ARS | Publication request: Effect of Elevated CO2 on Growth and Photosynthetic Characteristics of Chickpea (Cicer arietinum L.)

Submitted to: Indian Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 23, 2008
Publication Date: December 21, 2008
Citation: Pal, M., Talawar, S., Deshmukh, P., Vishwanathan, C., Khetarpal, S., Kumar, P., Luthria, D.L. 2008. Effect of elevated CO2 on growth and photosynthetic characteristics of chickpea (Cicer arietinum L.). Indian Journal of Plant Physiology. 13:4.

Interpretive Summary: The potential impact of climate change on agriculture has received significant attention during the past decade due to increased awareness about global warming. Chickpea, being the third most important pulse crop in the world, was selected as a model crop to study the influence of elevated carbon dioxide on growth and protein content. The plants exposed to elevated CO2 showed increases in growth characteristics---shoot length, total number of branches, and leaf area. A significant increase in leaf and shoot dry weight was recorded in elevated carbon dioxide-grown plants. The concentration of non-structural carbohydrates such as sugars and starch was higher in the elevated CO2-grown plants, which indicates higher photosynthetic activity. Total carbon concentration increased but the nitrogen concentration decreased in the leaves and resulted in higher C/N ratios. The seed yield of the elevated CO2-growth plants was higher due to a significant increase in the number of seeds per plant. This study suggests that rising atmospheric CO2 in the future may increase production and yield of chickpea crop plants but a simultaneous reduction in nitrogen concentration may decrease their protein content. This work was carried out at the Indian Agricultural Research Institute, PUSA, New Delhi, with grant support from the Fulbright Foundation and United States Education Foundation in India.

Technical Abstract: Chickpea (Cicer arietinum L.) cultivar Pusa 1108 was grown inside open-top chambers (OTCs) and exposed to ambient (370±20 microliters per liter) and elevated (550±50 microliters per liter) CO2 from germination till maturity of the crop to determine its growth and yield response. The plants exposed to elevated CO2 showed increases in growth characteristics---shoot length, total number of branches, and leaf area per plant. A significant increase in leaf and shoot dry weight was recorded in elevated carbon dioxide-grown plants. The concentration of non-structural carbohydrates such as sugars and starch was higher in the elevated CO2-grown plants, which indicates higher photosynthetic activity. Total carbon concentration increased but the nitrogen concentration decreased in the leaves and resulted in higher C/N ratios. The seed yield of the elevated CO2-growth plants was higher due to a significant increase in the number of seeds per plant. This study suggests that rising atmospheric CO2 in the future may increase production and yield of chickpea crop plants but a simultaneous reduction in nitrogen concentration may decrease their protein content.