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Measurement of light gradients and spectral regime in plant-tissue with a fiber optic probe

  • T C Vogelmann
  • Lars Olof Björn
Publishing year: 1984
Language: English
Pages: 361-368
Publication/Series: Physiologia Plantarum
Volume: 60
Issue: 3
Document type: Journal article
Publisher: Wiley Online Library

Abstract english

A method is described in which light gradients and spectral regime can be measured within plant tissue using fiber optics. A fiber optic probe was made by modifying a single optical fiber (200 μm diameter) so that it had a light harvesting end that was a truncated tip 20–70 μm in diameter. The probe was a directional sensor with a half-band acceptance angle of 17–20°. Light measurements were made as the fiber optic probe was driven through plant tissue by a motorized micromanipulator, and the light that entered the fiber tip was piped to a spectroradiometer. By irradiating green leaf tissue of the succulent Crassula falcata L. with collimated light and inserting the probe from different directions, it was possible to measure light quality and quantity at different depths. Collimated light was scattered completely by the initial 1.0 mm of leaf tissue, which also greatly attenuated all light except the green and far-red. Light scatter contributed significantly to light quantity and had a pronounced spectral structure. Immediately beneath the irradiated surface the amount of light at 550 nm was 1.2 times that of the incident light. The light gradient declined rapidly to 0.5 times incident light at 1.4 mm depth. In contrast, the amount of light at 750 nm increased during the initial 0.5 mm to 2.9 times incident light and then declined linearly to 0.5 times incident light at the dark side of the leaf (4.5 mm). The implications of the magnitude of the contribution of light scatter to the light gradient is also discussed.


  • Biological Sciences


  • ISSN: 0031-9317
Lars Olof Björn
E-mail: lars_olof [dot] bjorn [at] biol [dot] lu [dot] se

Professor emeritus

Molecular Cell Biology

+46 46 222 72 53