Test : Plant Life - 2 - Class 5 MCQ

Factors required for the germination of seeds:
There are several factors that are necessary for the germination of seeds. These factors include:
i. Nutrients:
- Seeds contain stored nutrients in the form of carbohydrates, proteins, and fats, which provide the necessary energy for the growth of the embryo during germination.
- These nutrients are broken down into simpler forms by enzymes, which can be utilized by the growing seedling.
ii. Warmth:
- Seeds require a suitable temperature range for germination to occur.
- Different seeds have different temperature requirements, but most seeds germinate well within a temperature range of 20-30 degrees Celsius.
- Warmth is necessary for activating the enzymes involved in the breakdown of stored nutrients and for promoting metabolic activities in the embryo.
iii. Air:
- Oxygen is essential for the process of respiration, which provides energy for the germinating seed.
- The embryo needs oxygen to carry out cellular respiration and produce ATP (adenosine triphosphate), which is required for various metabolic processes during germination.
iv. Water:
- Water is crucial for seed germination as it softens the seed coat and triggers metabolic activities.
- It provides the necessary medium for enzyme activity and helps in the breakdown of stored nutrients.
- Water also helps in the transport of nutrients from the surrounding soil to the growing seedling.
Therefore, all of the given factors (i.e., nutrients, warmth, air, and water) are essential for the germination of seeds. The correct answer is option D: All of these.

Dispersal of Seeds: Importance for Plants

(i) To avoid over-crowding, which results in weak plants:

- When seeds are dispersed, they are scattered away from the parent plant, reducing competition for resources such as sunlight, water, and nutrients.
- This helps prevent overcrowding, which can result in weaker plants that struggle to survive and reproduce.

(ii) To prevent seeds being dependent on parent plant:

- If seeds remain near the parent plant, they may not have access to sufficient resources or suitable conditions for growth and survival.
- Dispersal allows seeds to find new locations with better opportunities for growth, reducing their dependence on the parent plant.

(iii) To ensure the plants of a particular type spread to new areas:

- Dispersal enables plants to colonize new habitats and expand their range.
- This is important for maintaining genetic diversity within a species and for ensuring the survival and adaptation of the species to different environments.

Therefore, dispersal of seeds is important for plants because it helps them avoid over-crowding, reduces their dependence on the parent plant, and allows them to spread to new areas.

Answer: C. (i) and (iii) only

The correct match of seed and its means of dispersal is:
C. Cotton seeds - Air
- Cotton seeds are lightweight and have structures called trichomes, which are hair-like projections that help them catch the wind and get dispersed.
- The air currents carry the cotton seeds to new locations, allowing them to spread over large distances.
- This method of dispersal is known as anemochory, or wind dispersal.
- Cotton seeds are not dispersed by water (Pomegranate - water) or animals (Coconut - Animal, Pea - Animal).
Therefore, the correct pair is C: Cotton seeds - Air.

Explanation:
Introduction:
When a seed germinates and grows into a young plant, the size of the seed leaves gradually become smaller. This phenomenon occurs due to certain reasons.
Reasons for the gradual decrease in size of seed leaves:
1. The food that seed leaves have, have been used by the growing plant:
- Seed leaves, also known as cotyledons, contain stored nutrients such as carbohydrates, proteins, and fats.
- These nutrients provide the initial nourishment for the growing plant until it develops true leaves and starts photosynthesizing.
- As the young plant grows, it utilizes the stored food from the cotyledons, causing them to shrink in size.
- This is an essential process for the plant's survival and growth.
2. The seed leaves are absorbed back into the seed coat:
- In some plants, the cotyledons may be reabsorbed by the seed coat as the young plant develops.
- This reabsorption allows the plant to recycle the nutrients stored in the seed leaves and utilize them for further growth.
- As a result, the seed leaves may appear to shrink or disappear.
3. None of these:
- This option is incorrect as it does not provide a valid explanation for the gradual decrease in size of seed leaves.
Conclusion:
The correct answer is option C: "The food that seed leaves have, have been used by the growing plant." As the young plant grows, it utilizes the stored nutrients from the cotyledons, leading to a gradual decrease in the size of the seed leaves.

To classify the given crops in Rabi and Kharif, we need to understand the cropping seasons of these crops. Rabi crops are sown in winter (November-December) and harvested in spring (April-May), while Kharif crops are sown at the beginning of the monsoon season (June-July) and harvested in autumn (September-October). Based on this information, we can classify the given crops as follows:
Classification of crops:
- Wheat: Rabi
- Maize: Kharif
- Bajra: Kharif
- Gram: Rabi
Therefore, the correct classification of the given crops in Rabi and Kharif is:
Answer: A
- (i) Wheat - Rabi
- (ii) Maize - Kharif
- (iii) Bajra - Kharif
- (iv) Gram - Rabi

Agents of Dispersal
There are various agents of dispersal that help plants and organisms to spread their seeds or offspring to new locations. The options provided are air, water, and animals. Let's discuss each agent in detail:
Air:
- Wind is an effective agent of dispersal for lightweight seeds or fruits.
- Seeds or fruits can have adaptations such as wings, feathers, or hairs that allow them to be carried by the wind over long distances.
Water:
- Water is an important agent of dispersal for aquatic plants and organisms.
- Seeds or fruits can be buoyant and float on water, allowing them to be carried away to new locations.
Animal:
- Animals play a crucial role in dispersing seeds and propagules.
- Seeds can be dispersed by animals through ingestion and subsequent excretion.
- Some fruits and seeds have adaptations to attract animals, such as bright colors, sweet tastes, or hooks that attach to fur or feathers.
- Animals like birds, mammals, and insects can carry seeds or fruits over long distances.
All of these:
- All the options provided (air, water, and animals) are agents of dispersal.
- Different plants and organisms have different adaptations to utilize these agents for dispersal.
In conclusion, all of the options (air, water, and animals) are agents of dispersal for plants and organisms. They play a crucial role in spreading seeds or offspring to new locations, allowing for the colonization of new areas and the survival of species.

Reproduction through Leaves in Plants

Plants can reproduce through various methods, including the use of their leaves. Among the options provided, the plant that reproduces through its leaves is Bryophyllum (Option B).

Explanation:

• Bryophyllum: Bryophyllum is a succulent plant that belongs to the Crassulaceae family. It is commonly known as the "Mother of Thousands" or "Mother of Millions." This plant has a unique ability to reproduce through its leaves.


• Leaf Reproduction in Bryophyllum: Bryophyllum leaves have small plantlets or buds along their edges. These plantlets can develop and grow into new plants when they fall onto suitable soil or when the leaf touches the ground.


• Advantages of Leaf Reproduction: Leaf reproduction allows Bryophyllum to propagate rapidly and colonize new areas. It provides an efficient means of reproduction, especially in environments with limited resources.


• Other Options: While sugarcane (Option A), banana (Option C), and potato (Option D) are plants with different modes of reproduction, they do not reproduce through their leaves.

Therefore, the correct answer is Bryophyllum (Option B).

Note: It is important to understand that not all plants reproduce through their leaves. Different plants employ various reproductive strategies such as seed production, spore formation, or vegetative propagation through stems or roots.

Answer:
The correct match of the function of each part of the germinating seed is:
- Radicle: The radicle is the future root of the plant. Its main function is to anchor the plant in the soil and absorb water and nutrients from the soil.
- Plumule: The plumule is the future stem of the plant. Its main function is to develop into the shoot system of the plant, including the stem, leaves, and flowers.
- Cotyledon: The cotyledon is responsible for storing food for the developing seedling. It provides nutrients and energy for the initial growth of the plant until it can produce its own food through photosynthesis.
Therefore, the correct match of their function is:
Radicle: Future root
Plumule: Future stem
Cotyledon: Stored food
The correct answer is B: Radicle - future root, Plumule - future stem, Cotyledon - stored food.

Mode of Dispersal for Coconut Seedling
Air:
- Coconut seedlings are not typically dispersed by air as their large size and weight make it difficult for them to be carried by wind.
Animal:
- Animals, such as birds and mammals, may consume coconuts and their seedlings and then excrete them in a different location, allowing for dispersal.
- However, in the case of a coconut seedling growing on a sea shore, the chances of animal dispersal may be relatively low as there may be limited animal activity in that specific environment.
Explosion:
- The explosion is not a mode of dispersal for coconut seedlings.
Water:
- Water is the most likely mode of dispersal for a coconut seedling growing on a sea shore.
- The strong ocean currents and tides can carry the seedling away from its original location and deposit it onto another shore.
- The buoyant nature of coconut seedlings allows them to float on water and be transported over long distances.
In this case, the most suitable mode of dispersal for the coconut seedling growing on a sea shore would be water.

Plants that grow without seed:
- Banana: Bananas are propagated through a process called vegetative reproduction, where new plants grow from the shoots or suckers of the parent plant. This means that bananas do not require seeds to grow.

- Wheat, Rice, and Maize: These plants are monocots and reproduce through seeds. They do not grow without seeds, so options A, B, and D are incorrect.
In conclusion, the correct answer is C: Banana, as it is a plant that grows without the need for seeds.

Given statements:

• (i) Roots absorb water from soil


• (ii) Roots hold plant firmly in the soil


• (iii) Roots absorb minerals from the soil


• (iv) Roots make food for the plant

Incorrect statement:

• (iv) Roots make food for the plant

Explanation:

Roots have several functions, but they do not make food for the plant. The correct statement about roots is:

• (i) Roots absorb water from soil


• (ii) Roots hold plant firmly in the soil


• (iii) Roots absorb minerals from the soil

Therefore, option B: (i) (ii) (iii) only is the correct answer.

Explanation:
The correct statement regarding the different parts of a plant is that they can grow into a new plant. Here is a detailed explanation:
Seed:
- Seeds are the reproductive structures of plants.
- They contain an embryo, which can grow into a new plant when provided with the right conditions.
Stem:
- Stems are the main structural parts of a plant.
- They provide support and transport water, nutrients, and sugars between the roots and leaves.
- Stems can also grow roots and leaves at nodes, allowing them to grow into new plants.
Leaf:
- Leaves are the main sites of photosynthesis in plants.
- They capture sunlight and convert it into energy for the plant.
- In some plants, leaves can produce adventitious buds, which can grow into new plants.
Spore:
- Spores are reproductive structures that are produced by certain plants, such as ferns and mosses.
- They are capable of developing into new plants under suitable conditions.
Conclusion:
In summary, all the different parts of a plant, including seeds, stems, leaves, and spores, have the ability to grow into new plants. This is an essential characteristic of plants that allows them to reproduce and continue their life cycle.

• Layering: is the process where part of the aerial stem develops roots while still being attached to the parent plant. After developing roots, it is detached from the parent plant and grows as an independent plant.
• Grafting: is a technique that joins two plants into one such that a union is formed with the desirable characters. In this method one plant is selected for its roots, and is called the stock. The other plant is selected for its stems, leaves, flowers, or fruits and is called the scion. It is the fastest way of growing desirable varieties of fruiting trees & flowering shrubs on a large scale.
• Cutting: cutting refers to a process used during vegetative propagation whereby a piece of the plant’s stem is rooted in a growth medium such as moist soil. The stem cutting will thrive and grow as a new plant, which is entirely independent of the mother plant provided that the conditions are suitable. Plants like sugarcane, eggplant, black pepper, etc are propagated through stem cutting.

The main advantage of vegetative propagation is that it is quicker than seed reproduction. This method allows plants to grow and reproduce faster, often leading to earlier blooming and fruiting compared to plants grown from seeds. This makes vegetative propagation a valuable technique for gardeners and farmers.

Rice and jute grow well in clayey soil that has good water retention properties, whereas other crops like wheat, jowar, and cotton prefer different soil types.