33.アサガオとシソのストレス応答花成の制御機構(口頭発表)

概要

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Pharbitis nil, a short-day plant (SDP) , can be induced to flower by poor nutrition stress under long days (LD). Phenylalanine ammonia-lyase (PAL) was involved in this stress-responding flowering. Perilla frutescens var. crispa, a SDP, can be induced to flower by low-light intensity under LD. This may be stress-responding flowering. Accordingly, we analyzed the regulating mechanism of flowering under LD in both species. For poor nutrient-stress treatment, P. nil, Violet was cultured in tap water. Red-leafed P. frutescens was grown under different light intensities. In P. nil, the stress-responding flowering was inhibited by a PAL inhibitor, aminooxyacetic acid (AOA) , and this inhibition was overcome by salicylic acid (SA). Exogenous SA alone did not induce to flower indicating that some other factor (s) must be necessary. Because DNA demethylation can induce flowering, the stress could stimulate DNA demethylation. In fact, the treatment of P. nil with 5-azacytidin, a DNA demethylating reagent, together with SA induced flowering. P. frutescens was induced to flower by low-intensity light. This flowering was inhibited by aminooxypropionic acid (AOPP) , another PAL inhibitor. AOA or AOPP did not induce to flower under non-inductive condition. These suggest that PAL activity increase under low-intensity light. Thus, the metabolic pathway regulated by PAL may be involved in the regulation of stress-responding flowering in the both species.
2007-10-05