Aquatic adventitious roots of alligator weed and capacity for oxygen absorption

The formation of aquatic adventitious roots is a common response of terrestrial plants to flooding. Previous research has found that aquatic adventitious roots on submerged plants can absorb water and nutrients, but no experimental evidence hitherto has shown that adventitious roots can absorb oxygen, which benefits the submerged plants.

Schematic representation of the experimental set-up for profiling of the oxygen gradient towards an adventitious root surface under water.
Schematic representation of the experimental set-up for profiling of the oxygen gradient towards an adventitious root surface under water. The plant with adventitious roots was placed at the bottom of the water tank and the target adventitious root was fixed onto the background board. The whole potted Alternanthera philoxeroides plant was submerged with air-saturated water for about 1 h. The microelectrode was fixed on a micromanipulator, and used to measure the underwater oxygen profile over a distance of approx. 1200 μm by advancing a step of 50 μm every 5 s, moving towards the root surface.

In this study, Ayi et al. demonstrate that the aquatic adventitious roots of alligator weed (Alternanthera philoxeroides) formed upon submergence can absorb O2 from ambient water, thereby increasing the oxygen content in plant tissues. This enables the efficient utilization of carbohydrates for vigorous root growth and extending the plant’s life-cycle.

Root Biology Issue This paper is part of the Root Biology Special Issue.

Reference List

Qiaoli Ayi, Bo Zeng, Jianhui Liu, Siqi Li, Peter M. van Bodegom, Johannes H. C. Cornelissen, 2016, 'Oxygen absorption by adventitious roots promotes the survival of completely submerged terrestrial plants', Annals of Botany, vol. 118, no. 4, pp. 675-683 http://dx.doi.org/10.1093/aob/mcw051