Control of gas exchange: evidence for root-shoot communication on drying soil

Abstract

There is controversy in the literature about the more general aspects of root/shoot interaction on drying soil, e.g., in volume 11 (1988) of Plant Cell Environment. In different opinions on the subject, Kramer (1988) is worried about the shift in emphasis from traditional water relations to the idea of (bio-)chemical signaling in plants and increasing interest in root metabolism. The idea of root/shoot interaction and communication on drying soil does not exclude direct effects of a decrease in water potential on stomatal aperture, but rather includes an additional biochemical effect on the stomatal aperture independent of changes in leaf water relations (Schulze et al., 1988). ’The return (to emphasis on conditions in the soil) is not a circle. It is a helix.’ (Passioura, 1988).