Male meiotic studies in 29 species of lamiaceae from Sirmaur District of Himachal Pradesh, India

Abstract

Lamiaceae is a requisite depository of many important medicinal herbs, distributed all over the world. The detailed meiotic studies, firstly are helpful in solving taxonomic and evolutionary enigmas and secondly provide best chemotypes for further exploration and conservatory purposes. Male meiosis in 29 species of 54 populations belonging to the 18 genera of Lamiaceae has been undertaken for the first time from Sirmaur district of Himachal Pradesh falling in Western Himalayas. Euploid cytotypes are reported in Ajuga parviflora (n=8x=32), Nepeta eryostachys (n=4x=18) and N. graciliflora (n=4x=18). Besides, B-chromosomes in previously known cytotypes of five species, A. bracteosa (n=32+0-2B), Leucas lanata (n=11+0-1B), Lycopus europeus (n=11+0-1B), Phlomis bracteosa (n=11+0-1B) and Vitex negundo (n=16+0-1B), are reported for the first time. A substantial amount of meiotic abnormalities in the form of chromatin stickiness, cytomixis, chromatin bridges and laggards are reported in the presently worked out population that leads to the high variability in the microsporogenesis, pollen grain size heterogeneity and ultimately, reduce pollen viability. Only, the populations with B-chromosome had a low or negligible frequency of meiotic abnormalities.