Seed Germination and Gibberellins

Fo a plant to start growing, the seed must:

1) Absorb water- embryo activated- produce gibberelins. Giberrelins switch on the gene which codes for amylase and protease.

2) Stimulate production of enzymes to break down food stores

3) Uses these stores to produce ATP for building material- break through seed coat

• seeds bred lacking gene able to make gibberellins, didnt germinate! When gibberellins applied, germinate normally
• gibberellin biosynthesis inhibitors applied, cant germinate! need to break dormancy, if removed seeds germinate!
• as seeds exposed to gibberellin, rate of amylase synthesis increases. Important role switching on gene

They affect length of internodes- regions between leaves

Shorter Plant Advantage- few or no gibberellin, reduces waste and makes plants lass vulnerable to damage by weather and harvesting.