Q: Leaves are modified into spines in

Opuntia is a xerophytic plant. It grows in the dessert where water is very limited. In it, the leaves of areoles are modified into sharp and pointed spines. Their main function is of protection. The photosynthesis is done by leaf-like stem. Thus, the correct answer is 'Opuntia.'

Q: The standard petal of a papilionaceous corolla is also called as

\$\textbf{Correct option: C}\$\$\textbf{Solution:}\$Option C:\$\bullet\$ Papilionaceous corolla is the petals whorl present in the flowers of \$Papilionaceae\$ (sub-family of \$Fabaceae\$ family).\$\bullet\$ Papilionaceous corolla is a very different kind of aestivation in which five petals are present.\$\bullet\$ The largest petal is known as Vexillum or Standard and it overlaps two lateral petals called wings which further overlap two small anterior leaves called the keel.\$\bullet\$ Thus, there is one vexillum, two wings, and two keels present in the papilionaceous corolla.Hence the correct option is option C.

Question 1

Discuss the different modifications of leaves.

Accepted Answer

Modification Definition Example 1) TendrilsThe leaves are modified into slender wiry and coiled structures called leaf tendrils and support climbers to climb Pisum Sativum 2) SpinesThe leaves modified into a pointed structure and usually protect them from herbivores. Opuntia 3) PhyllodeIt is a green extended structure formed by the modification of petiole or rachis of leaf that carries out photosynthesis. Acacia 4) Storage leavesLeaves become fleshy due to storage of water and food material. Aloe 5) CotyledonsThe mature embryo shows either one or two cotyledons. Angiosperms and gymnosperms 6) Leaf bladdersSome of the leaves of aquatic plants modified into leaf bladders to trap small insects. Utricularia 7) Leaf PitcherLamina of the whole leaf is modified into a lid known as a pitcher which traps insects to fulfil the need of nitrogen. Nepenthes

Question 2

Which of following is incorrect for trichomes?

Accepted Answer

Trichomes are the epidermal outgrowths on the vegetative and reproductive parts of the plant. These are hair-like structures which may be unicellular or multicellular.Some trichomes are secretory in nature and are known as glandular trichomes. For example, tannins, resins, gum etc., are some products secreted by trichomes.Trichomes help in the absorption of water and minerals.It is not a leaf modification, hence, option A is incorrect. So, the correct answer is 'Trichomes are leaf modifications which minimize water loss'.

Question 3

Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams.

Accepted Answer

Dorsiventral leaves are present in dicot plant and have three main parts.Epidermis -The outermost covering of the leaf on the upper side called adaxial epidermis and on the lower side, it is known as the abaxial epidermis. A waxy thick layer cuticle is present and distinct. Stomata are higher on the abaxial epidermis and either lower or absent on adaxial epidermis.Mesophyll-The mesophyll is present below the epidermis and is composed of parenchyma which has chlorophyll and divided into palisade parenchyma present at the upper side while spongy parenchyma present at the lower side and contains a large number of intercellular space.Vascular bundles-These are surrounded by thick bundle sheath cells and can be seen in veins and midrib. These are distinct in size due to reticulate venation.

Question 4

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils. (a) Cucumber (b) Peas (c) Pumpkins (d) Grapevine (e) Watermelons

Accepted Answer

Identifying plants with stem or leaf tendrils in the given list of plants Plant  Type of tendril Cucumber stem tendril Peas leaf tendril Pumpkin  stem tendril Grapevine stem tendril Water melon stem tendril

Question 5

How is a pinnately compound leaf different from a palmately compound leaf?

Accepted Answer

Pinnately compound leaf: The leaflets are attached to the common axis, called as rachis.Examples include neem and Cassia fistula (also called as golden shower plant).Palmately compound leaf: The leaflets are attached at a common point on the leaf stalk.Examples include silk cotton (Bombax) and Cannabis.

Question 6

Leaves are modified into spines in

Accepted Answer

&#10;&#10;&#10;&#9;&#10;&#9;&#10;&#9;&#10;&#9;&#10;&#10;&#10;Opuntia is a&#10;xerophytic plant. It grows in the dessert where water is very&#10;limited. In it, the leaves of areoles are modified into sharp and&#10;pointed spines. Their main function is of protection. The&#10;photosynthesis is done by leaf-like stem. Thus, the correct&#10;answer is 'Opuntia.'&#10;&#10;&#10;

Question 7

In $Opuntia$, the stem is modified into a flattened green structure to perform the function of leaves (i.e. photosynthesis). State some other examples for modifications of plant parts for the purpose of photosynthesis.

Accepted Answer

The stem of Euphorbia is a fleshy and cylindrical structure. The stem in this plant carries out photosynthesis because of the presence of chlorophyll. The petiole in Acacia is modified to a lamina-like structure for photosynthesis, as the leaves are highly reduced.

Question 8

What do you mean by leaf venation? Explain various types of leaf venation with example.

Accepted Answer

Venation is the arrangement of veins in lamina of the leaf. Two types of venation are reticulate venation and parallel venation.(i) Reticulate Venation: When the veins are irregularly distributed to form a channel, it is known as reticulate Venation. Taproots are found in plants which have reticulate venation in their leaves. It can be seen tulsi, coriander (dhania), china rose, hibiscus, mango, etc. (ii) Parallel Venation: When the veins are parallel and do not form a network, it is known as parallel Venation.Fibrous roots are found in plants which have parallel venation in their leaves. It can be seen in wheat, maize, grass, banana, bamboo, etc.

Question 9

The standard petal of a papilionaceous corolla is also called as

Accepted Answer

$\textbf{Correct option: C}$$\textbf{Solution:}$Option C:$\bullet$ Papilionaceous corolla is the petals whorl present in the flowers of $Papilionaceae$ (sub-family of $Fabaceae$ family).$\bullet$ Papilionaceous corolla is a very different kind of aestivation in which five petals are present.$\bullet$ The largest petal is known as Vexillum or Standard and it overlaps two lateral petals called wings which further overlap two small anterior leaves called the keel.$\bullet$ Thus, there is one vexillum, two wings, and two keels present in the papilionaceous corolla.Hence the correct option is option C.

Question 10

Study the following statements and select the correct option.
(A) Buds are present in the axil of leaflets of the compound
leaf.
(B) Pulvinus leaf-base is present in some leguminous plants.
(C) In Alstonia, the petioles expand, become green and
synthesize food.
(D) Opposite phyllotaxy is seen in guava.

Accepted Answer

A swelling at the base of a petiole is known as pulvinus. It is a joint-like thickening at the base of a leaflet. It helps in growth-independent movement. For example, pea and gram. In an opposite leaf arrangement, two leaves arise from the stem at the same level and at the same node but in opposite sides of the stem. For example, guava. A bud is present in the axil of petiole in both simple and compound leaves but not in the axil of leaflets of the compound leaf. In Australian acacia, the leaves are small and are short-lived. The petioles are expanded and green and synthesize food.Thus, the correct answer is option A.

Revise with Concepts

Advanced Knowledge of Types of Leaves

Advanced Knowledge of Modification of Leaves

Quick Summary With Stories

Types of leaf

Modification of Leaf

Discuss the different modifications of leaves.

Which of following is incorrect for trichomes?

Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams.

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils.
(a) Cucumber
(b) Peas
(c) Pumpkins
(d) Grapevine
(e) Watermelons

How is a pinnately compound leaf different from a palmately compound leaf?

Leaves are modified into spines in

In $O p u n t i a$ , the stem is modified into a flattened green structure to perform the function of leaves (i.e. photosynthesis). State some other examples for modifications of plant parts for the purpose of photosynthesis.

What do you mean by leaf venation? Explain various types of leaf venation with example.

The standard petal of a papilionaceous corolla is also called as

Revise with Concepts

Advanced Knowledge of Types of Leaves

Advanced Knowledge of Modification of Leaves

Quick Summary With Stories

Types of leaf

Modification of Leaf

Discuss the different modifications of leaves.

Which of following is incorrect for trichomes?

Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams.

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils. (a) Cucumber (b) Peas (c) Pumpkins (d) Grapevine (e) Watermelons

How is a pinnately compound leaf different from a palmately compound leaf?

Leaves are modified into spines in

In Opuntia, the stem is modified into a flattened green structure to perform the function of leaves (i.e. photosynthesis). State some other examples for modifications of plant parts for the purpose of photosynthesis.

What do you mean by leaf venation? Explain various types of leaf venation with example.

The standard petal of a papilionaceous corolla is also called as

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils.
(a) Cucumber
(b) Peas
(c) Pumpkins
(d) Grapevine
(e) Watermelons

In $O p u n t i a$ , the stem is modified into a flattened green structure to perform the function of leaves (i.e. photosynthesis). State some other examples for modifications of plant parts for the purpose of photosynthesis.