R. Serraj et al., STRUCTURAL-CHANGES IN THE INNER-CORTEX CELLS OF SOYBEAN ROOT-NODULES ARE INDUCED BY SHORT-TERM EXPOSURE TO HIGH-SALT OR OXYGEN CONCENTRATIONS, Plant, cell and environment, 18(4), 1995, pp. 455-462
After a 2 h exposure of intact soybean nodules to high concentrations
of NaCl (100 mol m(-3)) or oxygen (80 kPa O-2), morphometric computati
ons carried out using an image analysis technique on semi-thin section
s showed that both treatments induced a decrease in the area of the in
ner-cortex cells, which were then characterized by a tangential elonga
tion, In contrast, no significant change in area occurred in the middl
e-cortex cells although their elongation decreased. Electron microscop
ic observations showed that in the inner-cortex cells changes included
the presence of wall infoldings, an enlarged periplasmic space and a
lobate nucleus whose chromatin distribution differed from that of the
control, Structural changes also occurred in the endoplasmic reticulum
, microbodies, mitochondria and plastids. From several of these change
s, which are similar to those noted in osmocontractil cells in respons
e to external stimuli, it can be hypothesized that the inner cortex ma
y provide a potential mechanism for the control of oxygen diffusion th
rough the nodules.