An Electron Microscopic Study of DNA-like Fibrils in Plant Mitochondria

Abstract

For the purpose to clarify wether or not the “DNA-like fibril” is the common component of the mitochondria of plant cells, the author carried out observations on the cells of eighteen species of eight phyla by electron microscopy.As the result it was found that the DNA fibril complexes are located in the electron-transparent regions of mitochondria in the plants cells belonging to Rhodophyta. Phaeophyta, Chlorophyta, Charophyta, Bryophyta, Pteriodophyta, Gymnospermae and Angiospermae. These results suggest that the DNA fibril complex is the common component of mitochondria in plant cells as well as in animal cells.The morphologic patterns of the DNA fibril complexes of various species observed under electron microscope are similar in that they are composed of fibrillar elements whose unit fibrils are apparently about 3mμ in width. The dense aggregates and the core-like structures, frequently encountered in some species, are supposed to be dense distribution of fibrils, but there seems to be some specificity in the morphologic structure of the DNA fibril complex specific to each species.