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Role of Temperature in the Physiology of Crop
Plants: Pre- and Postharvest
William Grierson
University of Florida, Lake Alfred, Florida (retired)
13I. INTRODUCTION
A. Importance of Temperature
Temperature, like the poor, is always with us but, like the poor, it is only too often overlooked. This is un-
fortunate, as temperature is a major factor in all things biological.
To a physicist, temperature is simply a manifestation of the kinetic energy of component atoms, ions,
and molecules.
To a chemist, the role of temperature is epitomized by the “Q 10 rule,” whereby, over some reason-
able range, the rate of a chemical reaction approximately doubles with every 10°C increase in tempera-
ture.
But to a biologist, temperature is the supreme conductor of the orchestra of life, initiating specific re-
actions and modulating, integrating, or suppressing them just as the conductor of a great orchestra calls
upon, modulates, or dismisses the diverse instruments, whose discrete voices are thereby integrated into
one harmonious whole. Regardless of the crop, or of the physiological response being monitored, con-
sideration of the role of temperature can often be the sine qua non in interpreting the phenomena being
investigated. It has been said that “The scientist shows his intelligence... by his ability to discriminate
between the important and the negligible” [1]. Only too often, temperature may appear to be a negligible
factor when, unnoticed, it plays some critical role.
B. Scope of This Chapter
Because every physiological and biochemical system of every crop plant is affected by temperature, it
would be impossible to cover all its manifestations in a whole textbook, much less in a single chapter.
Most aspects are, therefore, dealt with superficially. Specific examples are cited to indicate the types of
relationships that invite further study and, when such study does not suffice, may inspire further re-
search.
Citrus fruits, and most particularly the chilling injury (CI) syndrome, are represented in greater depth
because the writer and his colleagues devoted many years to research on citrus, particularly the study of
the basic mechanisms of chilling injury.