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...,
These experiments were conducted in Davis, CA, June-August, 2022. Seeds were germinated and grown for three weeks in PGV36  or PGR15 growth chambers (Conviron, Winnipeg, MB, Canada) as described above, at which point they were transferred to a field site. Approximately one week before the start of anthesis, plants were transferred to growth chambers. Controls were maintained in chambers with light, temperature, and humidity cycling in coordination with the local average daily forecast for the following week. Constant light plants were maintained at a constant 28°C, with 3200 μmol m-2 s-1 provided by metal halide and incandescent lamps. Jet lagged plants were entrained to the same conditions as the control plants but with a 3-hour phase delay. Plants were transferred to the field just before anthesis of the second or third pseudowhorl, just after dawn in the case of the constant light experiment and one hour before dawn for the jet lab experiment. In the latter case, florets that had op...,