Induced cytomictic crosstalk behaviour among micro-meiocytes of Cyamopsis tetragonoloba (L.) Taub. (cluster bean): Reasons and repercussions

Abstract

Cytomictic behaviour of chromosomes among pollen mother cells was observed in mutagenic studies in cluster bean (Cyamopsis tetragonoloba (L.) Taub.). The study of pollen mother cells (PMC) revealed various chromosomal aberrations among which cytomixis was notified due to its obtrusive peculiarity and is therefore given description in this article. Cytoplasmic and chromatin transmigration were discernible among contiguous or slightly distant PMCs through recreation of passage via direct cell-to-cell fusion or channel formation. This cytomictic phenomenon was invariably more pronounced at meiosis I as compared to meiosis II. Plasmodesmatal connections play a paramount role in aiding this behaviour by establishing intercellular crosstalks. The cellular intermingling resulted in syncyte cells which were identified due to their doubled size. Syncyte or unreduced PMC formation leading to unreduced fertile gametes is speculated to act as a possible way out for infraspecific polyploidization of species. Pollen fertility was computed, alongwith this heterosized pollens of varying diameter were segregated. Large sized pollens were 2n pollens; where size difference is a consequence of cytomixis. Cytoplasmic connections among pollens were also observed sporadically. It is opined that syncyte formation and 2n pollen production have evolutionary significance.

Keywords

• Cyamopsis tetragonoloba
• cytomixis
• heterosized pollens
• infraspecific polypoidy
• PMCs
• syncyte