Localization of phytochrome in oats by electron microscopy
J P Verbelen1, L H Pratt, W L Butler
1Department of Biology, University of California, San Diego, La Jolla, California 92093.
Plant Physiology
|October 1, 1982
Summary
Red light exposure causes phytochrome to redistribute within oat coleoptile cells, accumulating in small vacuoles. This light-induced change in phytochrome localization is crucial for plant photomorphogenesis.
Area of Science:
- Plant Biology
- Cell Biology
- Photomorphogenesis
Background:
- Phytochrome is a key photoreceptor in plants, regulating various light-dependent developmental processes.
- Understanding phytochrome localization is essential for elucidating its signaling mechanisms.
Purpose of the Study:
- To investigate the cellular localization of phytochrome in oat coleoptile cells under different light conditions.
- To determine the effect of red light illumination on phytochrome distribution.
Main Methods:
- Immunoelectron microscopy was employed to localize phytochrome.
- Ultrathin frozen sections and immunopurified, monospecific antibodies were used to enhance assay sensitivity and resolution.
- Oat (Avena sativa) seedlings, both etiolated and irradiated, were analyzed.
Main Results:
- In etiolated seedlings, phytochrome showed a diffuse appearance.
- Brief red light illumination induced phytochrome redistribution to a more particulate form.
- Phytochrome accumulation was observed in small vacuoles following illumination.
- In light-grown plants, phytochrome distribution was similar to dark-grown material, with a notable positive reaction in the nucleus.
Conclusions:
- Red light triggers a rapid sequestration of phytochrome into vacuoles in oat coleoptiles.
- The nucleus becomes a site of phytochrome localization in light-exposed and green oat seedlings.
- These findings provide insights into the dynamic nature of phytochrome and its role in light perception.
