Cytomixis in pollen mother cells of spearmint (Mentha spicata L.)

Abstract

Cytomixis was recorded during microsporogenesis in a tetraploid (2n=4x=48) genotype of spearmint (Mentha spicata L.), an aromatic plant of the family Lamiaceae. The phenomenon of cytomixis was observed in leptotene to pachytene stages of the first meiotic prophase. The migration of nuclear content involved all the chromosomes or part of the chromosomes of the donor cell. The occurrence of PMCs with chromosome numbers deviating from the tetraploid number (2n=48), derived from the process of cytomixis indicated the possibility of aneuploid and polyploid gamete production. The pollen fertility was found to be affected by this phenomenon and it seems possible that genetic factors might have also contributed towards the pollen sterility.