Chromosomal stickiness and related meiotic irregularities in Inula racemosa - a critically endangered medicinal herb of North Western Himalayas

Abstract

Background: The species Inula racemosa, a rare species of Kashmir Himalaya, has been included in the list of endangered species of India. In the present study, we aimed to make a more formal quantitative analysis of the fertility of /. racemosa, wild as well as transplanted populations, using a meiotic behaviour analysis and pollen viability test. Material and Methods: Inflorescences atan ideal stage for meiotic study were collected and fixed in acetic ethanol (1:3) for 24 h and stored in 70% alcohol under refrigeration at 4 °C until use. For slide preparation the anthers were squashed in 2% acetocarmine. Results: The present study revealed a peculiar chromosomal stickiness and formation of interbivalent chromatin connections among 2-4 bivalents. This stickiness of chromosomes along with interbivalent chromatin connections impairs the correct segregation of chromosomes, as a result single and double chromosomal bridges of different thickness, different number of lagging chromosomes, unequal separation, and multipolarity were continuously observed from anaphase I to microspore stage. Consequent to stickiness and associated meiotic abnormalities, the pollen grains varied greatly in size, individuals show 24.05-38.83% pollen sterility. Conclusions: The presence of sticky chromosomes in /. racemosa impairs the correct segregation during anaphase which compromises the pollen viability of the species. Although the percentage of pollen sterility was not completely concord to the high rates of observed chromosomal abnormalities but the findings can aid in the successful conservation and management of the species.