The stationary life of plants has led to the evolution of a complex gridded antioxidant defence system constituting numerous enzymatic components, playing a crucial role in overcoming various stress conditions. Mainly, these plant enzymes are superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferases (GST), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), which work as part of the antioxidant defence system. These enzymes together form a complex set of mechanisms to minimise, buffer, and scavenge the reactive oxygen species (ROS) efficiently. The present review is aimed at articulating the current understanding of each of these enzymatic components, with special attention on the role of each enzyme in response to the various environmental, especially abiotic stresses, their molecular characterisation, and reaction mechanisms. The role of the enzymatic defence system for plant health and development, their significance, and cross-talk mechanisms are discussed in detail. Additionally, the application of antioxidant enzymes in developing stress-tolerant transgenic plants are also discussed.

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The cuticular wax layer covers the aerial surface of plants and acts as a barrier between plants and the environment. The cuticle plays a key role in the protection of plants from pathogens, UV light, and transpiration. Variation in the wax quality and quantity is influenced by factors like the solvent used for extraction, species, ontogeny, and season. Compounds isolated from the cuticle layer have been studied by various methods and were found to play an important role from the ecological and physiological points of view. These compounds include esters, alcohols, ether, alkane, and aldehydes. Nonpolar compounds help reduce water loss in plants. The wax can be explored for its potential applications in developing sustainable green packaging material. This review article will facilitate biologists and nonbiologists to get comprehensive and updated knowledge about various aspects of cuticular wax including its chemical composition and variations among different species and seasons. Further studies of the wax composition will pave the way for classification of plant species and an understanding of plant protection from biotic and abiotic stresses.

There is an urgent need for a biodegradable, hydrophobic material that can be used in developing packaging materials. In this preliminary study, epicuticular wax has been extracted from the leaves of Calotropis procera and Alstonia scholaris using various solvents (i.e., ethanol, methanol, benzene, and acetone). The highest wax amounts were found to be 0.54 µg/cm 2 and 0.13 µg/cm 2 from Alstonia scholaris and Calotropis procera, respectively. The highest hydrophobicity (29.57%) was found to be in paper discs coated with epicuticular wax extracted with benzene from the adaxial surface of Calotropis procera.

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