The Root:The root is underground part of the plant and develops from elongationof radicle of the embryo.
Various types of root
1. Tap root: Originates from radicle. Dicotyledonous plants e.g., mustard,gram, mango.
2. Fibrous root: Originates from base of the stem. Monocotyledonous plants e.g., wheat, paddy.
3. Adventitious root: Originates from parts of the plant other than radicle. Banyan tree (Prop roots)Maize
(Stilt roots)
Root Cap:The root is covered at the apex by the thimble-like structure which protects the tender apical part of
the root. It is positively Geotropic, hydrotropic and negatively phototropic.
Regions of the root:
1. Region of meristematicactivity:Cells of this region have the capabilityto divide.
2. Region of elongation:Cells of this region are elongated and enlarged, responsible for root growth.
3. Region of Maturation:This region has differentiated and matured cells. Some of the epidermal cells of this region form thread-like root hairs for absorption of water and minerals
Modifications of Root:
Roots are modified for support, storage of food, respiration.......
• For support:Prop roots in Banyan tree, stilt roots in maize andsugarcane.
• For respiration:Pneumatophores in Rhizophora(Mangrove).
• For storage of food:Fusiform (radish), Napiform (turnip), Conical (carrot).
The Stem:Stem is the aerial part of the plant and develops from plumule of theembryo.It bears nodes and
internodes.
Modifications of Stem:
In some plants the stems are modified to perform the function of storage of food, support, protection
and vegetative propagation.
Modifications of Stem......
• For food storage:Rhizome (ginger), Tuber (potato), Bulb (onion), and Corm(colocasia).
• For support:Stem tendrils of watermelon, pumpkin, cucumber.
• For protection:Axillary buds of stem of Citrus, Bougainvillea get modified into pointed thorns.
• For vegetative propagation:Underground stems of grass, strawberry, lateral branches of mint and
jasmine.
• For assimilation of food:Flattened stem of Opuntia contains chlorophyll and performs
photosynthesis.
The Leaf: Develops from shoot apical meristem, flattened, green structure, manufacture the
food by photosynthesis. It has bud in axil. A typical leaf has leaf base, petiole and lamina.
Venation:The arrangement of veins and veinlets in the lamina of leaf.
Types of Venation:
1. Reticulate:Veinlets form a network as in leaves of dicotyledonous plants(China rose, Peepal).
2. Parallel:Veins run parallel to each other as in leaves of monocotyledonous plants (grass, maize).
Types of Leaves
Simple Compound
(Single leaf blade)(Leaf has number of leaflets)
e.g., mango, peepal
Pinnately Compound Palmately Compound
(Neem, rose) (Silk cotton)
Phyllotaxy: The pattern of arrangement of leaves on the stem or branch.
Types of phyllotaxy
Alternate Opposite Whorled
(Single leaf at a node) (Two leaves at a node) (More than two leaves in a whorl at a node)
e.g., China rose, Mustard e.g., Calotropis, guava e.g., Nerium,Alstonia
Modifications of Leaves:
• Tendrils: (Climbing) −Sweet wild pea
• Spines (Protection) −Aloe, Opuntia, Argemone
• Pitcher: (Nitrogen Nutrition) −Nepenthes
• Fleshy: (Storage) −Onion
The Inflorescence:The arrangement of flowers on the floral axis.
Main types of Inflorescence:
1. Racemose:Main axis is unlimited in growth-Radish, Mustard, Amaranthus. Flowers in Acropetal order.
2. Cymose:Main axis is limited in growth-Cotton, Jasmine, Calotropis. Flowers in Basipetal order.
3. Special type:Ficus, Salvia, Euphorbia.
The Flower:A flower is modified shoot and reproductive unit in angiosperms.
Flowers may be unisexual or bisexual, bracteate or ebracteate. Some features of flower are:
Symmetry of flower ............
Actinomorphic (radial
symmetry)
Zygomorphic (bilateral
symmetry)
Asymmetric (irregular)
On the basis of no. of
floral appendage................
Trimerous
Tetramerous
Pentamerous
On the basis of position of calyx,corolla,
androecium with respect to ovary
Hypogynous (superior ovary)
Perigynous (half inferior ovary)
Epigynous (inferior ovary)
Parts of aflower......( DRAW DIAGRAM )
1. Calyx:Sepals, green in colour, leaf like.Gamosepalous− (Sepals united)Polyseppalous− (Sepals free)
2. Corolla:Petals, usually brightly coloured to attract insects forpollinationGamopetalous− (Petals
united)Polypetalous − (Petals free)
Aestivation:The mode of arrangement of sepals or petals in floral bud with respect to other members of the same whore.
Types of aestivation:
1. Valvate:Sepals or petals do not overlap the sepal or petal at margins as in Calotropis.
2. Twisted:Sepals or petals overlap the next sepal or petal as in China rose.
3. Imbricate:The margins of sepals or petals overlap one another but not in any definite direction as in
Gulmohar.
4. Vexillary:The largest petal overlaps the two lateral petals which in turn overlap two smallest anterior
petals as in Pea. (Papilionaceous)
Perianth:If calyx and corolla are not distinguishable (tepals), they are called perianth
3. Androecium:Stamens (filament, anther), male reproductive organ and produce pollengrains. Stamens
may be epipetalous (attach to petals) or epiphyllous (attachto perianth). Stamens may be monoadelphous
(united into one bundle-china rose), diadelphous(two bundles-pea) or polyadelphous
(more than two bundles-citrus).
4. Gynoecium:Made up of one or more carpels, female reproductive part, consists of
stigma, style and ovary, ovary bears one or more ovules. Carpels maybe apocarpous
(free) or syncarpous (united). After fertilisation, ovules developinto seeds and ovary into fruit.
Placentation:The arrangement of ovules within the ovary.
Types of Placentation:
1. Marginal:Placenta forms a ridge along the ventral suture of ovary as in pea.
2. Axile:Margins of carpels fuse to form central axis as in China rose.
3. Parietal:Ovules develop on inner wall of ovary as in mustard.
4. Free central:Ovules borne on central axis, lacking septa as in Dianthus.
5. Basal:Placenta develops at the base of ovary as in sunflower.
The fruit:
After fertilization, the mature ovary develops into fruit. Theparthenocarpic
fruits are formed from ovary without fertilization.
.......................................................
SOME IMPORTANT QUESTIONS:
1. Define placentation. Describe various types of placentation.
Various types of root
1. Tap root: Originates from radicle. Dicotyledonous plants e.g., mustard,gram, mango.
2. Fibrous root: Originates from base of the stem. Monocotyledonous plants e.g., wheat, paddy.
3. Adventitious root: Originates from parts of the plant other than radicle. Banyan tree (Prop roots)Maize
(Stilt roots)
Root Cap:The root is covered at the apex by the thimble-like structure which protects the tender apical part of
the root. It is positively Geotropic, hydrotropic and negatively phototropic.
Regions of the root:
1. Region of meristematicactivity:Cells of this region have the capabilityto divide.
2. Region of elongation:Cells of this region are elongated and enlarged, responsible for root growth.
3. Region of Maturation:This region has differentiated and matured cells. Some of the epidermal cells of this region form thread-like root hairs for absorption of water and minerals
Modifications of Root:
Roots are modified for support, storage of food, respiration.......
• For support:Prop roots in Banyan tree, stilt roots in maize andsugarcane.
• For respiration:Pneumatophores in Rhizophora(Mangrove).
• For storage of food:Fusiform (radish), Napiform (turnip), Conical (carrot).
The Stem:Stem is the aerial part of the plant and develops from plumule of theembryo.It bears nodes and
internodes.
Modifications of Stem:
In some plants the stems are modified to perform the function of storage of food, support, protection
and vegetative propagation.
Modifications of Stem......
• For food storage:Rhizome (ginger), Tuber (potato), Bulb (onion), and Corm(colocasia).
• For support:Stem tendrils of watermelon, pumpkin, cucumber.
• For protection:Axillary buds of stem of Citrus, Bougainvillea get modified into pointed thorns.
• For vegetative propagation:Underground stems of grass, strawberry, lateral branches of mint and
jasmine.
• For assimilation of food:Flattened stem of Opuntia contains chlorophyll and performs
photosynthesis.
The Leaf: Develops from shoot apical meristem, flattened, green structure, manufacture the
food by photosynthesis. It has bud in axil. A typical leaf has leaf base, petiole and lamina.
Venation:The arrangement of veins and veinlets in the lamina of leaf.
Types of Venation:
1. Reticulate:Veinlets form a network as in leaves of dicotyledonous plants(China rose, Peepal).
2. Parallel:Veins run parallel to each other as in leaves of monocotyledonous plants (grass, maize).
Types of Leaves
Simple Compound
(Single leaf blade)(Leaf has number of leaflets)
e.g., mango, peepal
Pinnately Compound Palmately Compound
(Neem, rose) (Silk cotton)
Phyllotaxy: The pattern of arrangement of leaves on the stem or branch.
Types of phyllotaxy
Alternate Opposite Whorled
(Single leaf at a node) (Two leaves at a node) (More than two leaves in a whorl at a node)
e.g., China rose, Mustard e.g., Calotropis, guava e.g., Nerium,Alstonia
Modifications of Leaves:
• Tendrils: (Climbing) −Sweet wild pea
• Spines (Protection) −Aloe, Opuntia, Argemone
• Pitcher: (Nitrogen Nutrition) −Nepenthes
• Fleshy: (Storage) −Onion
The Inflorescence:The arrangement of flowers on the floral axis.
Main types of Inflorescence:
1. Racemose:Main axis is unlimited in growth-Radish, Mustard, Amaranthus. Flowers in Acropetal order.
2. Cymose:Main axis is limited in growth-Cotton, Jasmine, Calotropis. Flowers in Basipetal order.
3. Special type:Ficus, Salvia, Euphorbia.
The Flower:A flower is modified shoot and reproductive unit in angiosperms.
Flowers may be unisexual or bisexual, bracteate or ebracteate. Some features of flower are:
Symmetry of flower ............
Actinomorphic (radial
symmetry)
Zygomorphic (bilateral
symmetry)
Asymmetric (irregular)
On the basis of no. of
floral appendage................
Trimerous
Tetramerous
Pentamerous
On the basis of position of calyx,corolla,
androecium with respect to ovary
Hypogynous (superior ovary)
Perigynous (half inferior ovary)
Epigynous (inferior ovary)
Parts of aflower......( DRAW DIAGRAM )
1. Calyx:Sepals, green in colour, leaf like.Gamosepalous− (Sepals united)Polyseppalous− (Sepals free)
2. Corolla:Petals, usually brightly coloured to attract insects forpollinationGamopetalous− (Petals
united)Polypetalous − (Petals free)
Aestivation:The mode of arrangement of sepals or petals in floral bud with respect to other members of the same whore.
Types of aestivation:
1. Valvate:Sepals or petals do not overlap the sepal or petal at margins as in Calotropis.
2. Twisted:Sepals or petals overlap the next sepal or petal as in China rose.
3. Imbricate:The margins of sepals or petals overlap one another but not in any definite direction as in
Gulmohar.
4. Vexillary:The largest petal overlaps the two lateral petals which in turn overlap two smallest anterior
petals as in Pea. (Papilionaceous)
Perianth:If calyx and corolla are not distinguishable (tepals), they are called perianth
3. Androecium:Stamens (filament, anther), male reproductive organ and produce pollengrains. Stamens
may be epipetalous (attach to petals) or epiphyllous (attachto perianth). Stamens may be monoadelphous
(united into one bundle-china rose), diadelphous(two bundles-pea) or polyadelphous
(more than two bundles-citrus).
4. Gynoecium:Made up of one or more carpels, female reproductive part, consists of
stigma, style and ovary, ovary bears one or more ovules. Carpels maybe apocarpous
(free) or syncarpous (united). After fertilisation, ovules developinto seeds and ovary into fruit.
Placentation:The arrangement of ovules within the ovary.
Types of Placentation:
1. Marginal:Placenta forms a ridge along the ventral suture of ovary as in pea.
2. Axile:Margins of carpels fuse to form central axis as in China rose.
3. Parietal:Ovules develop on inner wall of ovary as in mustard.
4. Free central:Ovules borne on central axis, lacking septa as in Dianthus.
5. Basal:Placenta develops at the base of ovary as in sunflower.
The fruit:
After fertilization, the mature ovary develops into fruit. Theparthenocarpic
fruits are formed from ovary without fertilization.
.......................................................
SOME IMPORTANT QUESTIONS:
1. Define placentation. Describe various types of placentation.
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