Abstract: The ultrastructures of leaf and root in six cotton varieties under NaCl stress were studied using transmission electron microscope.The results showed that various organelles of mesophyll and root maintained morphological integrity under normal condition, while their ultrastructure changed under 0.3% NaCl stress.In mesophyll cells, the chloroplasts of Zhong 50, N52, N203 and K-1 began deformed, with ambiguity in membrane and disorganization in grana lamell.One part of chloroplasts was seriously destroyed.The arrangement of thylakoid was disordered, loosened and twisted.Some of the thylakoid membrane disintegrated and cavitated gradually, even disappeared.The hungry particles increased significantly.In root cells, the numbers of mitochondrion increased and the membrane systems destroyed.The cristaes of mitochondrion were reduced and even vague.The cytoplasm segregated from the cell wall, and the lamellae of nucleolus and mitochondrion suffered disruption.Meanwhile, the chromatin was polymerized and the cell nuclear was degraded.But the mid-maturing varieties N177 and N181 have been undamaged.The mitochondrion and the cell walls had been maintained morphological structure integrity completely.Comparative analysis indicated that the mid-maturing varieties N177 and N181 had anatomic adaptation to the salt stress.The above results showed that the salt resistance of N177 and N181 was stronger than the other four varieties.

Key words: Cotton, NaCl stress, Mesophyll cells, Root cells, Ultrastructure

CLC Number: 

• Q942.4