Root water transport under waterlogged conditions and the roles of aquaporins

Abstract

Water flow through plants roots can be affected when the soil is waterlogged and oxygen deficient. For species not adapted to these conditions, water flow usually decreases within minutes to days, depending on the oxygen concentration in the root and rhizosphere. During this time, the decrease in water flow is attributed to decreased root hydraulic conductance, through an inhibition of plasma-membrane aquaporins. There is increasing evidence that aquaporins may also be involved in the transport of gases, end products of anaerobic respiration, and signalling molecules; all of which are relevant to oxygen-deficient conditions. Eventually, primary roots die if continually starved of oxygen, but may be replaced with adventitious roots that can maintain the supply of water to the shoot. Here, we review the effects of waterlogging and oxygen deficiency on root hydraulic conductance and aquaporin activity.