AN AUTOMATED-SYSTEM FOR USE IN COLLECTING VOLATILE CHEMICALS RELEASEDFROM PLANTS

A system is described for the collection of volatiles produced by plan ts that minimizes stress on the plant in an environment that is free f rom chemical impurities. Air entering a volatile collection chamber co ntaining a plant is purified using a nonwoven fabric media infused wit h charcoal. A multitasking, computer-automated system is described tha t can simultaneously collect volatilized chemicals from plants as well as monitor and record environmental conditions associated with those collections. Collection of up to 16 samples can be made in varying sam pling order, flow rates, and user-specified time periods, without dist urbing the sampling environment. During the same time period, this sys tem is capable of simultaneously monitoring up to eight environmental parameters using any type of sensor with electrical signal outputs. A multiport base assembly was designed to fit around the base of the pla nt permitting air samples to be collected at the bottom of the chamber . The chamber can pass ambient light so the plant may follow its natur al photocycles. The entire system can be configured for continuous lab oratory duty or portable field use by utilizing components that run on DC voltages. For the purpose of testing the system's performance, we determined the periodicity of the release of volatiles from red and ye llow flowering four o'clock plants, Mirabilis ja[aba (Nyctaginaceae). The major chemical released from four o'clocks was identified as ocime ne. The onset of release occurred between 1400 and 1600 hr and increas ed with time with maximum amount of ocimene released during 1800-2000 hr, followed by a decrease in emission. No ocimene was detected after 2400 hr. Determination of the amount of ocimene released per flower wa s calculated for the 1800- to 2000-hr time period. Based on the number of open flowers during the 1800- to 2000-hr period, yellow four o'clo ck's released 80.9 (+/-7.3 SD) ng/hr/flower, while the red flowers rel eased 51.9 (+/-7.0 SD) ng/hr/flower.