Male gametophyte development of <i>Silene sangaria</i> Coode & Cullen (Caryophyllaceae), an endemic species from Turkey

Abstract

In this study, microspore formation (microsporogenesis), gamete formation (microgametogenesis), and pollen features of Silene sangaria, a species endemic to Turkey, was examined cytoembryologically and histochemically. The species is distributed along the Black Sea coast of Turkey. The materials were collected from the coast of Igneada village (Kirklareli province). The anthers, separated by size, were passed through ethyl alcohol concentration series, and embedded in historesin. Sections were sliced using a rotary microtome and stained with toluidine blue O for general histological observations, Coomassie brilliant blue for proteins, and periodic acid-Schiff for insoluble polysaccharides. The aceto-orcein squash technique was used for cytological observations, and lactophenol-aniline blue solution was used to assess pollen viability. The anthers of S. sangaria are tetrasporangiate, and its anther wall development is of basic type. The tapetum is secretory type, and cytokinesis is simultaneous type. As a result of meiotic division of microspore mother cells, 43.5% decussate, 28.2% rhomboidal, 21.1% tetrahedral and 7.2% isobilateral tetrads occur. The released microspores first pass through the first pollen mitosis to form vegetative and generative cells, then the generative cell passes through the second pollen mitosis to form two sperm cells. Pollen grains are three-celled when released from the anther. Pollen viability rate is high (91.82%). Mature pollen grain contains a high concentration of insoluble polysaccharide and protein.