Photosynthesis and nutrient composition of spinach and fenugreek grown under elevated carbon dioxide concentration

The effect of elevated carbon dioxide concentration on the changes in the biomass, photosynthesis and nutrient composition was investigated in two leafy vegetables. Spinach (Spinacia oleracea L.) and fenugreek (Trigonella foenum-graecum L.) plants were grown in open top chambers under either ambient (ACO₂, 350 ± 50 μmol mol⁻¹) or elevated (ECO₂, 600 ± 50 μmol mol⁻¹) CO₂ concentration and analyzed 40, 60 and 80 days after exposure. The plants grown in ECO₂ had higher net photosynthetic rate and lower stomatal conductance when compared with the plants grown in ACO₂. ECO₂ also changed the nutrient composition: a lower N, Mg and Fe contents and higher C and Ca contents were observed in the leaves of plants exposed to ECO₂ than in those grown at ACO₂.