The in situ hybridization signal was found in (i) the nodule cortex, with the notorious exception of the middle cortex, i.e. the cell layers in between the vascular traces and the external cortex, (ii) the vascular traces, and (iii) the non-infected cells of the infected zone, but not in the infected cells. The intensity of the signal varied with tissues and with treatments: it was higher in inner cortex and non-infected cells than in vascular traces and external cortex; under P deficiency, it was significantly increased in the inner cortex and in the non-infected cells.
Thus aquaporins of inner-cortex would contribute to the water uptake for the turgidity of inner-cortex cells in agreement with the osmoregulation hypothesis for nodule-permeability (Drevon et al. 1997). The aquaporin in non-infected cells of the infected zone suggest that aquaporin may be involved in solute transport from vascular traces towards the infected zone and reversely. The role of aquaporin in external cortex is more elusive.
Was this article helpful?