*Corresponding author Email id: leeborah@gmail.com
Plant-mediated transport is the major pathway of methane (CH4) emission from wetland paddy fields. The present experiment was conducted to understand the mechanism of CH4 transport through rice paddies. A field measurement of CH4 emission was done with three rice genotypes Ranjit, Piolee and Swarna Mahsuri to identify plant physiological and anatomical characteristics influencing gas emission, which could provide insight to the mechanism of CH4 transport. CH4 emission estimation by a closed chamber technique revealed significant variations in emission of CH4 among the varieties. Variety Ranjit was identified as a low emitting variety compared to the others. The leaf area index, tiller number, leaf and root dry weight were closely associated with CH4 emission. The rate of leaf transpiration, stomatal conductance, leaf stomatal frequency and size of the xylem vessels were identified to be strong determinants of CH4 emission suggesting a transport pathway of CH4 along with the transpirational xylem water flow and subsequently through open stomata of leaf blade. Low emitting variety Ranjit exhibited superior yield and yield attributing characteristics in terms of panicle dry weight and high density grain (%) highlighting the role of source–sink carbohydrate partitioning in regulating CH4 emissions. Cultivation of low emitting varieties with higher grain productivity can be an effective environmentally-friendly biological mitigation strategy for CH4 emission from rice paddies.
Methane, Plant-mediated transport, Transpiration, Stomatal frequency, Xylem, Source-sink carbohydrate partitioning, Biological mitigation
