Palynological characterization of succulents of the families Asphodelaceae and Asteraceae

Resumo

This study aimed to analyze palynologically succulent species: Asphodelaceae: Haworthia chloracantha Haw., Haworthia cymbiformis (Haw.) Duval, Haworthia limifolia (=Haworthiopsis limifolia) Marloth and Asteraceae: Othonna capensis LH Bailey and Senecio peregrinus Griseb. Closed buds were preserved in acetic acid, the acetolyzed grains were arranged on microscope slides, and 50 pollen grains of each species were photographed. Using light optical microscopy, measurements were made of each grain in the polar and equatorial views, in micrometers (µm). For scanning electron microscopy (SEM), the anthers were macerated on microscope slides to release the grains, which were metallized with gold-palladium and photographed. In Asphodelaceae, the grains are monads, monosulcate, medium to large in size, elliptical in scope, bilaterally symmetric, heteropolar, with foveolate, ornamentation microreticulate, perforated, mean exine thickness 1.98-1.42-2.21 micrometers. In Asteraceae, the grains are monads, tricolporate, medium in size, circular to subcircular in scope, radially symmetric, isopolar, oblate-spheroidal and prolate-spheroidal in shape, with perforated echinate ornamentation, average exine thickness 4.08-4.41 micrometers. The pattern of the grains of Haworthia are in line with literature of Asphodelaceae, although the verrucate exine was not observed in this study. For Othonna and Senecio, the echinate ornamentation and thicker exine are in line with the pattern of the Asteraceae.