Plant hormones

The hormone is said to be produced at one part of the body and moves to show its effect at different region of the body. It is found that there are five groups of hormones. Hormones are known to have controlling capacity in multicellular organisms.

Auxins

Auxins are the plant hormones which make the stem to elongate and stop the growth of lateral buds. Auxins help in the enhancement of apical dominance. The Auxins are generated at the stem tip, root tip and buds. Indole acetic acid is one of the Auxins released in plants. Auxins are known to get accumulated at the dark side of the plant tip where the sunlight does not fall much. The Auxins allow the cells in that region to divide largely generating a curve of the stem tip towards the side where the sunlight falls. This mechanism is called as phototropism.

The plants will have lateral buds situated at the nodal regions. But, Auxin plays an important role in apical dominance. Buds are meristematic regions, which remain dormant for some period. The dormancy of the buds is regulated by the plant hormone called Auxin. The lateral buds will become dormant, if the apical bud generates the adequate Auxin. If the apical region of the stem is removed or cut, then the lateral buds will lose their dormancy and will start growing. This makes the plant to look like a shrub and bushy in appearance.

Gibberellin

This hormone is known to enhance stem elongation. Gibberellins are not produced at the stem tip.

Cytokinin

Cytokinins are known to enhance cell division and they are found to be generated at the meristematic areas in the plant. Zeatin is a Cytokinin that is produced in corn.

Abscisic acid

This hormone is known to stop cell growth and enhance dormancy in seeds. The stomatal opening and closure are regulated by the presence of this hormone.

Ethylene

The fruit ripening occurs by the application of ethylene.