1. HORMONE PHYSIOLOGY AND SIGNAL TRANSDUCTION Huseyin Tombuloglu, Phd. GBE 304 Spring 2015

2. GIBBERELLINS

3. Gibberellins have a number of effects on plant development. They can:  stimulate rapid stem and root growth,  induce mitotic division in the leaves of some plants,  increase seed germination rate.  elongates plant internodes

4. Functions of Gibberellins Cell enlargement and cell divisions in sub-apical meristems. Growth in stems, fruits, and leaves. Stem and leaf expansion. Fruit development and expansion. Stimulation of flowering Cell divisions in some tissues. Dormancy and senescence. Seed germination.

5. Functions of Gibberellins Functions are similar to auxins, but GA has a much different chemical structure. Gibberellins cause cell expansion and cell divisions in sub-apical meristems. Interesting to note: Gibberellins applied to whole plants will increase or promote growth and expansion, but auxins applied to whole plants usually inhibit growth….what results is a concentration problem.

14. Cabbage can be induced to bolt and flower by applications of GA 3

16. Figure 20.4 Gibberellin induces growth in “Thompson Seedless” grapes