Growth regulators influence phytohormones present in plants and for that reason are used in the production of ornamental plants. They can be synthetic analogues or inhibitors of plant hormones and are used to influence the concentration or the site of action of hormones. The use of growth regulators began in the 1930s for diverse uses. Auxins in the form of indole-3-acetic, indole-3-butyric acid and alpha-naphthyl-3-acetic acid are used for the promotion of rooting in cuttings, gibberellins as gibberellic acid to promote growth and in the form of inhibitors to inhibit it. The active substance benzyl adenine, which affects cytokinins, is mainly used in in vitro techniques, while ethephon, which affects ethylene development, is effective in chrysanthemums, cyclamen, and bromeliads by affecting flowering. Abscisic acid increases tolerance to environmental stress. Growth regulators are classified as plant protection products and are strictly regulated due to their effect on plant life processes. For this reason and agricultural policy objectives, ornamental plant producers resort to non-chemical means of growth regulation to influence plant growth. Measures such as reduced fertilisation, drought stress, pot size, temperature control and pinching alter the growth and processes in the plant to such an extent that it is of a quality and marketable without the use of growth regulators.
|
