Meiotic behavior and pollen morphology variation in Centaurium pulchellum (Gentianaceae)
VIA DO PICO, G. M.; DEMATTEIS, M.
PLANT SYSTEMATICS AND EVOLUTION
Lugar: Wien; Año: 2010 vol. 290 p. 99 - 108
Centaurium pulchellum is an annual herb native from Europe, but introduced in South America, which is widely used in preparatrion of digestive infusions and bitter drinks. In this species was reported a wide variation in the aperture pattern of pollen grains which has been attributed to environmental factors or irregularities at meiosis. For this reason, it have been realized cytological and palinological studies on two different populations. The pollen grains analysis showed that some types are more frequent within each population, but the most common forms were the typical 3-colporate and 4-colporate. The cytological analysis revealed that the analyzed populations of C. pulchellum have chromosome number 2n=36. The presence of tetravalents at meiosis, strongly suggest that these populations are autotetraploid based on x=9. The meiotic behavior showed a significant percentage of irregularities in different phases: off-plate bivalents, precocious segregation, laggard chromosomes, bridges and cytomixis. However these irregularities would be not related to the variation in the aperture pattern of pollen grains. The heteromorphism in the pollen grains observed in C. pulchellum could be a normal condition to which the species is well adapted.