Influence of Flavonoids on Nodulation and Carbon Partitioning in Pea-Rhizobium Symbiosis

Rhizospheric application of nod regulators influenced the nodulation status, nodule efficiency and partitioning of assimilated CO₂ in Pisum sativum-Rhizobium leguminosarum symbiosis. Depending upon the plant growth stage, naringenin and flavone enhanced nodule number (22.8–87.6%), nodule weight (19.2–35.2%) and nitrogenase activity (17.8–108.6%). Syringaldehyde had negative effect on various parameters of symbiosis. Proportion of ¹⁴C-assimilates was higher in nodules of plants from naringenin and flavone treatments as compared to the control or syringaldehyde treatments. The enhanced nodule efficiency in naringenin and flavone treatments was reflected in the increased N content (12.7–50.4%) and biomass (4.3–35.1%) of plants.