Report on Chromosome Number Along with Chrom So-mal Chimera and Abnormal Shaped Anaphase of Acmella Ciliata

Abstract

Acmella ciliata(Kunth) synomyme Spilanthes acmella Murr. is a plant species under asteraceae family are investigated cytogenetically by orcein staining to find out chromosome number, chimeric status and overall mitotic cell division. The diploid chromosome number 2n=46 was found in most of the cells but some cells possess 2n =70 chromosomes in the same examined sample. So, we found two type cells according to their chromosome number which are indicated as type ‘a’ and ‘b’. The centromeric formulae of a type cell is 34m+6sm while 52m +18sm is for b type cells. The length of chromosomes range 3.68 to 2.30 µm in a type cell and 3.68 to 2.24 µm in b type cell that is approximately same in case of the length ranges. The total length of 2n chromosome complement of b type cell is greater than a type cell. The variable chromosome number indicates its chromosomal chimera. No satellites were found. Some cell possesses abnormal shaped anaphase which are clearly distinguishable to normal anaphase stage found in same species. Conventional karyotype analysis indicated that both type cell’s chromosome number are totally different with previous report. Therefore, the compilation of the above cytogenetical information proves that the Acmella ciliata showing variable chromosome number means its chromosomal chimera. This cytogenetical information will help in the study of plant chromosomal chimera in Bangladesh.