NIGHTTIME VARIATION IN VOLATILE CONTENT OF FLOWERS OF THE NIGHT BLOOMING PLANT GAURA-DRUMMONDII

Nighttime amounts were determined for five volatile chemicals identifi ed in extracts of Gaura drummondii flowers. The major component (2-met hylbutanal oxime, isomers 1 and 2) occurred at the highest level durin g the earliest sampling period (20:00-23:50 hr) in greenhouse and fiel d-grown plants. Grime levels decreased at subsequent sampling periods. Benzyl alcohol levels were greater in the latter part of the night (0 3:00-06:00 hr). 2-Phenylethanol or phenylacetaldehyde amounts did not change with respect to time. Average amounts (eta g/bloom) of each che mical summed for all time periods were greater for greenhouse plants t han for field grown plants. Three compounds that had not been identifi ed previously in Gaura drummondii were identified in methylene chlorid e extracts. These were benzyl alcohol, (Z)-jasmone, and eugenol.