MICROSPOROGENESIS AND THE MALE GAMETOPHYTE AT EPHEDRA DISTACHYA L.

This study describes the microsporogenesis and the male gametophyte in Ephedra distachya L., only one species of the Ephedraceae family growing spontaneous in Romania. Ephedra distachya L. is a dioecious plant. Light microscopy (lm) is used to examine the early developmental stages of the male cones and combined light (lm) and scanning electron microscopy (sem) were used to analyze the mature pollen grains. The pollen cones are clustered at nodes either sessile or stalked. They are oval-oblong, each is composed of 2-8 decussate pairs of membranous bracts, proximal bracts empty; each distal bract subtending a male flower composed of 2 basally fused, orbicular or obovate scales (false perianth); sessile anthers on staminal column. Ephedra distachya pollen is particularly abundant. Ephedra distachya has the polyplicate pollen type characterized by a pointed-oval shape and 6 longitudinal ridges and 6 valleys, due to alternation of thicker and thinner exine regions, inaperturate. In polar view, ridges are low and triangular. On the SEM analysis the pollen wall of Ephedra distachya is simple, so the SEM closely resembles the LM observation.