Plant Growth Hormones

Abstract

Many factors can cause and affect cell growth in the plant such as external (environmental) and internal factors; one of the most important internal factors is plant growth hormones. Many hormones required for cell growth, such as auxins, gibberellins, brassinosteroids, ethylene, jasmonates, salicylic acid, strigolactones and cytokinins which able to accelerate or promote growth, but, some hormone-like abscisic acid has an adverse effect on growth which increases seed dormancy by inhibiting cell growth. Also, plant hormones are able to breakdowns dormancy for many plants and can alleviate abiotic stress (salinity, extreme temperatures and, drought,…) which led to enhance germination and improve growth for many plants, whether naturally occurring in the plant or by adding it to the plant in its artificially formed or in the form of bio-or nano-fertilization in order to increase the productivity and improve its efficiency under extreme conditions. Therefore, this chapter will highlight and will provide data for the positive or/and negative effect of these hormones on many plants to achieve a rapid germination method. It will also shed light on the relationship of these hormones to some enzymes to accelerate growth.

The interplay of specific hormonal profile in fruit parts of sunflower inbred lines with contrasting dormancy levels during germination and dormancy breaking by exogenous application of plant growth regulators

“…Various endogenous factors, including phytohormones, are responsible for the regulation of seed germination and dormancy (Soliman, 2019). The hormonal balance and interaction in different fruit parts (embryo and seed cover layers) determine the occurrence, or not, of germination (Penfield, 2017).…”

Effects of High Voltage Electrical Discharge (HVED) on Endogenous Hormone and Polyphenol Profile in Wheat

“…In the early stage of germination, seed hydration triggers gibberellin biosynthesis in embryo meristems, which is subsequently directed into the aleuronic layer and endosperm, whereas it induces the synthesis of α-amylase, a major hydrolyzation enzyme, leading to the disruption of seed coat dormancy [ 18 ]. GA induces the expansion of embryo cells, radicle protrusion and the elongation of young cells, and may also increase seed osmotic and water potential [ 19 , 20 ]. GAs synthesize through different intermediaries including GA53 and G12, which convert to GA9 and GA20.…”