Gibberellin A20 content of Bryophyllum daigremontianum under different photoperiodic conditions as determined by gas-liquid chromatography.

The gibberellin A20 content of the long-short-day plant Bryophyllum daigremontianum (R. Hamet and Perr.) Berg. under different photoperiodic conditions was determined by gas-liquid chromatography. Purified extracts from ten plants were adequate for quantitative analysis by this method. The level of GA20 increased following transfer from long-day (LD) to short-day (SD) conditions until after 38 SD it was three times higher on a dry weight basis than in comparable plants under continuous LD. No GA20 could be detected in extracts of plants under permanent SD. These results are in agreement with earlier data obtained by assaying Bryophyllum extracts with the d-5 mutant of corn.