Pollination and Fertilization Quiz
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Questions and Answers

What is the primary role of pollen grains in plants?

  • To provide nutrition for developing seeds
  • To absorb sunlight for photosynthesis
  • To transfer male gametes to the stigma (correct)
  • To protect the ovule from external elements

    • What is double fertilization in plants?

  • The fusion of two pollen grains with one stigma
  • The fusion of male and female gametes in two separate flowers
  • The fusion of one sperm nucleus with the egg cell nucleus and another with two polar nuclei (correct)
  • The simultaneous fertilization of two different species

    • Which type of pollination is conducted by birds?

  • Elephophily
  • Ornithophily (correct)
  • Chiropterophily
  • Entomophily

    • What does artificial pollination involve?

    <p>Manual transfer of pollen by humans (A)</p> Signup and view all the answers

    What happens to the pollen grain after it lands on the stigma?

    <p>It forms a pollen tube for fertilization (C)</p> Signup and view all the answers

    What is one disadvantage of cross-pollination in plants?

    <p>It requires a larger number of pollen production. (A)</p> Signup and view all the answers

    Which condition allows cross-pollination to occur when male and female flowers are on different plants?

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

    In which type of dichogamy do the male anthers mature earlier than the stigma?

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

    Which of the following is NOT an agent of cross-pollination?

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

    What characteristic is typical of anemophilous flowers?

    <p>Feathery stigma that hangs out from the flower (D)</p> Signup and view all the answers

    Which plant feature helps in hydrophily?

    <p>Pollen grains with specific gravity allowing them to float (B)</p> Signup and view all the answers

    What is herkogamy in the context of cross-pollination?

    <p>A physical barrier preventing self-pollination (B)</p> Signup and view all the answers

    Which of the following is an example of entomophily?

    <p>Pollination by brightly colored and scented flowers (C)</p> Signup and view all the answers

    What is the process of transferring pollen from the anther to the stigma called?

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

    Which type of pollination involves the pollen of the same plant falling on its stigma?

    <p>Self-pollination (B)</p> Signup and view all the answers

    What is a disadvantage of self-pollination?

    <p>Poor quality of seeds (B)</p> Signup and view all the answers

    Which advantage is specifically associated with cross-pollination?

    <p>Production of healthier offsprings (C)</p> Signup and view all the answers

    What does cleistogamy refer to?

    <p>Self-pollinating flowers that do not open (A)</p> Signup and view all the answers

    Which of the following is a feature of self-pollination?

    <p>Indefinite preservation of parental traits (D)</p> Signup and view all the answers

    What is a disadvantage linked to cross-pollination?

    <p>Unreliable success of pollination (C)</p> Signup and view all the answers

    Which type of pollination occurs when pollen is transferred between flowers of the same species but different plants?

    <p>Cross-pollination (C)</p> Signup and view all the answers

    Flashcards

    Pollen grains

    Sticky or spiny structures that carry male gametes.

    Stigma

    The sticky part of a flower that receives pollen during pollination.

    Artificial Pollination

    Human-mediated transfer of pollen to stigma to produce new varieties.

    Fertilization

    The fusion of male and female gametes to form a zygote.

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    Double fertilization

    A process where one sperm fertilizes the egg and another fuses with polar nuclei.

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    Pollination

    The transfer of pollen from anther to stigma.

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    Self Pollination

    Pollen transfer within the same flower or plant.

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    Cross Pollination

    Pollen transfer between different flowers of the same species.

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    Advantages of Self Pollination

    Guaranteed pollination, preservation of parental traits.

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    Disadvantages of Self Pollination

    Leads to weaker offspring and lack of new varieties.

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    Advantages of Cross Pollination

    Healthier offspring, more viable seeds, potential for new varieties.

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    Disadvantages of Cross Pollination

    Pollination is not always certain.

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    Cleistogamy

    Self-pollination in closed flowers without opening.

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    Wastage of Pollens

    Production of excess pollens by plants to ensure pollination.

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    Unisexuality

    Condition where male and female flowers are on separate or same plants.

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    Dichogamy

    Differential maturation timing of male and female reproductive parts.

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    Self sterility

    Pollen from only other plants of the same species can fertilize.

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    Anemophily

    Pollination by wind, typically involving small, dull flowers.

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    Entomophily

    Pollination by insects, involving brightly colored and scented flowers.

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    Herkogamy

    Physical barriers prevent pollination between anthers and stigmas.

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    Study Notes

    Pollination and Fertilization

    • Pollination is the transfer of pollen grains from the anther to the stigma. A pollinator, such as an insect or wind, carries the pollen.

    • Types of Pollination:

      • Autogamy: Pollen from the same flower falls on the stigma.
      • Geitonogamy: Pollen from one flower falls on the stigma of a different flower on the same plant.
      • Allogamy (Cross-pollination): Pollen from one flower falls on the stigma of another flower on a different plant of the same species.

    Self-Pollination

    • Pollen from the anther to the stigma of the same flower or another flower of the same plant.

    • General qualities of a plant are consistent across its flowers.

    • Cleistogamy: Some flowers do not open; pollen is transferred without exposing the flower to external factors. Happens in some legumes.

    • Advantages:

      • Guaranteed pollination as stamen and carpels mature together.
      • Preserves parental characteristics indefinitely.
      • No pollen grain wastage.
      • Flowers don't need to be large or showy.
      • Scent and nectar aren't necessary.
      • Economical for the plant.

    • Disadvantages:

      • Weakening of a variety or species, poor quality of seeds, less vigorous offspring.
      • Weaker or defective plant characteristics are not eliminated making it impossible to breed improved varieties

    Cross-Pollination

    • Pollen transfer between flowers of different plants but of the same species.

    • Advantages

      • Healthier offspring.
      • Abundant and viable seeds.
      • Production of new varieties (e.g., cross-pollinating different varieties of the same species).

    • Disadvantages

      • Pollination is not always certain.
      • Wastage of pollen (as a large quantity is needed).
      • Uneconomical for the plant (as large and colorful flowers and nectar production).

    Conditions Favoring Cross-Pollination

    • Unisexuality: Male and female flowers grow on separate plants (e.g., palms) or on the same plant (e.g., cucumbers).
    • Dichogamy: Timing of maturation difference between male and female structures (e.g., protandry – anthers mature before stigma).
    • Self-sterility: Pollen from one plant will not fertilize the stigma of the same plant.
    • Herkogamy: Physical barriers between anther and stigma making self-pollination difficult (e.g., different heights of stigma and anther).
    • Heterostyly: Different heights of anthers and stigmas in some flowers hindering self-pollination (e.g., primrose).

    Agents of Cross-Pollination

    • Abiotic agents (non-living):

      • Wind (Anemophily): Flowers are small, lack bright colors, often dull green, minimal scent or nectar. The pollen is light, dry and smooth, the stigma is feathery to capture wind-blown pollen (e.g., grasses, trees).
      • Water (Hydrophily): Plants produce a large number of pollen grains that are buoyant in water (e.g., Vallisneria).

    • Biotic agents (living):

      • Insects (Entomophily): Flowers are large, brightly colored, and scent and nectar to attract insects (e.g., lilies, roses, fruit trees).
      • Birds (Ornithophily): Flowers are large with bright colors and a strong or sweet scent, and nectar from the flower (e.g., hummingbirds, honeysuckle).
      • Bats (Chiropterophily): Flowers produce nectar in the evening, and bloom at that time (e.g., Anthocephalous, Bauhinia).
      • Artificial Pollination: Humans manually transfer pollen (e.g., for creating different plant varieties).
      • Elephants (Elephophily): These pollinating agents are rather large (e.g., Rafflesia).

    Fertilization

    • Fusion of male and female gametes (nuclei).

    • Pollen grain (male gamete) fertilizes the ovule (female gamete)

    • Zygote forms

    • Zygote → Embryo → New baby plant.

    • Double Fertilization:

      • One sperm nucleus fuses with the egg nucleus to form the zygote (first cell of sporophyte).
      • Another sperm nucleus fuses with two polar nuclei to form the endosperm, the food source for the developing embryo.

    Fate of Floral Parts After Fertilization

    • Sepals, petals, and stamens usually wither and fall off.
    • Ovary wall becomes the fruit.
    • Ovule becomes the seed.
    • Integuments become the seed coat.
    • Fertilized egg becomes the embryo.

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    Related Documents

    Pollination and Fertilization PDF

    Description

    Test your knowledge on the processes of pollination and fertilization including different types of pollination. Explore concepts such as self-pollination and the advantages it offers. Understand the significance of pollinators and the mechanisms plants use to reproduce.

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