Plant Nutrition :: Plant Growth Regulators

Gibberellin

It is the active substance isolated from the soil borne fungus Gibberella fujikuroi the concentration of GA 3 is usually highest in mature seeds.
Reaching up to 18 mg / kg fresh weight in Phaseolus species, but it decreases rapidly as the seed mature.
In general, roots contain higher amounts of GA3 than shoots.
Gibberellins have also been found effective in overcoming both kinds of dormancy, buds as wells as seeds.
Treatments with Gibberllins has been observed and it substitute effectively for long day, low temperature or red light exposure requirements.

1. Gibberellic acid	Synthesis in leaf and induce shoot elongation (IAA + GA3)
2. Enhance metabolic activity	Mobilisation of reserve food material promotes growth and height, increase root actively and Kinetin production in root - translocate to growing Bud (GA3).
3. Shoot elongation	GA3 spray increase height of nursery seedlings
4. Delay senescence	Increase photosynthesis and proteins synthesis and thereby decrease abscission
5.Increase cambial growth and differentiation	Induce flower and fruit set (IAA + GA3)
6.Dwarf plant (genetically) to normal height	GA3
7.Promote flowering in long day plants	Substitute for long day conditions and cold treatment (vernalizations)
8. Induction of parthenocarpy	eg. Grapes
9. Breaking dormancy and leaf expansions


Seedling: shoot elonagation	Promote flowering	Induction of parthenocarphy