Calcium deficiency and plant ultrastructure

Abstract

Abstract Calcium deficiency was induced in developing potato sprouts by growing them in a humid atmosphere. As calcium deficiency symptoms occurred first at the elongation zone of the sprouts under the apical bud, tissue pieces of the cortex of this zone were prepared for electronmicroscopic investigation. Beginning stages of cytoplasm degeneration in the calcium‐deficient tissue were observed in cells adjacent to individual cells with severe calcium autolysis. The beginning breakdown of the cytoplasm was indicated by protuberances and beginning disintegration of the plasmalemma, accumulation of degenerative vesicles, and the beginning disintegration of the tonoplast. Most of the proplastids in relatively healthy‐looking cells in the neighborhood of the cells with calcium deficiency autolysis did not contain starch, while starch was abundant in most of the proplastids in the corresponding tissue of the control plants. This was considered as a result of the retarded growth of the calcium‐deficient sprouts.