McGraw. Hill, New York, 453 pp. MATSUURA, 11. 1935. A cytological study on ... (Lathyrus odoratus). - Proc. Camb. Phil. Sot.. 13: 148-156. 405-426. 59-72.
CHROMATIN EXTRUSION AND CYTOMIXIS I N POLLEN MOTHER CELLS OF HORDEUM By OM P. K A M R A INSTITUTE OF GENETICS, UNIVERSITY OF LCND, SWEDEN
(Received July 25t11, 1960)
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HROMATIN extrusion and cytomisis or the transfer of nuclear material from one cell to an adjacent cell has been reported in 1958). many plant genera for a number of years (SARVELLA, During cytological analysis of a number of barley mutants induced by X-rays and neutrons many pollen mother cells were found with a clear evidence of chromatin extrusion and transfer of chromatin from one cell to another. In the present paper this cytological evidence, along with a bibliography on chromatin extrusion and cytomixis is presented. Spikes of barley (Hordeum uulgure) containing pollen mother cells (PMC) in meiosis were fixed, stained by the Feulgen method after hydrolysis and squashed. The material used for the cytological studies was partially and completely sterile mutants induced in erectoides- 14 ilnd erectoides-23, exhibiting heterozygosity for one or more translocationr, homozygosity for asynapsis, failure of cytokinusis, etc.
OBSERVATIONS Evidence of chromatin extrusion and cytoniixis was clearly seen in several P M C in the various barley mutants studied. The proportion of I’M(; exhibiting the phenomena varied in different lines. In some sterile mutants as much as 40 per cent of the PMC showed evidence of chromatin extrusion and cytoniixis (Fig. 3). l’he earliest signs of chromatin extrusion were seen at early Fiachytenc. A t pachytene the chromatin material could be seen as protruding out of the main chromatin mass at one or more places (Figs. 1 to 5 ) . Protrusions ranging in number from one (Fig. 1) to eight (Fig. 3) or more could be easily seen in the various PMC. Signs of chroniatin extrusion occurring in the early stages persisted in the later ones and
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Figs. 1 to 5. l’liotomicrograplrs of pollen mother cells at pachytene and early prophase I with evidence o f chromatin extrusion (shown with darts). The extruded chromatin bodies may vary ill number from one (Fig. 1) to several (Figs. 2 to 5). Figs. G and 7. Photomicrographs of pollen mother cells at metaphase I with evidence of chromatin extru5ion (shown with darts). Chromatin bodies can be seen as protrusions budding out of the bivalents.
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Figs. 8 arid 9. Evidriice for cliromatiii extrusion at metaphasr I (Text same :I
