Osmoprotective Role of Sugar in Mitigating Abiotic Stress in Plants

Extreme ecological surroundings for plants such as drought and water scarcity, varying temperature from minimal to maximum level, and accumulation of salt and heavy metals diminish plant growth and hence need precise alteration or modification. To maintain osmotic harmony, plants secrete osmolytes and osmoprotectants as essential abiotic stress mitigators to encounter harsh environmental conditions through monitoring constant cellular homeostatic. There are some low-molecular-weight, nontoxic compounds that accumulate in plants in response to drought and salinity stress without snooping with normal metabolism. Soluble sugars such as sucrose, hexose, trehalose, RFO, and sugar alcohols and other osmolytes such as glycine betaine and proline amino acid act as the osmoprotectants. These sugars play an important role in the maintenance of cellular organizations, photosynthetic proficiency, and detoxification of reactive oxygen species by acting as metabolic signals in the stress conditions. Together, they shield plants by exercising a number of physiological responses, such as strengthening membrane integrity, harmonizing enzymatic/antioxidant activity, and fulfilling water requirement under several abiotic stresses including pesticide exposure. In spite of the fact that a connection surely exists between the amassing of explicit osmoprotective substances and stress tolerance, a causal connection between osmolyte gathering and improved resistance could not generally be affirmed. This chapter enlightens the mechanisms potentially involved in plant abiotic stress tolerance brought by osmoprotectants as well as concisely highlights important parts so far unmapped in the present framework.