Pollination Biology and Environmental Water Pollution Indicator of Onion (Allium cepa L.)

Abstract

Numerous genes in flowering plants, including onion (Allium cepa L.) govern morphological character differences in structure, shape, orientation, weight and number, etc. arising from their assortment and recombination due to pollination. Pollination in onion flower occurs mainly by insects (91%) and wind (9%), with gravity also contributing to the pollination process. The hybrid vigour seeds through cross pollination as an essential input in enhancing crop productivity. The present study reveals that an onion plant generally takes around 63 days to attain flowering position, and complete flowering condition in 70–72 days, which include 15–18 days for sprouting of the green hollow fleshy shoots along with about 45 days to complete the peduncle formation on the top small part of the bud. A. cepa L. takes around 160 days to produce mature seeds with life cycle completion. The onion bulb roots are used for the last 50 years to study chromosomal behaviour as an indicator of environmental water pollution. The presence of different impurities and heavy metals in the polluted water causes reduction in reproductive capacity of cells due to the occurrence of peculiarity from the normal mitotic cell division in onion . Cytotoxicity influences all morphological characters, including root growth retardation, mitotic index, chromosomal aberration, etc. Thus, the present investigation explores the effect of pollutant water on pollination biology, cytotoxicity, root apical meristem cells in onion. We report a significant (p < 0.05) in the mitotic index in polluted water as compared to normal water.