Sunflower pollinator visit scoring

Biological rhythms are ubiquitous. They can be generated by circadian
oscillators, which produce daily rhythms in physiology and behavior, as
well as by developmental oscillator such as the segmentation clock, which
produces modular developmental units in a periodic fashion. Here, we show
that the circadian clock controls the timing of late-stage floret
development, or anthesis, in domesticated sunflower. In these plants, what
appears to be a single inflorescence consists of up to thousands of
individual florets tightly packed onto a capitulum disk. While early
floret development occurs continuously across capitula to generate iconic
spiral phyllotaxy, during anthesis floret development occurs in discrete
ring-like pseudowhorls with up to hundreds of florets undergoing
simultaneous maturation. We demonstrate circadian regulation of floral
organ growth and show that the effects of light on this process are
time-of-day dependent. Disruption of circadian rhythms in floral organ
development causes loss of pseudowhorl formation. Thus, we show that the
sunflower circadian clock acts in concert with environmental response
pathways to tightly synchronize the anthesis of hundreds of florets each
day, generating spatial patterns on the developing capitulum disk. This
coordinated mass release of floral rewards at predictable times of day
likely promotes pollinator visits and plant reproductive success.