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The Relation of the Plastid to Nuclear Division in Anthoceros laevis
Caroline A. Lander
American Journal of Botany
Vol. 22, No. 1 (Jan., 1935), pp. 42-51
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2436172
Page Count: 10
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One chloroplast is found in each cell of the gametophyte, of the developing archegone and in the egg, and in the meristematic primary sporogenous and spore mother cells of the sporophyte. Before nuclear division the plastid moves to the side of the nucleus, constricts, and as its halves separate, fibers appear in close proximity to the nucleus. The daughter plastids move to opposite sides of the nucleus; the fibers increase in number and length between the plastids, and finally form the division spindle. The spindle is relatively well developed even while the nuclear membrane and nucleolus are still present. The chromosomes and nucleolus move toward the spindle, and the fibers increase in number on the side toward the nucleus. The nucleolus disappears at the equatorial-plate stage. Nuclear and cell division follow in the usual manner, the daughter plastids remaining at the broad poles of the spindle. The size and form of plastids vary, being more or less characteristic for each type of cell. The haploid chromosome number is four and the diploid number eight.
American Journal of Botany © 1935 Botanical Society of America, Inc.