**Seed Germination and Water**

When it comes to seed germination, water plays a crucial role. Seeds require water to initiate the germination process, but keeping seeds continuously submerged under water can actually prevent germination. Let's explore why this is the case:

**1. Seed Structure and Dormancy:**
Seeds have a protective outer covering called the seed coat, which helps to maintain dormancy and prevent premature germination. This seed coat is impermeable to water, meaning that water cannot easily penetrate and reach the embryo inside.

**2. Water Absorption:**
For germination to occur, seeds need to absorb water through a process called imbibition. During imbibition, the seed coat becomes permeable to water, allowing it to enter the seed and activate the metabolic processes necessary for germination.

**3. Oxygen Availability:**
Along with water, seeds also require oxygen to break down stored nutrients and convert them into energy for growth. Oxygen is necessary for respiration, which provides energy for the germination process. However, when seeds are submerged under water, the oxygen supply becomes limited, hindering the germination process.

**4. Anaerobic Conditions:**
When seeds are kept under water, they experience anaerobic conditions, meaning the absence of oxygen. In such conditions, the seed may undergo fermentation instead of aerobic respiration. Fermentation is an inefficient process that produces less energy and can lead to the death of the seed before germination can occur.

**5. Lack of Light:**
Seeds also require light for germination. When submerged under water, light cannot reach the seed, and this lack of light can inhibit germination.

**Conclusion:**
Keeping seeds under water prevents germination due to several factors. The impermeable seed coat restricts water absorption, the limited oxygen supply prevents respiration, anaerobic conditions hinder metabolic processes, and the absence of light inhibits germination. Therefore, the correct answer is option 'B': The seeds will not germinate when kept under water.

What happens if seeds are kept under water?
When seeds are kept under water, they undergo a process called imbibition. Here is what happens:
1. Imbibition:
- Imbibition is the process where seeds absorb water through their seed coat.
- The seed coat becomes permeable to water, allowing it to enter the seed.
2. Activation of metabolic processes:
- As water enters the seed, it activates metabolic processes within the seed.
- Enzymes become active, initiating the process of germination.
3. Germination is hindered:
- While seeds absorb water through imbibition, excessive water can actually hinder germination.
- If seeds are kept under water for a prolonged period, they may not germinate.
- This is because waterlogged conditions can deprive the seed of oxygen, which is essential for germination.
4. Lack of oxygen:
- When seeds are submerged in water, the oxygen supply to the seed is limited.
- Without sufficient oxygen, the seed's metabolic activities are hampered.
- This can prevent germination and lead to the death of the seed.
5. Seed dormancy:
- Some seeds have a natural dormancy period, during which they do not germinate even when provided with suitable conditions.
- Water alone may not be enough to break seed dormancy, and other factors such as temperature or light may be necessary.
In conclusion, keeping seeds under water may lead to the inhibition of germination due to limited oxygen supply. While imbibition is a crucial first step, prolonged waterlogging can hinder seed growth and even cause the seed to die.