Hypogeal Germination


Introduction

Hypogeal germination is a term used to describe the germination of a plant from a seed planted underground, as opposed to above ground. This type of germination is most commonly seen in plants that grow in the ground or in soil. The "Hypogeal" comes from a Greek word meaning "under".

When most people think of plants and seeds, they think of germination above ground. But if you look at a flower stalk or fruit tree, you will notice that some seeds are hidden underground. Some of these seeds have special adaptations that allow them to be planted and stay underground while they start to grow.

When this happens, we say the seeds have undergone hypogeal germination. The seedling emerges from the ground after sprouting beneath it because the cotyledon stays underground while the first true leaf grows above ground. Usually, the cotyledon will sprout just beneath the surface of soil and turn into the first leaves for photosynthesis, leaving behind an empty seed casing for support.

It's best to plant your seeds in pots or trays and then transplant them when they are ready rather than planting them directly into your garden bed where they can be harder to find when it's time to transplant them again .

You can also plant your seeds directly in the ground and keep them watered until they sprout. This is usually a more common method of germinating seeds than potting them, but it has its drawbacks. If you are planting directly into the garden bed, make sure that you water your seeds every day or two for at least a week after planting them so that they don't dry out.

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Epigeal germination

Epigeal germination is a form of natural plant propagation that occurs in a variety of ways.

  • In some cases, the seeds are actually planted directly into the ground. The most common example of this is when a farmer sows seeds for crops such as corn or wheat. These plants grow naturally from the seeds and need to be buried in the ground to truly sprout and grow.

  • A second example is when a tree falls over and creates its own "seed bed." This is actually how many species of trees propagate themselves naturally. The seeds fall to the ground, where they are buried by falling leaves and other forest debris, which then provide them with the right environment to grow into new trees.

  • Another example is through the use of epigeous bulbs, which are bulbs that grow underground but produce flowers above ground level, such as hyacinths, daffodils and tulips. These bulbs can be planted directly into soil or pots, where they will send up shoots with flowers at their tips. These are often referred to as "true" bulbs or "natural" bulbs, because unlike other types of flower bulbs that are grown in pots for simulated growth conditions before being shipped to growers, these bulbs never actually leave the ground−they just stay underground until the proper time to produce flowers.

What is the Hypogeal Germination Process?

When it comes to plant life, one of the most intriguing and important stages is germination. When a seed sprouts into a baby plant, the process can be rather miraculous to witness. The process can start with a seed falling to the ground, just waiting for the right conditions to grow.

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Depending on the type of seed and what's around it, it may start to break down. This process is called imbibition. Once this has occurred, the embryo inside the seed starts to grow. The seed coat becomes permeable and water flows into it from the soil. As this happens, a small root emerges from the end opposite of where the seed was attached.

This first root breaks through the seed coat and pushes upward through the soil until it reaches an area with enough oxygen for its roots to develop properly. The rest of the seeds embryo continues to grow as more water seeps in through that same hole until its entire body is free of the shell and ready to develop into a full-fledged plant!

The process of germinating a seed is not always easy. Some seeds, such as beans and peas, have hard coats that must be broken through before they can absorb water. Others have fleshy coats that are easily penetrated by water but require some sort of mechanical action to break apart.

Hypogeal Germination Seed Examples

The seeds of many plants are dormant and need to be stimulated in order to germinate. Seeds with hypogeal germination depend on the presence of light for germination, as opposed to geophytes which thrive in darkness.

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Examples of Hypogeal Seeds

1. Broccoli

Broccoli is a good example of a hypogeal germination seed. It is a member of the cabbage family, which includes kale, collards, kohlrabi and Brussels sprouts.

2. Sunflowers

Sunflowers are also hypogeal, but they are an unusual example because they grow from the center rather than the edge of their seeds. The outer shell contains food for the plant's first few days, after which it eventually dies off and leaves room for the emerging stem and leaves to grow out from inside the shell.

3. Peas And Beans

Peas and beans are also examples of hypogeal germination seeds because they grow downward instead of up through soil as most seeds do. This happens because these plants have long roots that grow under ground before emerging above ground as shoots or vines at some point during their lifecycles.

4. Maize

Maize is a cereal grain that grows in tropical areas worldwide. It has a hard outer shell and a soft interior filled with starch. Because it’s a cereal grain, maize must be planted in fields rather than directly into the garden bed like most other seeds.

5. Coconut

Coconuts are tropical trees that produce fruit known as coconuts or cocos or sometimes simply coconuts. They grow in clusters at the tops of their trunks where they hang from their branches by long stalks called peduncles. The coconut fruit consists of an outer fleshy layer called mesocarp and an inner brown shell that covers a thick white liquid called endosperm (or kernel).

Pros and Cons Related to Hypogeal Germination

pros

1. Hypogeal germination allows for greater control over when an organism germinates because it does not require an external stimulus such as light or temperature changes to trigger growth.

2. Hypogeal seeds have a high rate of survival because they are protected from environmental hazards such as drought or flooding by their outer covering until they have fully developed into plants that can survive on their own outside of their parent plant's root system.

3. Hypogeal seeds are also more likely to remain dormant until the right conditions exist for them to sprout if they are planted in areas where they would otherwise not survive due to lack of moisture or other resources necessary for life (e.g., sunlight).

cons

It is a slow process and may take anywhere between 1-15 years for the seedling to emerge from below ground level depending on the plant species and its growth rate.

Hypogeal germination is less reliable than epigeal germination because many seeds do not emerge from the ground even after they have been given adequate time to do so. Some seeds may not even come out at all if they do not receive enough light and nutrients while they are still in their shells.

Conclusion

In conclusion, hypogeal germination is a type of germination that occurs underground. This process is initiated by the radicle, which breaks through the seed coat and grows downward into the soil. Once the radicle reaches the soil surface, the cotyledons emerge and begin to photosynthesize. The hypocotyl then elongates, bringing the leaves above ground. Hypogeal germination is often used by plants that grow in hot, dry climates, as it helps them to avoid desiccation.

FAQs

1. What is hypogeal germination?

Hypogeal germination is a type of seed germination in which the cotyledons remain below ground while the shoot emerges above ground. This is in contrast to epigeal germination, in which the cotyledons emerge above ground along with the shoot.

2. What environmental conditions are necessary for hypogeal germination?

There are certain environmental conditions that are necessary for hypogeal germination to occur. One is that the soil must be moist but not waterlogged. The seed must also be in contact with the soil in order for it to imbibe water.

3. What are the steps of hypogeal germination?

The steps of hypogeal germination are as follows−

1) The seed absorbs water and swells.

2) The seed coat breaks open and the radicle emerges.

3) The radicle grows downward into the soil.

4) The cotyledons remain below ground.

5) The shoot emerges above ground.

4. What are some common plants that undergo hypogeal germination?

There are many common plants that undergo hypogeal germination, including corn, beans, and squash.

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Updated on: 13-Oct-2022

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