POLLEN MORPHOLOGY OF SOME ALLIUM SPECIES (AMARYLLIDACEAE) FROM IRAN

Pollen morphology of ۱۰ Allium L. taxa growing in Iran, representing three subgenera and six sections, were investigated via scanning electron microscopy. Pollen morphological characteristics indicated that pollen grains are monosulcate, heteropolar, and ellipsoidal. Polar axis revealed variation between ۱۳.۸۴ and ۲۰.۰۱ µm while Equatorial axis ranged from ۲۰.۴ to ۴۲.۳۷ µm. The forms of pollen grains were oblate, peroblate, and suboblate (mean of P/E ratio was ۰.۴۳ to ۰.۸۰). The aperture type and exine ornamentation were not homogeneous among the studied species. It was also observed that the sulcus extended from distal to proximal in two species of sect. Allium and one species of sect. Melanocrommyum. The exine was semitectate and the tectum was perforate. The variation in the main pollen characteristics in the investigated taxa allowed for recognizing two types of pollen grains in subg. Allium, Melanocrommyum and Amerallium: The first type had perforate rugulate trimming and high density of pollen perforations while the second type had perforate-striate-rugulate ornamentation and a low number of exine surface perforations.

Keywords:

Allium , Amaryllidaceae , Iran , Pollen grains , Pollen morphology