11.根寄生植物Striga hermonthicaおよびOrbanche minorの種子発芽過程におけるエチレンの関与の解析(口頭発表)

概要

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Seeds of root parasitic plants stay dormant until exposed to warm moist environment (conditioning). The conditioned seeds germinate in response to a germination stimulant. Striga seed germination is also induced by ethylene. The expression of ACC synthase and ACC oxidase genes in S. hermonthica was found to be responsive to the stimulant and to conditioning, respectively. We found that pre-treatment with GR24, a synthetic germination stimulant, during conditioning period decreases S. hermonthica seed germination induced by post-treatment with GR24. The present study was undertaken to investigate the mechanisms involved in the decrease of seed responsiveness to the post-treatment. ACC induced S. hermonthica seed germination in a concentration dependent manner, irrespective of GR24 concentrations in the pre-treatment, suggesting that higher concentrations of GR24 induce ACC biosynthesis. This was supported by the facts that higher concentrations of GR24 induced the expression of the ACC synthase gene and ethylene production. The involvement of ethylene in O. minor seed germination was also studied. Neither ACC nor ethephon induced O. minor seed germination. Germination induced by GR24 was not inhibited by 1-methylcyclopropene. Ethylene release from germinating O. minor seeds was not detected. These facts suggest that ethylene is not involved in O. minor seed germination.
植物化学調節学会の論文
2008-10-06