Effects of Coronatine on Some Physiological Properties of Plant Cells

Abstract

Cell wall free protoplasts were prepared from coleoptiles of oats and Italian ryegrass. When the protoplasts were exposed to 1mM coronatine and 0.6M mannitol, protoplasmic streaming stopped and cytoplasm aggregated toward one side of the protoplasts within 30min. At this initial stage, the plasma membrane seemed to have spherical shape and smooth surface, and then the protoplast contracted with time. Plasmolytic ability remained in the epidermal root hair cells of host plant after treatment with coronatine at 2.5mM or 1mM for 24 and 48hr. On the other hand, coronatine-induced hypertrophy of potato tuber tissue were markedly inhibited by N, N-dicyclohexyl-carbodiimide. The results suggest a close association between coronatine and membrane-bound ATPase. In addition, coronatine already changed the permeability 24-48hr before the development of hypertrophy on potato tuber tissues. These results suggest that the disruption of the cytoplasm induced by coronatine may be due to secondary effects brought about indirectly by physiological changes in the plasma membrane.