and Ultrastructural Studies of flower in Lagerstroemia indica (Lythraceae): stamens dimorphism

Lagerstroemia indica is a wide spread garden and ornamental plant appreciated for its long lasting summer flowering and flower color (from white to purple). This genus is belonging to Lythraceae family some which especially Lythrum are notable because of heteromorphic stamens and styles. Light and electron microscopic studies were taken on the flower structure and stamen and pollen dimorphism. Perianth is hexamerous; the 6 sepals are synsepalous and leather like and the petals are unguiculate، with an oval to orbicular crispate limb. The stamens are dimorphic، 6 outer stamens are usually larger، both as to filament and anther، and reddish in floral buds and opened flowers. Instead، inner stamens (29-30) are smaller and bright yellow in color. In the end of first day of flower opening، outer and inner anthers were observed as reddish and yellowish respectively. Both anthers had extended epidermal cells diferentiated into the upper and lower epidermis significantly. Anthers were dorsifix، extrose، dehiscing by longitudinal slits. Cryomicroscopic studies showed extended epidermis and functional pollen grains (contain many organelles) in outer anthers. The pollen grains from outer anthers were smaller، thin walled and more regular in compared to those of inner anthers. Large anthers produced tricolporate pollen grains while in inner anthers، pollen grains showed some features such as pseudocolpi، pseddopores and exin protrusions. Pollen surface in outer anthers was relatively blunt in the polar region and meridional ridges of mesocolpial regions and in the other regions was scabrate while pollen surface in inner anthers was between striped and regulate in the polar regions and meridional ridges of mesocolpial regions and in the other regions was as distinct regulate to verucate and punctuate. The gynoecium was five-carpellate، and the placentation was axial.