The flagellar apparatus ultrastructure in Leptosira erumpens (Deason & Bold) lukesová and its contribution to the understanding of phylogenese relationships within the microthamniales (chlorophyta)

Abstract

The actual spatial configuration of the flagellar apparatus in biflagellate zoospores of the terrestrial green alga Leptosira erumpens is described. The basal bodies are displaced with respect to each other in the counter clockwise direction (CCW). The two types of microtubular roots consist of 2 microtubules (R2) and 8 microtubules (R8) respectively. The latter type of microtubular root is arranged in a 7-over-1 orientation. The two basal bodies are connected to each other anteriorly by a large striated distal connecting fibre. The microtubular roots are connected to the adjacent basal body via a striated proximal fibre and linked with the lower side of the distal connecting fibre. A single striated rhizoplast runs from one basal body along a large mitochondrion towards the nuclear envelope. The distinct eyespot (stigma) is intimately associated with a series of ca. 10 microtubules originating from one of the eight-membered microtubular roots.

In order to investigate the role that non-molecular characters play in the understanding of evolutionary relationships within the Microthamniales, a datamatrix was compiled for a preliminary phylogenetic analysis. Along with the present data of L. erumpens non-molecular (in great majority morphological) data of 15 more microthamnialean species and 2 selected outgroup species were included within this set. Despite incompleteness of the data, a distinct phylogenetic signal was found. This encouraged us to compare our results with a recent phylogenetic reconstruction based on molecular data.