Nitrogen and Carbon Dynamics in Brassica under Elevated CO₂ and Moisture Stress Condition

A study was carried out to see the effects of elevated levels of CO₂ on partitioning of Nitrogen and Carbon in two cultivars of Brassica species viz. RH-30 and Pusa Gold under moisture stress condition. Results revealed that elevated CO₂ increased the C content of the leaves, stem and root;however, there was significant reduction in N content in various part of the plant at various stages of growth which could be linked to the overall alteration plants C: N ratio. Betweenthe two cultivars higher C content was recorded in RH-30 cultivar. The higher level of C was also recorded in elevated CO₂ of 550 ppm and under moisture stress conditions, indicating that crop growth under 55O ppm of CO₂ has some amelioration effect when compared to ambient. More accumulation of carbon may result in the better root growth, root number (both secondary and tertiary) and volume of root under due to elevated CO₂ which may further help in the absorption of available water and nutrients. The higher level of carbon content was not only recorded in the leaf during flowering, but also recorded in the pre-flowering stage indicating that C could be used as a storage carbon during reproductive development under the elevated CO₂ condition.