Cytoplasmic Localization of Deoxyribonucleic Acid in Allium cepa

Abstract

IT is believed generally that the normal complement of deoxyribonucleic acid (DNA) occurs exclusively on the chromosomes. However, that this is true of all plant cells has been contested. Thus ultra-violet absorption microscopy was used to show that it occurred predominantly in the cytoplasm of the root meristem cells of Vicia faba which had been treated with pectinase¹. These results were supported by results obtained from fractionated homogenates of roots of V. faba and Allium cepa². It was claimed that this localization was dependent on the lifelike preservation of the cytoplasmic particles, and that if these were damaged in any way the DNA would diffuse to the nuclei. However, these results were inadequate, partly because of the extreme variability of the commercial pectinase samples that were available¹, and partly because it was just as reasonable to postulate that homogenization caused the DNA to diffuse from the nuclei instead of to the nuclei³.