SURESH DANI AND SONS CLASSES
CHAPTER - 5
MORPHOLOGY OF FLOWERING PLANTS
• Branch of science which deals with the study of external form, structure and various modifications of plants
is called Plant Morphology.
• Body of a common angiosperm plant is differentiated into underground root system and aerial shoot system.
Shoot system includes stem, branches, leaves & flowers.
• Root, stem and leaves represent vegetative part of a plant while flowers show reproductive part of a plant.
Fig. : Parts of a flowering plant
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, SURESH DANI AND SONS CLASSES
ROOT
1. INTRODUCTION
Definition: Root is non-chlorophyllous and under ground part of plant. It is positive geotropic, positive
hydrotropic and Negative phototropic.
The main characters of root are as follows:
(1) Roots usually develop from Radicle of seed.
(2) Roots do not bear nodes and internodes.
(3) Roots possess unicellular root hairs.
(4) Lateral roots arise endogenously from pericycle.
(5) Roots do not bear buds for vegetative propagation except sweet potato and Indian rose wood.
1.1 Types of roots:
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(1) Tap roots: They develop from radicle in acropetal succession, e.g. Dicot plants.
(2) Adventitious roots: They arise from any part of the plant body other than radicle, e.g. Monocot plants,
Grasses, Monstera, Banyan tree.
Note: NCERT places Fibrous root system separately but it comes under adventitious root system.
Differences between Tap root and Adventitious root
S.No. Tap root Adventitious root
1 They arise from the radicle of embryo. They arise from stem as well as leaves.
2 It is single main root. Many long roots arise in a group.
3 Main root is quite thick as compared to All the roots are fibrous.
the others.
4 Primary root is perennating. Primary root is short lived.
5 They are always underground. They may be underground or aerial.
6 Distinction of primary, secondary & There is no such distinction.
tertiary roots is quite conspicuous.
1.2 Regions of root:
(i) Root cap: It is a smooth cap shaped structure present at the apex of root. It secretes mucilage, which
lubricates the passage of root through the soil. In Hydrophytes, root cap is either absent or replaced
through root pockets. e.g. Pistia, Eichhornia.
(ii) Zone of cell division: The cells of this region are in active state of division, having thin wall and dense
protoplasm.
(iii) Zone of cell elongation: Maximum growth in the cells occurs. These cells lose the power of division.
(iv) Zone of cell Maturation: The cells of this region are differentiated into permanent tissue. Root hairs are
also present in this zone, which help in absorption of water.
Fig.: The regions of the root-tip
The main function of the root system are absorption of water and minerals from the soil, providing anchorage
to the plant storing reserve food material and synthesis of plant growth regulators.
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, SURESH DANI AND SONS CLASSES
1.3 Modifications of Roots:
1.3.1 Modifications of Tap roots:
(1) Fleshy taproot : They are modified for storage of food.
(i) Fusiform : It is thickest at middle and spindle shaped. e.g. Radish.
(ii) Conical : It is cone shaped. It is thickest at the base and gradually tapering at the apex.
e.g. Carrot.
(iii) Napiform: It is quite thick at the base and abruptly tapering at the apex. e.g. Turnip and beet root.
(iv) Tuberous: They are swollen taproots and do not possess any definite shape e.g. Mirabilis jalapa.
(2) Nodulated roots:
• These are found in the plants of sub-family Papilionaceae.
• The secondary, tertiary roots and sometimes the primary root develop numerous small or large irregular
swellings called root nodules.
• The latter contains symbiotic nitrogen fixing bacteria Rhizobium. e.g. Pea, groundnut and soyabean.
(3) Reproductive Roots:
• Adventitious buds develop at some taproots or their branches that help in vegetative reproduction e.g.
Dalbergia, Populus.
Morphology of Flowering Plants 123
CHAPTER - 5
MORPHOLOGY OF FLOWERING PLANTS
• Branch of science which deals with the study of external form, structure and various modifications of plants
is called Plant Morphology.
• Body of a common angiosperm plant is differentiated into underground root system and aerial shoot system.
Shoot system includes stem, branches, leaves & flowers.
• Root, stem and leaves represent vegetative part of a plant while flowers show reproductive part of a plant.
Fig. : Parts of a flowering plant
120 Morphology of Flowering Plants
, SURESH DANI AND SONS CLASSES
ROOT
1. INTRODUCTION
Definition: Root is non-chlorophyllous and under ground part of plant. It is positive geotropic, positive
hydrotropic and Negative phototropic.
The main characters of root are as follows:
(1) Roots usually develop from Radicle of seed.
(2) Roots do not bear nodes and internodes.
(3) Roots possess unicellular root hairs.
(4) Lateral roots arise endogenously from pericycle.
(5) Roots do not bear buds for vegetative propagation except sweet potato and Indian rose wood.
1.1 Types of roots:
Morphology of Flowering Plants 121
, SURESH DANI AND SONS CLASSES
(1) Tap roots: They develop from radicle in acropetal succession, e.g. Dicot plants.
(2) Adventitious roots: They arise from any part of the plant body other than radicle, e.g. Monocot plants,
Grasses, Monstera, Banyan tree.
Note: NCERT places Fibrous root system separately but it comes under adventitious root system.
Differences between Tap root and Adventitious root
S.No. Tap root Adventitious root
1 They arise from the radicle of embryo. They arise from stem as well as leaves.
2 It is single main root. Many long roots arise in a group.
3 Main root is quite thick as compared to All the roots are fibrous.
the others.
4 Primary root is perennating. Primary root is short lived.
5 They are always underground. They may be underground or aerial.
6 Distinction of primary, secondary & There is no such distinction.
tertiary roots is quite conspicuous.
1.2 Regions of root:
(i) Root cap: It is a smooth cap shaped structure present at the apex of root. It secretes mucilage, which
lubricates the passage of root through the soil. In Hydrophytes, root cap is either absent or replaced
through root pockets. e.g. Pistia, Eichhornia.
(ii) Zone of cell division: The cells of this region are in active state of division, having thin wall and dense
protoplasm.
(iii) Zone of cell elongation: Maximum growth in the cells occurs. These cells lose the power of division.
(iv) Zone of cell Maturation: The cells of this region are differentiated into permanent tissue. Root hairs are
also present in this zone, which help in absorption of water.
Fig.: The regions of the root-tip
The main function of the root system are absorption of water and minerals from the soil, providing anchorage
to the plant storing reserve food material and synthesis of plant growth regulators.
122 Morphology of Flowering Plants
, SURESH DANI AND SONS CLASSES
1.3 Modifications of Roots:
1.3.1 Modifications of Tap roots:
(1) Fleshy taproot : They are modified for storage of food.
(i) Fusiform : It is thickest at middle and spindle shaped. e.g. Radish.
(ii) Conical : It is cone shaped. It is thickest at the base and gradually tapering at the apex.
e.g. Carrot.
(iii) Napiform: It is quite thick at the base and abruptly tapering at the apex. e.g. Turnip and beet root.
(iv) Tuberous: They are swollen taproots and do not possess any definite shape e.g. Mirabilis jalapa.
(2) Nodulated roots:
• These are found in the plants of sub-family Papilionaceae.
• The secondary, tertiary roots and sometimes the primary root develop numerous small or large irregular
swellings called root nodules.
• The latter contains symbiotic nitrogen fixing bacteria Rhizobium. e.g. Pea, groundnut and soyabean.
(3) Reproductive Roots:
• Adventitious buds develop at some taproots or their branches that help in vegetative reproduction e.g.
Dalbergia, Populus.
Morphology of Flowering Plants 123
