Fundamental study on technological development for sustainable agriculture using halophytes

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In order clarify the salt-tolerant mechanism of halophytes, the research was focused on the physiological and biochemical characteristics of the most common osmoprotectant, glycine betaine (GB). The results were summarized below.1)Salt-tolerant species accumulates GB in seeds.Germinating process of the seeds is the most salt-stress- acceptable period. How to clear the salt effect during germination was studied and we clarified that salt-tolerant species accumulates GB in seeds in a fashion dependent on the salt-tolerance. The amount of GB accumulated was correspondent to the strength to salt-tolerance of the species.2)Life cycle of halophytes under salt-stress.The salt-stress during germination was overcome by inherent GB in seeds. After germination the plant produced GB by itself. During growth GB accelerated the photosynthetic ability by producing a photosynthetic protein, plastocyanin. During maturation the plant accumulates GB in seeds for its next generation. It was found that the … More plant adapts itself to the environmental stresses by controlling the organic molecule like GB.3)Difference in salt-tolerance among barley varieties.About 340 variety species of barley seedlings were kindly supplied from Germplasm Center, Okayama University. Among them, 14 species were already known the salt-tolerance. The GB content of the 14 species was analyzed by capillary electrophoresis which we developed. The result was clearly shown that the GB content was proportional to the strength to salt-stress. It was also found that the present method was quite suitable for selecting the salt-tolerant species among more than ten thousands of barley varieties.4)Characterization of proteins induced by GB treatment under salt-stress.Common bean was cultured hydroponically under salt-srtess condition and GB was added to the medium. After incubation proteins in the leaves were analyzed by 2-dimesional gel electrophoresis. One of the newly appeared spots was analyzed by maldi-tof-MS and searched the sequences by protein database. Plastocyanin was found to be induced by the presence of GB. The other proteins composing thylakoid membrane was under investigation. Less