LOCALIZATION IN THE DEVELOPING FUCUS EGG
309
The inferred instability of rhizin suggested a further important possibility. If rhizin were sufficiently unstable, then it should be possible for
an isolated cell to establish large rhizin gradients across its own environment. In particular, if the incipient rhizoid pole secreted most rhizin and
if rhizin decayed faster than it could diffuse to the antipodal pole, then
the developing egg could establish an external rhizin gradient
which
would act back to amplify its own polarization.
If such amplification really did occur, then in cell pairs interacting
primarily through rhizin gradients, each egg would tend to germinate
toward the other's rhizoid pole rather than the other's center. Hence pair
2.
POLARIZED.
>
^
ATMOSPHERE
WHOLE
POPULATION
o
o
FIG. 11. Diagram to illustrate concept of correlated polarization of nearby cell
pairs. For simplicity each pair is imagined to consist of a source cell and a responder
cell, but mutual interaction would give about the same result. The distributions
indicated in the body of the table are those of the outgrowth directions of responder
cells each of which is imagined to lie on the right of a source cell.
SOURCE CELLS
—
I
.
T
UNPOLARIZED
ATMOSPHERE