LOCALIZATION IN THE DEVELOPING FUCUS EGG
303
HOURS AFTER FERTILIZATION
FIG. 6. Time course of polarizability of Fucus eggs by various vectors. (All at 15°C
in natural seawater.) Percent polarized by a vector = 2X (percent rhizoids toward
the favored hemisphere minus 50%). (1) Whitaker, 1936; (2) eggs exposed to 1 hour
of light from a 40-watt bulb a meter away (Whitaker and Lowrance, 1936); (3) eggs
centrifuged at 150,000 g for 5 minutes (Whitaker, 1940b); (4) eggs exposed to an
hour of flow at 100^/second (Bentrup and Jaffe, 1968); (5) eggs exposed to 30 mV
per egg diameter for 2 hours (Bentrup, 1967). All results with Fucus furcatus except
last one which was with Fucus serratus.
HOURS AFTER FERTILIZATION
FIG. 7. Relationship of the time of photopolarizability to that of germination of
Pelvetia fastigiata eggs. All were cultured at 15°C in natural seawater, and at various
time exposed for an hour to 100 ft-c of white light from a wide-angle source.
Aliquots observed for germination were exposed at 5 to 6 hours. Percent polarized
= 2X (percent rhizoids toward dark hemisphere minus 50%). (From Jaffe, unpublished.)