• The word morphology means external structure. We need to understand standard technical terms and standard definition.
  • Root system- The underground part of plant called root system.
  • Shoot system- The portion of plant which above the ground called shoot system.

THE ROOTS-

  • Important terms-
    • Dicotyledonous plant- Those plant which have 2 cotyledons (seed leaves). When they germinate(or grow), 2 leaves come first.
    • Primary roots- It is main root which grow inside the soil. It bear many sub roots(or lateral roots) as referred to secondary roots, tertiary roots etc.
  • Types of root system-
    • 1. Tap root system- It consist main thick root(or tap root) which grow directly form seed, and smaller lateral roots branch off form it. ex- pea, carrot, etc.
    • 2. Fibrous root system- It have many thin, similar-sized roots arise from base of stem, instead of a single main root. ex- wheat(gehoon), grass(ghaas) etc.
    • 3. Adventitious root- It arise form parts of plant other than radical. ex.- Sugarcane(ganna), Banyan tree(baragat) etc.
  • Functions of roots-
    • Absorption of water and mineral form soil.
    • Provide the proper grip of plant parts.
    • Store reserve food material.
    • Synthesis of plant growth regulators.
  • Region of roots-
    • Root cap- It is protective tissue at the tip of root that covers and safeguards the growing root apex as it pushes through soil.
    • Region of meristematic activity- The cell of this region present few thin layered with dense protoplasm and they divided continuously.
    • Region of elongation- It is the part of root which just behind the root tip where cells elongate rapidly and increasing the length of root.
    • Region of maturation- It is the part of root where cell differentiate into specialized tissues (such as xylem, phloem and root hairs) for performing specific functions.
    • Root hairs- It is thin, hair-like extension of root epidermal cells that increase the surface area for water and mineral absorption form the soil. The root hair form in region of maturation. Root hair absorb water and mineral form soil.
  • Modifications of Root-
    • In many plants, the root are modified to perform many function other that absorption and conduction of water and minerals.
    • In modification the root change their shape and modified to support, storage of food and respiration.
      • Prop root- They are adventitious that grow form the stem or branches of a plant and provide extra support. ex- banyan tree, etc.
      • Stilt root- The are adventitious roots that grow obliquely form the lower nodes of the stem to provide additional support. ex- maize, sugarcane, etc.
      • Pneumatophores root- It is specialized root which grow vertically above the ground in swampy areas to help in gas exchanges. ex- mangroves and Rhizophora, etc.

THE STEM-

  • The stem are the opposite side of roots which bearing leaves, branches, flowers and fruits.
  • The stem develop in germinating of seed from embryo of plumule.
  • The stem contain notes (region of stem where leave are born) and internodes (region between 2 nodes).
  • Also stem bear buds (axillary or terminal).
  • Functions of stem-
    • Spreading out branches which bear leaves etc.
    • It transport water and mineral to conduct photosynthesis.
    • Some stem can perform functions like storage of food, support, protection and vegetative propagation.

Modifications of Stem

  1. Functions and Types of Modifications:
    • Stems can undergo structural changes to adapt and perform various functions beyond the typical stem role.
    • Underground stems:
      • Found in plants like potato, ginger, turmeric, zaminkand, and Colocasia.
      • Function: Store food and act as perennation organs to survive unfavorable growth conditions.
    • Stem tendrils:
      • Develop from axillary buds.
      • Slender, coiled structures helping climbing plants like gourds (cucumber, pumpkin, watermelon) and grapevines.
    • Thorns:
      • Modified axillary buds that turn into pointed, woody structures (e.g., Citrus, Bougainvillea).
      • Function: Protection against herbivores.
  2. Special Modifications:
    • Arid region plants (e.g., Opuntia, Euphorbia):
      • Stems become flattened or cylindrical and green to perform photosynthesis, compensating for reduced leaves.
    • Spreading stems:
      • Examples: Grasses and strawberries spread via underground stems for colonization of new niches.
    • Lateral branches:
      • Found in mint, jasmine, banana, and Chrysanthemum. These develop into new plants under the soil or above the ground, aiding in propagation.

The Leaf

  1. Structure:
    • Parts: Leaf base, petiole, and lamina (leaf blade).
    • Veins and veinlets provide rigidity and transport (water, minerals, and food).
  2. Types of Venation:
    • Reticulate: Network-like veinlets (common in dicots).
    • Parallel: Veins run parallel (characteristic of monocots).
  3. Types of Leaves:
    • Simple Leaf: Single lamina.
    • Compound Leaf:
      • Pinnately compound: Leaflets on a common axis (e.g., neem).
      • Palmately compound: Leaflets arise from a common point (e.g., silk cotton).
  4. Phyllotaxy (Leaf Arrangement):
    • Alternate: Single leaf per node alternates (e.g., sunflower).
    • Opposite: Pair of leaves at each node (e.g., guava).
    • Whorled: Multiple leaves form a circle at a node (e.g., Alstonia).
  5. Modifications:
    • Tendrils: For climbing (e.g., peas).
    • Spines: For defense (e.g., cacti).
    • Food Storage: Seen in onion and garlic.
    • Photosynthesis by petioles: In Australian acacia.
    • Insect-catching leaves: In pitcher plant, Venus flytrap.

The Inflorescence

  1. Definition:
    • Arrangement of flowers on the floral axis.
    • Two types:
      • Racemose: Main axis grows continuously; flowers in acropetal order (older at the base, younger at the tip).
      • Cymose: Main axis ends in a flower; flowers in basipetal order (younger at the base, older at the tip).

The Flower

  1. Structure:
    • Parts: Calyx, corolla (accessory), androecium, gynoecium (reproductive organs).
    • Flowers can be bisexual (both androecium and gynoecium) or unisexual.
  2. Symmetry:
    • Actinomorphic: Radial symmetry (e.g., mustard).
    • Zygomorphic: Bilateral symmetry (e.g., pea).
    • Asymmetric: No symmetry (e.g., canna).
  3. Floral Types:
    • Trimerous, tetramerous, pentamerous: Based on multiples of 3, 4, or 5.
    • Bracteate: Flowers with bracts at the base.
    • Ebracteate: Flowers without bracts.
  4. Position of Floral Parts:
    • Hypogynous: Ovary superior; other parts below (e.g., mustard).
    • Perigynous: Ovary half-inferior; other parts at the same level (e.g., rose).
    • Epigynous: Ovary inferior; other parts above (e.g., guava).

Extra Insights for Competitive Exams

  1. Stem Adaptations:
    • Rhizomes (ginger): For storage and vegetative propagation.
    • Bulbs (onion): Compact stem surrounded by fleshy leaves.
  2. Leaf Modifications:
    • Phyllode: Petiole replaces the leaf (Australian acacia).
    • Insectivorous plants: Nutrient-deficient soil leads to leaf traps for insects.
  3. Inflorescence Examples:
    • Racemose: Mustard.
    • Cymose: Jasmine.
  4. Key Terminology:
    • Perennation: Surviving adverse conditions.
    • Thalamus: Base of flower supporting floral organs.
  5. Memory Aids:
    • “Leaves of monocots run parallel like train tracks.”
    • “Racemose grows continuously like a race track.”

1. Parts of a Flower

  • Four Floral Whorls:
    1. Calyx (outermost, sepals protect buds)
    2. Corolla (bright petals attract pollinators)
    3. Androecium (male part: stamens with filament and anther)
    4. Gynoecium (female part: carpels with stigma, style, ovary)

2. Detailed Study of Floral Parts

2.1. Calyx
  • Outer whorl, consists of sepals (green, leaf-like).
  • Types:
    • Gamosepalous: Sepals united.
    • Polysepalous: Sepals free.
2.2. Corolla
  • Composed of petals, often colored for pollination.
  • Types:
    • Gamopetalous: Petals united.
    • Polypetalous: Petals free.
  • Shapes: Tubular, bell-shaped, funnel-shaped, or wheel-shaped.
  • Aestivation: Arrangement in buds:
    • Valvate: Margins just touch.
    • Twisted: Margins overlap in one direction (e.g., China rose).
    • Imbricate: Irregular overlapping (e.g., Cassia).
    • Vexillary: Unique to legumes (e.g., pea).
2.3. Androecium
  • Male organ; stamens with filament (stalk) and anther (pollen sacs).
  • Types of Union:
    • Epipetalous: Attached to petals (e.g., brinjal).
    • Epiphyllous: Attached to perianth (e.g., lily).
    • Monoadelphous: Stamens in one bundle (e.g., China rose).
    • Diadelphous: Two bundles (e.g., pea).
    • Polyadelphous: More than two bundles (e.g., citrus).
2.4. Gynoecium
  • Female organ; carpels consist of stigma (pollen reception), style (connects stigma to ovary), and ovary (contains ovules).
  • Types:
    • Apocarpous: Free carpels (e.g., lotus).
    • Syncarpous: Fused carpels (e.g., tomato).
  • Placentation (Ovule Arrangement):
    • Marginal: Along one side (e.g., pea).
    • Axile: Attached to central axis (e.g., tomato).
    • Parietal: Attached to inner walls (e.g., mustard).
    • Free Central: Central axis without septa (e.g., Dianthus).
    • Basal: Single ovule at base (e.g., sunflower).

3. Fruits

  • Ripened ovary after fertilization; may be parthenocarpic (develop without fertilization).
  • Structure: Pericarp (fruit wall) differentiates into epicarp (outer), mesocarp (middle), and endocarp (inner).
  • Examples:
    • Drupe: Mango (fleshy mesocarp), Coconut (fibrous mesocarp).

4. Seeds

  • Formed from ovules; consists of seed coat and embryo.
  • Dicot Seed (e.g., gram):
    • Embryo with two cotyledons.
    • Structures: Testa (outer), Tegmen (inner), Micropyle (small pore), Radicle (root), Plumule (shoot).
    • Non-Endospermic: Mature seeds lack endosperm.
  • Monocot Seed (e.g., maize):
    • Single cotyledon (scutellum), endosperm bulky for storage.
    • Protective layers: Coleoptile (plumule), Coleorhiza (radicle).

5. Classification

  • Flowering plants classified by morphological and reproductive features:
    • Habit: Herb, shrub, or tree.
    • Inflorescence: Racemose (indeterminate) or cymose (determinate).
    • Floral formula and diagram represent the arrangement and relation of floral parts.

6. Example Families

Fabaceae (Legume Family):
  • Flower: Zygomorphic, papilionaceous (vexillary aestivation).
  • Economic Importance: Pulses (pea), oils (soybean), fibers (sunhemp).
Solanaceae (Potato Family):
  • Flower: Actinomorphic, bicarpellary ovary.
  • Economic Importance: Food (potato), medicine (belladonna).
Liliaceae (Lily Family):
  • Flower: Actinomorphic, monocot characteristics.
  • Economic Importance: Ornamentals (tulip), medicine (Aloe).

Extra Knowledge for Competitive Exams

  1. Floral Formulas: Key tool for identifying plant families.
    • Example: Fabaceae: % K(5) C1+2+(2) A(9)+1 G1
  2. Placentation Importance: Axile placentation often seen in crops.
  3. Fruit Types: Drupe (mango) vs. Capsule (mustard).
  4. Aestivation Patterns: Essential for taxonomy; twisted common in Malvaceae.
  5. Monocot vs. Dicot Seeds:
    • Monocots: One cotyledon, parallel venation (e.g., grasses).
    • Dicots: Two cotyledons, reticulate venation (e.g., peas).

Understanding these concepts helps in identifying plant families, understanding crop features, and applying knowledge in agriculture or ecology.

These all are the notes of chapter 5 in biology. And important questions are below HERE. *#THANKS FOR VISITING, VISIT AGAIN#*😊

Q1: What is the root system?
A: The underground part of the plant is called the root system.

Q2: What is a tap root system?
A: A tap root system has a thick main root (tap root) growing from the seed, with smaller roots branching off. Example: Pea, carrot.

Q3: What is a fibrous root system?
A: A fibrous root system has many thin roots of similar size arising from the stem base. Example: Wheat, grass.

Q4: What are adventitious roots?
A: Roots that grow from plant parts other than the seed or radicle. Example: Sugarcane, banyan tree.

Q5: Name two functions of roots.
A:

  1. Absorb water and minerals from the soil.
  2. Provide support to the plant.

Stem System

Q6: What is the shoot system?
A: The part of the plant above the ground is called the shoot system.

Q7: What are nodes and internodes?
A:

  • Node: A region on the stem where leaves grow.
  • Internode: The space between two nodes.

Q8: Name one function of stems.
A: Stems transport water and minerals and support leaves, flowers, and fruits.

Q9: What is a stem tendril?
A: A thin, coiled structure growing from the stem that helps climbing plants like cucumber and grapevine.

Leaves

Q10: What is the structure of a leaf?
A: A leaf has three parts:

  1. Leaf base (attaches to the stem),
  2. Petiole (stalk),
  3. Lamina (flat part).

Q11: What are the two types of venation in leaves?
A:

  1. Reticulate venation: Veins form a network (common in dicots).
  2. Parallel venation: Veins run parallel (common in monocots).

Q12: What is phyllotaxy? Name its types.
A: The arrangement of leaves on a stem or branch. Types:

  1. Alternate: One leaf per node (e.g., sunflower).
  2. Opposite: Two leaves per node (e.g., guava).
  3. Whorled: Several leaves in a circle at a node (e.g., Alstonia).

Flower and Inflorescence

Q13: What is inflorescence?
A: The arrangement of flowers on the floral axis.

Q14: What are the types of inflorescence?
A:

  1. Racemose: Flowers grow continuously with younger flowers at the top. Example: Mustard.
  2. Cymose: Flowers stop growing, with younger flowers at the base. Example: Jasmine.

Q15: What are the four parts of a flower?
A:

  1. Calyx: Green, leaf-like sepals that protect the bud.
  2. Corolla: Bright petals that attract pollinators.
  3. Androecium: Male part (stamens).
  4. Gynoecium: Female part (carpels).

Fruit and Seed

Q16: What is a fruit?
A: A fruit is a ripened ovary after fertilization.

Q17: What is a drupe? Give an example.
A: A drupe is a fruit with a fleshy middle layer. Example: Mango, coconut.

Q18: What are the differences between monocot and dicot seeds?
A:

  • Monocot: One cotyledon, parallel veins. Example: Maize.
  • Dicot: Two cotyledons, network veins. Example: Gram.