Adjustment of leaf temperature measurements in LI-COR 6200 assimilation chamber using energy balance calculations

Abstract

A study was conducted under field conditions to evaluate the use of leaf temperatures obtained by energy budget calculations ( Tl b) to adjust the leaf thermocouple readings ( Tl t) in a LI-COR 6200 portable photosynthesis system. The relationship between Tl t, Tl b and chamber air temperature ( Ta) was found to be: Tl b=1.77 Tl t−0.77 Ta ( R 2=0.97). The fitted coefficients are similar to those found in a previous study where a leaf temperature controlling device was used. The results indicate that this relationship can be successfully used to adjust leaf temperature measurement. Under field conditions, neglecting this correction caused errors larger than 10% in stomatal conductance to water vapor ( g s) and intercellular CO 2 concentration ( c i) 15 and 39% of the time, respectively.