Effect of substrate salinity on growth and on submicroscopic structure of leaf cells of Atriplex halimus L

For optimal growth Atriplex halimus requires slight salinization of the growth substrate. It tolerates higher salt concentrations, but concentrations above 14 atm retard growth. At 9-14 atm, changes in the submicroscopic structure of leaf cells occur, viz. swelling of chloroplasts and mitochondria, appearance of numerous large lipid droplets, swelling of the nuclear membranes, extensive vacuolization, and distortion of the tonoplast with formation of numerous myelin bodies. There is no fundamental difference between the changes induced by chloride and sulphate types of salinity, although plants grown under sulphate salinity are much poorer in appearance. It is not yet possible to correlate structural changes with gross physiological phenomena. More direct investigations on the functions of the salt-affected organelles are needed.