Pollen micromorphology and ultrastructure of the genus Reseda (Resedaceae) and its taxonomical relations in Iran

In this research, the pollen grains of 18 taxa of the genus Reseda in Iran were examined by light microscopy (LM), scanning electron microscopy (SEM), and two taxa by transmission electron microscopy (TEM). Pollen micromorphology quantitative characteristics were different among the studied taxa. Among pollen micromorphological qualitative characteristics, exine ornamentation had the highest variety (with five characteristic states) and muri shape around lumina had the lowest (one characteristic state). Moreover, the results showed that sulcus exine ornamentation had diversity. Palynological analysis grouped the studied taxa into three types and two subtypes (two Reseda-Leucoreseda types and a Reseda mixed type that includes Reseda-Phyteuma subtype and Reseda-luteola subtype). The taxa of section Reseda had a heterogeneous palynological situation along with the other section. According to the obtained palynological dendrogram, section luteola merged with section Reseda. Pollen wall data differed between Reseda luteola and the closely related taxon (Reseda macrobotrys) (pollen wall thickness, the situation of endexine and the number of intine layers).