Abiotic stresses are significant environmental issues that restrict plant growth, productivity, and survival while also posing a threat to global food production and security. Plants produce compatible solutes known as osmolytes to adapt themselves in such changing environment. Osmolytes contribute to homeostasis maintenance, provide the driving gradient for water uptake, maintain cell turgor by osmotic adjustment, and redox metabolism to remove excess level of reactive oxygen species (ROS) and reestablish the cellular redox balance as well as protect cellular machinery from osmotic stress and oxidative damage. Perceiving the mechanisms how plants interpret environmental signals and transmit them to cellular machinery to activate adaptive responses is important for crop improvement programs to get stress–tolerant varieties. A large number of studies conducted in the last few decades have shown that osmolytes accumulate in plants and have strong associations with abiotic stress tolerance. Production of abundant osmolytes is needed for tolerance in many plant species. In addition, transgenic plants overexpressing genes for different osmolytes showed enhanced tolerance to various abiotic stresses. Many important aspects of their mechanisms of action are yet to be largely identified, especially regarding the relevance and relative contribution of specific osmolytes to the stress tolerance of a given species. Therefore, more efforts and resources should be invested in the study of the abiotic stress responses of plants in their natural habitats. The present review focuses on the possible roles and mechanisms of osmolytes and their association toward abiotic stress tolerance in plants. This review would help the readers in learning more about osmolytes and how they behave in changing environments as well as getting an idea of how this knowledge could be applied to develop stress tolerance in plants.

The application of ultrasonic energy can inactivate many enzymes. The ultrasound shock waves produce cavitation and acoustic streaming in the liquid medium, which generates adequate mechanical, thermal, and chemical effects to inactivate enzymes. The extremely fast cycles of pressurization and depressurization and the resultant (localized) high temperature lead to rapid formation and collapse of bubbles. The rapid formation and collapse of bubbles is capable of breaking the hydrogen bonds as well as the van der Waals interactions in polypeptide chains. The application of ultrasound alters the secondary and tertiary structure of enzymes and leads to the loss in their biological activity. In this article, the authors review the recent advances made in the inactivation of common enzymes by the application of ultrasound alone or in combination with heat and pressure. The associated inactivation mechanisms and the factors affecting the enzyme inactivation are also reviewed.