PLANT PHYSIOLOGY , Vol 105, Issue 2 519-527, Copyright © 1994 by American Society of Plant Biologists
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CELL BIOLOGY AND SIGNAL TRANSDUCTION |
Photopolarization of the Fucus sp. Zygote by Blue Light Involves a Plasma Membrane Redox Chain
F. Berger and C. Brownlee
Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, United Kingdom (F.B., C.B.)
Zygotes of fucoid algae are photopolarized by unidirectional blue light
(BL). Polar axes are formed, fixed, and expressed by germination of a
rhizoid. Hexacyanoferrate(III) ions (HCF) specifically inhibit transduction
of the BL signal. HCF reduction by Fucus sp. zygotes occurs on the outer
surface of the plasma membrane at higher rates in BL than in dark. These
observations suggest that BL signal transduction involves a redox chain in
the plasma membrane. Low doses of HCF (<50 pmol cell-1) inhibit
photopolarization but not germination, hence uncoupling both processes.
Exposure during the photosensitive period to higher doses of HCF together
with BL significantly inhibits germination. Further results suggest that BL
transduction is dependent on photosynthetic products that could also
interact with redox processes.