On the Difficulties of Measuring Oxygen Release by Root Systems of Wetland Plants

Abstract

The suitability of bathing whole root systems in nutrient solutions for measuring root oxygen release was re-examined. The rate of oxygen release from the roots of the wetland plant Juncus ingens was measured in oxygen-depleted solution (oxygen concentration < 15 μMOL L −1 ) and in a titanium (III) citrate buffer with a low redox potential similar to that of natural sediments (E H < −200 mV). When incubated in a solution containing 15 μmol O 2 l −1 in a closed chamber, J. ingens roots consumed oxygen until all the oxygen in the chamber was exhausted and there was zero net oxygen exchange between the roots and the solution (...)