• Applied Biological Chemistry
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• v.39 no.1
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• pp.84-88
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• 1996

To determine brassinolide in rice(Oriza sativa L.) using HPLC equipped with fluoresence detector, a highly sensitive fluorescence reagent. 1-cyanoisoindole-2-m-phenylboronic acid, was synthesized from the reaction of o-phthaldehyde, m-phenylboronic acid and KCN, then was reacted with brassinolide. The formation ratio of brassinolide boronate exhibited 90% up at the ratio of $20\;:\;1({\mu}g/{\mu}g)$ of 1-cyanoisoindole-2-m-phenylboronic acid and brassinolide respectively. The detection limit of brassinolide boronate with fluoresence detector was 0.16 ng. Brassinolide was detected in heading stage(biomass : 10 g) and panicle formation stage(biomass : 100 g) of the rice(Oryza sativa L.) with quantity of $0.8\;{\mu}g\;and\;0.2\;{\mu}g$respectively. However, brassinolide was not detected in blooming and elongation stage.