Journal article

Publication year: 1984

Pages: 269-277

Journal: Plant, Cell and Environment

Volume number: 7

Issue number: 4

ISSN: 0140-7791

DOI Link: https://doi.org/10.1111/1365-3040.ep11589464

Publisher: Wiley

Abstract: 

Although daylength has a major effect on flowering and several other
aspects of plant development, the actual environmental time signals for
the beginning and the end of day are obscure. An intensive
spectroradiometric study was carried out in three contrasting
environments: namely, unshaded sites, a mature oak woodland and a sugar
beet crop. Spectral photon distributions were obtained describing
numerous twilight phases and intervening photoperiods throughout the
year. From each, absolute photon fluence rates, photon fluence rate
ratios and phytochrome photoequilibria were calculated. Although
substantial changes in spectral composition occurred during twilight,
they were less capable of providing reliable and accurate time signals
than the absolute fluence rate; this was especially apparent beneath the
canopies. Thus, spectral changes are unlikely to be valuable in
photoperiodic perception. The results are discussed in relation to the
possible involvement of the known plant photoreceptors in
photoperiodism.

Harvard Citation style: Hughes, J., Morgan, D., Lambton, P., Black, C. and Smith, H. (1984) Photoperiodic time signals during twilight, Plant, Cell and Environment, 7(4), pp. 269-277. https://doi.org/10.1111/1365-3040.ep11589464

APA Citation style: Hughes, J., Morgan, D., Lambton, P., Black, C., & Smith, H. (1984). Photoperiodic time signals during twilight. Plant, Cell and Environment. 7(4), 269-277. https://doi.org/10.1111/1365-3040.ep11589464