(1) Both root system and trunk have lenticels (gas exchange pores) and aerenchyma (interconnected air-filled spaces), the former features comprising up to 51% of the volume of some mangrove roots.(2) This tissue probably aided photosynthetic gas exchange much like the lenticels of modern trees.(3) Corks are deliberately punched at right angles to the growth of the cork tree, so that any lenticels, occasional knots in the wood, remain transverse and the risk of possible leakage due to lenticels is minimized.(4) Finally, long-term morphological changes are induced, such as the formation of lenticels and aerenchyma to improve the oxygen permeability of the tissue.(5) P occidentalis can develop adventitious roots and lenticels in response to flooding; however it appears to require aerated soils during the growing season.
