Abstract: The effects of salt stress on the ultrastructure of cells membrane system were studied under laboratory conditions. The results showed that salt stress destroyed the normal construction of cells membrane system in Maize, the nuclear membrane, mitochondrion membrane, plasma membrane, chloroplast membrane and vacuolar membrane were destroyed at 50 mmol·L^-1 NaCl stress. The most conspicuous changes were swelling of the thylakoid membrane and disorganization of grana. At 100 mmol·L^-1 NaCl stress, the nuclear membrane, mitochondrion membrane, plasma membrane, chloroplasts membrane and vacuolar membrane were destroyed seriously. The plasma membranes were destroyed and the cracked chloroplasts congested intercellular spaces. The outer membranes of chloroplasts were destroyed, and even disintegrated. The mesophyll cells were full of membrane structures, the direction of grana aline changed and nappe decreased, the basal granule and matrix had not limits, some basal granule and chloroplasts disintegrated. The nuclear membranes were destroyed and disintegrated, chromosome of nuclear were highly condensed, the quantity of mitochondrion increased, its membrane was destroyed, even wholly mitochondrion was disjointed. The vacuolar membrane was destroyed. Because some biomembrane system were destroyed, the cells were full of vesicles. The mesophyll cells arises plasmolysis, even cell wall ruptured and wholly cell moltened.

Key words: salt stress, Maize, mesophyll cells, biomembrane, ultrastructure