Salt Regulation and Leaf Senescence in Aging Leaves of Jaumea carnosa (Less.) Gray (Asteraceae), a Salt Marsh Species Exposed to NaCl Stress

Abstract

The effects of increasing salt stress on leaf senescence and salt regulation were investigated in the halophyte Jaumea carnosa in hydroponic culture experiments. The plants were grown in Hoagland's nutrient solution plus additional NaCl salt (0, 300,400, 500 mMNaCl). Decreases in nucleic acids, protein, and chlorophyll were used as indicators of leaf senescence. The results indicated no definitive pattern of acceleration in leaf senescence with increasing salt stress. Salt regulation was also unaffected as leaves aged under increasing NaCI concentrations. The results are consistent with those of previous studies of the halophyte which indicated that the species was very tolerant of high NaCI concentrations.