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Questions and Answers
What is a seed?
What is a seed?
A seed is the mature ovule after fertilization that contains an embryonic plant, stored food material for nourishment, and a protective seed coat.
Which of the following describes monocotyledonous seeds?
Which of the following describes monocotyledonous seeds?
Albuminous seeds have endosperm present.
Albuminous seeds have endosperm present.
True
Which of the following are examples of dicotyledonous seeds?
Which of the following are examples of dicotyledonous seeds?
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Exalbuminous seeds are seeds without endosperm.
Exalbuminous seeds are seeds without endosperm.
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What is the function of the seed coat?
What is the function of the seed coat?
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What is the role of cotyledons in seeds?
What is the role of cotyledons in seeds?
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What is a hilum in a seed?
What is a hilum in a seed?
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What is the function of the micropyle?
What is the function of the micropyle?
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Which statement about the radicle is true?
Which statement about the radicle is true?
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Study Notes
Seed Structure and Types
- A seed is a mature ovule post-fertilization, consisting of an embryo (young plant), stored food for nourishment, and a protective seed coat.
- Two primary types of seeds based on cotyledon count:
- Monocotyledonous Seeds: Contain one cotyledon (seed leaf). Examples: maize, wheat, rice, coconut.
- Dicotyledonous Seeds: Have two cotyledons. They absorb and store food from endosperm prior to germination. Examples: gram, bean, peanut, apple.
Endosperm Classification
- Seeds categorized based on endosperm presence:
-
Albuminous (Endospermic) Seeds: Contain endosperm; cotyledons are thin and membranous. Examples include:
- Albuminous Dicot Seeds: poppy, custard apple.
- Albuminous Monocot Seeds: cereals, millets, palm seeds.
-
Exalbuminous (Non-Endospermic) Seeds: Lack endosperm; cotyledons are thick and fleshy for food storage. Examples include:
- Exalbuminous Dicot Seeds: mango, mustard, gram, pea.
- Exalbuminous Monocot Seeds: orchids, Vallisneria, Amorphophallus.
-
Albuminous (Endospermic) Seeds: Contain endosperm; cotyledons are thin and membranous. Examples include:
Basic Seed Structure
- Major components:
- Cotyledon: Acts as food storage and first leaf of the seedling.
- Epicotyl: The embryonic portion above the cotyledon, developing into the stem and leaves.
- Hypocotyl: The segment between the cotyledons and the radicle of the embryo.
- Radicle: The root tip of the plant embryo, develops into the root.
- Hilum: A scar on the seed indicating where it was attached to the ovary wall.
- Micropyle: A small opening on the seed's concave side for water absorption and gas exchange during germination.
- Seed Coat: The outer protective layer of the seed encompassing the embryo and food supply.
Special Structures in Monocot Seeds
- Coleoptile: A sheath protecting the plumule as it grows out of the soil.
- Aleurone Layer: A protein layer lining the endosperm, rich in starch, crucial for energy during germination.
- In maize grains, the seed coat and pericarp fuse to form a protective layer surrounding the endosperm.
Germination Process
- The micropyle allows for water absorption, essential for the germination process.
- The radicle is equipped with a protective sheath called coleorhiza, ensuring safe downward growth.
- The plumule, protected by the coleoptile, emerges upward, leading to the plant’s shoot development.
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Description
Test your knowledge on the classification and structure of seeds in plants. This quiz covers the characteristics of monocotyledonous and dicotyledonous seeds, including their parts and examples. Perfect for students studying botany or plant science!
