ABSTRACT
Plant growth and development are entirely dependent on signal-transducing molecules, phytohormones, produced within the plants. Phytohormones play a major role in the genetic expression of necessary genes in plants to induce cellular-level activities. Phytohormones are classified into different categories based on their expression characteristics. Along with traditional phytohormones (cytokinin and abscisic acid etc.), other classes (strigolactones, brassinosteroids and salicylates) have been recently characterized. Genetic-level changes can be acquired in growing plants through the application of phytohormones in the growing media. Different factors in the environment can affect a plant's developmental susceptibility in various ways. Physiological changes in plants that cause tissue damage due to environmental conditions are very common in plants. Abiotic stress can affect plant growth on a cellular level. This is one of the major reasons that depletes plants of vital nutrients and biochemicals. Therefore, it is essential to introduce a system in sessile plants that will improve their tolerance toward adverse environmental conditions. Stress tolerance in plants can be achieved through genetic modifications. Enzymes and transcription factors play a very important role in such modifications. The objective of this chapter is to discuss the characterization of phytohormones and genetic-level modifications to enhance the tolerance levels in plants.
