Cuvette Temperatures and Transpiration Rates

A cuvette which automatically opens between sampling periods and thus reduces internal temperature buildups was developed for use in measuring transpiration rates of intact plants in the field. In a closed cuvette air—temperature buildups of 5°—7°C and needle—temperature buildups of 17°C above ambient air temperatures are not uncommon, and these temperature alterations are reflected in the transpiration of the enclosed foliage. The open—closed cuvette reduced the buildups by 50% or more.