This ppt includes the following- 1.What is Seed Germination 2.Pattern Of Seed Germination 3.Physiology Of Seed Germination 4.Various Roles of GA in Seed Germination

1. SEED GERMINATION & ROLE OF GA
By- Ardhendu Das
M.Sc. Genetics (4th Sem)
University of Calcutta

2. What is Seed Germination ??
What are the basic requirements for Seed Germination ??
~ * Water * Gases * Light * Temperature
~ It is a process that begins with the water uptake by the dry seed & ends with
the emergence of embryonic axis from its surrounding tissue.
What are the different types of Seed Germination ??
~ 1. Epigeal Germination 2. Hypogeal Germination

3. Germination can be divided majorly into 3 categories depending upon the phases of
uptake of water
1. Phase 1 – Imbibition [ The dry seed takes up water rapidly by this process ]
2. Phase 2 – Lag Phase [ Embryo expands & radicle emerges from the seed coat ]
3. Phase 3 – Mobilization Of Reserve Food [ Water uptake resumes & the stored food
reserves of the seed are fully mobilized ]

4. Which will grow into the new seedling & has a specialized absorptive organ- scutellum
The Structure Of Cereal Grain
1. The Embryo
1. Endosperm
2. Pericarp
Starchy Endosperm
Aleurone Layer
Consists of thin walled cells (filled with starch grains).
Non-living at maturity.
Consists of thick walled primary cell wall.
Contains large number of protein storing vacuoles.
The wall of a fruit, developed from the ovary wall

5. • In 1926 E Kurosawa discovered that a substance produced by a
fungal pathogen Gibberella Fujikuroi caused the
‘’Foolish Seedling Disease’’ in rice.
• In 1935 T Yabuta & Y Sumiki named the substance
Gibberellin.
• Site Of Synthesis : Embryo
• Site Of Response : Aleurone Layer
• Role In Seed Germination :
Gibberellin passes to the aleurone layer & helps in the secretion of α-amylase ( breaks down
starch into maltose- absorbed by the embryo) into the endosperm.

6. Gibberellin Signal Transduction : Cereal Aleurone Layers

8. Fig : Pathway Of α-amylase
Production In Response To GA

9. Fig : Activation
&
Inactivation
Of
Gibberellin
Response

10. References
Youtube Videos :
• https://youtu.be/_XPxNvX70No
• https://youtu.be/6dg-9xw9UZg
Images From Google :
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Physiology Of Seed Germination By Miller B. McDonald
• https://www.researchgate.net/profile/Yuan-
Yeu_Yau/post/what_are_the_differences_between_seed_coating_and_seed_priming/attachment/59d63213c49f478
072ea15e1/AS%3A273630024405010%401442249889540/download/Seed+germination.pdf