A method for measuring the respiration rate and respiratory quotient of detached plant tissues

A 'respirometer' is described. The atmosphere inside a container is monitored by sensors for O-2, CO2 and temperature, and is refreshed with air or a special gas mixture once a specified amount of O-2 has been consumed by a plant tissue. The rate of respiration and respiratory quotient (RQ) are calculated. The system can measure respiration with an accuracy which is limited mainly by the precision of the sensors. Single measurements can be made in a few minutes, or the equipment set to monitor changes in respiration over periods of weeks. The units are easy and cheap to assemble, acid several can be connected to a single controlling computer to allow replicate measurements. Changes in the respiration rates of ripening bananas were monitored over a 10-day period. The results had low levels of variance between measurements, were consistent between replicates, and were comparable with published data. Ways in which the apparatus can be used to measure respiration at different levels of O-2 and CO2 are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.