Effect of salt stress on ultrastructure of mesophyll cells in white clover.

The ultrastructural changes of mesophyll cells during salt stress were observed in white clover(Trifolium repens L.) using transmission electron microscopy.The results showed that mesophyll cells arranged loosely and various organelles structure was integrated,at the same time,some starch grains and lipid globules were presented in chloroplasts in the control group.The influence of mild salt stress on msesophyll cell ultrastructure was less.But moderate and severe salt stress induced ultrastructure changes in mesophyll cells.Chloroplast membrane system produced injury;chloroplasts changed from the long oval into around ball;the layers gradual disintegrated,and its contour changed;the minor internal layers happened light expand;the number of grana lamella reduced,and a large number of starch granules appeared;mitochondrial cristae disappearance and mitochondrial swelling,the cell internal structure changed simplify,and even degradation.