Karyomorphology of Two Species of the Genus Spilanthes (Heliantheae-Asteraceae)

Abstract

In present investigation karyotype of mitotic chromosomes were determined, two species of the genus Spilanthes, namely Spilanthes acmella (L.) Murray and Spilanthes calva DC. from plants transplanted in earthen pots collected from different localities from Central Nepal in my home garden. The somatic chromosome number determined in present study were 2n=36 for both species, Spilanthes acmella (L.) Murray and Spilanthes calva DC. The chromosomes total length ranged from 0.6 to 1.6 µm in Spilanthes acmella (L.) Murray and 0.4 to 2.1µm in Spilanthes calva DC. The relative length ranged from 2.3 to 12.1 µm in the species Spilanthes calva and 2.0 to 8.5 µm in the species Spilanthes acmella. The Karyotype formula were M16+m2+sm16+st2 in Spilanthes calva DC. and M22 +sm14 in Spilanthes acmella (L.) Murray cytologically obtained by using 2% aceto-orcein. The karyotype of the two species shows considerable variation exists in morphology of chromosome and structure. The variation in karyomorphology shows evolved nature of this species which play a great role in evolution. Int. J. Appl. Sci. Biotechnol. Vol 8(4): 422-426