Rising atmospheric CO2: Potential impacts on chickpea seed quality

Abstract

Experiments on chickpea (Cicer arietinum L.) were performed in open-top chambers during 2010–11 and 2011–12 to assess effects of atmospheric CO2 enrichment on the quality of seeds. Although no physical modification was observed, an increase in seed water uptake was recorded in plants grown under enriched atmospheric CO2 condition. Germination of seeds reduced by 45–47%, while seed leachate conductivity increased by 10–17%. Seedling vigor decreased, although root and shoot lengths and seedling biomass showed negligible changes. Similarly, atmospheric CO2 enrichment reduced field emergence of seedlings with no change in root characteristics of the emerged seedlings. A decrease in protease activity supports the reduced seed viability, although no change in grain phosphatase and α-amylase activities were recorded. Increase in carbon content in germinating seed-cotyledon along with decrease in N in cotyledon resulted in large increase in C:N ratio for the plants grown under enriched CO2 condition. The starch content increased with no change in soluble sugar in germinating seed-cotyledons. This indicates more carbonaceous seeds from plants grown under enriched CO2 environment. Results suggest that rising atmospheric CO2 might have adverse impact on viability and germination of chickpea seeds, and cause nutritional imbalance through increase in C with dilution of N contents in germinating seed-cotyledons.