Abstract
Light-induced modification of gravitropism in etiolated roots of Zea mays cv Bear × W38 is a low fluence response mediated by phytochrome. This cultivar has a threshold of 10−6 mol m−2 and becomes saturated with 10−2 mol m−2 of red light. The maximum light-mediated response of 32 degrees downward from horizontal occurs in roots 10 to 30 millimeters in length, 120 to 165 minutes after irradiation. Reciprocity is valid from 2 to at least 9,000 seconds and the response can be about 90% reversed by far red light. Photoreversibility is lost (`escape' occurs) about 20 minutes after red irradiation but appears to be regained 60 to 80 minutes later. A red light-induced (or synchronized) nutation in the apparent curvature rather than unusual escape characteristics may explain these results.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Irvine J. E., Freyre R. H. Diageotropism in Vanilla Roots. Science. 1961 Jul 7;134(3471):56–57. doi: 10.1126/science.134.3471.56. [DOI] [PubMed] [Google Scholar]
- Mandoli D. F., Briggs W. R. Phytochrome control of two low-irradiance responses in etiolated oat seedlings. Plant Physiol. 1981 Apr;67(4):733–739. doi: 10.1104/pp.67.4.733. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Suzuki T., Tanaka M., Fujii T. Function of Light in the Light-induced Geotropic Response in Zea Roots. Plant Physiol. 1981 Feb;67(2):225–228. doi: 10.1104/pp.67.2.225. [DOI] [PMC free article] [PubMed] [Google Scholar]