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Cytological Disturbances Influencing Fertility in Bromus inermis
Etlar L. Nielsen
Vol. 116, No. 4 (Jun., 1955), pp. 293-305
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/2473483
Page Count: 13
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1. Mutual pollination of two first-generation inbred plants of smooth bromegrass (Bromus inermis Leyss.) resulted in a morphologically uniform progeny of F1 plants characterized by low self- and cross-fertility. 2. Microsporocyte lethality during prophase results from the accumulation of ribonucleic acid (RNA) in chromocenters that eventually hinders normal nuclear development. Surviving sporocytes are generally characterized by the presence of numerous tiny RNA droplets in the cytoplasm, these being particularly conspicuous during anaphase and telophase. 3. B-chromosomes result in mitotic upsets, such as stickiness, multiple chromatin bridges, anaphase multiple associations, and so forth. Collapse of the microspore occurs prior to pollen mitosis in most of the F1 plants. 4. Asynapsis occurs with depauperization and severe contraction of the chromosomes. Possible interrelations of the behaviors outlined are discussed.
Botanical Gazette © 1955 The University of Chicago Press