NON-DESTRUCTIVE CELLULAR MEASUREMENTS AND ANALYSIS OF NITROGEN METABOLISMS FOR HIGHER PLANTS SUBJECTED TO ENVIRONMENTAL STRESSES

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When plants are subjected to environmental stresses, it is known that nitrogen metabolisms are modified in plants. However, detailed mechanisms for modification in nitrogen metabolisms are not known in plants subjected to environmental stresses, and thus physiological mechanisms for stress adaptation were studied in the present study by using non-destructive measurements in the cellular level.When the water status of single cells in the growing soybean seedings was measured, it was found that a water potential field associated with cell growth existed in the zone of elongation. When growth was disturbed either by applying environmental stresses or excision, the water potential field associated with cell growth was collapsed, and thus, it became apparent that non-destructive cellular measurements should be used to study stress response under environmental stresses in intact plants.In order to check the nitrogen metabolism related to differentiation, tissue culture of carrot cells was us … More ed. When the concentration of ammonium ions was kept relatively high in the tissue culture medium, non-embryogenic callus was induced. When the concentration of nitrate was increased and that of ammonium ions was decreased, embryogenic callus was differentiated. When differences in protein synthesis between non-embryogenic callus and embryogenic callus were analyzed, streptavidin-binding proteins were found in embryogenic callus and not found in non-embryogenic callus. When embryogenesis in carrot cells proceeded, quantitative differences in cytoskeleton proteins, i.e., actin, a-and b-tubulins were observed. When blossom-end rot occurs in tomato fruits, it is known that cell wall components and cytoskeleton components are degraded in cells od fruits.Immediately after blossom-end rot appeared in tomato fruits, cytoskeleton components were analyzed. Streptavidin-binding proteins began to disappear before cytoskeleton components disintegrated in fruits. From these findings, newly found streptavidin-binding proteins seem to be related to formation and maintenance of cytoskeleton components in cells under environmental stresses. Less