The nuclear DNA content in dormant tubers of Helianthus tuberosus L. cv OBI and in explants activated for several hours by 2,4-D was measured by in situ cytometry of Feulgen-stained nuclei and by flow cytofluorimetry of isolated DAPI-stained nuclei. The pattern of variation of mean nuclear DNA content was nearly the same using either method. During activation, DNA content reached a maximum at 9 h. Cytophotometric analysis of optical density profiles of the nuclei and molecular analysis of restricted DNAs indicated that the observed increase at 9 h is probably not related to chromatin decondensation due to a different pattern of cytosine methylation but rather to DNA synthesis. At 15 h amitoses occurred ana generated pairs of similar sized nuclei, having an equal DNA content. Concomitantly, the class of nuclei with the highest DNA value disappeared whilst a class with a lower DNA content increased. Between 9 and 20-25 h, DNA content decreased, then increased up to 35 h, when a single DNA class accumulated. This led to a major uniformity of the cell population, which never showed apoptotic events. At 40 h the first regular mitoses were observed. © 1997 Taylor & Francis Group, LLC.
Bregoli A.M., Crosti P., Cavallini A., Cionini G., Del Duca S., Malerba M., et al. (1997). Nuclear DNA distribution and amitotic processes in activated helianthus tuberosus tuber parenchyma. PLANT BIOSYSTEMS, 131(1), 3-12 [10.1080/11263504.1997.10654161].
Nuclear DNA distribution and amitotic processes in activated helianthus tuberosus tuber parenchyma
Bregoli A. M.;Del Duca S.;Natali L.;Serafini-Fracassini D.;
1997
Abstract
The nuclear DNA content in dormant tubers of Helianthus tuberosus L. cv OBI and in explants activated for several hours by 2,4-D was measured by in situ cytometry of Feulgen-stained nuclei and by flow cytofluorimetry of isolated DAPI-stained nuclei. The pattern of variation of mean nuclear DNA content was nearly the same using either method. During activation, DNA content reached a maximum at 9 h. Cytophotometric analysis of optical density profiles of the nuclei and molecular analysis of restricted DNAs indicated that the observed increase at 9 h is probably not related to chromatin decondensation due to a different pattern of cytosine methylation but rather to DNA synthesis. At 15 h amitoses occurred ana generated pairs of similar sized nuclei, having an equal DNA content. Concomitantly, the class of nuclei with the highest DNA value disappeared whilst a class with a lower DNA content increased. Between 9 and 20-25 h, DNA content decreased, then increased up to 35 h, when a single DNA class accumulated. This led to a major uniformity of the cell population, which never showed apoptotic events. At 40 h the first regular mitoses were observed. © 1997 Taylor & Francis Group, LLC.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
