Microsporogenesis in three wild species of the genusAntirrhinumL. (A. litigiosumPau,A. pulverulenthumLazaro andA. subbaeticumGüemes, Sánchez and Mateu)

Abstract

The diploid chromosome number (2n = 2x = 16) in three wild species A. litigiosum Pau, A. pul- verulenthum Lazaro and A. subbaeticum Guemes, Sanchez & Mateu, belonging to the genus Antirrhinum was cytologically observed. Genetic stability of the simultaneous meiotic division type was found in these natural growing snapdragons. The synchronicity at the initial meiotic stages and at tetrad and pollen creation was high and disappeared with the diakinesis initiation. Refl ecting the systematic position of the studied species into Antirrhinum, the performed investigation mani- fested similarity: in the presence of univalents and quadrivalent confi gurations parallel with bivalents at the early meiotic stages; in the type of disturbances at metaphase and anaphase stages; in the tetrad formation and pollen characteristics; in the particularity of the tapetal cell division. There were dissimilarities in the bivalent chiasma formation and localisation and in the level of the meiotic dis- orders. Seven different chromosome associations were observed at diakinesis and metaphase one in A. pulveru- lenthum PMCs, while in the other two Antirrhinum species they ranged between 12 and 13. The highest value of ring bivalents, total and mean chiasma number per bivalent, was found in A. pulverulenthum PMCs, while the lowest value of these characteristics was evaluated in the A. litigiosum cells. The chromosome behaviour during anaphase stages showed more changes in A. subbaeticum PMCs and the most regularity in the A. pul- verulenthum cells, which were refl ected in the value of the pollen fertility (83.7% and 98.4% respectively). The established specify and differences demonstrated genetic diversity between A. litigiosum, A. pulverulenthum and A. subbaeticum genomes.