FORMATION OF MALE GENERATIVE STRUCTURES IN JASMINUMFRUTICANS (OLEACEAE)
Jasminum fruticans L. is a heterostyled species of the family Oleaceae, represented by plants of two morphological forms, long-styled and short-styled. The plant grows in the areas with Mediterranean climate. The species occurs in Russia on the Southern Coast of the Crimea and the Black Sea coast of the Caucasus. A comparative study of phenology of the generative sphere and the main stages of the anther formation in the two floral morphs of J. fruticans is conducted in the Southern Coast of the Crimea. It is shown that the onset of phenological stages and their duration and course of the anther development do not depend on the floral morph of the plant. The period of intragemmal formation of flower (July-February) is is characterized by a formation of archesporial cells and differentiation of sporogenous tissue. During budding (March-April), microsporegenesis and postmeiotic development of male generative sphere take place. The wall of the J. fruticans anther develops centrifugally. The tapetum is of a secretory type. It is formed from the primary parietal layer. The developed anther wall is composed of the epidermis, irregularly double-layered endothecium, middle layer and several layers of tapetum cells. The sporogenous tissue is formed by 2 to 4 layers of cells. The microsporogenesis in J. fruticans follows a simultaneous type. Mature pollen grains are three-celled. The pollen grains of short-styled plants (46.58 ± 0.25 pm) are larger than the those of long-styled flowers (36.49 ± 0.25 pm). Morphologically normal pollen of long-styled plants comprises 84 %, and the the share of morphologically normal pollen grains in short-styled flowers is 78 %.