NCERT Class 11 Biology Chapter 6 Notes Anatomy Of Flowering Plants- Download PDF Notes

Download NCERT Notes for Class 11 Biology Chapter 6 PDF

This chapter talks about the inside parts of roots, stems, and leaves in flowering plants. It explains different types of plant tissues, like xylem and phloem and how they help in transport. Students can get the NCERT notes for class 11 Biology chapter 6 PDF from the link given below. This PDF can be accessed offline without the internet. Having the NCERT Class 11 Biology Notes is a valuable resource to score well in exams.

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Anatomy of Flowering Plants Class 11 Notes

To fully understand the concepts, it’s important to thoroughly go through the notes, which are provided below. These notes cover tissues, tissue systems, and the internal structure of roots, stems, and leaves in flowering plants. Diagrams and flowcharts are included to make learning easier. Students can use these points for step-by-step revision. Following the Anatomy of Flowering Plants Class 11 Notes will also help build a strong base for later chapters.

What are Tissues?

A group of similar or dissimilar cells that perform essentially the same function and have a common origin is called a tissue. Tissues can be classified into two main types:

1. Meristematic tissues

2. Permanent tissues

Meristematic Tissue

All the cells of a plant embryo are capable of division, but with the growth of the plant, this feature is confined to certain regions. Such embryonic regions that have the capability of unlimited growth and cell divisions are said to be meristems. A meristem is a region in which cell divisions occur.

The Characteristics of Meristematic Cells

The following are the main characteristics of a meristematic tissue.

(1) The cells of meristematic tissue are thin-walled and are compactly arranged without any intercellular spaces.

(2) They take a deep stain and have larger nuclei.

(3) They have dense cytoplasm, either with very small vacuoles or without any vacuoles.

(4) The protoplast of meristematic cells is devoid of reserve food materials and plastids, and it has a poorly developed endoplasmic reticulum.

Classification of Meristematic Tissues

Meristems based on position in the plant body are divided into three main types:

• Apical meristem: The apical meristem occurs at the apices of roots and shoots. It is responsible for the increase in length of the root and shoot axes.

  Intercalary meristem: This meristem lies between regions of permanent tissues. It is responsible for the increase in length of the plant or its organs.

• Lateral meristems: This meristem is present along the lateral sides of the stem and root. It is responsible for the increase in diameter and formation of secondary permanent tissues.

Permanent Tissues

Permanent tissues are formed as the result of division and differentiation in meristematic tissues. Based on constituent cells, permanent tissues are of two types:

Simple and complex tissue

Simple tissue

Simple tissues are homogeneous and composed of only one type of cell. They are further divided into three types:

Parenchyma

• It is the most abundant cell in plants.
• They are oval, isodiametric, or polygonal with intercellular spaces.
• Plasmodesmata are commonly present in parenchyma cells.
• They are involved in various functions like photosynthesis, respiration, secretion, and storage.

Collenchyma

• Usually found in stems beneath the epidermis.
• The collenchyma cells are living and contain protoplasm.
• Being flexible, it provides tensile strength to the plant body.

Sclerenchyma

• The sclerenchyma cells are composed of thick-walled cells.
• These are considered dead cells.
• They have a lignin deposit.

Complex Tissue

A complex tissue is a collection of different types of cells that form a structural unit and perform a specific function. Xylem and phloem present in plants are complex tissues.

Xylem

It is mainly concerned with the conduction of water and minerals, and also provides support. It is composed of:

• Xylem vessels
• Tracheids
• Xylem Parenchyma
• Xylem fibres

Phloem

Phloem is a specialised complex tissue mainly responsible for the transport of food materials. It consists of :

• Sieve tubes
• Companion cells
• Phloem fibres
• Phloem parenchyma

The Tissue System

A tissue system usually consists of only one tissue or a collection of tissues that perform the same function. There are mainly 3 types of tissue systems:

• Epidermal tissue system

• The ground tissue system

• Vascular tissue system

Epidermal Tissue System

• They form the epidermis of the plants.

• They have compactly packed cells.

• They have large vacuoles.

• If the epidermis is absent, it is called epiblema.

• It is modified to form

Stomata

• In Dicotyledonous, there are bean-shaped stomata.

• In grasses, a dumbbell-shaped stoma is present.

Root hair

• It is a unicellular structure.

Shoot hair

• It is multicellular

The Ground Tissue System

• It forms the main bulk of the plant body, and it extends from the epidermis to the centre of the axis.
• The ground system can be distinguished into the cortex, pericycle, pith, and medullary rays.

Vascular Tissue System

• It consists of a variable number of vascular bundles, which are arranged in a ring in the roots.
• The vascular bundles conduct water and raw food materials from roots to leaves, and prepared food from leaves to different parts.
• Based on the arrangement of xylem and phloem, they are of 3 types: Radial, Conjoint closed, Conjoint open

Anatomy of Dicotyledonous and Monocotyledonous Plants

The anatomy of dicot and monocot plants has been described below:

Dicotyledonous Root

• This is the outermost layer of thin-walled cells.

• Usually,2-6 vascular bundles are present.

• Vessels appear angular or polygonal in transaction.

• Cambium appears as a secondary meristem at the time of secondary growth.

• Pith is absent or poorly developed.

Monocotyledons Root

• The pericycle gives rise to lateral roots only.

• Usually, 6-20 vascular bundles are present.

• Vessels appear oval or rounded in transmission.

• Cambium is altogether absent.

• The pith is large and well-developed.

Dicotyledonous Stem

• In a dicot stem, vascular bundles are conjoint, collateral, endarch, and open.

• Vascular bundles are arranged in a ring and are of nearly the same size.

• The phloem is composed of sieve tubes, companion cells, and phloem parenchyma.

• Pith is present.

• Secondary growth occurs in the dicot stem

• Wood formation occurs.

Monocotyledons Stem

• Ground tissue in monocot stems is usually undifferentiated.

• Vascular bundles are conjoint, collateral, endarch, and closed.

• Vascular bundles are scattered and of various sizes.

• Phloem parenchyma is absent in this stem.

• Pith is absent.

Dicotyledonous (Dorsiventral) Leaf

• The dicot leaf is dorsiventral.

• Stomata are mostly confined to the lower epidermis.

• It has reticulate venation.

• A single main vein is present, which runs through the centre of the lamina.

• Vascular bundles are of conjoint, collateral, open type

• Bulliform cells are absent.

Monocotyledons (Isobilateral) Leaf

• It is bilateral, ie..same from both sides.

• It has equal stomata on both the lower and upper epidermis.

• It has a parallel Venation.

• The mesophyll is not differentiated.

• The diameters of veins and veinlets are the same.

Secondary Growth

• It leads to an increase in the girth of plants.

• Tissues involved in secondary growth are the vascular cambium, the cork cambium

Vascular Cambium

It is responsible for secondary growth in the stellar region.

Formation of Vascular Cambium

• In the dicot stem, vascular cambium is partly secondary in origin because intrafascicular cambium is already present within vascular bundles between the primary xylem and primary phloem.

• After dedifferentiation in medullary rays, arch cells are considered as intrafascicular cambium.

• The vascular cambium produces secondary cambium at the inner side and secondary phloem at the outer side.

• The activity of the cambium is 8 times more, due to the formation of secondary phloem outer side.

• It leads to wood formation.

Also, Read

• NCERT Notes for Class 11 Physics
• NCERT Notes for Class 11 Chemistry
• NCERT Notes for Class 11 Mathematics

Anatomy Of Flowering Plants Previous Year Questions and Answers

Some of the questions which have come up in past years from the chapter are given below. To solve these questions easily, students can use the NCERT Class 11 Biology Chapter 6 Notes Anatomy of Flowering Plants.

Question 1. What is the fate of primary xylem in a dicot root showing extensive secondary growth?

Option 1. It is retained in the centre of the axis

Option 2. It gets crushed

Option 3. May or may not get crushed

Option 4. It gets surrounded by primary phloem

Answer :

In dicot roots, secondary growth occurs due to the activity of the vascular cambium, which forms secondary xylem (inside) and secondary phloem (outside). During this process, the primary xylem, which was originally at the centre, remains intact because new secondary xylem is formed around it. Therefore, the primary xylem is retained in the centre of the root axis and does not get crushed (unlike primary phloem, which usually does get crushed).

Hence, the correct answer is option (1) It is retained in the centre of the axis.

Question 2. What is the fate of primary xylem in a dicot root showing extensive secondary growth?

Option 1. It is retained in the centre of the axis

Option 2. It gets crushed

Option 3. May or may not get crushed

Option 4. It gets surrounded by primary phloem

Answer :

The primary xylem is retained in the centre of the axis while the primary phloem is crushed. In many plants, this arrangement allows the xylem to continue functioning in water and nutrient transport, even as the plant grows. The crushing of the primary phloem enables the plant to develop a secondary phloem, which takes over the function of food transport.

Hence, the answer is option (1) It is retained in the centre of the axis

Question 3. Which one of the following cell types always divides by anticlinal cell division?

Option 1. Fusiform initial cells

Option 2. Root cap

Option 3. Protoderm

Option 4. Phellogen

Answer :

Anticlinal cell division, a type of cell division in which the cells divide perpendicular to the surface, is how protoderm cells proliferate, increasing the plant's surface area. This kind of cell division is different from others, such as periclinal division, which thickens the tissue by dividing cells parallel to the surface.

Hence, the answer is option (3) protoderm

Also Read:

• NCERT Solution
• NCERT Solutions for Class 11
• NCERT Solutions for Class 11 Biology

Chapter-Wise NCERT Class 11 Notes Biology

The chapter-wise notes are given below. These notes will help you quickly revise important concepts and prepare well for exams.