Efficient nitrogen remobilization and nitrogen partitioning to seeds in Camelina sativa grown under contrasting nitrogen regimes.

backgroundCamelina (Camelina sativa) is an emerging intermediate oilseed crop, commonly grown between main crops for biofuel production. A related Brassica oilseed, canola, exhibits low nitrogen remobilization efficiency. To evaluate the possibility of a similar limitation in camelina, nitrogen remobilization and partitioning to seeds was examined by growing plants under starkly contrasting nitrogen regimes. Camelina variety ‘Suneson’ was grown on nutrient film tables, using nutrient solutions containing 6.5 mM (HN) or 0.65 mM (LN) nitrogen. Nitrogen was either removed at the onset of flowering or continued until plant maturity (four treatments). Single leaves, entire shoot and root systems, silicles (fruit pericarp), and seeds were harvested in weekly intervals starting with the onset of flowering, and analyzed for dry weight, carbon, and nitrogen contents.

resultsNitrogen treatments profoundly affected plant development, with reduced branching, reduced height, smaller leaves, and strongly accelerated shoot and leaf senescence observed under LN. Nitrogen was efficiently remobilized from leaves, shoots, and silicles to seeds, with residual nitrogen concentrations as low as 0.3% of dry weight observed in mature shoot systems of LN-removed plants, and a nitrogen harvest index of 0.6 to 0.7 depending on treatment. N regimes strongly influenced seed yield and composition, with seed N between 2.8% (HN-removed) and 4.5% of dry mass (HN-continued), while seed oil varied between 25% (HN-continued) and 45% (HN-removed).

conclusionsCamelina exhibits efficient nitrogen remobilization and partitioning to seeds under starkly contrasting nitrogen regimes, supporting its reputation as a low-input crop and justifying renewed interest in this emerging agricultural commodity.