ABSTRACT

Botryococcus braunii (Kiitzing, 1849) is a colonial member of Chlorophyceae, characterized by an original organization of colonies and a considerable production of lipids. Widely distributed in freshwater lakes, reservoirs or ponds, it also inhabits brackish waters and ephemeral lakes. On light microscopy observations (Figure 10.1), the colonies, variable in size from 30 ym up to 2mm, appear to consist of single or multiple cell clusters united by transparent and refringent strands. The cells, generally pyriform (7 x 13 pm), are arranged around the periphery of the cluster and embedded within cups of a matrix impregnated by oil. Ultrastructural investigations show that the matrix consists of outer walls originating from successive cellular divisions (Figure 10.1); more or less closely pressed to each other, these outer walls ensure colony cohesion.