Germination

A seed remains dormant until the favourable conditions of its germination arrive. At this time, an embryo present inside the seedremains inactive though all the processes of life continue.

Once the favourable conditions for its germination arrive, it starts germinating.

Germination is the process by which mature seed begins to grow into a new plant under suitable growth conditions.
A seed requires water, oxygen and appropriate temperature for germination. These requirements can be proven with the help of simple experiments.

In an experiment to prove that water is necessary for germination, the seeds in the beaker containing wet cotton wool will germinate, while the seeds in the beaker containing dry cotton wool will not germinate.

In an experiment to prove that oxygen is necessary for germination, the seeds in the flask containing wet cotton wool and a test tube of normal water will germinate, while the seeds in the flask containing wet cotton wool and a test tube of pyrogallic acid will not germinate because this acid absorbs oxygen.

Similarly, in an experiment to prove that suitable temperature is necessary for germination, if the seeds in the beaker containing wet cotton wool are kept in an ordinary room, they will germinate. On the other hand,if the seeds in the beaker containing wet cotton wool are kept in the refrigerator, they will not germinate because extremely cold temperature does not allow seed germination.

The three bean seeds experiment also demonstrates that oxygen and water along with the optimum temperature are necessary for seed germination.

The bean seed consists of two parts: an epicotyl and a hypocotyl.

Germination can be broadly classified into epigeal and hypogealon the basis of elongation of hypocotyl and epicotyl, respectively.

Bean seeds and castor seeds undergo epigeal germination, while sweet pea seeds and gram seeds undergo hypogeal germination.

Mangrove plants germinate via a special type of germination known as viviparous germination.

All kinds of germination give rise to seedlings.

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  • Q1

    Name the type of plants that are capable of germinating at low temperature.

    Marks:1
    Answer:

    Temperate plants are capable of germinating at low temperature.

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  • Q2

    Name the type of plants that are capable of germinating at high temperature.

    Marks:1
    Answer:

    Tropical plants are capable of germinating successfully at high temperature.

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  • Q3

    Explain the term seed dormancy.

    Marks:1
    Answer:

    It is a state in which seed does not show any signs of growth even after maturation.

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  • Q4

    State any one example of seed.

    Marks:1
    Answer:

    Bean seed

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  • Q5

    What is a seed?

    Marks:1
    Answer:

    Seed is the ripened ovule after fertilisation.

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