Types and Function of Phytohormone and Their Role in Stress

Abstract

Plants require sunlight, water, oxygen, and minerals to grow and flourish. Along with the external environments, plant cell functioning is regulated by chemicals and plant hormones, also known as phytohormones or plant growth regulators (PGRs). Plant hormones are chemical substances, like signalling molecules found in plants at extremely low concentrations. Hormones such as auxins, cytokinins, gibberellins, ethylene, abscisic acid, jasmonic acid; salicylic acid, brassinosteroids, and strigolactones are the classes of plant hormones playing vital role in plant. All these hormones are produced in practically every region of the plant and are distributed throughout the plant. Hormones, as well as external variables, play a vital role in processes such as vernalisation, phototropism, seed germination, and dormancy, because these hormones are responsible for translating the external signal into adaptive growth and developmental changes, that help plant to survive better. They also evolved as cellular signal molecules with important roles in the modulation of immunological responses to bacteria, insect herbivores, and beneficial microorganisms. Hence, plant hormones govern a variety of biological activities ranging from growth and development to biotic and abiotic responses. This chapter will focus on various classes of plant hormones and their role in growth and development along with the stress.

In Vitro Regeneration of Ragleaf (Crassocephalum crepidioides (Benth.) S.Moore) Using Kinetin

“…Similar reports were given by Bulya et al (2023) and Hairuddin et al (2023) in maize and medicinal plants, respectively. The weekly increase in these parameters further suggests that kinetin at higher concentrations tends to increase the growth of plantlets positively, and this corroborated the report of Vaishnav & Chowdhury (2023), who observed that in a hormone-free medium, the rate of growth was very poor. Although PGR media has been helpful in the growth of this plant, there are reports of other members of Asteraceae that developed in a medium without PGRs.…”

“…The first stage in mass propagating ragleaf is determining the proper concentration of plant growth hormones, such as kinetin, for shoot and root induction. Kinetin, a synthetic cytokinin PGR, plays a crucial role in tissue culture, mainly, in promoting cell division and induction of meristematic cells, which are the precursors of shoot formation (Xiong et al;Vaishnav & Chowdhury, 2023). In their report, Hairuddin et al (2023) reported positive roles of auxin and cytokinin in maize under in vitro micropropagation.…”

Using NGS Technology and Association Mapping to Identify Candidate Genes Associated with Fusarium Stalk Rot Resistance

“…The second gene analyzed, a probable serine/threonine kinase, acts as a positive regulator of brassinosteroid (BR) signaling. Brassinosteroids, another class of growth-promoting regulator, regulate many aspects of plant growth and development, including cell expansion and elongation (in combination with auxin) and vascular differentiation [69][70][71][72][73]. The necessity of brassinosteroids in plant growth and development has been demonstrated by the identification of many BR-deficient dwarf mutants and subsequent BRs treating experiments [74].…”

Editorial: Cooperation of gene regulatory networks and phytohormones in cell development and morphogenesis

“…Some of the most well-known phytohormones include auxins, cytokinins, gibberellins, ethylene, abscisic acid, and JA. These hormones can stimulate or inhibit growth, mediate cellular differentiation, and contribute to the plant’s response to environmental stimuli ( Vaishnav et al., 2023 ). It is the cooperation of GRNs and phytohormones that inhibits cell development and morphogenesis.…”