Blue light but not red light induces a calcium transient in the moss Physcomitrella patens (Hedw.) B., S. & G

In caulonemal filaments of the moss, Physcomitrella patens, which had been incubated in darkness, 3 s irradiation with blue light (lambda(max) 450 nm) at fluence rates of 100 micromole m-2 s-1 and above caused a transient increase in cytosolic calcium ion concentration. [Ca2+]cyt, which was both int...

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Bibliographic Details
Published in:Planta 1998-10, Vol.206 (2), p.278-283
Main Authors: Russell, A.J, Cove, D.J, Trewavas, A.J, Wang, T.L
Format: Article
Language:English
Subjects:
Biological and medical sciences
blue light
Calcium
complementary DNA
cytosol
dark
Fluence
Fundamental and applied biological sciences. Psychology
Inlets
inorganic ions
ion transport
Kinetics
Light
light intensity
lighting
Luminescence
morphogenesis
Mosses
mosses and liverworts
Optical filters
photoreceptors
Physical agents
Plant cells
Plant physiology and development
plant proteins
red light
transgenic plants
Vegetative apparatus, growth and morphogenesis. Senescence
Wavelengths
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Summary:In caulonemal filaments of the moss, Physcomitrella patens, which had been incubated in darkness, 3 s irradiation with blue light (lambda(max) 450 nm) at fluence rates of 100 micromole m-2 s-1 and above caused a transient increase in cytosolic calcium ion concentration. [Ca2+]cyt, which was both intensity- and time-dependent. Measurements of [Ca2+]cyt were made using moss transformed with the cDNA for apoaequorin and reconstituting the Ca2+ -dependent photoprotein aequorin in the cytosol by incubation in coelenterazine. In response to blue light at fluence rates of 100-1000 micromole photons m-2 s-1, [Ca2+]cyt increased transiently from a basal level of approximately 50 nM to between 200 and 700 nM. Irradiation with red light did not evoke any measurable change in [Ca2+]cyt. The presence of calcium in the incubating medium was not required for the increase in [Ca2+]cyt to occur. A mutant strain, gad-139, was identified which required an irradiance of only 1 s to evoke a response. The kinetics showed a delay of approximately 6 s from the beginning of illumination before the beginning of the increase in [Ca2+]cyt. The data suggest that the activation of a photoreceptor rather than the direct opening of calcium channels is involved in this blue-light response.
ISSN:0032-0935
1432-2048
DOI:10.1007/s004250050401