A GROWTH CABINET PROVIDING VARIABLE SPECTRAL PHOTON DISTRIBUTIONS AT HIGH FLUENCE RATES

Authors

  • J. E. HUGHES,

    1. Plant Physiology Section, Department of Physiology and Environmental Science, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough, Leics., UK
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    • *

      Current address: Biologisches Institut II, SchänzlestraßBe 1, D-7800 Frieburg, West Germany.

  • L. HEATHCOTE,

    1. Plant Physiology Section, Department of Physiology and Environmental Science, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough, Leics., UK
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    • Deceased April 1984.

  • K. BAMBRIDGE,

    1. Plant Physiology Section, Department of Physiology and Environmental Science, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough, Leics., UK
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  • C. R. BLACK

    1. Plant Physiology Section, Department of Physiology and Environmental Science, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough, Leics., UK
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Summary

A plant growth cabinet providing a flexible facility for photomorphogenic and photoperiodic research is described. The growth chamber is divided into quarters which are optically isolated, and has a recirculating air-conditioning system. The various light sources and filters available are discussed in relation to their desirable features. The chosen sources of white light (metal halide discharge lamps) are capable of generating approximately 800 μmol m−2 s−1 (400 to 700 nm). Tungsten-halogen filament lamps are used to provide longer wavelengths. Infra-red filters (acrylic sheet and water) reduced heat loading to a negligible level. Data are presented for internode length in plants of Chenopodium album L. grown under different fluence rates of supplementary far-red light in the new cabinet.

Principal Abbreviations
ζ

The ratio of the spectral photon fluence rates in the 655 to 665 and 725 to 735 nm bands

φc

The ratio of the concentrations of the far-red light absorbing form of phytochrome (Pfr) and total phytochrome (PtOt), calculated from the spectral photon distribution and in vitro absorbance data of Vierstra * Quail (1983), according to the method of Tasker (1977) (see Hughes et al. 1984)

λ

Wavelength

B:R

The ratio of the spectral photon fluence rates in the 410 to 500 and 610 to 700 nm bands

PAR

Photosynthetically active radiation (400 to 700 nm)

SPD

Spectral photon distribution

T

Transmittance, the ratio of transmitted and incident fluence rates

Ancillary