Karyomorphological studies of some lithophytic species of the genus Dendrobium Sw. (Orchidaceae) from Manipur, India: a cytotaxonomic approach

• Published in: Nucleus (Calcutta) 2023-08, Vol.66 (2), p.145-150
• Main Authors: Sharma, Hidangmayum Bishwajit, Bhattacharyya, Debjyoti
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Cell Biology; Chromosome number; Chromosomes; Cytology; Dendrobium; Diploids; Karyotypes; Life Sciences; Orchidaceae; Original Article; Polyploidy; Species
• ISSN: 0029-568X; 0976-7975
• DOI: 10.1007/s13237-023-00421-x

In this study, karyomorphological studies of five lithophytic species of the genus Dendrobium Sw. from Manipur (Orchidaceae) were made. These were viz., Dendrobium aphyllum (Roxb.) C.E.C. Fisch., D. crepidatum Lindl., D. devonianum Paxt., D. fimbriatum Hook. and D. nobile Lindl. Chromosome counts of those five lithophytic species were studied for the first time from Manipur, India. Dendrobium shows the basic chromosomes number X = 19 and 20. The five species studied were diploid (2n) with chromosome number 2n = 40 in three species ( D. aphyllum , D. fimbriatum and D. nobile ) and 2n = 38 in remaining two species ( D. crepidatum and D. devonianum ). The highest Total Chromosome Length (TCL) and Mean Chromosome Length (MCL) were observed in D. fimbriatum (59.45 μm and 4.07 μm respectively), while D. nobile had lowest TCL (53.50 μm) and MCL (3.25 μm). Chromosomes were mostly median to sub-median in all studied taxa, however, median chromosomes were more dominant. No polyploids were observed. Categorization as per Stebbins’ classification were done for all the species; the karyotype asymmetry of D. crepidatum and D. fimbriatum were in 3A category while the remaining three species viz., D. aphyllum , D. devonianum and D. nobile were in 3B category. The present study will help in establishing taxonomic and ecological relationships between lithophytic species of the genus based upon cytology.