EFFECTS OF VARYING SALINITY ON LEAVES OF ZOSTERA-CAPENSIS SETCHELL .1. ULTRASTRUCTURAL-CHANGES

The ultrastructural morphology of leaf blade epidermal cells of the se agrass Zostera capensis Setchell was found to change with salinity. Ep idermal cells of plants exposed to high salinity (40 parts per thousan d) compared with those exposed to low salinity (2 parts per thousand) were characterized by the presence of complex wall ingrowths, a highly invaginated plasmalemma, mitochondria closely associated with the pla sma membrane, many chloroplasts, an increase in the width of an electr on-dense layer in the outer tangential wall, and smaller vacuoles. In addition, the relative area of mitochondria and chloroplasts increased with salinity. Leaf blade epidermal cells of plants exposed to very h igh salinity (60 parts per thousand) showed signs of damage.