UNIT
– II
CHAPTER 5: MORPHOLOGY OF FLOWERING PLANTS
Seed – Plumule – stem
Radical – root
Types of roots à Taproot, Fibrous root, Adventitious root.
Regions of root - Region of maturation
Region of elongation
Region of meristematic tissues.
Root cap
Modification of roots:
· Storage- carrot, turnip
· Prop root- banyan tree (support)
· Stilt root – maize, sugarcane
· Pneumatophores- rhizophora (mangroves)
The stem: Plumule have nodes and internodesbears with axillary /terminal buds
Modification of stems :
1. Storage - potato, ginger, tturmeric (perennation)
2. Tendrils – axillary buds –coils - support (watermelon)
3. Thorns - axillary buds – citrus (protection)
4. Flattened stem – opuntia (do photosynthesis)
5. Vegetative propagation (grass, jasmine, banana)
The leaf:
· Short apical meristem gives rise to leaves arranged in acropetal order
· Do photosynthesis
· Three main parts are leaf base, petiole and lamina (leaf blade)
· Have stipules
· Leguminous petioles have pulvinus. (midrib)
· Venation - arrangement of veins and veinlets on a leaf.
Types of venation :
· Parallel- monocot leaves
· Reticulate – dicot leaves
Types of leaves:
1. Simple leaves
2. Compound leaves - Pinnately compound (eg. Neem) and Palmately compound (eg. Silk cotton)
Phyllotaxy: Pattern of arrangement of leaves on the stem /branch.
1. Alternate- china rose
2 Opposite- guava
3. Whorled- alstonia
Modification of leaves:
1. Tendrils - pea (support)
2. Spines - cacti (protection, water ioss)
3. Storage - onion/ garlic
4. Petiole leaves – acacia
5. Pitcher leaves – insectivorous plant (venus fly trap)
The inflorescence: Arrangement of flowers on the floral axis
Types of inflorescence: Depending on whether the apex gets converted in to a flower/continues to grow there are two major types;
1. Racemose. Main axis continues to grow laterally (in an acropetal succession)
2. Cymose. Main axis terminates in a flower so limited growth (basipetal order)
The flower:
· Four whorls. Sepal, petal, gynoecium, and androecium
· Thalamus/receptacle
· Trimerous/tetramerous/pentamerous/polymerous
· Bracteates/ebracteate/bract. (Protective sheet around the flower)
· Bisexual/unisexual
· Actinomorphic (mustard ) zygomorphic ( pea ) asymmetric ( canna )
Based on the position of ovary:
1. Hypogynous ovary ( mustard ) superior
2. Perigynous ovary ( rose ) half inferior
3. Epigynous ovary ( guava, cucumber ) inferior
Parts of flower:
1. Calyx. Made of sepals. Can be gamosepalous/polysepalous
2. Corolla. Made of oetals. Gamopetalous/ polypetalous
· Aestivation: Arrangement of sepals/ petals in floral bud
· Main types are valvate (petunia alba , calotropis)
twisted(china rose ), imbricate( gulmohur) vexillary (pea, bean )
3. Androecium.
· Staminode- sterile stamen
· Epipetalous. Attached to the petal
· Epiphyllous- attached to the perianth
· Polyadelphous- Free stamens
· Monoadelphous- united as one bunch ( china rose )
· Diadelphous – united two bundles ( pea )
· Polyadelphous – many bundles ( citrus )
4. Gynoecium- one/ more carpels
· Ovules attached on the wall of ovary called placenta.
· Apocarpous - Free carpels ( lotus, rose )
· Syncarpous - Carpels are fused (mustard, tomato )
· After fertilization ovules devopls into seed.
· Ovary develops into fruit
· Placentation: Arrangement of ovules within the ovary.
· Different types are marginal (pea), axile (china rose, lemon, tomato),
Parietal (mustard), freecentral (primrose) and basal (sunflower)
The fruit:
· Parthenocarpic fruit: Formation of fruits without fertilization of ovary. Ex. Seedless grapes, seedless orange.
· Two parts of a fruit are pericarp and seeds.
· Pericarp has epicarp, mesocarp and endocarp
· Both mango and coconut are known as drupe fruits (fruits formed from single ovary /carpel)
· Perianth: Fused petals and sepals.
The seed:
· Fertilized ovules.
· Made up of seed coat and an embryo
· Embryo with radical and plumule with one cotyledon or two cotyledon
Structure of a dicot seed:
· Seed coat, Testa and tegmen
· Hilum - small pore (place where it is attached to fruit)
· Micropyle. (water enters)
· Endosperm, cotyledons, embryonal axis (plumule and radicle)
· Mature seeds in dicot do not have endosperm called non-endospermic seeds. ( stored food is utilized by embryo)
Structure of monocotyledonous seed:
· Mostely endosperm except orchids
· Endosperm is bulky and store food
· Aleurone layer (produce enzymes to hydrolise proteins for embryo )
· Cotyledon is scutellum
· Protective coats- coleoptiles (piumule ), coleorhizae ( radical )
Semi – technical description of a typical flowering plant:
· Scientific language
· Floral diagram and floral formula (check text book)
Floral formula by symbols:
Br - Bracteate
_
K - Calyx G - Inferior ovary
C - Corolla
P - Perianth
A - Androecium
G - Gynoecium
G Superior Ovary
CHAPTER 5: MORPHOLOGY OF FLOWERING PLANTS
Seed – Plumule – stem
Radical – root
Types of roots à Taproot, Fibrous root, Adventitious root.
Regions of root - Region of maturation
Region of elongation
Region of meristematic tissues.
Root cap
Modification of roots:
· Storage- carrot, turnip
· Prop root- banyan tree (support)
· Stilt root – maize, sugarcane
· Pneumatophores- rhizophora (mangroves)
The stem: Plumule have nodes and internodesbears with axillary /terminal buds
Modification of stems :
1. Storage - potato, ginger, tturmeric (perennation)
2. Tendrils – axillary buds –coils - support (watermelon)
3. Thorns - axillary buds – citrus (protection)
4. Flattened stem – opuntia (do photosynthesis)
5. Vegetative propagation (grass, jasmine, banana)
The leaf:
· Short apical meristem gives rise to leaves arranged in acropetal order
· Do photosynthesis
· Three main parts are leaf base, petiole and lamina (leaf blade)
· Have stipules
· Leguminous petioles have pulvinus. (midrib)
· Venation - arrangement of veins and veinlets on a leaf.
Types of venation :
· Parallel- monocot leaves
· Reticulate – dicot leaves
Types of leaves:
1. Simple leaves
2. Compound leaves - Pinnately compound (eg. Neem) and Palmately compound (eg. Silk cotton)
Phyllotaxy: Pattern of arrangement of leaves on the stem /branch.
1. Alternate- china rose
2 Opposite- guava
3. Whorled- alstonia
Modification of leaves:
1. Tendrils - pea (support)
2. Spines - cacti (protection, water ioss)
3. Storage - onion/ garlic
4. Petiole leaves – acacia
5. Pitcher leaves – insectivorous plant (venus fly trap)
The inflorescence: Arrangement of flowers on the floral axis
Types of inflorescence: Depending on whether the apex gets converted in to a flower/continues to grow there are two major types;
1. Racemose. Main axis continues to grow laterally (in an acropetal succession)
2. Cymose. Main axis terminates in a flower so limited growth (basipetal order)
The flower:
· Four whorls. Sepal, petal, gynoecium, and androecium
· Thalamus/receptacle
· Trimerous/tetramerous/pentamerous/polymerous
· Bracteates/ebracteate/bract. (Protective sheet around the flower)
· Bisexual/unisexual
· Actinomorphic (mustard ) zygomorphic ( pea ) asymmetric ( canna )
Based on the position of ovary:
1. Hypogynous ovary ( mustard ) superior
2. Perigynous ovary ( rose ) half inferior
3. Epigynous ovary ( guava, cucumber ) inferior
Parts of flower:
1. Calyx. Made of sepals. Can be gamosepalous/polysepalous
2. Corolla. Made of oetals. Gamopetalous/ polypetalous
· Aestivation: Arrangement of sepals/ petals in floral bud
· Main types are valvate (petunia alba , calotropis)
twisted(china rose ), imbricate( gulmohur) vexillary (pea, bean )
3. Androecium.
· Staminode- sterile stamen
· Epipetalous. Attached to the petal
· Epiphyllous- attached to the perianth
· Polyadelphous- Free stamens
· Monoadelphous- united as one bunch ( china rose )
· Diadelphous – united two bundles ( pea )
· Polyadelphous – many bundles ( citrus )
4. Gynoecium- one/ more carpels
· Ovules attached on the wall of ovary called placenta.
· Apocarpous - Free carpels ( lotus, rose )
· Syncarpous - Carpels are fused (mustard, tomato )
· After fertilization ovules devopls into seed.
· Ovary develops into fruit
· Placentation: Arrangement of ovules within the ovary.
· Different types are marginal (pea), axile (china rose, lemon, tomato),
Parietal (mustard), freecentral (primrose) and basal (sunflower)
The fruit:
· Parthenocarpic fruit: Formation of fruits without fertilization of ovary. Ex. Seedless grapes, seedless orange.
· Two parts of a fruit are pericarp and seeds.
· Pericarp has epicarp, mesocarp and endocarp
· Both mango and coconut are known as drupe fruits (fruits formed from single ovary /carpel)
· Perianth: Fused petals and sepals.
The seed:
· Fertilized ovules.
· Made up of seed coat and an embryo
· Embryo with radical and plumule with one cotyledon or two cotyledon
Structure of a dicot seed:
· Seed coat, Testa and tegmen
· Hilum - small pore (place where it is attached to fruit)
· Micropyle. (water enters)
· Endosperm, cotyledons, embryonal axis (plumule and radicle)
· Mature seeds in dicot do not have endosperm called non-endospermic seeds. ( stored food is utilized by embryo)
Structure of monocotyledonous seed:
· Mostely endosperm except orchids
· Endosperm is bulky and store food
· Aleurone layer (produce enzymes to hydrolise proteins for embryo )
· Cotyledon is scutellum
· Protective coats- coleoptiles (piumule ), coleorhizae ( radical )
Semi – technical description of a typical flowering plant:
· Scientific language
· Floral diagram and floral formula (check text book)
Floral formula by symbols:
Br - Bracteate
_
K - Calyx G - Inferior ovary
C - Corolla
P - Perianth
A - Androecium
G - Gynoecium
G Superior Ovary