Continuous air-exchange roomette and gas-meting system

Abstract

Portable, controlled-environment systems with precise control of airflow rate, gas concentration, humidity, irradiance, and temperature have been constructed with considerable expense and custom design. This roomette exposure system was built from materials common to most laboratories. Desiccators were used for the exposure of hydroponically grown Kentucky bluegrass (Poa pratensis L.) plants to ethylene concentrations of 10 to 3200 µL/L for up to 10 d. Airflow rate and ethylene influx were controlled with separate barostat towers with 1.0-and 0.152-mm inside-diameter capillary tubes, respectively. An air exchange rate of 7.5 volumes/h and a stirring magnet prevented increased temperatures and moisture con-densation while replenishing CO2. Roomette temperature and irradiance were subject to ambient conditions deviating from the mean by 15 and 18%, respectively. Relative humidity was maintained at 85 ± 8% with humidifying stacks. This system can be used for effective, low-cost, modifled-atmosphere experiments with intact plants as well as plant parts.