Asexual propagation could be an escape to sustain the constraints of inefficient gametic system in the evolving endemic species: evidence from meiotic anomalies encountered in Aponogeton bruggenii (Aponogetonaceae)

The present study deals with the cytogenetics of Aponogeton bruggenii S.R.Yadav and Govekar (Aponogetonaceae) sporting asexual propagation. Mitotic metaphase in the root-tips revealed that the species is a polyploid with 2n = 56 chromosomes. Male meiosis was mostly abnormal. A total of 2023 pollen mother cells were observed, of which 448 showed normal and the remaining 1575 abnormal meiosis. Mostly, the stickiness and precocious separation was recorded at diakinesis and metaphase (I and II), respectively. Chromatin bridges, laggards, disorientation, ring formation were detected at various stages of meiosis ranging from diakinesis to telophase. Consequent to chromatin transfer, heterogeneously sized pollen grains, i.e. small, normal, large and fused were observed, hampering gametic efficiency and fruit set. However, the species resorts to vegetative propagation by means of underground tubers, possibly as a survival strategy to sustain dispersion and speciation.