CHAPTER - 6
ANATOMY OF FLOWERING PLANTS
Anatomy: Anatomy is the study of internal structure of organisms. Plant
anatomy includes organization and structure of tissues.
Tissue: A group of interdependent identical or non-identical cells along with
intercellular substance having common origin to perform a specific (definite) function
in multicellular organisms is called tissue.
Meristematic tissues: The meristematic tissue is made up of the cells which have the
capability to divide. Meristems in plants are restricted to a specialized regions and
responsible to the growth of plants.
Meristems
Apical meristem Intercalary meristem Lateral meristem
• Occurs at the tips of roots and • Occurs between mature tissue •Occurs in the mature
shoots • short lived regions of roots and
shoots
• Primary meristem • Primary meristem • Secondary meristem
• Increase the length of plant • Capable of forming branch •Appears later than primary
and flower many meristem and
responsible for secondary
growth
Axillary bud: The buds which are present in the axils of leaves and are responsible for
forming branches or flowers.
Permanent tissues: The permanent tissues are derived from meristematic tissue and are
composed of cells, which have lost the ability to divide.
Types of Permanent Tissue
Simple Complex
Parenchyma Collenchyma Sclerenchyma Xylem Phloem
, Parenchyma: Thin walled cells, with intercellular spaces, cell wall is made up of
cellulose. It performs the function like photosynthesis, storage, secretion.
Collenchyma: It is formed of living, closely packed isodiametric cells. It’s cells are
thickened at the corners due to deposition of cellulose and pectin. It provides
mechanic support to the growing parts of the plant.
Sclerenchyma: It is formed of dead cells with thick and lignified walls meant for
mechanical support. They have two types of cells: fibres and sclereids.
Xylem: Xylem consists of tracheids, vessels, xylem fibres and xylem parenchyma. It
conducts water and minerals from roots to other parts of plant.
Protoxylem: The first formed primary xylem elements.
Metaxylem: The later formed primary xylem elements.
Endarch xylem: Protoxylem lies towards the centre and metaxylem towards the
periphery of the organ.
Exarch xylem: Protoxylem towards periphery and metaxylem towards the centre.
Phloem: Phloem consists of sieve tube elements, companion cells, phloem fibres and
phloem parenchyma. Phloem transports the food material from leaves to various parts
of the plant.
Protophloem: First formed phloem with narrow sieve tubes.
Metaphloem: Later formed phloem with broader sieve tubes.
The Tissue System:
1. Epidermal tissue system: It includes cuticle, epidermis, epidermal hairs, root
hairs, trichomes and stomata.
2. The ground tissue system: It is made up of parenchyma, collenchyma,
sclerenchyma. In dicot stems and roots the ground tissue is divided into
hypodermis, cortex, endodermis, pericycle, medullary rays and pith.
3. The vascular tissue system: It includes vascular bundles which are made up of
xylem and phloem.
ANATOMY OF FLOWERING PLANTS
Anatomy: Anatomy is the study of internal structure of organisms. Plant
anatomy includes organization and structure of tissues.
Tissue: A group of interdependent identical or non-identical cells along with
intercellular substance having common origin to perform a specific (definite) function
in multicellular organisms is called tissue.
Meristematic tissues: The meristematic tissue is made up of the cells which have the
capability to divide. Meristems in plants are restricted to a specialized regions and
responsible to the growth of plants.
Meristems
Apical meristem Intercalary meristem Lateral meristem
• Occurs at the tips of roots and • Occurs between mature tissue •Occurs in the mature
shoots • short lived regions of roots and
shoots
• Primary meristem • Primary meristem • Secondary meristem
• Increase the length of plant • Capable of forming branch •Appears later than primary
and flower many meristem and
responsible for secondary
growth
Axillary bud: The buds which are present in the axils of leaves and are responsible for
forming branches or flowers.
Permanent tissues: The permanent tissues are derived from meristematic tissue and are
composed of cells, which have lost the ability to divide.
Types of Permanent Tissue
Simple Complex
Parenchyma Collenchyma Sclerenchyma Xylem Phloem
, Parenchyma: Thin walled cells, with intercellular spaces, cell wall is made up of
cellulose. It performs the function like photosynthesis, storage, secretion.
Collenchyma: It is formed of living, closely packed isodiametric cells. It’s cells are
thickened at the corners due to deposition of cellulose and pectin. It provides
mechanic support to the growing parts of the plant.
Sclerenchyma: It is formed of dead cells with thick and lignified walls meant for
mechanical support. They have two types of cells: fibres and sclereids.
Xylem: Xylem consists of tracheids, vessels, xylem fibres and xylem parenchyma. It
conducts water and minerals from roots to other parts of plant.
Protoxylem: The first formed primary xylem elements.
Metaxylem: The later formed primary xylem elements.
Endarch xylem: Protoxylem lies towards the centre and metaxylem towards the
periphery of the organ.
Exarch xylem: Protoxylem towards periphery and metaxylem towards the centre.
Phloem: Phloem consists of sieve tube elements, companion cells, phloem fibres and
phloem parenchyma. Phloem transports the food material from leaves to various parts
of the plant.
Protophloem: First formed phloem with narrow sieve tubes.
Metaphloem: Later formed phloem with broader sieve tubes.
The Tissue System:
1. Epidermal tissue system: It includes cuticle, epidermis, epidermal hairs, root
hairs, trichomes and stomata.
2. The ground tissue system: It is made up of parenchyma, collenchyma,
sclerenchyma. In dicot stems and roots the ground tissue is divided into
hypodermis, cortex, endodermis, pericycle, medullary rays and pith.
3. The vascular tissue system: It includes vascular bundles which are made up of
xylem and phloem.
