Journal article

Publication year: 1985

Pages: 509-516

Journal: Plant, Cell and Environment

Volume number: 8

Issue number: 7

ISSN: 0140-7791

DOI Link: https://doi.org/10.1111/j.1365-3040.1985.tb01686.x

Publisher: Wiley

Abstract: 

The spectra of incoming daylight and shadelight in a mature oak woodland
were measured at intervals during the canopy cycle, and mean
transmittance spectra were derived. Transmittance was spectrally neutral
at ca. 0.55 during the light phase but, following leaf emergence, transmittance of PAR (400–700 nm) fell to ca. 0.1. Simultaneously, the red : far‐red transmittance ratio fell to
circa 0.6. Both showed little change during the summer and autumn until
senescence, indicating that the optical properties of the canopy were
surprisingly stable. There was no evidence that cloud cover influenced
mean canopy transmittance, although transient sunflecks introduced great
variability which, in combination with sampling bias, might explain
previous contradictory reports. The red : far‐red fluence rate ratio in
the woodland showed a temporary increase in late summer, a result of a
small increase in the red : far‐red ratio of incoming daylight during
this period. Reflectance and transmittance spectra and pigment content
of sun and shade leaves were measured. Leaf transmittance spectra showed
changes correlated with those of the canopy, and were related to
changes in pigment content.

Harvard Citation style: Hughes, J., Morgan, D. and Black, C. (1985) Transmission properties of an oak canopy in relation to photoperception, Plant, Cell and Environment, 8(7), pp. 509-516. https://doi.org/10.1111/j.1365-3040.1985.tb01686.x

APA Citation style: Hughes, J., Morgan, D., & Black, C. (1985). Transmission properties of an oak canopy in relation to photoperception. Plant, Cell and Environment. 8(7), 509-516. https://doi.org/10.1111/j.1365-3040.1985.tb01686.x