Characterization of adaptation in phototropism of Arabidopsis thaliana
- Michigan State Univ., East Lansing (United States)
Phototropic curvature has been measured for etiolated Arabidopsis thaliana seedlings with and without a preirradiation. A bilateral preirradiation with 450-nm light at a fluence greater than about 0.1 micromole per square meter causes a rapid densensitization to a subsequent 450-nanometer unilateral irradiation at 0.5 micromole per square meter. Following a refractory period, the capacity to respond phototropically recovers to the predesensitization level, and the response is then enhanced. The length of the refractory period is between 10 and 20 minutes. Both the time needed for recovery and the extent of enhancement increase with increasing fluence of the bilateral preirradiation. Based on the relative spectral sensitivities of desensitization and enhancement, these responses can be separated. Desensitization is induced by blue light but not by red light. Enhancement, however, is induced by both blue and red light. Thus, enhancement can be induced without desensitization but only vice versa. Both desensitization and enhancement affect only the magnitude of the response and do not affect the fluence threshold.
- DOE Contract Number:
- AC02-76ER01338
- OSTI ID:
- 6095093
- Journal Information:
- Plant Physiology; (United States), Journal Name: Plant Physiology; (United States) Vol. 95:2; ISSN 0032-0889; ISSN PLPHA
- Country of Publication:
- United States
- Language:
- English
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