Meiotic analysis in some species of family Cyperaceae from North India

The present study reports the chromosome counts and meiotic analysis including microsporogenesis and pollen fertility in 7 species in the family Cyperaceae from North Indian states. We here add the chromosome record for four species of Cyperaceae. During the present investigation, in some meiotic cells of Cyperus difformis and Isolepis setacea, chromatin threads were found which were typical for the species with inverted meiosis. So present investigation gives the idea of the presence of inverted meiosis in these two genera. Pseudomonad formation, the special feature of the family Cyperaceae where three nuclei out of four degenerate and gives the final product of one pollen per PMC. The course of meiosis in most of the accessions was observed to be regular except for some individuals of Cyperus paniceus, Scirpus mucronatua and Isolepis setacea which showed certain meiotic abnormalities in meiocytes involving cytomixis, chromatin stickiness, chromatin bridges, lagging chromosomes, and interchromosomal connections of bivalents. Being a holocentric family agmatoploidy, symploidy, and polyploidy can play important role in karyotype evolution. The Family shows considerable heterogeneity in chromosome numbers ranging from n = 2 to 60. The family exhibits several base numbers (x=5-14, 16, 20-23, 26, 27, 29, 30, 36, 38, 60) and x=5 is regarded as the most relevant base number for the family. Other base numbers have supposed to be secondarily derived from the ancestral number x=5.

Automated summary

The present study conducted chromosome counts and meiotic analysis on 7 species of Cyperaceae from North India, uncovering the possibility of inverted meiosis and discussing chromosomal abnormalities within the family. It was also found that the family exhibits considerable heterogeneity in chromosome numbers and base numbers, suggesting potential karyotype evolution pathways.