Anatomical and Morphological Adaptation of Plants to Waterlogging1

Most agricultural crops are mesophytes which require an environment which is neither too wet nor too dry for maximum growth and productivity. Once soil becomes waterlogged, air space is displaced with water. The O 2 remaining in the soil, either dissolved in water or trapped in air cavities, is quickly depleted by respiration of plant roots and soil microorganisms (69). O 2 replenishment in the soil is very inefficient because of the stow diffusion of atmospheric O 2 into the waterlogged soil. Root systems are thus suddenly plunged into an anaerobic condition by waterlogging. If waterlogging continues for a tong period, the reducing processes in the rhizosphere aggravate the plant condition. Waterlogging does not necessarily occur only when the soil is inundated. Rather, waterlogging often occurs when water fills a critical proportion of the soil air spaces, depending upon the species of the plant involved. Such problems are prevalent in fields having poor drainage, that is, when underground and surface drainage is inadequate to remove water from the soil after a rain.