Test: Plants - Class 6 MCQ

The correct answer is C: Radicle.
The embryo is the early stage of development in a plant seed. It consists of several parts, and the radicle is the first part to grow. Here is a breakdown of the different parts of the embryo and their order of growth:

1. Cotyledon: The cotyledon is a structure that stores food for the developing plant. It is not the first part to grow.
2. Plumule: The plumule is the embryonic shoot that will develop into the stem and leaves. It grows after the radicle.
3. Radicle: The radicle is the embryonic root that emerges first from the seed. It is responsible for anchoring the plant and absorbing water and nutrients from the soil. The radicle is the first part of the embryo to grow.
4. Leaves: The leaves are not part of the embryo but develop from the plumule. They are responsible for photosynthesis and usually grow after the radicle and plumule.

In summary, the radicle is the first part of the embryo to grow. It emerges from the seed and develops into the root system of the plant, providing support and nutrient absorption.

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.

• Apple is a type of fruit crop that is cultivated and harvested during the Rabi season.
• Rabi crops are grown during the winter season, which usually starts in November and lasts until April.
• These crops require a cool climate for their proper growth and development.
• Apple trees need a period of winter dormancy to produce high-quality fruits, and the Rabi season provides the ideal conditions for this.
• The flowering and fruiting of apple trees occur during the spring season, which follows the winter period.
• Rabi crops are sown in the autumn and are harvested in the spring.
• Other examples of Rabi crops include wheat, barley, gram, mustard, and peas.
• Kharif crops, on the other hand, are cultivated during the monsoon season and include crops like rice, maize, cotton, and soybean.
• Spongy is not a term used to categorize crops and is not related to apple cultivation.

Therefore, the correct answer is B: Rabi.

The crop peanut belongs to the Kharif season. Here is why:
The crop peanut is commonly known as groundnut and is grown primarily for its edible seeds. It is an important oilseed crop and a staple food in many countries. Here is a detailed explanation of why peanut belongs to the Kharif season:
Kharif Season:
1. Kharif season refers to the monsoon season in India, which typically starts in June and lasts till September.
2. During the Kharif season, the rainfall is abundant, and the temperature is suitable for the growth of certain crops.
3. Crops that are sown during the Kharif season are generally harvested in the autumn months.
4. These crops require a warm and humid climate to grow properly.
Peanut cultivation characteristics:
1. Peanut crops require a warm climate with temperatures ranging between 25 to 35 degrees Celsius.
2. They require well-drained soil with a pH range of 6 to 7.5.
3. Moisture is essential for the growth of peanut plants, especially during the initial stages.
4. Excessive rainfall or waterlogging can negatively affect the crop.
5. The duration of the peanut crop is around 120 to 150 days from sowing to harvesting.
6. The crop is usually sown in June or July and harvested in September or October.
Conclusion:
Considering the cultivation characteristics and the timing of sowing and harvesting, it is clear that peanut belongs to the Kharif season. It is important to note that crop seasons may vary in different regions, but in India, peanut cultivation is predominantly associated with the Kharif season.

Tea Plant Propagation Methods
Tea plants are commonly propagated through various methods, but the most common and effective method is through cuttings. Here is a detailed explanation of how a tea plant is propagated:
1. Collecting Cuttings:

• Select healthy and disease-free tea plant branches for propagation.
• Cut 4-6 inch long stem cuttings from the selected branches.
• Ensure the cuttings have at least three to four leaves.

2. Preparing the Cuttings:

• Remove the lower leaves from the cuttings, leaving only the top two or three leaves.
• Dip the cut ends of the stems in a rooting hormone powder to enhance root development.
• Plant the prepared cuttings immediately or store them in a cool, moist environment until planting.

3. Planting the Cuttings:

• Prepare a well-draining potting mix or soil for planting the cuttings.
• Make holes in the soil using a pencil or any pointed object.
• Insert the cuttings into the holes, ensuring that at least one node is buried in the soil.
• Gently press the soil around the cuttings to provide stability.

4. Providing Suitable Growing Conditions:

• Place the planted cuttings in a warm and humid environment, preferably with a temperature range of 68-86°F (20-30°C).
• Ensure the cuttings receive indirect sunlight to promote growth.
• Mist the cuttings regularly to maintain high humidity levels.
• Water the cuttings when the soil feels slightly dry, but avoid overwatering as it may lead to root rot.

5. Root Development and Transplanting:

• After a few weeks, the cuttings will start developing roots.
• Monitor the growth and development of the root system.
• Once the roots are well-established, usually within 3-6 months, the cuttings can be transplanted into larger pots or directly into the ground.

By following these steps, tea plants can be successfully propagated through cuttings. This method ensures genetic consistency and quicker plant development compared to growing tea plants from seeds.

How has deforestation affected wildlife?
Deforestation has had a significant impact on wildlife, leading to various negative consequences. Here are some ways in which deforestation affects wildlife:
Near Extinction of Species:

• Due to deforestation, habitats of many animal species have been destroyed, pushing them to the brink of extinction. Forest-dependent species such as orangutans, tigers, and gorillas are particularly vulnerable.
• The loss of habitat disrupts the natural balance, making it difficult for certain species to find suitable conditions to survive and reproduce.

Lack of Shelter:

• Deforestation removes trees and vegetation that provide animals with essential shelter and protection from predators.
• Without adequate shelter, animals are exposed to harsh weather conditions, making them more susceptible to disease, stress, and death.
• Many species, including birds and mammals, rely on specific types of trees for nesting and breeding, which become scarce with deforestation.

Lack of Food:

• Deforestation leads to the destruction of food sources for wildlife.
• Trees provide fruits, nuts, and seeds that form a significant part of the diet for many animal species.
• With the loss of forested areas, animals struggle to find enough food, leading to malnutrition, decreased reproductive success, and ultimately population decline.

Disruption of Ecosystems:

• Forests play a crucial role in maintaining balanced ecosystems. They provide habitats for countless species and support intricate food webs.
• Deforestation disrupts these ecosystems, affecting the entire web of life, including plants, animals, and microorganisms.
• The loss of biodiversity can have cascading effects, leading to imbalances in populations, reduced resilience to environmental changes, and potential ecosystem collapse.

In conclusion, deforestation has a profound impact on wildlife. It threatens species with extinction, deprives animals of shelter and food, and disrupts crucial ecosystems. Conservation efforts and sustainable land use practices are essential to mitigate these negative effects and preserve biodiversity.

Correct answer is B. All of these

The green plants carry on the process of photosynthesis. During this process, they take in carbon dioxide from the atmosphere and reduce it to sugars. Simultaneously green plants absorb water from the soil and oxidize it by the process of photolysis to release electrons and oxygen as a by-product of photosynthesis. 
So, the correct answer is option B.

Sugarcane can be grown from:

• Stems: Sugarcane is primarily grown from stem cuttings. The stems of the sugarcane plant contain nodes, which are the points where the leaves emerge. These nodes also have buds, which can grow into new plants when planted in the soil.
• Roots: While sugarcane is primarily propagated through stem cuttings, it is possible to grow sugarcane from the roots as well. If the roots are intact and have buds, they can be planted in the soil to grow into new plants.
• A and B both: Sugarcane can be grown from both stems and roots. Stem cuttings are the most common and efficient method of propagation, but if the roots have buds, they can also be used to grow new plants.

In summary, sugarcane can be grown from both stems and roots. Stem cuttings are the most common method of propagation, but if the roots have buds, they can also be used to grow new plants.

The correct answer is Water, Oxygen, and Proper Temperature.

About Germination:

• It is the process by which an organism grows from a (Seed or from a similar structure). The term is applied to the (Sprouting of a Seedling) from a seed of an Angiosperm or Gymnosperm.
• The growth of a (Sporeling from a Spore), such as the spores of (Ferns, Bacteria Fungi, and the growth of the Pollen Tube) from the Pollen Grain of a Seed Plant.
• Germination is also the process of Reactivation of the Metabolic machinery of the seed resulting in the emergence of (Radicle and Plumule).
• The Seed of a Vascular plant is a small package that is produced in a (Fruit or Cone) after the joining of (Male and Female Reproductive cells).
• The fully developed Seeds contain an Embryo. In most of the Plant Species some store (Food reserves, wrapped in a Seed coat).
• All the seeds require specific (Internal or Environmental) conditions to resume growth. Under proper conditions, the Seed begins to Germinate and the Embryo resumes its growth and developing into a Seedling Stage.
• All seeds needed (Water, Oxygen, and Proper Temperature) to Germinate. Some seeds require a proper way of light conditions also. Some germinate better in Full light conditions, while others require (Darkness to Germinate).
• When a seed is exposed to the proper conditions, (Water and Oxygen) are taken in through the Seed coat. 
  • Water is required for Germination, most of the Mature seeds are extremely dry and needed significant amounts of water, relative to the Dry weight of the seed, before (cellular metabolism and growth resume).
  • The requirement of Oxygen by the (Germinating of seeds for Metabolism).
  • Proper Temperature requirement for effects of (cellular metabolic and growth rates). Seeds from Different Species and seeds from the Same Plant species (Germinate over a wide range of temperatures).