Gibellins

Gibellins are a class of plant hormones that play a crucial role in various aspects of plant growth and development. These compounds are diterpenoid carboxylic acids and are synthesized in young leaves, roots, and developing seeds. The most well-known gibberellin is gibberellic acid (GA3).

Gibberellins are involved in a multitude of physiological processes. They promote stem elongation by stimulating cell division and elongation. This is particularly evident in their ability to overcome genetic dwarfism. Furthermore, gibberellins are essential for seed germination, often breaking seed dormancy and initiating the growth of the embryo. They also play a role in flowering, influencing the transition from vegetative growth to reproductive development, and can induce flowering in certain plants.

Beyond these primary functions, gibberellins also contribute to fruit development, promoting fruit set and enlargement in some species. Their application in agriculture is widespread, including their use to increase fruit size, promote malting in barley, and improve crop yields. The biosynthesis and action of gibberellins are complex, involving a series of enzymatic steps and interaction with specific receptors within plant cells. Understanding gibberellin pathways is vital for manipulating plant growth for agricultural and horticultural purposes.