Gamma-induced infraspecific polyploidy via cytomixis-mediated syncyte formation in Papaver somniferum (Papaveraceae)

Authors: GIRJESH KUMAR, SANA NASEEM

Abstract: This is the first report on the phenomenon of syncyte manifestation through cytomictic transmigration in Papaver somniferum L. The occurrence characteristics and cytological depictions of cytomixis in the meiotic course of gamma-irradiated population reveal the mechanism leading to the origin of the cell fusions/syncytes. The event was more frequent in meiosis I and rare in meiosis II, indicating that the process atrophies at the end of the first meiotic division. The degree of occurrence of the phenomenon virtually concurred with the increase in the treatment dose of gamma irradiation. The phenomenon also affected the qualitative composition of postmeiotic products, i.e. tetrads and pollen grains. Heterosized pollen grains ranging from large to small size are also reported. In general, the occurrence of large-sized pollens is associated with unreduced gametes/syncytes and is an indication of the production of 2n pollens. Although occurring in low frequency, syncytes could play a decisive role in plant evolution as they can lead to the production of plants with higher ploidy levels. They may have potential applications in germplasm improvement in the sense of diversity and thus should be given more attention in future studies.

Keywords: Gamma irradiation, cytomixis, syncyte, heterosized pollen grains, poppy

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