ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Electron microscope observations of thin sections of nodules of subterranean clover and barrel medic, after fixation in KMnO4 or OsO4, show that following infection there is a marked increase in the amount of endoplasmic reticulum, in the number of ribosomes, Golgi bodies, mitochondria and proplastids in the host cells.As the infection thread approaches the nucleus, large gaps appear in the nuclear membrane. During the formation of the membrane envelopes around the rhizobia, after their release from the infection thread, the reticulum changes from a predominantly plate-like to a vesicular form. As the bacteroids develop the plastids of the host cells become filled with starch, and become aligned, with the mitochondria, against the cell walls of the host cells. Plastids in noninvaded cells also become starch-filled. Bacteroids and host cells enlarge further and finally the bacterioids occupy most of the cytoplasm of the host cell, except for the nuclear region and vacuole. With OsO4 fixation the nucleoplasm, predominantly fibrillar before infection, with a dense staining nucleolus, becomes packed with dense ribosome-like (≅150 A° diameter) granules. No such changes occur in the nuclei of non-infected cells. In the proplastids and plastids many small, electron dense particles (≅60 A° diameter) (phytoferritin?) are observed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00409746
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