A simple, battery-operated, temperature-controlled cuvette for respiration measurements

We designed a simple, portable, battery-operated, temperature-controlled cuvette to measure respiration of small samples of plant tissue in the field. The cuvette is built around a peltier cell and is controlled with a data logger. The cuvette maintained sample temperature within 0.5 degrees C over a temperature range of 5 to 45 degrees C and operated for 6-8 h from a 12 V 105 ampere-hour "deep-cycle" battery. Based on measurements with this cuvette, we found that, at 15 degrees C, CO(2) efflux from dark respiration of white pine (Pinus strobus L.) foliage was 40% greater during the day than at night.