Anatomy of Flowering Plants - Class 11 Biology - Chapter 6 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Anatomy of Flowering Plants | NCERT | Biology | Class 11
If a stem is girdled:
A) Root dies first.
B) Stem dies first.
C) Both die together.
D) None of the above would die.
The correct answer is A) Root dies first.
Girdling involves the removal of a strip of bark and the vital underlying phloem layer from around the entire circumference of a plant's stem. This action disrupts the downward transport of food (sugars) synthesized in the leaves via the phloem to the roots. As a result, since the roots no longer receive the necessary nutrients to sustain themselves, they begin to die first due to lack of nourishment.
The transpiration process takes place mostly in the ____________ of the plant.
A) roots
B) leaves
C) stems
D) flowers
The correct answer is B) leaves.
Transpiration is primarily the process where plants lose excess water in the form of vapor, and this mostly occurs through the leaves. Historical experiments by Stephan Hales concluded that leaves function as the main organs responsible for transpiration. Additionally, it is through the leaves that plants efficiently exchange gases with their surrounding environment.
A thick vein present in the middle of the leaf is called
A) lamina
B) petiole
C) sepal
D) midrib
The correct answer is D) midrib.
The midrib is the thickest vein located at the center of the leaf. It divides the lamina, or leaf blade, into two sections, with smaller veins branching out from the midrib.
Ovules are present within the:
A) Petals
B) Anther
C) Ovary
D) Stigma
The correct answer is C) Ovary.
The ovary of a flower is responsible for containing small bead-like structures known as ovules. These ovules are significant as they function as the female sex cells within the plant reproductive system.
Leaves are absent in a cactus plant - state true or false and why.
False - Cactus plants do have leaves, but they are highly modified into spines.
Most cacti do not have typical leaves as seen in other plants. Instead, the leaves are modified into spines, which help in various ways:
Defense against herbivores
Reducing water loss by minimizing airflow near the cactus surface and providing shade
Photosynthesis is carried out by the enlarged stems of the cactus rather than leaves.
Flowers like lotus grow on:
A water
B bushes
C trees
The correct answer is A) water.
Flowers such as the lotus and water lily thrive in aquatic environments, specifically growing on water. In contrast, other flowers like lilacs are commonly found on bushes, and flowers like hibiscus grow on trees.
The fruit seed and pulp of this tree have medicinal value. They help in relieving symptoms of asthma, leprosy, ringworms, fever, and heart related diseases.
A. Amaltas
B. Palas
C. Axlewood
The correct answer is:
A. Amaltas
Amaltas is renowned for its medicinal value, particularly useful in relieving symptoms of asthma, leprosy, ringworms, fever, and heart-related diseases.
What is the axillary bud?
An axillary bud is an embryonic shoot located in the axil, which is the angle or junction between a plant's stem and a leaf or branch. Originating exogenously from the outer-cortex layer of the plant at this axillary junction, these buds have the potential to develop into new stems.
Occasionally, these buds may evolve to produce flowers instead of branches, in which case they are referred to as floral buds. This capability allows axillary buds to be a crucial component in the plant's growth, either by extending vegetative parts or by supporting reproduction.
Axillary buds might remain dormant for some periods or can sprout new shoots immediately post formation. These buds are vital for promoting plant growth and are sometimes called lateral buds due to their position on the sides of branches or stems.
What will happen to a plant if xylem is removed?
If the xylem, which is the water-conducting tissue in plants, is removed, several critical functions would be impaired. The xylem is responsible for transporting water from the roots to various parts of the plant, including the leaves and stems. Removal of the xylem would halt this upward movement of water, resulting in wilting of leaves due to dehydration. This interruption in water supply would not only inhibit the plant's ability to synthesize food through photosynthesis but also prevent it from performing other essential physiological activities. Ultimately, the absence of xylem would lead to the death of the plant.
I am a distinct whitish oval scar on the concave side of the seed. Who am I?
A) Hilum
B) Tegmen
C) Testa
D) Micropyle
The correct answer is A) Hilum.
The hilum is identified by a distinct whitish oval scar on the concave side of the seed. This feature marks the area where the ovule was originally attached to the ovary wall via the placenta, making it a crucial identifier in seed anatomy.
A plant that has a well-differentiated body, special tissues for transport of water and other substances, but does not have seeds or fruits is a:
A Bryophyte
B Angiosperm
C Gymnosperm
D Pteridophyte
The correct answer is D - Pteridophyte.
Pteridophytes represent a group of plants which are characterized by having a well-differentiated body and specialized tissues for the transport of water and substances throughout the plant. Crucially, they do not produce seeds or fruits. This distinguishes them from other vascular plants such as angiosperms and gymnosperms, which do produce seeds.
Find out the wrong statement about angiosperm roots.
A Xylem is centripetal in growth in the young roots.
B Cuticle is absent in young stages.
C The apex is protected by root cap.
D Vascular bundles are collateral.
The incorrect statement about angiosperm roots is:
Option D: Vascular bundles are collateral.
In angiosperm roots, vascular bundles are radial, not collateral. This means that xylem and phloem are positioned on different radii rather than being arranged adjacent to each other, which is characteristic of collateral vascular bundles found in plant stems.
Option A is correct because in young roots of angiosperms, the xylem growth is centripetal; the earlier formed xylem, or protoxylem, is located towards the peripheral side, while the later formed xylem, or metaxylem, is towards the centre.
Option B is also correct as the cuticle, which is commonly present in stems to prevent water loss, is absent in young roots.
Option C correctly states that the apex of the root is protected by a root cap which helps in protecting the root apex as it grows through the soil.
The distribution of stomata is equal on both surfaces of the leaf are seen in:
A. Monocot leaf
B. Dicot stem
C. Monocot stem
D. Dicot leaf
The correct answer is A. Monocot leaf
Monocot leaves usually exhibit a feature known as amphistomatic condition, where the distribution of stomata is equal on both upper and lower surfaces of the leaf. This characteristic is specific to monocot plants, making option A the correct choice.
New rose plants can be obtained from:
A) stem cuttings
B) leaf cuttings
C) root cuttings
D) flowers
The correct answer is: A) stem cuttings
Reproduction in plants can occur through various parts, and different species have preferences for specific propagative parts.
Specifically for roses, stem cuttings are taken from the plant. These cuttings are then planted in moist soil where they develop roots. Over time, these stem cuttings will grow into fully functional rose plants. This method is efficient and commonly used for rose propagation.
Gymnosperms are a good source of wood.
A. True
B. False
The correct option is A. True
Pine, fir, cedar, and spruce are some of the common gymnosperms extensively utilized as sources of wood in the lumbering industry.
Which of the following cannot be the vegetative parts of a plant?
A) Leaf
B) Flower
C) Stem
D) Root
The correct answer is B) Flower.
Vegetative parts of a plant include structures such as the leaf, stem, and root, which are involved in growth and nutrient processing. For example, in Bryophyllum, the leaf acts as a vegetative part, in Strawberry, it is the stem, and in Onion, it is the root.
In contrast, the flower is specifically the sexual reproductive part of a plant and is not considered a vegetative part. Hence, option B, Flower, cannot be classified as a vegetative part of a plant.
Growth rings are formed by the activity of:
A. Xylem
B. Phloem
C. Both Xylem and Phloem
D. Cambium
Growth rings in trees, also known as annual rings, are primarily formed due to the activity of the cambium layer. This is a crucial vascular tissue that plays a significant role in the development of these rings. Let's break down the function of the different options provided to understand why cambium is the correct answer:
Xylem and Phloem are both types of vascular tissues in plants. Xylem is responsible for the transport of water and nutrients from the roots to the leaves, while phloem facilitates the transport of food produced by photosynthesis from the leaves to other parts of the plant. However, neither of these tissues directly contributes to the formation of growth rings.
The Cambium is a layer of actively dividing cells between the xylem and phloem. It is responsible for secondary growth in plants, including the production of new xylem and phloem cells. As cambium adds new layers to the xylem, these accumulate to form the visible bands known as growth rings. Consequently, the cambium plays a key role in shaping these growth indicators, reflecting environmental conditions and the age of the tree.
Thus, the correct answer to the question "Growth rings are formed by the activity of:" is:
D. Cambium
Consider the following properties and identify the tissue:
a) It is a complex permanent tissue.
b) Tracheids and vessels are the components of this tissue.
c) Conductive tissue.
d) Also provides mechanical strength.
Sclerenchyma
Phloem
Collenchyma
Xylem
The correct option is D. Xylem.
Explanation:
Xylem is a complex permanent tissue: It comprises multiple types of cells and is crucial for the transportation of water and minerals within plants.
Components of Xylem: It includes tracheids, vessels, xylem parenchyma, and xylem fibers.
Tracheids and vessels play a significant role in the conduction of water.
Xylem fibers provide mechanical strength and support.
With these attributes, Xylem fits all the given properties, making it the correct answer.
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Ask Chatterbot AINCERT Solutions - Anatomy of Flowering Plants | NCERT | Biology | Class 11
Draw illustrations to bring out the anatomical difference between
(a) Monocot root and Dicot root
(b) Monocot stem and Dicot stem
(a) Monocot Root vs. Dicot Root
Monocot Root:
Epidermis: Outermost layer, similar to dicot root.
Cortex: Several layers with intercellular spaces.
Endodermis: Single layer of barrel-shaped cells with Casparian strips.
Pericycle: Present just inside the endodermis.
Xylem and Phloem: More than six (polyarch) xylem bundles.
Pith: Large and well-developed.
Secondary Growth: Absent.
Dicot Root:
Epidermis: Outermost layer, similar to monocot root.
Cortex: Several layers with intercellular spaces.
Endodermis: Single layer of barrel-shaped cells with Casparian strips.
Pericycle: Present inside the endodermis with the initiation of lateral roots and vascular cambium.
Xylem and Phloem: Typically two to four xylem and phloem patches.
Pith: Small or inconspicuous.
Secondary Growth: Present.
Illustrations:
*Figure (a) Dicot Root (b) Monocot Root*
(b) Monocot Stem vs. Dicot Stem
Monocot Stem:
Epidermis: Outermost layer, covered with cuticle, may bear stomata and trichomes.
Hypodermis: Sclerenchymatous.
Vascular Bundles: Scattered, surrounded by sclerenchymatous bundle sheath, and closed.
Ground Tissue: Parenchymatous, large and conspicuous.
Phloem Parenchyma: Absent.
Water-containing Cavities: Present within vascular bundles.
Dicot Stem:
Epidermis: Outermost protective layer covered with cuticle, may bear stomata and trichomes.
Cortex: Made up of hypodermis (collenchymatous cells), and inner cortex (parenchymatous cells).
Endodermis: Rich in starch grains (starch sheath).
Pericycle: Present in the form of semi-lunar patches of sclerenchyma.
Vascular Bundles: Arranged in a ring, conjoint, open, and with endarch protoxylem.
Medullary Rays: Parenchymatous cells between vascular bundles.
Pith: Parenchymatous cells with large intercellular spaces.
Illustrations:
*Figure (a) Dicot Stem (b) Monocot Stem*
Cut a transverse section of young stem of a plant from your school garden and observe it under the microscope. How would you ascertain whether it is a monocot stem or a dicot stem? Give reasons.
To ascertain whether the transverse section of a young stem under the microscope is a monocot or dicot stem, observe the following key features:
For Dicot Stem:
Vascular Bundles Arrangement: Vascular bundles are arranged in a ring.
Vascular Bundles Type: They are conjoint, open, and may present with endarch protoxylem.
Presence of Pith: Typically have a large, conspicuous central region called the pith.
Hypodermis: Hypodermis consists of collenchymatous cells.
Medullary Rays: Presence of medullary rays (layers of parenchyma between vascular bundles).
For Monocot Stem:
Vascular Bundles Arrangement: Vascular bundles are scattered throughout the ground tissue.
Vascular Bundles Type: They are conjoint, closed, and surrounded by a sclerenchymatous bundle sheath.
Pith and Cortex: Typically, the ground tissue is not differentiated into cortex and pith.
Hypodermis: Hypodermis is sclerenchymatous.
Absence of Medullary Rays: Medullary rays are generally absent.
By examining these structural differences, you can determine whether the stem is monocot or dicot.
The transverse section of a plant material shows the following anatomical features - (a) the vascular bundles are conjoint, scattered and surrounded by a sclerenchymatous bundle sheaths. (b) phloem parenchyma is absent. What will you identify it as?
Based on the given anatomical features:
Vascular bundles are conjoint, scattered, and surrounded by a sclerenchymatous bundle sheath.
Phloem parenchyma is absent.
The plant material can be identified as a monocotyledonous stem.
In monocot stems, the vascular bundles are scattered throughout the ground tissue and are surrounded by a sclerenchymatous bundle sheath, and they lack phloem parenchyma.
What is stomatal apparatus? Explain the structure of stomata with a labelled diagram.
Stomatal Apparatus:The stomatal apparatus consists of the stomatal aperture, guard cells, and the surrounding subsidiary cells. This apparatus is crucial for regulating transpiration and gaseous exchange in plants.
Structure of Stomata:
Guard Cells:
In most plants, they are bean-shaped.
In grasses, guard cells are dumb-bell shaped.
The outer walls of guard cells are thin, and the inner walls are highly thickened.
Guard cells contain chloroplasts.
Stomatal Pore:
It is the opening between the guard cells.
Subsidiary Cells:
These are specialized epidermal cells around the guard cells.
Labelled Diagram:
(a) shows stomata with bean-shaped guard cells.
(b) shows stomata with dumb-bell shaped guard cells.
This diagram illustrates the different shapes of guard cells and their positioning relative to the stomatal aperture.
Name the three basic tissue systems in the flowering plants. Give the tissue names under each system.
The three basic tissue systems in flowering plants are:
Epidermal Tissue System
Epidermal cells
Stomata
Epidermal appendages (trichomes and hairs)
Ground or Fundamental Tissue System
Parenchyma
Collenchyma
Sclerenchyma
Vascular or Conducting Tissue System
Phloem
Xylem
Each tissue system is characterized by its structure and specific functions within the plant body.
How is the study of plant anatomy useful to us?
The study of plant anatomy is useful for several reasons:
Understanding Structure and Function: It helps us understand the internal structure and functional organization of higher plants.
Identification and Classification: Anatomical features aid in the identification and classification of plants.
Adaptations: By studying plant anatomy, we can observe how plants have adapted to diverse environments.
Agriculture and Horticulture: Knowledge of plant anatomy is crucial for improving agricultural and horticultural practices.
Medicine and Pharmacology: Many drugs are derived from plants, and understanding their anatomy can enhance drug development.
Plant Breeding and Biotechnology: Insights from plant anatomy can be applied in plant breeding and genetic modification.
Hence, plant anatomy plays a critical role in various biological sciences and applied fields.
Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams.
The internal structure of a dorsiventral (dicotyledonous) leaf can be described as follows:
Epidermis: This is the outermost layer covering both the upper surface (adaxial epidermis) and the lower surface (abaxial epidermis) of the leaf. The epidermis has a conspicuous cuticle, and the abaxial surface usually bears more stomata. The adaxial epidermis may lack stomata.
Mesophyll: The tissue located between the upper and lower epidermis is called the mesophyll. This is where photosynthesis takes place. The mesophyll is divided into two types:
Palisade Parenchyma: Located beneath the adaxial epidermis, consists of columnar cells arranged vertically and parallel to each other.
Spongy Parenchyma: Situated below the palisade parenchyma, consists of oval or round loosely arranged cells with large intercellular spaces and air cavities.
Vascular System: Comprises vascular bundles which are found in the veins and midrib of the leaf. The xylem is located on the upper side, while the phloem is located on the lower side within the vascular bundles. These bundles are surrounded by a layer of thick-walled bundle sheath cells.
Here is a labelled diagram of a dorsiventral leaf showing these structures:
(a) Upper Epidermis or Adaxial Epidermis
(c) Palisade Parenchyma
(d) Spongy Parenchyma
(e) Lower Epidermis or Abaxial Epidermis
(f) Stomata
(h) Vascular Bundle
(i) Xylem
(j) Phloem
This structure typically facilitates optimal photosynthesis and gas exchange while regulating water loss.
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Ask Chatterbot AINotes - Anatomy of Flowering Plants | Class 11 NCERT | Biology
Comprehensive Notes on the Anatomy of Flowering Plants for Class 11
Introduction to Flowering Plant Anatomy
The anatomy of flowering plants involves understanding the internal structure and functional organisation of higher plants. Just as the external morphology reveals similarities and differences among plants, the internal structure, or anatomy, presents numerous insights into their adaptation and function. This article delves into the complex organisation of tissues and organs in angiosperms (flowering plants) and highlights distinct differences between dicotyledons and monocotyledons.
The Tissue Systems in Flowering Plants
The Epidermal Tissue System
The epidermal tissue system forms the outermost covering of the entire plant body and includes various components:
- Epidermal Cells: Comprise a single layer of elongated cells that form a continuous layer.
- Stomata: Structures involved in gaseous exchange and transpiration, composed of guard cells that control their opening and closing.
- Trichomes: Hairs in the shoot system that can be secretory and help reduce water loss.
The Ground Tissue System
The ground tissue system consists of all tissues except epidermis and vascular bundles. It includes:
- Parenchyma: Cells usually found in the cortex, pericycle, pith, and medullary rays, serving various functions including photosynthesis.
- Collenchyma and Sclerenchyma: Provide mechanical strength to different parts of the plant.
The Vascular Tissue System
The vascular system consists of complex tissues, mainly xylem and phloem. These tissues form vascular bundles that facilitate the transport of water, minerals, and nutrients. Vascular bundles can be:
- Open: With cambium, capable of forming secondary tissues (common in dicots).
- Closed: Without cambium, incapable of forming secondary tissues (common in monocots).
Anatomy of Dicotyledonous Plants
Dicotyledonous Root
The internal structure of a dicot root includes:
- Epiblema: Outermost layer with unicellular root hairs.
- Cortex: Layers of parenchymatous cells with intercellular spaces.
- Endodermis: Single layer of barrel-shaped cells, with casparian strips that are water-impermeable.
- Vascular Bundles: Composed of xylem and phloem arranged in a radial pattern.
Dicotyledonous Stem
The cross-section of a dicot stem includes:
- Epidermis: Outermost protective layer.
- Cortex: Made up of hypodermis, cortical layers, and endodermis rich in starch grains.
- Pericycle: Contains sclerenchymatous patches.
- Vascular Bundles: Arranged in a ring, characteristic of dicot stems.
Dorsiventral (Dicotyledonous) Leaf
A dorsiventral leaf shows a clear differentiation in tissue structure:
- Epidermis: Covers the upper (adaxial) and lower (abaxial) surfaces, with more stomata on the lower surface.
- Mesophyll: Consists of palisade parenchyma (elongated cells) and spongy parenchyma (loose cells with air spaces).
- Vascular System: Veins and midrib surrounded by thick-walled bundle sheath cells.
graph TD;
A[Epidermis] --> B[Palisade Parenchyma];
B --> C[Spongy Parenchyma];
C --> D[Lower Epidermis with Stomata];
D --> E[Vascular System];
Anatomy of Monocotyledonous Plants
Monocotyledonous Root
Similar to dicot roots but with key differences:
- Vascular Bundles: More numerous (polyarch).
- Pith: Larger and well-developed compared to dicots.
Monocotyledonous Stem
Monocot stems exhibit:
- Hypodermis: Sclerenchymatous.
- Vascular Bundles: Scattered and surrounded by a sclerenchymatous bundle sheath, with water-containing cavities inside.
Isobilateral (Monocotyledonous) Leaf
Monocot leaves show these distinctive features:
- Stomata: Present on both surfaces of the leaf.
- Mesophyll: Not differentiated into palisade and spongy parenchyma.
- Bulliform Cells: Located along the veins, they regulate leaf rolling during water stress.
Summary and Key Takeaways
Plants comprise various tissues that carry out essential functions such as food assimilation, storage, transport, and providing mechanical support. The three major tissue systems in plants are:
- Epidermal Tissue System: Includes epidermal cells, stomata, and epidermal hairs (trichomes).
- Ground Tissue System: Comprises the cortex, pericycle, and pith.
- Vascular Tissue System: Consists of xylem and phloem that transport nutrients and water.
Differences in internal structures between monocot and dicot plants are significant, particularly in their vascular bundles and the occurrence of secondary growth in dicots. Understanding these anatomical distinctions provides deeper insights into their functional adaptations and growth mechanisms.
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