Nighttime variation in volatile content of flowers of the night blooming plant Gaura drummondii

Nighttime amounts were determined for five volatile chemicals identified in extracts ofGaura drummondii flowers. The major component (2-methylbutanal oxime, isomers1 and2) occurred at the highest level during the earliest sampling period (20:00–23:50 hr) in greenhouse and field-grown plants. Oxime levels decreased at subsequent sampling periods. Benzyl alcohol levels were greater in the latter part of the night (03:00–06:00 hr). 2-Phenylethanol or phenylacetaldehyde amounts did not change with respect to time. Average amounts (ηg/bloom) of each chemical summed for all time periods were greater for greenhouse plants than for field grown plants. Three compounds that had not been identified previously inGaura drummondii were identified in methylene chloride extracts. These were benzyl alcohol, (Z)-jasmone, and eugenol.