Correlative Sem And Tem Of Plant Spermatozoids: Equisetum arvensel.

Abstract

<jats:p>The phylogenetic position of mosses, ferns and fern allies is enhanced by detailed knowlegde of gametophyte reproductive structures, in particular the spermatozoid (freeswimming sperm). The number and placement of flagella in conjunction with their ultrastructure and that of the multilayered structure (MLS) has been used to establish related groups. Herein, ultrastructural details of pre-release spermatozoids obtained via TEM are compared with the morphological appearance of fully mature (free-swimming) spermatozoids obtained via SEM. This represents the first intensive study of any plant sperm cell that correlates 3-dimensional SEM images with TEM ultrastructural features.</jats:p><jats:p><jats:italic>Equisetum arvense</jats:italic> L. is a fern ally commonly refered to as ‘horsetail’. The mature spermatozoid (Fig. 1) is twisted into approximately 3.5 revolutions, or gyres. A complex locomotory apparatus (Fig. 2), involving approximately 55 flagella, dominates the anterior region of the cell. The basal bodies subtending these flagella feature a well-defined stellate pattern and occur in 4 irregular rows staggered over approximately 1.75 gyres. </jats:p>