Tolerance of barley to root O2 deficiency: growth responses, internal aeration, and ion uptake by seminal and adventitious roots

Barley (Hordeum vulgare L.) is a cereal and is relatively sensitive to waterlogging, but with some genotypic variation in tolerance. The effects of waterlogging on nutrient uptake by seminal and adventitious roots of barley genotypes with contrasting root porosity were studied. Increased porosity of adventitious roots is an advantage for growth and nutrient uptake in low oxygen conditions. Higher root porosity enhanced internal oxygen movement and associated radial oxygen loss, but roots were oxygen­ deficient as evidenced by responses to increased oxygen supply. Greater root porosity and increased adventitious root numbers were key traits for waterlogging tolerance.