Progress toward Understanding the Molecular Basis of Fruit Response to Hypoxia

Oxygen has shaped life on Earth as we know it today. Molecular oxygen is essential for normal cellular function, i.e., plants need oxygen to maintain cellular respiration and for a wide variety of biochemical reactions. When oxygen levels in the cell are lower than levels needed for respiration, then the cell experiences hypoxia. Plants are known to experience root hypoxia during natural environmental conditions like flooding. Fruit, on the other hand, is known to be hypoxic under normal oxygen conditions. This observation could be explained (at least partially) as a consequence of diffusional barriers, low tissue diffusivity, and high oxygen consumption by respiration. From the physiological point of view, hypoxia is known to have a profound impact on fruit development, since it is well documented that a low oxygen environment can significantly delay ripening and senescence of some fruit. This effect of a low-oxygen environment is readily used for optimizing storage conditions and transport, and for prolonging the shelf life of several fruit commodities. Therefore, further understanding of the complex relationship between oxygen availability within the cell and fruit development could assist postharvest management.