Recovery from Salinity and Drought Stress in the Perennial vs. the Annual and .

Current agricultural problems, such as the decline of freshwater and fertile land, foster saline agriculture development. and species, with a long history of human consumption, are ideal models for developing halophyte crops. A greenhouse experiment was set up to compare the response of the perennial and the two annual and to 30 days of salt stress (watering with 700 mM NaCl) and water deficit (complete withholding of irrigation) separate treatments, followed by 15 days of recovery. The three species showed high tolerance to salt stress, based on the accumulation of ions (Na, Cl, Ca) in the shoots and the synthesis of organic osmolytes. These defence mechanisms were partly constitutive, as active ion transport to the shoots and high levels of glycine betaine were also observed in non-stressed plants. The three halophytes were sensitive to water stress, albeit to a lesser extent. In fact, showed a lower reduction in shoot fresh weight than or , no degradation of photosynthetic pigments, a significant increase in glycine betaine contents, and full recovery after the water stress treatment. The observed differences could be due to a better adaptation of to a drier natural habitat, as compared to the two species. However, a more gradual stress-induced senescence in the perennial may contribute to greater drought tolerance in this species.