The Role of Gibberellin in Stem Elongation & Seed Germination
Experimental evidence for the role of gibberellin in stem elongation
- Gibberellins are a group of hormones that help plants grow by stimulating cell division and elongation in the stem
- Dwarf plant varieties have been shown to have very low levels of gibberellins
- This is often due to a mutation in a gene involved in the synthesis of gibberellins
- Under experimental conditions, treating these dwarf varieties with gibberellins results in them growing to the same height as normal varieties
- Some farmers apply gibberellin to shorter plants to stimulate growth
Experimental evidence for the role of gibberellin in seed germination
- The fact that gibberellins stimulate germination and the breaking of dormancy has been shown by many experiments
- For example:
- Seeds of mutant varieties of the Arabidopsis plant that do not produce gibberellins can be induced to germinate if gibberellins are applied
- Seeds of certain lettuce varieties that require light in order to germinate can be made to germinate in the dark if gibberellins are applied
