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Polar Growth of Hormosira banksii Zygotes in Shake Culture
I. M. Sussex
American Journal of Botany
Vol. 54, No. 4 (Apr., 1967), pp. 505-510
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2440842
Page Count: 6
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Zygotes of the fucalean alga Hormosira banksii initiate rhizoidal outgrowths in stationary culture 15 hr after fertilization and are then recognizably polar. By 24 hr most embryos are two-celled, and a few are four-celled. In a dark-grown population orientation of the developmental axis, as indicated by the direction of the rhizoidal outgrowth, was random around the vertical axis. In a unilaterally illuminated population the rhizoid usually emerged on the shaded side. Zygotes grown in light or darkness in shake culture, where they were continuously reoriented, usually developed as polar embryos, indicating that gradients of environmental factors are not required for initiation of polar growth. Some apolar embryos developed in stationary and shake cultures, but they were most frequent in dark shake cultures.
American Journal of Botany © 1967 Botanical Society of America, Inc.