Elevated CO2 enhances carbohydrate assimilation at flowering stage and seed yield in chickpea (Cicer arietinum)

Abstract

Rising atmospheric CO2 concentration can stimulate plant growth through enhanced photosynthesis and carbohydrate assimilation. A study was planned to analyse the effects of elevated CO2 (eCO2) (570 ± 45 µmol mol−1) on photosynthesis, carbohydrate assimilation and photorespiratory enzymes and their gene expression in desi (Pusa 1103) and kabuli (Pusa 1105) chickpea genotypes. The findings showed higher rate of photosynthesis in both desi and kabuli chickpea genotypes under elevated CO2 and was accompanied with increased starch and sugar concentration and rubisco activity. Expression of rbcS and rbcL genes was higher under elevated CO2 during flowering stage but non-significant changes occurred in expression at podding stage. Shoot biomass and seed yield was significantly higher in both chickpea genotypes under eCO2. Glycolate oxidase activity decreased under eCO2 and the reduction was greater in desi compared to kabuli genotype, suggesting suppressed photorespiration in both the chickpea genotypes. The finding of this study concludes that chickpea crop can perform better under eCO2 environment due to increased rate of photosynthesis and suppressed photorespiration. Between two types of chickpea, desi may respond better to eCO2 owing to its higher sink potential than kabuli types.