Chilling Sensitivity in Plants: Do the Activation Energies of Growth Processes Show an Abrupt Change at a Critical Temperature?

Abstract

The rates of increase in dry weight, leaf area, and length of hypocotyl plus radicle of mung bean (Vigna radiata L.) and morning glory (Pharbitis nil Chois) all show marked responses to decreasing temperature, although when drawn as Arrhenius plots these responses resemble smooth curves rather than sets of intersecting straight lines. Chilling sensitivity was shown to be dependent on temperature, light intensity, and the previous history of the plant. It is argued on theoretical grounds that changes in membrane lipid mobility would not be expected to cause abrupt changes in the slope of such Arrhenius plots at either the enzyme or whole plant level.