Physiological effects of gibberellins :

1. Stem elongation.:The most prominent effect of gibberellins on plant is stem intemodal elongation. Application of gibberellin on genetically dwarf plants causes them to grow well. They also help cell growth of leaves and other aerial parts except roots. 

2. Bolting and flowering: Some biennial plants grow as rosette of leaves on a very short condensed stem, in the first year of growth and then in the next year there develop an elongated shoot and bear flowers. This phenomenon is known as bolting. Exogenous application of gibberellin induces the bolting and flowering in the same year, e.g. Cabbage, Radish. 

3. Seed germination: Some of the light sensitive seeds like lettuce, barley etc. can germinate with the treatment of gibberellins even in complete dark, which otherwise require specific light conditions. 

4. Parthenocarpy: Gibberellins have been found to be more effective than auxins in causing parthenocarpic development of seedless Suits in pomaceous plants like apples, pears, etc. 

5. Breaking of dormancy: Gibberellins are effective in overcoming the natural dormancy in potato tubers and buds in winter. 

6. Vernalisation: Vernalisation or low-temperature treatment of some plants can be replaced by gibberllins 

7. Sex-expression: Gibberllins have masculinzing effect on genetically female plants of Cannabis. They can also replace female flowers with male flowers on monoecious plants of cucurbits.