A WHOLE-PLANT, OPEN, GAS-EXCHANGE SYSTEM FOR MEASURING NET PHOTOSYNTHESIS OF POTTED WOODY-PLANTS

Chambers were constructed to measure gas exchange of entire potted gra pevines (Vitis vinifera L.). The plant enclosures were constructed fro m Mylar film, which is nearly transparent to photosynthetically active radiation. Maintaining a slight, positive, internal pressure allowed the Mylar chambers to innate like balloons and required no other means of support. The whole-plant, gas-exchange chamber design and construc tion were simple and inexpensive. They were assembled easily, equilibr ated quickly, and did not require cooling. They allowed for the measur ement of many plants in a relatively short period. This system would e nable the researcher to make replicated comparisons of treatment influ ences on whole-plant CO2 assimilation throughout the growing season, W hile CO2 measurement was the focus of this project, it would be possib le to measure whole-plant transpiration with this system.