Karyomorphometrical analysis of Spilanthes Jacq. (Asteraceae) using image analysis system

摘要

This study was aimed to bring out the Karyotype characteristics of four species of Spilanthes to check for marked symmetry or asymmetry in the chromosomal complements with the aid of semi-automatic image analysis system. The chromosome number of Spilanthes calva and S. radicans was 2n = 78, and in S. ciliata and S. uliginosa it was 2n = 52. The four investigated taxa of Spilanthes are monobasic with the secondary number X 2 = 13. The size of chromosome ranged from 0.50–1.62 μm. The chromosome pairs with secondary constriction are varying from one to three in various taxa. The karyotypes show that considerable variation exists in chromosome morphology and structure among the species studied. In Spilanthes the lesser values for all the parameters of karyomorphology show its rather evolved nature. Such type of variation is important from the evolutionary view point.