Plant Hormones and Seed Dispersal
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Questions and Answers

Which type of seed dispersal involves seeds being eaten and later excreted by animals?

  • Self-dispersal
  • Animal Dispersal (correct)
  • Wind Dispersal
  • Water Dispersal
  • What is a primary advantage of seed dormancy for plants?

  • Ensures seeds do not require dispersal
  • Allows embryos to mature before conditions improve (correct)
  • Promotes immediate growth regardless of conditions
  • Increases the rate of germination
  • What requirement is essential for successful germination of seeds?

  • Stable and suitable environmental conditions (correct)
  • Presence of animal digestive enzymes
  • High levels of competition
  • Absence of water
  • Which type of seed dispersal involves the use of features that allow for flight through the air?

    <p>Wind Dispersal</p> Signup and view all the answers

    How do some seeds manage to remain dormant until environmental conditions are suitable?

    <p>By maintaining a waterproof Testa</p> Signup and view all the answers

    What is the primary function of fruit in plants?

    <p>To protect the seed and allow for seed dispersal</p> Signup and view all the answers

    Which seed feature is primarily responsible for protecting the seed before germination?

    <p>Testa</p> Signup and view all the answers

    In dicot plants, where is the food for the developing embryo mostly stored?

    <p>In the cotyledons</p> Signup and view all the answers

    Which mechanism is NOT known for seed dormancy?

    <p>Submergence in water</p> Signup and view all the answers

    What type of seed is formed from the endosperm in monocot plants?

    <p>Endospermic seed</p> Signup and view all the answers

    Which part of the seed develops into the root during germination?

    <p>Radicle</p> Signup and view all the answers

    Which of the following describes a mechanism of genetic selection for seedless fruits?

    <p>Selecting plants that produce very few seeds and propagating them asexually</p> Signup and view all the answers

    What is the first part of the new plant that emerges from the seed?

    <p>Radicle</p> Signup and view all the answers

    What type of germination arrangement is typically seen in seeds with two cotyledons?

    <p>Dicot germination</p> Signup and view all the answers

    What happens to the ovule after fertilization?

    <p>It dries out and develops into the seed</p> Signup and view all the answers

    Study Notes

    Plant Hormones and Fruiting

    • Auxins are plant hormones used to induce fruiting without fertilization.

    Seed Dispersal

    • Dispersal ensures survival by relocating seeds away from the parent plant, reducing competition.

    Animal Dispersal

    • Seeds are ingested by animals, passing through their intestines where digestive enzymes can aid germination.
    • Examples include tomato and apple seeds, which require this process for germination.

    Wind Dispersal

    • Seeds must be lightweight and possess a large surface area to facilitate wind transport.
    • Notable examples include sycamore and dandelion seeds.

    Self-Dispersion

    • Pea pods dry and develop lines of weakness, curling and splitting to eject seeds.
    • Gorse exemplifies self-dispersing plants.

    Water Dispersal

    • Seeds contain air pockets to keep them buoyant, allowing for long-distance dispersal.
    • The yellow water lily showcases this dispersal method.

    Dormancy

    • Dormancy is a period of reduced growth/metabolism despite suitable germination conditions.

    Advantages of Dormancy

    • Protects plants from adverse conditions that could harm new growth.
    • Allows seeds to spread, reducing competition.
    • Gives embryos time to mature until conditions improve.

    Breaking Dormancy

    • Seeds often have waterproof coatings (Testa) that prevent water entry, maintaining dormancy until conditions are favorable.

    Seed Formation

    • Post-fertilization, the ovule swells and toughens to form the seed coat.
    • The zygote develops into a seed embryo, while the triploid endosperm becomes a food storage system.
    • The integuments thicken to form the protective Testa.

    Seed Structure

    • Embryo: Develops into the new plant.
    • Testa: Tough outer coat protecting the seed.
    • Radicle: First root part to emerge.
    • Plumule: Develops into the shoot.
    • Cotyledons: Seed leaves that store food, can be one (monocots) or two (dicots).

    Seed Types

    • Endospermic seeds (e.g., maize, wheat) store food in the endosperm.
    • Non-endospermic seeds (e.g., broad bean) store nutrients primarily in cotyledons.

    Fruit Formation

    • Fruits protect seeds and aid in dispersal.
    • Seedless fruits, like watermelons, are developed through genetic selection or treatment to break seed dormancy.
    • Chemical soaking can wash out inhibitors, and application of hormones can enhance fruit production.

    Germination

    • Germination is the process when a seed begins to grow.

    Requirements for Germination

    • Water: Acts as a solvent and medium for hormones/enzymes.
    • Oxygen: Essential for aerobic respiration and energy production.
    • Temperature: Necessary for enzyme activity.
    • Food: Reserves in the seed provide energy for new tissue development.

    Stages of Germination

    • Emergence of the radicle forms the root.
    • Plumule grows upwards to form the shoot, leading to initial weight loss.
    • Leaves break the surface, initiating photosynthesis, and the plant starts gaining weight.
    • Hypogeal Germination: Seed remains underground.
    • Epigeal Germination: Seed grows above ground.

    Asexual Reproduction

    • Involves no gametes, resulting in genetically identical offspring to the parent plant.

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    Related Documents

    Plant Reproduction.docx

    Description

    Explore the role of plant hormones in inducing fruiting without fertilization. This quiz also covers the importance of seed dispersal methods, particularly animal dispersal, and how it aids in plant survival and germination processes.

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