The period of time each day during which an organism receives illumination; day length.
- ‘The greenhouse was heated all winter and supplemental lighting extended the photoperiod to prevent dormancy.’
- ‘For enzymatic activities and sugar determinations, samples were collected at the middle of the photoperiod.’
- ‘Applying balancing pressure did not affect the growth of N-deprived plants except during the photoperiod of day 3 and the dark period of day 4.’
- ‘Canola seedlings were grown in chambers at 23°C, 50% humidity, under 16/8 h day/night photoperiods.’
- ‘Measurements and sampling were done in the middle of the photoperiod at all sampling times.’