Abstract
Light-induced coleoptile stimulation and mesocotyl suppression in etiolated Avena sativa (cv. Lodi) has been quantitated. Etiolated seedlings showed the greatest response to light when they were illuminated 48 to 56 hours after imbibition. Two low-irradiance photoresponses for each tissue have been described. Red light was 10 times more effective than green and 1,000 times more effective than far red light in evoking these responses. The first response, which resulted in a 45% mesocotyl suppression and 30% coleoptile stimulation, had a threshold at 10−14 einsteins per square centimeter and was saturated at 3.0 × 10−12 einsteins per square centimeter of red light. This very low-irradiance response could be induced by red, green, or far red light and was not photoreversible. Reciprocity failed if the duration of the red illumination exceeded 10 minutes. The low-irradiance response which resulted in 80% mesocotyl suppression and 60% coleoptile stimulation, had a threshold at 10−10 einsteins per square centimeter and was saturated at 3.0 × 10−8 einsteins per square centimeter of red light. A complete low-irradiance response could be induced by either red or green light but not by far red light. This response could be reversed by a far red dose 30 times greater than that of the initial red dose for both coleoptiles and mesocotyls. Reciprocity failed if the duration of the red illumination exceeded 170 minutes. Both of these responses can be explained by the action of phytochrome.
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Selected References
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- Elliott W. M., Shen-Miller J. Similarity in dose responses, action spectra and red light responses between phototropism and photoinhibition of growth. Photochem Photobiol. 1976 Mar;23(3):195–199. doi: 10.1111/j.1751-1097.1976.tb07241.x. [DOI] [PubMed] [Google Scholar]
- Hillman W. S. Responses of Avena and pisum tissues to phytochrome conversion by red light. Plant Physiol. 1966 May;41(5):907–908. doi: 10.1104/pp.41.5.907. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hopkins W. G., Hillman W. S. Relationships between phytochrome state and photosensitive growth of Avena coleoptile segments. Plant Physiol. 1966 Apr;41(4):593–598. doi: 10.1104/pp.41.4.593. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Klein R. M. Reversible effects of green and orange-red radiation on plant cell elongation. Plant Physiol. 1979 Jan;63(1):114–116. doi: 10.1104/pp.63.1.114. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Loercher L. Phytochrome changes correlated to mesocotyl inhibition in etiolated Avena seedlings. Plant Physiol. 1966 Jun;41(6):932–936. doi: 10.1104/pp.41.6.932. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pratt L. H., Briggs W. R. Photochemical and Nonphotochemical Reactions of Phytochrome in vivo. Plant Physiol. 1966 Mar;41(3):467–474. doi: 10.1104/pp.41.3.467. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Quail P. H., Briggs W. R. Irradiation-enhanced Phytochrome Pelletability: Requirement for Phosphorylative Energy in Vivo. Plant Physiol. 1978 Nov;62(5):773–778. doi: 10.1104/pp.62.5.773. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schiff J. A. A green safelight for the study of chloroplast development and other photomorphogenetic. Methods Enzymol. 1972;24:321–322. doi: 10.1016/0076-6879(72)24079-4. [DOI] [PubMed] [Google Scholar]
- Vanderhoef L. N., Quail P. H., Briggs W. R. Red Light-inhibited Mesocotyl Elongation in Maize Seedlings: II. Kinetic and Spectral Studies. Plant Physiol. 1979 Jun;63(6):1062–1067. doi: 10.1104/pp.63.6.1062. [DOI] [PMC free article] [PubMed] [Google Scholar]