Palynological observations on the genus Scorzonera L. (Asteraceae) from north-east Anatolia (Turkey)

Abstract

Pollen morphology of the 13 taxa of Scorzonera L. (Asteraceae) from Turkey was investigated by using light (LM) and scanning electron microscopy (SEM). As a result of LM and SEM observations, it was found that the pollen types are generally isopolar, radially symmetric, triangular in polar view, and lophate, with lophae ornamentations that are echinate-perforate and an exine thickness ranging from 6.99 to 11.82 ?m. The present study found that the lacunae ornamentation of S. laciniata subsp. laciniata and S. tomentosa is perforate-microrugulate, that of S. suberosa and S. cinerea is perforate-microreticulate, that of S. pseudolanata is perforate-psilate, and that of the others is perforate. Prolatespheroidal pollen shapes were observed in S. insica, and oblate-spheroidal shapes were observed in the rest of the examined taxa, e.g. S. tomentosa, S. pseudolanata, and S. sericea. Spine length ranged between 1.3 and 4.63 ?m among the examined taxa. S. tomentosa (4.63 ?m) showed the highest value. S. insica (1.3 ?m) showed the lowest value. PCA analysis based on the 16 palynological traits showed that polar axis, equatorial diameter, pollen diameter, colpus length, colpus width, and exine and spine length were the most important characters in explaining total variation among the examined taxa. The results also indicated that pollen characters would be useful in separating the examined taxa. © TÜBİTAK.