Seeds Flashcards
Seed coat
The outer protective layer of the seed, serves as a barrier to prevent water loss, mechanical damage, and pathogen entry
Layers of seed coat
Testa and tegmen
The thick outer layer of a seed coat
Testa
The delicate inner layer of a seed coat
Tegmen
Hilum
a scar or mark on the seed coat where the seed was attached to the ovary wall of the parent plant
Micropyle
A tiny opening in the seed coat, located near the hilim, through which wager can enter the seed during germination
The site where the pollen tube enters during fertilization in some plants
Micropyle
Endosperm
a vital tissue found inside the seed, and its primary function is to provide nutrition to the developing embryo during germination
Endosperm is formed during?
It is formed during fertilization process and plays a critical role in seed development
Embryo
the young plant that is developing inside the seed coat
Epicotyl
the tiny shoot of an embryo, from which the entire shoot system develops.
The tip of the epicotyl is called?
Plumule
Hypocotyl
The stage of transition for the growing shoot and root of the embryo
Radicle
Tiny root of the embryo
Cotyledons
They are the leaves of the embryo that provide nourishment to the developing plant
What are the types of germination?
Epigeal germination and Hypogeal germination
Epigeal germination
The cotyledons emerge above the soil surface
Process of Epigeal germination
• Water absorption makes the seed swell, cracking the seed coat
• The elongating hypocotyl lifts the cotyledon above the soil
• The cotyledons open, and true leaves develop
Hypogeal germination
The cotyledons remain below the soil surface
Hypogeal germination process
• Water absorption causes the radicle to grow downward, anchoring the seedling
• The epicotyl elongates, pushing the shoot upward, while cotyledons stay underground
• True leaves emerge above ground, with cotyledons providing nourishment
Seed dispersal
The process by which seeds are transported from their parent plant to new locations, which helps reduce competition, colonize new areas, and promote genetic diversity
Types of seed dispersal
Wind, animal, water, gravity, explosive, human-mediated
Wind dispersal
Lightweight seeds with structures like hair or tufts carried by the wind to new locations
Animal dispersal
Seeds attach to animal fur or are ingested and later excreted, spreading to distant areas
Water dispersal
Seeds float on water to reach new places
Gravity dispersal
Heavy seeds simply fall and spread near the parent plant due to gravity
Explosive dispersal
Seeds are ejected forcefully from the parent plant when the seed pod bursts open
Human-mediated dispersal
Humans unintentionally transport seeds through activities like farming or travel
