Plants, like other living organisms, require oxygen and water supplies for sustaining their normal growth and development. The water requirement is generally met through a coordinated system of root-to-shoot communication. However, excessive soil moisture in the rhizosphere can impact normal functioning of plants by restricting oxygen supplies to the roots. To survive under hypoxic conditions, plants show cellular, molecular, and functional level adaptations. One temporary response could be switching to anaerobic respiration, and maintain energy production to some extent, via glycolysis and ethanol fermentation. However, root respiration, water, and nutrient uptake, and hormonal synthesis are severely impacted under sustained periods of oxygen deficiency. These belowground changes, in turn, affect shoot performance and yield formation by interfering with the key physiological processes.