Plant Nutrition :: Plant Growth Regulators


  • 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



7.Promote flowering in long day

Substitute for long day conditions and cold treatment (vernalizations)


8. Induction of parthenocarpy

 eg. Grapes


9. Breaking dormancy and leaf


Seedling: shoot elonagation Promote flowering Induction of parthenocarphy


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