Seed Germination Process Quiz
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Questions and Answers

What is the first part of the seed that emerges during germination?

  • Plumule
  • Radicle (correct)
  • Epicotyl
  • Cotyledon
  • In hypogeal germination, which part of the seed grows first?

  • Epicotyl (correct)
  • Cotyledons
  • Radicle
  • Hypocotyl
  • What is the role of endosperm in monocot seeds?

  • It provides nourishment to the embryo until photosynthesis begins. (correct)
  • It helps to absorb nutrients from the soil.
  • It functions as a reservoir of water for the seed.
  • It protects the seed during dormancy.
  • What happens to the cotyledons during hypogeal germination?

    <p>They dry out and fall off. (D)</p> Signup and view all the answers

    Which of the following statements about dicot seeds is true?

    <p>Most dicot seeds lack endosperm. (A)</p> Signup and view all the answers

    What type of respiration do seeds switch to once oxygen becomes available?

    <p>Aerobic respiration (D)</p> Signup and view all the answers

    Which of the following seeds typically exhibit hypogeal germination?

    <p>Maize (A)</p> Signup and view all the answers

    What is the initial step in the seed germination process?

    <p>Absorption of water. (D)</p> Signup and view all the answers

    Which environmental factor is NOT required for seed germination?

    <p>Nutrients. (C)</p> Signup and view all the answers

    During epigeal germination, which part of the seed pushes the cotyledons out of the soil?

    <p>Hypocotyl (A)</p> Signup and view all the answers

    What facilitates the absorption of water and nutrients for the young plant after germination?

    <p>Radicle (A)</p> Signup and view all the answers

    During the process of imbibition, what happens to the seed?

    <p>It absorbs water and swells. (D)</p> Signup and view all the answers

    What is produced during seed metabolism, aiding growth and cellular activities?

    <p>ATP (D)</p> Signup and view all the answers

    What is the primary purpose of seed dormancy?

    <p>To ensure germination occurs under optimal conditions. (A)</p> Signup and view all the answers

    In which stage of seed germination does respiration initiate?

    <p>Activation of enzymes. (B)</p> Signup and view all the answers

    Which component protects the radicle in monocot seeds?

    <p>Coleorhiza. (C)</p> Signup and view all the answers

    Which type of seeds have persistent endosperm during embryo development?

    <p>Albuminous seeds (B)</p> Signup and view all the answers

    What characterizes a monocotyledon seed?

    <p>Single cotyledon with a prominent endosperm (D)</p> Signup and view all the answers

    Which part of the dicotyledon seed serves as the attachment site to the ovary wall?

    <p>Hilum (C)</p> Signup and view all the answers

    What is the function of the aleurone layer in monocot seeds?

    <p>Protein storage (C)</p> Signup and view all the answers

    What is true about non-endospermic seeds?

    <p>They completely utilize their endosperm during embryo development (D)</p> Signup and view all the answers

    Which component of the seed is responsible for water absorption?

    <p>Micropyle (D)</p> Signup and view all the answers

    What describes the structure of dicot seeds?

    <p>Two fleshy cotyledons attached to an embryonal axis (B)</p> Signup and view all the answers

    Which of the following is a characteristic of the radicle in a seed?

    <p>It is the root precursor in seed development (B)</p> Signup and view all the answers

    Which layer of fruit is considered the outermost?

    <p>Exocarp (D)</p> Signup and view all the answers

    What is a defining characteristic of simple fruits?

    <p>They develop from a single ovary of a single flower. (B)</p> Signup and view all the answers

    Which fruit type develops from several ovaries in multiple flowers?

    <p>Multiple fruit (C)</p> Signup and view all the answers

    An example of an aggregate fruit is:

    <p>Strawberry (B)</p> Signup and view all the answers

    In which type of fruit is the edible part primarily tissue other than ovary tissue?

    <p>Accessory fruit (B)</p> Signup and view all the answers

    What role do cotyledons play in the early life of a plant?

    <p>They serve as the first leaves and can make food. (B)</p> Signup and view all the answers

    Seed dormancy is best described as which of the following?

    <p>A state preventing seeds from germinating in favorable conditions. (D)</p> Signup and view all the answers

    Which of the following is NOT a cause of seed dormancy?

    <p>Favorable environmental conditions. (B)</p> Signup and view all the answers

    Which of the following is a benefit of seed dormancy for plants?

    <p>Ensures survival during adverse environmental conditions. (B)</p> Signup and view all the answers

    How does seed dormancy help in environmental conditions?

    <p>It helps seeds to disperse over long distances through unfavorable conditions. (D)</p> Signup and view all the answers

    What is one way that seed dormancy acts as a survival mechanism?

    <p>It helps seeds endure extreme temperatures for years. (D)</p> Signup and view all the answers

    What triggers the process allowing a dormant seed to germinate?

    <p>The right combination of light, temperature, and moisture. (A)</p> Signup and view all the answers

    What kind of plants typically show epigeal germination?

    <p>Dicot plants such as castor and cotton. (D)</p> Signup and view all the answers

    What is the role of scarification in seed dormancy?

    <p>To break or soften the seed coat for water and gas permeability (D)</p> Signup and view all the answers

    Which method of overcoming seed coat dormancy involves soaking seeds in acid?

    <p>Acid scarification (D)</p> Signup and view all the answers

    What is required for successful refrigerated stratification of seeds?

    <p>Moisture, cold, and oxygen (D)</p> Signup and view all the answers

    What defines a parthenocarpic fruit?

    <p>An ovary that develops into fruit without fertilization (D)</p> Signup and view all the answers

    What happens to the ovary wall during the process of fruit development?

    <p>It develops into the pericarp (A)</p> Signup and view all the answers

    Which of the following is NOT a method for overcoming seed dormancy?

    <p>Thermal stratification (C)</p> Signup and view all the answers

    What is the primary function of a fruit in relation to seeds?

    <p>To provide protection for the enclosed seeds (B)</p> Signup and view all the answers

    What is a common characteristic of giberellins acid (GAs) related to seed dormancy?

    <p>They promote seed growth and germination (B)</p> Signup and view all the answers

    Flashcards

    Endospermic or albuminous seeds

    Mature seeds that still contain endosperm after embryo development. The endosperm provides nutrients for the growing embryo.

    Non-endospermic or exalbuminous seeds

    Mature seeds where the endosperm is completely used up during embryo development. The embryo obtains nutrients directly from the cotyledons.

    Cotyledon in monocot seeds

    A single cotyledon in a monocot seed. It functions as a food storage organ.

    Aleurone layer

    The outer layer of the endosperm in monocot seeds. It is rich in proteins.

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    Embryo in monocot seeds

    The embryo in monocot seeds, located in a groove at one end of the seed. It has a single large cotyledon called the scutellum.

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    Coleoptile

    A protective sheath covering the plumule in monocot seeds.

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    Coleorhiza

    A protective sheath covering the radicle in monocot seeds.

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    Hilum

    A scar on the seed coat marking the point of attachment to the ovary wall.

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    Epicotyl

    The region between the plumule and the point of attachment of the cotyledons. It's essentially the stem portion above the cotyledons.

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    Dicot seed

    A seed with two cotyledons. These seeds typically have a root, a shoot, and a large endosperm that provides nutrients for the developing seedling.

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    Monocot seed

    A seed with a single cotyledon. These seeds typically have a root, a shoot, and a smaller endosperm, as the cotyledon serves as a storage organ.

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    Seed germination

    The process where a dormant embryo within a seed becomes active, grows out of the seed coat, and develops into a seedling.

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    Imbibition

    The absorption of water by the dry seed, causing it to swell. This triggers the activation of enzymes and the start of metabolic processes.

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    Activation of Enzymes

    The process where enzymes inside the seed become active after imbibition. These enzymes break down stored food reserves, providing energy for growth.

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    Growth of Embryo

    The stage where the embryo starts to grow, utilizing the food resources from the endosperm or cotyledons.

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    Mobilization of Food Reserves

    Stored food reserves in the seed (starch, proteins, fats) are converted into readily usable forms like sugars and amino acids for growth.

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    Aerobic Respiration in Germination

    The seed switches from anaerobic respiration (without oxygen) to aerobic respiration (with oxygen) as it sprouts and gains access to air.

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    Embryo Growth and Seed Coat Break

    The embryo inside the seed grows and expands, eventually causing the protective seed coat to break.

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    Radicle Growth and Root Development

    The radicle, the first part of the embryo to emerge, grows downward to form the primary root.

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    Plumule Growth and Shoot Development

    The plumule, another part of the embryo, grows upwards to form the shoot, the aboveground portion of the plant.

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    Emergence of Seedling

    The seedling emerges from the soil, marking the end of germination and the start of the plant's independent life

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    Hypogeal Germination

    A type of germination where the cotyledons remain underground and the epicotyl grows upwards, forming an arch.

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    Epigeal Germination

    A type of germination where the hypocotyl grows upwards, pushing the cotyledons above the soil surface.

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    Exocarp

    The outermost layer of a fruit, often consisting only of the epidermis.

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    Mesocarp

    The middle layer of a fruit, varying in thickness.

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    Endocarp

    The innermost layer of a fruit that shows variation between different species.

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    Simple fruit

    A fruit developing from a single ovary of a single flower.

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    Compound Fruit

    A fruit that develops from multiple ovaries, either from one flower or multiple flowers.

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    Scarification

    The process of breaking, scratching, mechanically altering, or softening the seed coat to make it permeable to water and gases.

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    Mechanical scarification

    Rubbing seeds against a rough surface, like sandpaper, to weaken the seed coat.

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    Hot water scarification

    Soaking seeds in hot water (77 to 100°C) to soften the seed coat.

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    Acid scarification

    Soaking seeds in a concentrated acid (like hydrochloric or sulfuric acid) for a short time to weaken the seed coat.

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    Stratification

    Exposing seeds to low temperatures (2 weeks to 3 months) in a moist planting medium to promote germination.

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    Fruit

    A mature ovary of a flower that contains seeds.

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    Pericarp

    The thickened wall of a fruit that develops from the ovary wall.

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    Parthenocarpic fruit

    Fruit development that occurs without fertilization, resulting in seedless fruits.

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    Seed Dormancy

    A state where seeds don't germinate even under favorable conditions.

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    Seed Coat Dormancy

    A thick or hard seed coat prevents water and air from reaching the embryo, preventing germination.

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    Rudimentary Embryo Dormancy

    The embryo is underdeveloped and needs to mature before germination can occur.

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    Embryonic Dormancy

    Germination is delayed by chemical mechanisms within the embryo.

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    Importance of Seed Dormancy: Survival

    Dormancy allows seeds to survive harsh conditions like drought and cold, ensuring plant survival.

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    Importance of Seed Dormancy: Seed Bank

    Dormant seeds can remain viable for years, providing a source of new plants even if existing ones die.

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    Importance of Seed Dormancy: Dispersal

    Dormancy helps seeds travel long distances over land or water, allowing for wider dispersal.

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    Importance of Seed Dormancy: Timing

    Dormancy ensures that seeds germinate only under optimal conditions, increasing chances of successful growth.

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    Study Notes

    Seed and Fruit Development

    • This chapter covers the structure, germination, dormancy, and development of seeds and fruits.

    Learning Objectives

    • Students will be able to recognize seed structure.
    • Students will be able to explain seed germination.
    • Students will be able to explain seed dormancy.
    • Students will be able to describe fruit development.

    Seed Structure

    • Flowering plants produce seeds in various shapes, sizes, and colors.
    • A seed is a small embryonic plant enclosed in a seed coat, usually with stored food.
    • Seeds develop from fertilized ovules.
    • Generally, a seed has three parts:
      • Seed coat: The outermost covering of a seed, developing from the integuments of the ovule. It usually has a hard, leathery outer layer (testa) and a thin, papery inner layer (tegmen). The seed coat protects the seed from environmental factors like sunlight, water, and parasites. Its hardness prevents germination under unsuitable conditions.
      • Endosperm: A triploid nutritive tissue providing stored food for the developing embryo. It forms from the fusion of a haploid male gamete with a diploid central cell within the embryo sac.
      • Embryo: Consists of an embryonal axis with a radicle (the lower end, developing into the root system) and a plumule (the upper end, developing into the shoot system). Additionally, it typically includes cotyledons (embryonic seed leaves).

    Seed Cotyledons

    • Cotyledons are embryonic seed leaves.
    • They store food for the growing embryo.
    • Seeds with one cotyledon are monocotyledonous (e.g., maize, wheat).
    • Seeds with two cotyledons are dicotyledonous (e.g., beans, gram).

    Embryo Morphology (Dicots)

    • The seedling consists of a plumule and a radicle.
    • The region between the radicle and the point of attachment of the cotyledons is the hypocotyl.
    • The region between the plumule and the point of attachment of the cotyledons is the epicotyl.

    Seed Germination

    • The process where a dormant embryo becomes active, grows out of the seed coat, and develops into a seedling.
    • Factors influencing germination include moisture/water (imbibition), air (oxygen), suitable temperature, and light or darkness requirements, depending on the seed.
    • Stages of Germination: imbibition, activation of enzymes, respiration, growth of the embryo, and emergence of the seedling.
    • Stored food within the seed is broken down via hydrolytic enzymes which provides nutrients.
    • The radicle grows downwards to form the primary root.
    • The epicotyl grows in and the plumule develops into the stem and leaves.

    Seed Germination Types

    • Hypogeal germination: The hypocotyl grows first, pushing the plumule (shoot) above ground. The cotyledons remain in the soil, avoiding desiccation. Typical of monocots.
    • Epigeal germination: The hypocotyl grows first, pushing the cotyledons above ground. The cotyledons eventually become green, enabling photosynthesis. Typical of dicots.

    Seed Dormancy

    • A state where seeds are prevented from germinating even under favorable environmental conditions.
    • Causes of seed dormancy include:
      • Hard seed coat: prevents entry of water and oxygen, thus inhibiting growth. Methods of overcoming this include mechanical, heat, or acid scarification.
      • Immature embryo(Rudimentary embry): Embryo needs to develop further.
      • Excessive salts: high concentration of solutes inhibiting germination.
      • Light sensitivity: positive (needs light) or negative (needs dark).
        • Chilling requirement for germination
      • Inhibitors such as ABA inhibiting germination via metabolic changes.

    Fruit Development

    • Fruit develops from the mature, ripened ovary after fertilization.
    • It contains one or more seeds.
    • Fruit develops as the ovary wall (pericarp) thickens after fertilization.
    • The three layers of the pericarp are:
      • Exocarp
      • Mesocarp
      • Endocarp
    • Fruits can be simple, aggregate, or multiple depending on the flower structure.
    • Types of fruits including:
      • Simple
      • Aggregate
      • Multiple
      • Accessory

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    Description

    Test your knowledge on the fascinating process of seed germination. This quiz covers key topics such as hypogeal and epigeal germination, the role of cotyledons, and the importance of environmental factors. Perfect for students studying plant biology.

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