Definition of long-day in US English:



  • (of a plant) needing a long period of light each day to initiate flowering, which therefore happens naturally as the days lengthen in the spring.

    • ‘It is well known that a long-day plant can be induced to flower if the long night is interrupted by a short period of light.’
    • ‘Arabidopsis is classified as a facultative long-day plant, whereas maize is originally a short-day one.’
    • ‘Cereals of temperate origin are typically long-day plants, and this causes heading during spring and early summer, so that the crop ripens towards the end of the growing season.’
    • ‘In the long-day plant Arabidopsis, flowering is accelerated under photoperiods exceeding a critical daylength.’
    • ‘The genetic control of flowering has been extensively studied in Arabidopsis, a quantitative long-day plant that flowers faster under long days than short days.’
    • ‘In Arabidopsis thaliana and other long-day rosette plants, it has been shown that photoperiodic control of stem elongation is mediated by GAs.’