A System for Continuous Monitoring of Whole Shoot CO2Exchange as an Adjunct to Growth Analysis Experiments in Controlled Environments

Abstract

A multichannel system is described in which continuous CO2 exchange measurements of whole shoots can be made on plants grown in controlled environments such as growth cabinets, glasshouses, or plastic houses. The shoot enclosure is made from a coated polypropylene film which not only combines excellent light transmittance with poor permeability to CO2 but can also be tailored easily to individual shoot systems of various sizes ensuring a rapid response time for CO2 exchange measurements. Air speeds within the enclosure are regulated precisely; temperature and relative humidity are also controlled to within narrow limits, during daylight hours and at night. Thus, the aerial environment of enclosed shoots parallels closely that of non-enclosed plants. The system compliments a root respiration chamber designed earlier; used in conjunction with growth analysis data, the two systems facilitate quantitative determinations of the carbon economy of entire plants throughout all stages of growth.