Diurnal regulation of plant growth*


  • *

    This work is supported in part by NSF grant DBI-0227103 to J. N. M and Cynthia Weinig.

Julin N. Maloof. Fax: +1 530 752 5410; e-mail: jnmaloof@ucdavis.edu


Life occurs in an ever-changing environment. Some of the most striking and predictable changes are the daily rhythms of light and temperature. To cope with these rhythmic changes, plants use an endogenous circadian clock to adjust their growth and physiology to anticipate daily environmental changes. Most studies of circadian functions in plants have been performed under continuous conditions. However, in the natural environment, diurnal outputs result from complex interactions of endogenous circadian rhythms and external cues. Accumulated studies using the hypocotyl as a model for plant growth have shown that both light signalling and circadian clock mutants have growth defects, suggesting strong interactions between hypocotyl elongation, light signalling and the circadian clock. Here, we review evidence suggesting that light, plant hormones and the circadian clock all interact to control diurnal patterns of plant growth.