Growth Hormones

Grasses, lacking a nervous system to respond to different environmental stimuli, have growth-promoting and growth-inhibiting hormones. This is how they are presented:

Growth-promoting hormones:

      Auxins. Produced in metathematic tissue, it is translocated throughout the plant and influences cell elongation, inhibits lateral growth and leaf ageing, while promoting seed formation and root growth.

High levels of Auxins inhibit growth depending on the plant tissue.. Certain herbicides are based on auxin content, such as the broadleaf herbicide 2,4-D

Gibberellic acid. Production site is the meristematic tissue of young leaves, roots and seeds. Promotes cell division, cell elongation and seed germination. Commercial preparations are available, e.g. for greening of bermudagrass.

Cytokinins. Its production takes place at the root tips. Stimulates cell division, inhibits leaf ageing. Overcomes certain environmental stresses.

Growth inhibiting hormones:

Ethylene. Gas produced in leaf tissue. Promotes leaf ageing, inhibits root growth, lateral growth and cell elongation.

Abscisic acid. Produced in chloroplasts. Promotes stomatal closure and ageing of the plant. It is a result of high levels of drought stressexcess humidity, nutritional deficit or excess salinity.

Biostimulants: Promote growth when given in small amounts. They increase photosynthetic ratios, decrease leaf ageing, increase germination and root growth, help turf establishment, while increasing salinity tolerance and drought resistance. Their commercial preparation is based on seaweed extracts or even through fungicide inhibitors of sterol biosynthesis (constituents of cell membranes) such as propiconazole, tridimefon and others.

The growth regulators are based on the production of these hormones