Plant-mediated CH4 transport can enhance ecosystem CH4 emission by transporting soil-produced CH4. This pathway can exceed diffusion and ebullition as the dominant CH4 emission route. However, limited studies have investigated the morphological and anatomical factors influencing CH4 transport in plants. Through a series of manipulative experiments on the shoots and roots, this study examines the role of root and shoot structures in CH4 transport and release in six widespread wetland species: Carex rostrata Stokes, Carex lasiocarpa Ehrh., Carex aquatilis Wahlenb., Iris pseudacorus L., Juncus effusus L., and Alocasia odora (Lodd.) Spach. CH4 flux from all investigated species dropped significantly after clipping fine roots, while it did not change significantly after removing coarse roots. Shoot clipping and sealing significantly decreased CH4 flux from the investigated Carex species, but not from the other species. Our results demonstrate the important role of fine roots in controlling CH4 flux, whereas coarse roots play a minor role. Leaf blades are the major release site of CH4 from Carex species, while micropores at the shoot base are the primary release site of CH4 from the other species. Our study suggests that integrating plant-specific anatomical and morphological characteristics into global methane models is crucial to better predict and mitigate climate change impacts.
Ge et al. (Sun,) studied this question.