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Plant Science
Germination
1. What is a seed2. Requirements for germination3. How does a seed germinate4. Parts and Function of Monocot Seed5. Parts and Function of Dicot seed6. Process of germination and emergence
What is a seed?
A Seed is
• Young embryonic plant in a dormant or resting stage with a supply of food and 1 or more seed coats.
Three Basic Parts of Seed
Parts1. Embryo2. Food Supply3. Ovary wall or seed coat
Requirements for Germination
1. Favorable Temperatures2. Sufficient Moisture3. Air (Oxygen)4. Presence or absence of light
Seed Germination
1. Absorption of Watera. Absorbs 35-100 % of their weightb. Causes seed coat to swell
Seed Germination
2. Seed Proteins are activated, which activates the enzyme system
a. Stimulates enzyme systemb. Requires more moisture and oxygen
Seed Germination
3. Seed root (radical) emerges. a. Anchors root to soil
Seed Germination
4. Seed’s plumule or embryonic shoot begins to emerge.
a. Shoot will push its way up through soil to the sunlight
Seed Germination
5. Leaves Form and food production via photosynthesis starts.
Monocot Seed
Parts:1. Seed coat2. Endosperm3. Embryo
a. Cotyledonb. Epicotylc. Hypocotyld. Radicle
Monocot Seed
• Seed Coat- tissue surrounding the embryo, protects the inner parts
Monocot Seed
• Endosperm- source of starch or energy (food) until germination is complete
Monocot Seed
• Embryo- contains cotyledon, which breaks down the starch in the endosperm to provide food for the embryo
Monocot Seed
• Epicotyl- shoot above the cotyledon
Monocot Seed
• Hypocotyle- stem below cotyledon
Monocot Seed
• Radicle- develops into primary root of the plant.
• Absorbs water during germination
• Radicle dies after permanent roots form
Monocot Seed
Dicot Seed
• Seed Coat• Embryo– Two cotyledons– Epicotyl– Hypocotyl– Radicle
Dicot Seed
• Seed Coat- protection
Dicot Seed
• Embryo- miniature plant containing:– Two cotyledons– Epicotyl– Hypocotyl– Radicle
Dicot Seed
• Two Cotyldons- seed leaves, food storage
Dicot Seed
• Epicotyl- first true leaves, shoot, and everything above the cotyledon
Dicot Seed
• Hypocotyl- first true stem between root and first node of the stem, pulls the seed upward
Dicot Seed
• Radicle- forms the root system; absorbs water
Germination and Emergence : Monocot Seed
1. Seed Swells
Germination and Emergence : Monocot Seed
2. Radicle grows down
Germination and Emergence : Monocot Seed
3. First internode and epicotyl grow up
Germination and Emergence : Monocot Seed
4. After epicotyl emerges new leaves form and food production starts
Germination and Emergence : Monocot Seed
5. New root system develops above the first internode just beneath the soil
Germination and Emergence : Monocot Seed
6. Temporary root system ceases to function and dies
Germination and Emergence : Dicot Seed
1. Seed swell
Germination and Emergence : Dicot Seed
2. Radicle grows down
Germination and Emergence : Dicot Seed
3. Hypocotyle elongates• Forms an arch that breaks soil surface
Germination and Emergence : Dicot Seed
4. Hypocotyl reaches light, elongation ceases and hypocotyl straightens up pulling cotyledons out of soil
Germination and Emergence : Dicot Seed
5. Cotyledons turn green and manufacture food until new leaves develop
Germination and Emergence : Dicot Seed
6. As new leaves develop, the cotyledons die, dry up, and fall off
