Radial O2-loss barrier induction and arenchyma formation
Many wetland species form both aerenchyma and a barrier to radial oxygen loss (ROL) in roots, which enhance internal O2 diffusion to the root apex. Shiono et al. study the dynamics of these features for short or long roots of rice, Oryza sativa, when they are exposed to non-aerated conditions and find that barrier induction commences more quickly in longer roots; there are no differences in aerenchyma formation. ROL barrier induction occurs before histochemically detectable changes in putative suberin and lignin deposits can be seen, suggesting that the structural changes required for barrier functioning are subtle.
