Antioxidant responses are associated with differences in drought tolerance between maize and sorghum.

Abstract

Drought is a major cause of decreased yield in crops worldwide. Sorghum (Sorghum bicolor) and maize (Zea mays) are two of the key crops in Africa serving as human food as well as livestock feed. For improved crop production, selection for drought resilient genotypes is imperative and the biological basis for drought tolerance ought to be fully understood to achieve such selection. Sorghum can tolerate drought better than maize and it is a key model for studying the physiological and biochemical mechanisms conferring drought tolerance. In this study, comparative analyses in terms of changes in growth, chlorophyll content, ROS content, lipid peroxidation level and the activity of antioxidant enzymes were investigated. Exposure to drought triggered ROS generation in both plant species. However, sorghum showed less cell damage under water deficit compared to maize. Furthermore, differences in antioxidant enzyme activity between maize and sorghum were identified. Our findings reveal differences in and association between the physiological and biochemical responses of maize and sorghum to drought, which may be relevant for breeding drought tolerant crops.

Keywords

• Reactive oxygen species
• antioxidant enzyme activity
• oxidative stress
• maize
• sorghum