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Science. 2016 Aug 5;353(6299):587-90. doi: 10.1126/science.aaf9793.

Circadian regulation of sunflower heliotropism, floral orientation, and pollinator visits.

Author information

1
Department of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA.
2
Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA 22904, USA.
3
Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA 22904, USA. Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA 94720, USA.
4
Department of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA. slharmer@ucdavis.edu.

Abstract

Young sunflower plants track the Sun from east to west during the day and then reorient during the night to face east in anticipation of dawn. In contrast, mature plants cease movement with their flower heads facing east. We show that circadian regulation of directional growth pathways accounts for both phenomena and leads to increased vegetative biomass and enhanced pollinator visits to flowers. Solar tracking movements are driven by antiphasic patterns of elongation on the east and west sides of the stem. Genes implicated in control of phototropic growth, but not clock genes, are differentially expressed on the opposite sides of solar tracking stems. Thus, interactions between environmental response pathways and the internal circadian oscillator coordinate physiological processes with predictable changes in the environment to influence growth and reproduction.

PMID:
27493185
DOI:
10.1126/science.aaf9793
[Indexed for MEDLINE]
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