ABSTRACT
Agriculture is the art and science of producing different crops such as cereals, pulses, vegetables and fruits to feed the growing world population. The global population is estimated to reach 9 billion by 2050 for which agricultural production/productivity or major crops needs to be enhanced by 1.1–1.3% per year. However, global environmental change or abiotic stress is one of the foremost limiting factors affecting agricultural production, by adversely affecting various morphological, physiological, molecular and biochemical changes, leading to poor plant performance and productivity. Most of the abiotic stresses cause outbursts of reactive oxygen species in plant cells, termed as oxidative stress, that may disintegrate important biomolecules like lipid, protein and DNA, leading to hypersensitive response/cell death/apoptosis. To scavenge the adverse effects of oxidative stress, plants have evolved antioxidant systems, primarily classified into two categories: enzymatic and non-enzymatic antioxidants. The non-enzymatic antioxidants including ascorbic acid, glutathione, tocopherol, carotenoids, flavonoids, proline, raffinose family oligosaccharides and sugar alcohols have elicited significant scientific attention owing to their crucial role in plant acclimatization during abiotic stress. The present chapter discusses distinct non-enzymatic antioxidants, underlying mechanisms of their role during abiotic stress tolerance and the status of their improvements in plants.
