NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants: Here you will study the internal structure and functional organization of higher plants. Study of the internal structure of plants is called anatomy. Solutions of NCERT class 11 biology chapter 6 anatomy of flowering plants carry impressive explanation of all the questions which are based on the anatomy of all the flowering plants. You need to remember that plants have cells as the basic unit, cells are organized into tissues and in turn, the tissues are organized into organs. This chapter of the anatomy of flowering plants will tell you about the different organs in a plant that shows differences in their internal structure and it is important to know because you are going to get questions related to this in NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants. Within angiosperms, the monocots and dicots are also seen to be anatomically different. Internal structures also show adaptations to diverse environments. If you are looking for an answer from any other chapter even from any other class then go with NCERT Solutions, there you will get all the answers of NCERT easily.
There are three types of tissue systems related to which you will get questions as well as answers in solutions for NCERT class 11 biology chapter 6 anatomy of flowering plants:
The epidermal tissue systems are made of:
- epidermal cells
- epidermal appendages
Here the important topics of NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants are mentioned below:
6.1 The Tissues
6.1.1 Meristematic Tissues
6.1.2 Permanent Tissues
18.104.22.168 Simple Tissues
22.214.171.124 Complex Tissues
6.2 The Tissue System
6.2.1 Epidermal Tissue System
6.2.2 The Ground Tissue System
6.2.3 The Vascular Tissue System
6.3 Anatomy of Dicotyledonous and Monocotyledonous Plants
6.3.1 Dicotyledonous Root
6.3.2 Monocotyledonous Root
6.3.3 Dicotyledonous Stem
6.3.4 Monocotyledonous Stem
6.3.5 Dorsiventral (Dicotyledonous) Leaf
6.3.6 Isobilateral (Monocotyledonous) Leaf
6.4 Secondary Growth
6.4.1 Vascular Cambium
126.96.36.199 Formation of cambial ring
188.8.131.52 Activity of the cambial ring
184.108.40.206 Springwood and autumn wood
220.127.116.11 Heartwood and sapwood
6.4.2 Cork Cambium
6.4.3 Secondary Growth in Roots
In this chapter, monocotyledonous and dicotyledonous plants show marked variation in their internal structures. They differ in type, number and location of vascular bundles and based on this you will get questions along with their answers in CBSE NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants. The secondary growth occurs in most of the dicotyledonous roots and stems and it increases the girth (diameter) of the organs by the activity of the vascular cambium and the cork cambium.
After going through NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants, you must be able to understand all the answers to the following questions, which are mentioned below:
Q1. State the location and function of different types of meristems.
Meristem refers to the simple tissue composed of a group of similar and immature cells which can divide and form new cells. ON the basis of position, there can be three types of meristem including apical meristem, intercalary meristem and lateral meristem. The location and function of these meristems are as follows:
|Type of meristem
||Location of meristem
||Function of meristem
|It occurs at the tips of roots and shoots
||It increases the length of plants
|It occurs between mature tissues especially in grasses
Intercalary meristem aids in the regeneration of grasses after they have been grazed by herbivores
|It occurs on the sides of mature tissues of roots and shoots
||It causes an increase in the girth of plants
Q2. Cork cambium forms tissues that form the cork. Do you agree with this statement? Explain.
Cork cambium or phellogen is the secondary meristem that develops in the region of cortex to replace the outer epidermal cells that will provide protection to the stem and root from infections. Cork cambium is composed of thin-walled rectangular cells and it cuts off cells on both sides. The outer cells differentiate to form cork or phellem while the inner cells differentiate into secondary cortex or phelloderm. Together, the phellogen, phellem, and phelloderm constitute the periderm. The cork is impervious to water but allows gaseous exchange through the lenticels. Hence, cork cambium forms tissues that form the cork
Q3. Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?
The increase in girth of a plant body is called secondary growth. The tissues involved in secondary growth are vascular cambium and cork cambium. In a young stem, vascular cambium is found in the form of patches as a single layer between the xylem and phloem. During the later stage, it forms a complete ring. Soon, the cambial ring becomes active and begins to cut off new cells towards the inner and the outer sides. The cells which are cut off towards pith mature into secondary xylem while those which are cut off towards the periphery after maturation develops into secondary phloem. The cambium is most of the times more active on the inner side than on the outer. This is the reason, the amount of secondary xylem produced is more than secondary phloem. The primary and secondary phloems get gradually crushed due to the continued formation and accumulation of secondary xylem. Then at some places, the cambium forms a narrow band of parenchyma, which passes through the secondary xylem and the secondary phloem in the radial directions. These are the secondary medullary rays.
Q5. Cut a transverse section of young stem of a plant from your school garden andobserve it under the microscope.
How would you ascertain whether it is amonocot stem or a dicot stem? Give reasons.
An unknown sample can be identified to be either dicot stem or monocot stem based on the following characteristics-
Characteristics of a dicot stem-
1. The vascular bundles are conjoint, collateral, and open, with a strip of cambium between the xylem and phloem.
2. The vascular bundles are arranged to form a ring, around the centrally-located pith
3. The ground tissue is differentiated into the collenchyma, parenchyma, endodermis, pericycle, and pith.
4. In between the vascular bundles, medullary rays are present.
Characteristics of monocot stem-
1. The hypodermis is made up of sclerenchyma.
2. The Vascular bundles are conjoint, closed and scattered.
3. Each vascular bundle is surrounded by a sclerenchymatous bundle sheath.
4. Phloem parenchyma is absent.
5. Water-containing cavities are present within the vascular bundles.
Q7. Why are xylem and phloem called complex tissues?
Complex tissues are tissues made up of more than one types of cells. Since xylem and phloem are consists of different kinds of elements, they are called complex tissues. Xylem is consists of vessels, tracheid, xylem fibre and xylem parenchyma
1. Tracheids- These are elongated, thick-walled dead cells having pointed ends. These lack protoplasm
2. Vessels- These are long, tubular, and cylindrical structures that are formed from the vessel members, with each having lignified walls and large central cavities. Vessels being dead lack protoplasm.
3. Xylem fibres consist of thick walls with an almost insignificant lumen. These provide mechanical support to the plant.
4. Xylem parenchyma is made up of thin-walled parenchymatous cells that help in the storage of food materials and in the radial conduction of water
Phloem is made up of sieve tube, companion cells, phloem parenchyma and phloem fibres
1. Sieve tube- The sieve tube elements are tube-like elongated structures associated with companion cells. The end walls of sieve tube elements are perforated to form the sieve plate. Sieve tube elements are living cells containing cytoplasm and nucleus.
2. Companion cells- These cells are parenchymatous in nature and they help in maintaining the pressure gradient in the sieve tube elements.
3. Phloem parenchyma- These cells help in the storage of food and they are made up of long tapering cells, with dense cytoplasm.
4. Phloem fibres- These are made up of elongated sclerenchymatous cells with thickened walls.
Q8. What is stomatal apparatus? Explain the structure of stomata with a labelleddiagram.
Stomata are tiny pores or holes found to be present in the epidermis of leaves. The major function of these stomata is to regulate the process of transpiration and gaseous exchange. The stomatal pore remains surrounded by specialised cells called guard cells which in turn are surrounded by subsidiary cells.
The stomatal pore, guard cells and the surrounding subsidiary cells together constitute the stomatal apparatus.
The gaseous exchange is maintained by guard cells. In dicots, guard cells are bean-shaped while in monocots, guard cells are dumbell shaped.
The three basic tissue systems in the flowering plants include epidermal tissue system, ground tissue system and vascular tissue system.
1. Epidermal tissue system- It forms the outermost covering of whole plant body. It consists of tissues like epidermis, stomata, epidermal appendages (trichomes and hairs) etc.
2. Ground tissue system- All the tissue between the epidermis and vascular bundle forms the ground tissues. It consists of simple permanent tissues like parenchyma, sclerenchyma, collenchyma, mesophyll etc. It includes pericycle, cortex, pith and medullary rays
3. Vascular tissue system- The vascular tissue system consists of complex tissues, xylem and phloem that together form vascular bundles.
Q10. How is the study of plant anatomy useful to us?
The study of plant anatomy useful to us in the following ways
1. The study of anatomy helps to know the structures of plants that can be of commercial value. For example, jute, flax etc.
2. Study of anatomy can help in knowing the age of trees
3. By knowing the anatomical details, we can identify the unknown plant samples.
4. Anatomy may also help in understanding the structural adaptations of plants with respect to diverse environmental conditions.
The internal structure of a dorsiventral leaf-
The leaf lamina of a dorsiventral leaf has 3 parts: epidermis, mesophyll and vascular system.
1. Epidermis- The epidermis is two layered. The upper epidermis is called adaxial epidermis and the lower one is called abaxial epidermis. More number of stomata are present on the abaxial epidermis.
2. Mesophyll- Inner to epidermis, mesophyll tissue is present. There are two types of cells in the mesophyll i.e. palisade parenchyma and spongy parenchyma. The palisade parenchyma is placed adaxially while the spongy parenchyma is situated below the palisade parenchyma and extends to the lower epidermis. There are numerous large spaces and air cavities between the cells of spongy parenchyma.
3. Vascular system- The vascular bundles are surrounded by a layer of thick-walled bundle sheath cells. They are conjoint and closed.
Q13. What is periderm? How does periderm formation take place in the dicot stems?
The periderm refers to the collective term used to signify phellogen, phellem, and phelloderm in a plant stem. Periderm formation in plants, mainly occur to replace the existing epidermis.
Formation of periderm
The formation of periderm occurs during secondary growth. During this process, to replace the broken outer epidermal layer and the cortical layer, the cells of the cortex turn meristematic. As a result of this, cork cambium or phellogen is formed. The phellogen is composed of thin-walled, narrow and rectangular cells. Later on, the phellogen cuts off cells on its either side. The cells of the outer side give rise to the phellem or cork which due to the deposition of suberin in its cell wall is impervious to water. Similarly, the inner side forms secondary cortex or phelloderm which is mainly parenchymatous in nature.
If you are unable to determine these questions or facing any problem to understand them, then go through the book again and then try to solve all the given questions by yourself and then match it from the CBSE NCERT solutions for class 11 biology chapter 6 anatomy of flowering plants, as it will help you to prepare not only for the school exam even also for other competitive exams like NEET.
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