Oxygen consumption under hypoxic conditions

Even during optimal growth conditions, the availability of oxygen to plant cells can get limited due to the diffusion resistance of the tissue for oxygen. However, plants can probably regulate the rate of respiratory oxygen consumption which is thought to play a role during periods of low-oxygen stress as it postpones oxygen to become limiting as respiratory substrate. At present, limitation of oxygen becomes more and more important in the context of climate change and concomitant changed environmental stress conditions such as flooding. One mechanism by which plants can react to survive periods of low-oxygen stress is to save on oxygen by downregulating energy requiring processes such as storage metabolism. For this, a series of drastic metabolic adaptations is initiated in plants upon hypoxia. In this chapter, it is discussed how plants adapt to low-oxygen availability via metabolic responses and by regulating respiratory oxygen consumption as a function of the actual oxygen concentration.