Intra-specific variability in cytomictic and meiotic aspects ofunderutilizedVitex negundo L. from North-West Himalaya: putative causes and consequences

Abstract

Vitex negundo Linn., a widely distributed medicinal species of North-western Himalaya, has been studied for detailed cytological aspects. Present studies on eight populations reveals this species having 34 chromosomes, which largely show regular behaviour. Besides, studied populations of this species are unusual in exhibiting cytomixis largely between paired meiocytes at prophase and rarely between 3-4 meiocytes at anaphase. Comparison of frequency of cytomictic cells prepared using fixed and fresh anthers reveals scarce influence of anther fixation on percentage of cells showing cytoplasmic connections and chromatin transfer. Analysis of cytomictic index of plants inhabiting varying altitudes indicate overall less cytomictic index in populations from lower altitudes. Further analysis of dividing meiocytes for chromosomal number and behaviour reveals that out of eight populations, five (Govind-sar, Palli-morh, Kharoot-morh, Billawar and Rajouri) populations contains all and three contain maximum diploid cells, where as minority of cells of latter three populations exhibit near haploidy and polyploidy. Similarly translocations, manifested by occurrence of multivalent have been noted in 16-33% euploid PMCs of 4 populations (Palm, Bilr, Khrm, and Kol). Comparison of frequency of cells showing chromatin migration and meiotic anomalies reveal existence of inverse relations in these parameters. Existence of cytomictic and meiotically aberrant cells also account for the production of few deviant sized pollen grains along with normal ones. All these anomalies along with their possible cause and consequences are presented in communication.