An automated computer-controlled gas-exchange system for continual monitoring of physiological activities in plants

Abstract

A computer-controlled automated gas-exchange system was developed to perform repetitive measurements of physiological activities in intact plants. Shoot and root temperatures, flow rates, gas pressures, rates of leaf CO2 and H2O exchange, and rates of CO2 exchange, H2 evolution, and C2H2 reduction by the roots can be determined for four plants in a single experiment. The controlling computer operates 32 switches that control gas flows, sampling devices, lighting, and irrigation and it records and processes analog data from 15 measuring instruments. Rates of physiological activities are calculated automatically and results are printed and stored on diskettes for later plotting or analysis. A wide variety of experimental protocols are possible with little need for computer programming, because the system is controlled by a master program and an interactively developed file of experimental variables. The values recorded from the measuring instruments are proportional (r2 > 0.999) to either independent determinations or to calibration standards and the rates of physiological processes, measured with the system, are reproducible and within expected ranges.