Abstract
Mitotic activity and nuclear DNA content in endosperm of Zea mays cv. Złota Karłowa were examined. DNA content was cytophotometrically measured on squashed preparations after Feulgen procedure. Mitotic activity in endosperm was determined till the stage when embryo sack reached 4.5 mm in length. Some of mitotic figures show multiplied DNA content. Endosperm nuclei have various DNA contents which increase throughout endosperm development. DNA content enhancement indicates endoreduplication in progress. Some nuclei with high DNA content display changes in chromatin structure, which are expressed by the presence of strands and aggregates of chromatin characterised by high staining intensity. A conclusion has been drawn that mitotic divisions and the endoreduplication phase of nuclear DNA may occur simultaneously and dominate one over another at different phases of endosperm development.
Keywords
endosperm; mitotic activity; endoreduplication; DNA content; Zea mays