Classification of Seeds and Germination Types

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Questions and Answers

What is the primary role of the embryo in plant development?

To absorb nutrients from the soil

To protect the seed from external factors

To develop into a new plant (correct)

To assist in seed dispersal

Which type of seed has no endosperm at maturity?

Albuminous seeds

Exalbuminous seeds (correct)

Auxiliary seeds

Endospermic seeds

Which layer of the seed coat is known as the Testa?

Outer layer (correct)

Endosperm layer

Inner layer

Seed integument

What is the function of the appendages on some seeds?

To assist in seed dispersal or identification Signup and view all the answers

Which of the following is considered a non-endospermic dicot?

Pea Signup and view all the answers

What type of germination ensures that cotyledons remain below or on the surface of the ground?

Hypogeal germination Signup and view all the answers

Which seed coat type contains two integuments?

Bitegmic Signup and view all the answers

Which crop's seeds are characterized by the presence of an aril?

Nutmeg Signup and view all the answers

What is the main stored food material in cereal seeds?

Carbohydrates Signup and view all the answers

Which of the following is an example of a monocot?

Wheat Signup and view all the answers

What type of seed is found in all legumes?

Non-endospermic seeds Signup and view all the answers

Which germination type is exemplified by most monocots?

Hypogeal germination Signup and view all the answers

Which method of pollen grain dissemination involves snails?

Malacophily Signup and view all the answers

Which of the following is NOT a feature of double fertilization in angiosperms?

Presence of only one polar nucleus Signup and view all the answers

What type of seed behavior is classified as 'Orthodox'?

Seeds that can withstand desiccation and remain viable Signup and view all the answers

Which example is a type of epigeal germination?

Cotton Signup and view all the answers

Which agent is associated with hydrophily?

Water Signup and view all the answers

What is the total number of cells present in an embryo sac?

7 cells Signup and view all the answers

Which of the following is a characteristic of recalcitrant seeds?

Short shelf life Signup and view all the answers

Which type of pollination occurs when pollen is transferred to another flower?

Cross Pollination Signup and view all the answers

Study Notes

Classification of Seeds

Seeds can be classified based on usage into cereals, oilseeds, pulses, fiber, green manure, vegetables, medicinal, and sylvicultural species.
Two main categories based on cotyledons: monocots (one cotyledon) and dicots (two cotyledons).
Seeds with endosperm are termed endospermic (e.g., all cereals, castor, fenugreek), while those without are non-endospermic (e.g., all legumes).
Germination types include hypogeal (cotyledons remain below ground) and epigeal (cotyledons emerge above ground).

Germination Types

Hypogeal Germination: Common in monocots and some dicots like gram, pea, and maize.
Epigeal Germination: Found in species such as bean, cotton, and sunflower.
Hypo-epigeal Germination: Example includes Peperomia peruviana.

Storage Behaviour

Orthodox Seeds: Includes most food crops, beans, fruits like peach and guava, able to withstand drying and low temperatures.
Recalcitrant Seeds: Found in forest and horticultural crops like avocado, cacao, mango, and rubber; sensitive to drying.

Pollination

Pollen release occurs from mature anthers, leading to self-pollination (autogamy) or cross-pollination (allogamy).
Various agents facilitate pollen dissemination:
- Wind (anemophily)
- Water (hydrophily)
- Insects (entomophily)
- Birds (ornithophily)
- Snails (malacophily)
- Wasps (waspophily)
- Flies (myophily)
- Bats (chiropterophily)

Fertilization

Involves fusion of male and female gametes to form an embryo.
Embryo sac consists of 7 cells and 8 nuclei, with distinct structures including egg apparatus (1 egg cell and 2 synergids) and polar nuclei (2 in center).
Angiosperms undergo double fertilization, utilizing 2 male nuclei.

Seed Structure and Development

Embryo: Immature plant with one cotyledon in monocots and typically two in dicots.
Monocot Examples: Wheat, rice, banana, palm.
Dicot Examples: Legumes, daisies, tomatoes, and oak trees.
Endosperm:
- Albuminous Seeds: Endosperm persists at maturity; common in most monocots (e.g., cereals).
- Exalbuminous Seeds: Endosperm consumed during development; found in most legumes.
Seed Coat:
- Composed of two layers: outer layer (testa) and inner layer (tegmen).
- Provides mechanical protection to the embryo.
- Unitegmic: Single integument in ovule.
- Bitegmic: Two integuments, with variations in seed coat development.

Appendages of Seed

Different crops exhibit various seed coat appendages aiding in dispersal or identification:
- Awn (paddy)
- Hilum (pulses)
- Caruncle (castor, tapioca)
- Aril (nutmeg)
- Hairs (cotton)
- Wings (moringa)

Germination Classification

Hypogeal Germination: Maintains cotyledons below ground surface during growth, typical of many monocots and certain dicots.

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Description

Explore the fascinating world of seeds with this quiz covering their classification based on usage and cotyledon types. Understand the mechanisms of germination and the storage behaviors of orthodox and recalcitrant seeds. Test your knowledge on different types of germination and their examples.