Methane as a Constituent of the Internal Atmosphere of Vascular Hydrophytes1

Methane has been detected as a constituent of the internal atmosphere of Elodea canadensis and Myriophyllum exalbescens growing in ponds with organic substrates. The gas apparently diffuses from the anoxic substrates into the root or rhizoidal portion of the plants. High concentrations of the gas within the plants have been observed during the winter under an ice cover. Methane was also present during the night and early hours during summer. When the gas was added experimentally to pond water, it appeared quickly in the internal atmosphere of plants, apparently diffusing into shoot tissues. In dark‐bottle experiments methane disappeared slowly from internal tissues. It was displaced rapidly from light bottles during periods of active photosynthesis.