CYTOLOGICAL INVESTIGATIONS OF LITHOBIONTIC MICROORGANISMS IN GRANITIC-ROCKS

This paper shows the ultrastructure of lithobiontic organisms in a gra nitic rock from the exterior to the interior, where fissures are found 1-2 mm from the surface. There is clear differentiation at cell level between mycobiont and photobiont cells located on the rock surface wh ich forms part of the lichen thallus and prokaryotic and eukaryotic ce lls (algae and fungi) found in the fissures. As well as the observatio ns at the ultrastructural level of the microorganisms which live in fi ssures and cavities, immunolabelling techniques with colloidal gold ha ve been applied to obtain an immunolocalization of Rubisco enzyme in s ome of the cells. The technique applied here permits Rubisco enzyme to be identified in algae-like cells belonging to fissures where it is d ifficult to identify the pyrenoid. The mineral environment of the cell s situated inside the fissures is investigated by Energy Dispersive Sp ectrometry (EDS). The biotite particles present in the fissure walls, as well as some lithobiont microorganisms, show a depletion of potassi um from interlayer positions.