The Leaf

Identify the plant which has compound leaves:

1. Banana
2. Banyan
3. Mango
4. Rose

Answer

Rose

Reason — A compound leaf is a leaf in which the lamina is divided into several smaller leaflets attached to a common stalk (rachis). Rose leaf is a compound leaf with incisions upto midrib.
Banana, Banyan, Mango have simple leaves.

Which one of the following is not an insectivorous plant:

1. Pitcher plant
2. Venus flytrap
3. Bladderwort
4. Cactus

Answer

Cactus

Reason — Cactus has modified leaves into spines due to which it does not trap insects. Insectivorous plants trap and digest insects to obtain nutrients, especially nitrogen, from nutrient-poor soils.
Pitcher plant is insectivorous; traps insects in a pitcher-shaped leaf. Venus flytrap is insectivorous; snaps shut when insects touch its trigger hairs. Bladderwort is insectivorous; uses tiny bladder-like traps to catch small aquatic organisms.

This leaf shows parallel venation

1. Banana
2. Mango
3. Banyan
4. Guava

Answer

Banana

Reason — In Banana leaves, veins runs parallel to each other. Parallel venation means the veins in the leaf run parallel to each other from the base to the tip. It is commonly found in monocot plants.
Mango, Banyan, Guava have reticulate venation.

The point on the stem from where the leaf arises is :

1. Petiole
2. Lamina
3. Node
4. Trunk

Answer

Node

Reason — The points on the stem from where the leaves and branches originate are called nodes.
Petiole is the stalk that connects the leaf to the stem. Lamina is the flat, green part of the leaf (leaf blade). Trunk is the main woody stem of a tree.

Which one of the following is essential for photosynthesis :

1. Carbon dioxide
2. Nitrogen
3. Oxygen
4. Soil

Answer

Carbon Dioxide

Reason — Carbon dioxide is needed for photosynthesis. Photosynthesis is the process by which green plants make their food using carbon dioxide, water, sunlight, and chlorophyll.
Plants need nitrogen for growth and making proteins, but it is not a raw material for photosynthesis. Oxygen is actually produced during photosynthesis, not required as a raw material. Soil provides water and minerals, but photosynthesis can occur without soil if the plant receives water and nutrients by other means (e.g., hydroponics).

Which part of the leaf attaches the leaf base to the stem ?

1. Leaf blade
2. Lamina
3. Leaf apex
4. Petiole

Answer

Petiole

Reason — The basal part of a leaf is a stalk called petiole, which is attached to the stem at the node. It acts like a "handle" that supports the leaf and connects it to the plant's vascular system (xylem and phloem), through which water and food are transported.
The leaf blade (or lamina) is the broad, flat green part of the leaf. Lamina is another name for the leaf blade. The apex is the tip of the leaf.

The bud found at the tip of the shoot is termed as :

1. Axillary bud
2. Apical bud
3. Adventitious bud
4. Floral bud

Answer

Apical bud

Reason — Apical means at the apex or tip. The tip of the shoot has buds called apical buds or terminal buds. They are responsible for the vertical growth of the stem.
Axillary bud is found in axil. Adventitious bud develops from unusual places such as roots, leaves, or internodes. Floral bud develops into a flower.It may occur at different positions and is not defined by being at the shoot tip.

The divided, smaller parts of the lamina of a compound leaf are called as :

1. Leaf spines
2. Stipules
3. Leaflets
4. Tendrils

Answer

Leaflets

Reason — In a compound leaf, the leaf blade or lamina is divided into smaller units called leaflets. In a compound leaf, the lamina (leaf blade) is divided into several smaller units. These smaller divisions are called leaflets.
Spines are modified leaves or parts of leaves that protect the plant. Stipules are small leaf-like structures found at the base of the petiole in some plants. Tendrils are thin, coiling structures used for climbing.

Which of the following is not an example of a compound leaf ?

1. Rose
2. Silk cotton
3. Neem
4. Prickly poppy

Answer

Prickly poppy

Reason — Prickly poppy has a simple leaf because its lamina is undivided and forms a single leaf blade, although it may have deep lobes. Rose, silk cotton, and neem have compound leaves in which the lamina is divided into separate leaflets attached to a common stalk. Therefore, prickly poppy is not an example of a compound leaf.

The plant which has whorled phyllotaxy is :

1. Nerium
2. Jasmine
3. Mint
4. Peepal

Answer

Nerium

Reason — Phyllotaxy is the arrangement of leaves on a stem. Nerium has whorled phyllotaxy as it has more than two leaves attached at each node, arranged in a whorl.
Jasmine and Mint have opposite phyllotaxy. Peepal has alternate phyllotaxy.

Assertion: Root hairs are fine hair-like projections found on plant roots and they help in absorbing water and minerals from the soil.

Reason: Fibrous root system consists of numerous fine branches arising from the base of the stem, providing a large surface area for the absorption of water and minerals. So root hairs are not found.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is true but R is false.

Reason — A is true as root hairs are very small, thin extensions of the outer cells of roots and help to absorb water and minerals from the soil.
R is false because even in fibrous roots, root hairs are present. In fact, root hairs are found in almost all young roots, whether the plant has tap root or fibrous root.

Therefore, A is true but R is false is the correct option.

Assertion: The leaves which are directly attached to the stem without a petiole are called 'sessile' leaves.

Reason: Sessile leaves do not participate in the process of photosynthesis as they lack chlorophyll and petiole.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is true but R is false.

Reason — A is true as leaves that are attached directly to the stem without a stalk (petiole) are called sessile leaves.
R is false as sessile leaves do participate in photosynthesis because they generally contain chlorophyll just like other green leaves.

Therefore, A is true but R is false is the correct option.

Assertion: Terminal and axillary buds help plants to grow in length.

Reason: Apical buds are present at the tips of stems and are responsible for the vertical growth of the plant.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true but R is not the correct explanation of A.

Reason — A is true as terminal buds (also called apical buds) are present at the tip of the stem and help in increase in length. Axillary buds are present in the axil of leaves and can develop into branches, which also continue growth.
R is true as apical buds are located at the tips of stems and are responsible for the vertical growth (increase in length) of the plant.

Therefore, Both A and R are true but R is not the correct explanation of A is the correct option.

Assertion: Insectivorous plants are dependent on insects, which they trap and digest for their nutrition.

Reason: Insectivorous plants grow in soil that is poor in nitrogen and need to obtain it from other sources.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true and R is the correct explanation of A.

Reason — A is true as insectivorous plants trap and digest insects to obtain nutrients.
R is true as these plants usually grow in nitrogen-poor soils. Since nitrogen is essential for growth and is lacking in the soil, they obtain it by digesting insects.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Match the terms given in column A with those of column B.

Answer

Name the following:
(i) The part of the plant which grows under the ground.
(ii) The part of the plant which grows above the soil.
(iii) The wide flat portion of the leaf.

Answer

(i) Root
(ii) Shoot
(iii) Lamina / Leaf Blade

What are the four functions of roots?

Answer

The main four functions of the roots are as follows:

1. It helps to anchor the plant firmly to the soil.
2. It absorbs water and minerals from the soil for the growth of the entire plant.
3. It transports the absorbed water and minerals to the shoot system.
4. It binds the soil together so that it does not get washed away during rain or blown away by wind.

Mention the functions of the following:
(i) Spines
(ii) Tendril
(iii) Scale leaves

Answer

(i) Spines — Spines are modifications of leaves as a pointed structure that help to reduce the loss of water by transpiration.
(ii) Tendril — In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled structures called tendrils. They coil around the object they touch and support the plant to climb up.
(iii) Scale Leaves — Leaves modified as thick and fleshy or thin and dry are called Scale Leaves. Their function is to store food and protect the buds.

Define venation. What are the different types of venation found in the leaves?

Answer

Arrangement of veins in the lamina is called venation. It is mainly of two types

1. Reticulate Venation — In this type of venation, veins and veinlets are irregularly distributed in the lamina, forming a network. Example - Mango, Peepal, etc.
2. Parallel Venation — In this type of venation, veins run parallel to each other. Example - Banana, Maize, etc.

Describe the modifications of leaf in any one insectivorous plant?

Answer

In Venus Flytrap, the leaves have long pointed hairs. It is divided into two parts having midrib in between like a hinge. When an insect visits the leaf, it closes its two parts and traps the insect. The insect is then digested by digestive juices secreted by the plant.

Write the two main functions of leaves?

Answer

Two main functions of the leaves are:

1. Photosynthesis.
2. Transpiration.

Define:
(i) Photosynthesis
(ii) Transpiration

Answer

Photosynthesis — Photosynthesis is the process by which a plant leaf prepares own food from water and carbon dioxide in the presence of chlorophyll and sunlight.

Transpiration — Transpiration is the process by which water is lost in the form of water vapour by evaporation from the surface of leaves and other aerial parts of a plant.

Name the following :
(i) Two organ systems of the plant
(ii) Two main types of the root system
(iii) Five parts of the shoot system
(iv) Three types of phyllotaxy
(v) Two types of venation

Answer

(i) The Root system and the Shoot system.
(ii) The Tap root system and the Fibrous root system.
(iii) Stem, Buds, Leaves, Flowers, and Fruits.
(iv) Alternate, Opposite, and Whorled.
(v) Reticulate venation and Parallel venation.

Define the terms given below :
(i) Phyllotaxy
(ii) Leaf
(iii) Autotrophic nutrition
(iv) Leaf tendril
(v) Vegetative propagation

Answer

(i) Phyllotaxy — The arrangement of leaves on a stem or its branch is called phyllotaxy. Phyllotaxy are of three types- Alternate, Opposite, and Whorled.

(ii) Leaf — Leaves are the flat and green parts of the shoot that grow laterally from the nodes of the stem. They perform important functions like photosynthesis and transpiration.

(iii) Autotrophic nutrition — All green plants have the capability to prepare their own food, and are therefore called autotrophs, and this method of nutrition is called autotrophic nutrition.

(iv) Leaf tendril — In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled structures called tendrils. They are sensitive to touch. As they touch any object, they coil around it and support the plant to climb up.

(v) Vegetative propagation — Sometimes new plants may also be produced from other (vegetative) parts of the plant such as the roots, stems and leaves instead of seeds. This type of reproduction is called vegetative propagation.

Give a term for the following.
(i) The fine hair-like projections from the ends of the root branches.
(ii) The part of the stem between two successive nodes.
(iii) The kind of leaves without a petiole.
(iv) The technical term of a leaf stalk.
(v) The pigment which traps solar energy for the process of photosynthesis.

Answer

(i) Root hairs
(ii) Internode
(iii) Sessile leaves
(iv) Petiole
(v) Chlorophyll

Giving examples, differentiate between Tap root and Fibrous root

Answer

Differences between Tap Root and Fibrous Root:

Giving examples, differentiate between Simple leaf and Compound Leaf

Answer

Differences between Simple leaf and Compound leaf:

Giving examples, differentiate between Parallel venation and Reticulate Venation

Answer

Differences between Parallel venation and Reticulate venation:

What is the modification seen in Bryophyllum? Explain.

Answer

Modification seen in bryophyllum are:

1. Bryophyllum is a plant whose leaves produce adventitious buds in their margin.
2. The adventitious buds grow into new plants when they fall off from the parent plant.

What purpose is served by the spines borne on the leaves of cactus ?

Answer

Cactus being a desert plant needs to conserve water. So, its leaves are modified into pointed structures called as spines to reduce the loss of water by transpiration.

Explain why leaf survival is so important to the plant ?

Answer

Leaf survival is so important to plants because:

1. The leaf makes food for the plants by photosynthesis.
2. The leaf gets rid of excess water from plants through transpiration.
3. The leaf carries out the process of respiration in plants.
4. The leaf helps in providing cooling effect to the plant through transpiration.

Give an example of the following and draw generalized diagrams for the same:

(i) Simple leaf and compound leaf.

(ii) Parallel venation and reticulate venation.

Answer

(i) Banyan is an example of simple leaf while Rose is an example of compound leaf.

Below diagram shows simple and compound leaves:

(ii) Banana is an example of parallel venation while Peepal is an example of reticulate venation.

Below diagram shows reticulate and parallel venation:

Enlist some of the advantages of transpiration to green plants?

Answer

The two main advantages of transpiration to green plants are as follow:

1. Cooling effect — The water keeps on evaporating from the leaf surface during transpiration. The heat required for evaporation of water is obtained from the plant itself and thus, the plant cools itself when it is in hot environment.
2. Transpirational pull — The roots of the plant pull up more water from the soil to make up for the water loss during transpiration. As a result, important mineral salts, which is essential for the plant growth, are also brought along with the water from the soil.

Why do some plants have to trap insects?

Answer

Insectivorous plants trap insects because they grow in soil which is usually thin and is also low in nutrients, so insectivorous plants eat insects to fulfil their nitrogen demand.

Explain some of the modifications of leaves found in plants?

Answer

Modifications of leaves are as follows:

1. Leaf tendril — In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled structures called tendrils. They coil around the object they touch and support the plant to climb up. E.g., Sweet Pea.
2. Leaf spines — In some plants, leaves are modified into pointed structures called spines. Spines help to reduce water loss by transpiration. E.g., Cactus.
3. Scale leaves — In some plants like Onion and Ginger, thick and fleshy or thin and dry scale leaves are present, respectively. Their function is to store food and protect the buds.

What is a tendril? Explain its use to the plants?

Answer

In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled structures called tendrils. They are sensitive to touch. As they touch any object, they coil around it and support the plant to climb up. E.g., Sweet pea.

Distinguish between the following pairs on the basis of the words indicated in the brackets []:

Spines and scale leaves [significance]

Answer

Difference between Spines and scale leaves on the basis of significance:

Distinguish between the following pairs on the basis of the words indicated in the brackets []:

Vegetative and reproductive parts [parts of the plant].

Answer

Difference between Vegetative and reproductive parts on the basis of parts of the plant:

Distinguish between the following pairs on the basis of the words indicated in the brackets []:

Alternate and opposite phyllotaxy [number of leaves at each node].

Answer

Difference between Alternate and opposite phyllotaxy on the basis of number of leaves at each node :

Distinguish between the following pairs on the basis of the words indicated in the brackets []:

Pine and peepal [shape of the leaf].

Answer

Difference between Pine and peepal on the basis of shape of the leaf:

Distinguish between the following pairs on the basis of the words indicated in the brackets []:

Reticulate and parallel venation [2 examples of each].

Answer

Difference between Reticulate and parallel venation on the basis of 2 examples:

Draw a neat diagram of a simple, petiolate leaf showing reticulate venation and label its seven important parts. Answer the following questions:

(i) Write one important function of axillary buds.

(ii) What are the two main function of leaves ?

(iii) Name two plants which have leaves with serrated margins.

(iv) Why do some plants have tendrils (modified leaflets) ?

(v) Name a plant in which the leaves are modified into spines.

Answer

Diagram:

(i) One important function of axillary buds is to develop into lateral shoots or branches, contributing to the plant's overall growth and structure.

(ii) The two main functions of leaves are:

1. Photosynthesis — The process by which a plant leaf prepares or synthesises food from water and carbon dioxide in the presence of chlorophyll and sunlight is called photosynthesis.
2. Transpiration — This is the process by which water is lost in the form of water vapour by evaporation from the surface of leaves and other aerial parts of a plant. It has a cooling effect and develops a suction force to make roots absorb more water with mineral ions.

(iii) China rose and Rose.

(iv) In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled structures called tendrils. They are sensitive to touch. As they touch any object, they coil around it and support the plant to climb up.

(v) Cactus

The figures given below show three insectivorous plants. Study the same and answer the following questions :

A

B

C

(i) Name the plants shown as A, B and C.

(ii) For which specific nutritional element do these plants trap insects ?

(iii) In which Indian state is plant A found abundantly ?

(iv) Which part of the leaf is modified into a pitcher in plant A ?

(v) Write one specific feature of the soil in which these plants usually grow.

Answer

(i)
Plant A — Pitcher Plant
Plant B — Bladderwort
Plant C — Venus Flytrap

(ii) These plants trap insects to meet their nitrogen demands.

(iii) Pitcher plant is found abundantly in Meghalaya.

(iv) In a Pitcher plant, the lamina is modified into a pitcher.

(v) The soil where these plants usually grow is deficient in nitrates.

The figures given alongside represent the different kinds of leaf arrangements on the stem. Study the figures and answer the following :

(i) Give a technical term for the arrangement of leaves on the stem.

(ii) Name the three kinds of arrangements shown in the figure A, B and C respectively.

(iii) Give one example of each kind of arrangement.

Answer

(i) Phyllotaxy.

(ii)
Figure A shows Alternate phyllotaxy.
Figure B shows Opposite phyllotaxy.
Figure C shows Whorled phyllotaxy.

(iii)
An example of Alternate phyllotaxy — Mint
An example of Opposite phyllotaxy — Jasmine
An example of Whorled phyllotaxy — Oleander (Nerium)

Draw neat diagrams of the following and give an example of each:

(i) A simple leaf.

(ii) A compound leaf with leaflets arising from different points along the main stalk.

(iii) A compound leaf with leaflets arising from one single point.

(iv) A simple leaf with reticulate venation.

(v) A simple leaf with parallel venation.

Answer

(i) Diagram of simple leaf:

Example — Banyan

(ii) A compound leaf with leaflets arising from different points along the main stalk:

Example — Rose

(iii) A compound leaf with leaflets arising from one single point:

Example — Silk Cotton

(iv) A simple leaf with reticulate venation:

Example — Peepal

(v) Diagram of a simple leaf with parallel venation

Example — Banana

Complete the crossword using the clues given below. Check your performance with the correct solutions given at the end of the chapter.

Clues across :

1. Plant that bears buds in leaves for propagation.
2. The flattened green part of leaf.
3. Underground plant part.
4. Structure that develops into flower.

Clues down :

5. The central big vein of a leaf.
6. A modification seen in cactus.

Answer

Across :
1. Bryophyllum
2. Lamina
3. Root
4. Bud

Down :
5. Midrib
6. Spine

John, Sandeep and Shubham, three class 6 students, were discussing their school garden project. They had collected leaves of Banyan, Rose and Sitk cotton for a herbarium. While comparing them, they noticed that the Banyan leaf looked quite different from the other two. Shubham, who was confident about leaf types, explained that Banyan has a simple leaf, whereas Rose and Silk cotton have compound leaves. Answer the following questions:

(i) What is the main difference between a simple leaf and a compound leaf?

(ii) How do the leaves of Rose and Silk cotton differ from each other even though both are compound leaves?

(iii) Segregate the following leaves as simple and compound: Neem, Peepal, Guava, Mango, Gulmohar and Banana.

(iv) What is the difference between 'petiole' and 'midrib' ?

Answer

(i) A simple leaf has a single, undivided leaf blade (lamina) whereas a compound leaf has the leaf blade divided into many smaller parts called leaflets.

(ii) Rose leaf is a compound leaf with incision upto midrib whereas Silk cotton leaf is a compound leaf with with incision upto petiole.

(iii) Peepal, Guava, Mango, Banana are simple leaves.
Neem and Gulmohar are compound leaves.

(iv) The basal part of a leaf is a stalk called petiole. Petiole continues into a lamina as midrib.