A GENERAL RELATIONSHIP BETWEEN CO2-INDUCED REDUCTIONS IN STOMATAL CONDUCTANCE AND CONCOMITANT INCREASES IN FOLIAGE TEMPERATURE

Simultaneous measurements of the temperatures and stomatal conductance s of leaves of sour orange trees growing in normal and CO2-enriched ai r, together with similar data for water hyacinths and cotton, suggest that a plant's foliage temperature response to atmospheric CO2-enrichm ent is directly proportional to its degree of stomatal closure, i.e. t hat plants that experience a greater stomatal closure in response to a tmospheric CO2 enrichment experience a greater warming of their foliag e. The data also suggest that this primary relationship may be modifie d by CO2-induced changes in leaf chlorophyll content that may have imp lications for global climate change.