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Relations between CO 2 Exchange Rate, CO 2 Compensation, and Mesophyll Resistance from a Simple Field Method 1
Author(s) -
Cary J. W.
Publication year - 1977
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1977.0011183x001700030028x
Subject(s) - photosynthesis , photorespiration , biology , compensation point , respiration , botany , diffusion , biophysics , physics , thermodynamics , transpiration
An equation is developed that relates apparent photosynthesis to CO 2 light compensation values, resistance to CO 2 light compensation values, resistance to CO 2 diffusion in air, and the apparent mesophyll resistance to CO 2 transport. the equation also yields values for total photosynthesis and light respiration from measurements of apparaent photosynthesis. A simple method for measuring leaf CO 2 exchange rates in the field with a hand‐operated syringe is described. Results obtained with this device and data published in recent literature are used with the new equation to show that photosynthesis be limited more by mesophyll resistance than by photorespiration.