Abiotic Stress in Agricultural Crops Under Climatic Conditions

Crop stress has been identified as one of the problems that threaten global food security. Crop stress is an injurious deviation from the normal physiological processes that result into a decline in crop yields. It could be due to biotic factors (biotic stress, i.e. insect pests and disease pathogens) or abiotic factors (abiotic stress, i.e. drought, flooding, radiation and nutrient deficiencies). Agricultural crops normally undergo series of physiological processes (photosynthesis, respiration, stomatal functions and nutrition) during developmental stages of their life cycles that are sensitive to environmental conditions. The stressed environmental impact on the crops during growth and development leads to biochemical and morphological modifications in plant species. This chapter details the predominantly occurring abiotic stresses of crops that are directly or indirectly associated with the disruption of the normal growth and developmental processes in crops. The effects of abiotic stress in plants range from the qualitative and quantitative changes in the synthesis of type of proteins in crops to the disruption of the flower bud formation and pollination process in plant, as well as impaired nutrient uptake resulting in poor crop yields. About 51–82% crop yield in world agriculture is lost annually due to abiotic stress. The mechanisms of the four principal abiotic stresses (temperature, water, radiation, nutrients, etc.) are presented in the chapter. An understanding of the mechanisms of abiotic stress in agricultural crops could help farmers to optimize the crop productivity under the changing climate. This chapter therefore focuses on causes of the abiotic stresses affecting world food crops, their effects and possible stress coping strategies to promote global food sufficiency.