The effects of temperature and light on particles associated with crayfish visual membrane: a freeze-fracture analysis and electrophysiological study

Depending on the pre-experimental treatment, densities as well as sizes of particles associated with the visual membranes in the eyes ofProcambarus clarkii varied. The highest mean particle density (5268 ± 969 μm2) and the smallest mean particle diameter (5.57 ± 1.35 nm) were found in crayfish which had been kept in the dark for 10 weeks in aerated fresh water of 10 ° C. Crayfish kept under a 12 h dark/light regime in water of 10 ° C or 30 ° C for three weeks displayed particle densities of 1076 ± 180 and 2899 ± 249 μm−2, respectively; particle diameters were of the order of 8 nm.