Accumulation of Phenylpropanoids in the Cotyledons of Morning Glory (Pharbitis nil) Seedlings during the Induction of Flowering by Low Temperature Treatment, and the Effect of Precedent Exposure to High-Intensity Light

Extracts from the cotyledons of seedlings of Pharbitis nil strain 'Violet' cultured at low temperature, which induces their flowering even in continuous light, with or without precedent exposure to high-intensity light, which shortens the period of low temperature required for flowering, were analyzed by HPLC for substances correlating with the flower-inducing process. The content of two phenylpropanoids were found to increase during the low-temperature, and were identified as 3-O-feruloylquinic acid and dehydrodiconiferyl alcohol-13-O-β-D-glucoside. The increase was more rapid in the cotyledons exposed to high-intensity light before the low-temperature. This suggests that the accumulation of these compounds is correlated to the promotive effect of high-intensity light on the flower-induction by low temperature.