Ozone risk assessment of castor (Ricinus communis L.) cultivars using open top chamber and ethylenediurea (EDU)

Abstract

Castor bean (Ricinus communis L.) an important non-edible oilseed crop, is a prominent feed stock towards the generation of renewable materials for industrial production which has multiple applications ranging from cosmetics to biofuels industry. India accounts for 76% of the total world production of castor oil seed. However, major concern for developing countries like India where expanding economy led to rapid increases in gases like NOx, CO and VOCs photochemically form ozone. Ozone is strong oxidant that damages agriculture, ecosystems, and materials with considerable reduction in crop yields and crop quality. One way to reduce ozone induced loss is to focus on the adapting crops to ozone exposure by selecting cultivars with demonstrated ozone resistance. An experiment was conducted for ozone risk assessment of castor cultivars to select cultivar with demonstrated resistance against ozone pollution. This study comprise an open top chamber experiment with three treatments viz. (i) control (ambient ozone concentration), (ii) enhanced ozone (average 75 ppb for 4 h daily throughout the growing season), and (iii) EDU application. Results suggested that the ozone pollution substantially affected growth and physiology of castor cultivars. Crop biomass and yield was also negatively influenced by ozone pollution. Developed defence provided strength to withstand against ozone pollution to the experimental crop cultivars. However, developed defence is cultivar specific and positively correlated with the resistance against ozone pollution. Study concluded that the damage to ozone is directly dependent on the antioxidative potential of plant species. However, ozone adaptability is based on the genetic makeup of the cultivar and yield related loss to ozone can be minimizing by selecting ozone tolerant variety as seen in cultivar Nidhi-999.