The study of the rhizosphere by scanning electron microscopy

Electron Microscopical Studies of the Microflora of Roots of Sand Dune Grasses

“…Cells and root hairs lacking mucigel were extensively colonized by bacteria and actinomycetes (Plate 2, Nos 8 and 9). These micro-organisms must have been adhering very firmly to the root surface to remain in situ during the dehydration procedure, as Campbell and Rovira (1973) found that the critical point drying method tended to reduce the microflora of the rhizoplane.…”

“…In roots which had a complete epidermal layer, the surface was often partially covered with material which is considered to represent 'mucigel' (Dart, 1971;Greaves and Darbyshire, 1972;Campbell and Rovira, 1973) and this term will be used hereafter in reference to it. The extent of the mucigel layer varied from an almost complete cover which obscured junctions between adjacent epidermal cells and through which the root hairs penetrated (Plate i.…”

“…The scanning electron microscope can reveal micro-organisms on the surface (Campbell and Rovira, 1973;Dart, 1971;Marchant, 1970). The transmission electron microscope has been used to study the penetration of root tissue by bacteria (Greaves and Darbyshire, 1972;Foster and Rovira, 1973;Rovira, 1972).…”

Electron microscopic study of associative n2-fixing bacteria in roots of rice seedlings

“…These intercellular spaces were filled with mucigel and seemed to be rich in nutrients for bacteria. Most investigators have reported that microorganisms in the plant rhizoplane are distributed in the basal part of the root, ruptured sites, cell junctions, lateral roots or root hairs, but not in the root apex (2)(3)(4)(5)(6)(7)(8)(9)(10)(12)(13)(14)(15). Although we could not compare directly the distribution of the N 2 -fixing bacteria in the basal part and root tip region of rice root in this experiment, we consider that the root tip region is favorable for microorganism multiplication since young epidermal and root cap cells may secrete exudates, in addition to the debris of the sloughed-off root cap cells.…”

“…Both transmission (TEM) and scanning electron microscopy (SEM) have been applied to the investigation of rhizosphere microorganisms by several researchers (2)(3)(4)(5)(6)(8)(9)(10)(11)(12)(13)(14)(15). However, only a few ultrastructural studies of associative N 2 -fixing bacteria with plant roots have been reported.…”