in the toxic ions load in leaf tissues, but with a stable Transport rate that characterises caper tolerance through maintaining appropriate selective transport. Indeed, caper plants can grow under saline stress and reduce toxic effects through morpho-physiological adaptation associated with vacuolar compartmentalisation, cation selectivity, and ion selective transport from roots to leaves. Given its plasticity mechanisms, caper stands as a promising sustainable native resource suitable for damaged and saline lands.