Contribution of calcium ions and hydrogen ions to the signal transduction chain in phytochrome-mediated spore germination. [Onoclea sensibilis L]

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5941750

Wayne, R

Red light stimulates germination in the spores of Onoclea sensibilis L. Phytochrome is confirmed to be the photoreceptor pigment in the germination response by demonstrating red-far-red photoreversibility. External Ca/sup 2 +/ is required for this response with a threshold at a submicromolar concentration. Red light stimulates an increase in the total concentration of intracellular calcium in the spores as determined by atomic absorption spectroscopy. Subsequent exposure to far-red light inhibits the red light-induced increase in intracellular calcium. The majority of the increase occurs 5 minutes after the onset of irradiation. The calcium-antagonist, La/sup 3 +/ inhibits both germination and the red light-induced increase in intracellular calcium. Using /sup 31/P-nuclear magnetic resonance spectroscopy, the author tested the hypothesis that a sustained increase in intracellular pH contributes to the signal transduction chain. He never detected a red light-induced increase in intracellular pH or a change in portion efflux. An artificially induced change in intracellular pH of greater than 1 pH unit (5.8-7.2) has no effect on germination. Although the intracellular pH can be varied in magnitude greater than it would be expected to change if it were acting as an intracellular signal, germination of Onoclea spores is independent of intracellular pH in this range. These data indicate that a sustained increase in intracellular pH does not contribute to the single transduction chain phytochrome-mediated fern spore germination. Therefore, Ca/sup 2 +/, but not pH, contributes to the signal transduction chain in phytochrome-mediated fern spore germination.

• Research Organization: Massachusetts Univ., Amherst (USA)
• OSTI ID: 5941750
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM COMPOUNDS
BIOLOGICAL EFFECTS
FERNS
PHOTOSYNTHESIS
SPORES
GERMINATION
ABSORPTION SPECTROSCOPY
CATIONS
INFRARED RADIATION
LANTHANUM
NUCLEAR MAGNETIC RESONANCE
PH VALUE
PHOSPHORUS 31
PHYTOCHROMES
ALKALINE EARTH METAL COMPOUNDS
CHARGED PARTICLES
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
IONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
METALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PHOTOCHEMICAL REACTIONS
PIGMENTS
PLANTS
PROTEINS
RADIATIONS
RARE EARTHS
RESONANCE
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
550501* - Metabolism- Tracer Techniques