Morphological relationship between paraflagellar swelling and paraxial rod in Euglena Gracilis

euglena is a mobile photosynthetic and photosensitive cell which dwells in fresh water. Euglena has an important evolutionary role, therefore its morphology has been and still is a subject of interest. The structures in Euglena which are involved in photoreception and signal transduction and transmission have been well studied. In this paper morphological and ultrastructural evidence of a single stable structure formed by the photoreceptor (paraflagellar swelling) and the other specialized flagellar structures of Euglena gracilis (paraxial rod) is provided using conventional and non-conventional SEM and TEM, on detergent treated cells, and on isolated flagella retaining their photoreceptor.