Loss of photosystem II induced by a nitrate deficiency in photoorganotrophically grown Anabaena variabilis

概要

論文の詳細を見る
When photoorganotrophically trained cells of Anabaena variabilis were grown in nitrate-free medium, they lost the activity of photosynthetic oxygen evolution and became devoid of phycobilin pigments. These cells (H cells) lacked the fluorescence emission characteristic of photosystem II chlorophyll, and their lamellar fragments failed to photoreduce DPIP even in the presence of diphenylcarbazide as the electron donor, suggesting that the loss of photosynthetic oxygen evolution in H cells is primarily due to degeneration of an integral part of photosystem II. These characteristics of H cells closely resembled those of heterocysts differentiated from normal, vegetative cells in [i] the deficiency of phycobilin pigments, [ii] the loss of photosystem 11 activity, [iii] the photoorganotrophic mode of cell growth, depending upon the organic substances furnished externally or provided from neighboring vegetative cells, and [iv] the manner of transformation from normal cells, both types of cells being induced in the absence of nitrate. In spite of such similarity, light and electron microscopic observations revealed that H cells differed significantly from heterocysts. Furthermore, the readiness with which H cells resumed photosystem II activity and the independence of this resumption from cell growth exclude the possibility that the nutritional enrichment of heterocysts was responsible for the loss of photosynthetic activity.
日本植物生理学会の論文