Growth and yield responses of castor bean (Ricinus communis L.) to two enhanced CO2 levels

Abstract

Growth and yield responses of castor bean (Ricinus communis L.) to two elevated CO2 levels (550 and 700 ppm) were evaluated up to the maturity of first order spikes in open top chambers (OTCs). The growth characteristics – root and shoot lengths, root volume, root:shoot ratios, leaf area, dry weights of different plant parts, leaf area duration and crop growth rate increased with 550 and 700 ppm of CO2 levels compared with ambient control. The spike length, pod and seed yield of first order spikes increased under enhanced CO2 levels over ambient control. Elevated CO2 levels significantly increased the total biomass and yield of castor bean, however enhanced CO2 levels per se did not changed the content and quality of the castor oil. A positive response of castor bean to increased CO2 concentrations is a good indication for its future existence in potentially changed climatic conditions.