Gibberellin : A plant elongation growth regulator
- Gibberellin is a weakly acidic growth hormone. E. Kurusawa discovered the active substance from the filtrate of a fungi named Gibberella fujikuroi.
- This fungi causes Bakanae disease in the rice plants.
- GA3 was the first gibberellin to be isolated in its pure form and remains the most extensively studied.
- There are more than hundred gibberellins reported from the different organisms such as fungi and the higher plants.
👌👌Remember - Barley endosperm test and drop test are used as a bioassays of gibberellins.
- The major sites of gibberellin production in plants are Apical shoot buds, young leaves near the shoot tips, root tips and the developing seed.
- Mevalonic acids is derived from acetyl coenzyme. This the precursor of synthesis of gibberellic acid.
- Describe this growth regulator is transported through simple diffusion as well as through the conducting channel.
- Gibberellin hormone enhances seed germination by increasing the efficiency of synthesis of alpha - amylase and thus overcomes dormancy.
- In photoblastic seeds that is lettuce seed germination occurs by application of gibberellin even in dark.
- When gibberellin is sprayed on the rosette plant like cabbage there is Rapid expansion of internode and flowers with long stock are produced. This phenomenon is called bolting.
- If gibberellin hormone is sprayed on a single gene dwarf plant, genetic dwarfism is overcome and the plant becomes long.
- This can be seen as maize, pea etc. On female plants male flowers are produced by the application of the gibberellin and thus it promotes maleness.
- They are also important and potent parthenocarpic agents. Gibberelic acid is used to speed up the malting process in brewers Industries.
- Spraying sugarcane crop with gibberellin increase the length of the stem thus increase the yield as much as 20 tons per acre.
- Spraying Juvenile conifers with gibberellin, increase the maturity period thus leading to early seed production.
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