Impact of Elevated Atmospheric Carbon Dioxide on Yield, Vitamin C, Proximate, Fatty Acid and Amino Acid Composition of Capsicum (Capsicum Annuum)

Abstract

A steady increase in the atmospheric CO2 concentration due to human activities in the last few decades is largely believed to be a major cause of climate change. Since agriculture is a climate sensitive system, there is a growing concern that the CO2 added to the air is changing the nutritional composition of fruits, grains and vegetables. Based on this hypothesis, the present experiment work was conducted to study the effect of enhanced atmospheric CO2 on nutritional and biochemical composition of chili (Capsicum annuum). Five local varieties of capsicum (Angrika, Best Choice, Diana, Magama, and 99PE-1689) were grown under two concentrations of CO2, i.e. 400µmol mol-1 (ambient) and 1000µmol mol-1 (elevated) under controlled conditions in green houses. Fruits were harvested at two stages of maturity and analyzed for proximate, elemental, fatty acid and amino acid concentration. Capsicum fruits grown under higher CO2 concentration had different nutritional composition.Vitamin C, protein, ash and fat contents decreased significantly (P≤0.05), acidity decreased non-significantly (P>0.1) whereas sugar and fiber contents increased significantly under enhanced CO2. Elemental composition showed a significant increase in C, H, Fe, Mn and a decrease in N, Ca, Mg and Zn contents. Few elements (S, K and Cu) showed no significant trend with elevated CO2. Fatty acids, with few exceptions,were not much affected by CO2 enrichment. Amino acids decreased with elevated concentration of CO2. The effect of enhanced CO2 was more pronounced at the fully matured (red) stage as compared to the premature (green) stage of capsicum fruit. Enhanced atmospheric CO2 lowered the nutritional quality of capsicum fruit by decreasing its vitamin C, proteins, Ca, Mg and Zn contents.