Estudios cromosómicos en especies argentinas de vernonia (Asteraceae)

Abstract

Se estudian los cromosomas de once especies de Vernonia de Argentina. Los resultados incluyen el recuento en siete especies que nunca se han investigado citológicamente. Los cariotipos de seis taxones son analizados, cinco de ellos se describen por primera vez sobre: V. chamaedrys n = 17, 2n = 34 = 22m + 12 sm; V.loretensis n= 17, 2n = 34 = 20 m + 14 sm; V.rubricaulis n = 16, 2n = 32 = 20m + 12sm; V.remotiflora n = 14, 2n = 28 = 16m + 12sm y V.lepidifera n= 10, 2n = 20 = 8 m + 12sm. El registro de 2n = 4x = 28 para V.remotiflora apoya la existencia del número cromosómico básico x = 7. En un inoforme previo un conteo de cromosomas muestra que Vernonia es multibasic con x = 7, 9, 10, 11, 12, 15, 17 y 19. La importancia de los resultados se discuten en relación a los datos cromosómicos disponibles para el géneroThe chromosomes of eleven Vernonia species from Argentina are studied. The results include counts in seven species that have never been investigated cytologically. The karyotype of six taxa are analized, five of them are described forthe first time: V. chamaedrys n=17, 2n=34= 22m + 12 sm; V. /oretensis n=17, 2n=34= 20m + 14 sm; V. rubricaulis n=16, 2n=32= 20m + 12sm; V. remotiflora n=14, 2n=28= 16m + 12sm and V. /epidifera n=10, 2n=20= 8m + 12sm. The record of 2n=4x=28 for V. remotiflora supports the existence of the basic chromosome number x=7. Previously reported chromosome counts show that Vernonia is multibasic with x=7, 9, 10, 11, 12, 15, 17 and 19. The significance of the results is discussed in relation to chromosomal data available for the genus.