Chapter 9: Exercise Solutions

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1. Choose Correct Option

 

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2. Answer the Following Questions

A. Two of the vegetables we consume are nothing but leaf bases. Which are they?

Answer:Onion and Garlic

The vegetables that are primarily fleshy leaves organized as a bulb areOnion

andGarlic. The edible part of the bulb consists of

fleshy leavesthat show

concentric arrangementand

store food material.

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B. Opuntia has spines but Carissa has thorns. What is the difference? Answer: The difference lies in their

morphological origin:

 

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C. Teacher described Hibiscus as solitary Cyme. What does it mean?

Answer:

Cymose Inflorescence: The term "cymose" refers to an inflorescence where thegrowth of the peduncle is finite or limited

because theapical meristem terminates into a flower.

Characteristics:

• In a cymose arrangement, theoldest flower is at the apex
• New flowers are produced in basipetal succession

Solitary Cyme: If the flower is described as "solitary Cyme," it indicates a condition where asingle flower terminates the growth of the axis.

Additional Note: Hibiscus is also cited as an example of anactinomorphic flower

(radial symmetry), meaning it can be cut along any diameter and shows mirror images.

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3. Write Notes On A. Fusiform Root

Definition: The fusiform root is a type of modification of the tap root used forfood storage.

Characteristics:

• Swollen in the middle

  andtapers towards both ends

• Forms a

  spindle-shaped structure

Example

: Radish (Raphanus sativus)

 

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B. Racemose Inflorescence

Definition: In a racemose inflorescence, thegrowth of the peduncle

(main axis) isinfinite or unlimited.

Key Features:

• Apical bud remains freefor continuous growth
• Older flowers

  are located at thebase

• Flowers are borne in

  acropetal succession(base to apex)

• Order of opening is

  centripetal(when peduncle is disc-shaped)

Advantage: Allows continuous production of new flowers while older ones mature and are pollinated.

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C. Fasciculated Tuberous Roots Definition: These roots are a type of modification of

adventitious rootsused for

food storage. Characteristics:

• Appear as a

  cluster of rootsarising from a

  single point

• Becomethick and fleshy

  due tostored food

• Typically found at the

  base of the stem

Examples

: Dahlia, Asparagus

 

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D. Region of Cell Maturation

Definition: This region constitutes themajor portion of the root.

Characteristics:

• Cells undergodifferentiation

  to form various types of tissues

• Cells are generallyimpermeable to water

  due tothick-walled nature

Functions:

• Fixation of the plantin soil
• Conduction of absorbed substances
• Development of lateral roots

 

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E. Rhizome

Definition: A rhizome is a modification of theunderground stem

used forperennation, storage, and vegetative propagation.

Characteristics:

• Prostrate,dorsiventrally thickened, and

  brownishin color

• Grows either

  horizontally or obliquelybeneath the soil

• Exhibits

  nodes and internodes

• Bearsscale leaves

  andterminal/axillary buds

Growth Patterns:

• Sympodial growth: Growth continues with lateral buds (e.g., Ginger, Turmeric, Canna)
• Monopodial growth: Terminal bud brings about growth (e.g., Nymphea, Nelumbo/Lotus, Pteris/Fern)

Examples

: Ginger (Zingiber officinale), Turmeric (Curcuma domestica)

 

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F. Stolon

Definition: A stolon is aslender lateral branch

that originates from thebase of the main axis.

Growth Pattern:

• May initially growupward

  like an ordinary branch

• Bends and touches the ground
• Terminal buddevelops into a new shoot when on ground
• Adventitious roots

  develop at the point of contact

Function:

Vegetative propagation Example: Mentha (Mint)

 

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G. Leaf Venation

Definition: Venation is defined as themode of arrangement of veins and veinlets

within theleaf lamina.

Functions of Veins:

• Conduction of water, minerals, and food
• Establish the structural frameworkof the lamina

Importance: Provides mechanical strength and support to the leaf while allowing nutrient and water transport.

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H. Cymose Inflorescence Definition: In a cymose inflorescence, the

growth of the peduncle(main axis) is

finite or limited. Key Features:

• Apical meristem terminates in a flower
• Oldest flower

  is located at theapex

• New flowers are produced in

  basipetal succession(apex to base)

• Order of opening is

  centrifugal(if peduncle is compressed from top)

Advantage: Ensures efficient pollination of flowers that mature in sequence from the center outward.

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I. Perianth Definition: The perianth is the

floral whorlpresent when the

calyx and corolla remain undifferentiated. Structure:

• Individual units are called

  tepals

Types

:

• Polyphyllous: Tepals are

  free(not fused)

• Gamophyllous: Tepals are

  fusedtogether

Sub-types:

• Sepaloid perianth: Green tepals that can perform photosynthesis
• Petaloid perianth: Brightly colored tepals that assist in pollination

Functions

:

• Protects

  the inner floral whorls

• Assists in pollination(if brightly colored)
• Performs photosynthesis

  (if green)

Examples

: Lily, Amaranthus, Celosia

 

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J. Vexillary Aestivation

Definition: Vexillary aestivation is amode of arrangement

seen inflower buds.

Structure(Butterfly-shaped corolla with 5 petals):

Characteristic of: Corolla ofPisum sativum

(Pea) and other Fabaceae family plants

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K. Axile Placentation Definition: Placentation describes the

mode of arrangement of ovuleson the

placentainside the

ovary. In Axile Placentation:

• Ovules are located on the

  central axisof a

  multilocular ovary

• Multiple ovules arranged along the central column

Examples

: China rose, Cotton

Significance: Allows for efficient distribution of nutrients to multiple developing seeds.

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4. Identify the Following Figures and Write Down the Types of Leaf Arrangement Based on the figures illustrating phyllotaxy, the types of leaf arrangement are:

Alternate Phyllotaxy

• Pattern: Single leaf arising from each node
• Arrangement: Leaves appear at alternating positions along the stem
• Example: Mango

Opposite Decussate Phyllotaxy

• Pattern: A pair of leaves from each node
• Arrangement: Consecutive pairs arranged at aright angle (90°)

  to each other

• Example: Calotropis

 

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5. Students Were on an Excursion...

A. Wiry Outgrowth Between Leaf and Stem Structure Observed: Stem tendril

Definition: A modification of abud

that develops into athin, wiry, coiled structure.

Origin: Modification ofaxillary bud

(located in the axil, or in between the leaf and stem) Function: Provides

additional support for climbing Characteristics:

• Thin and wiry
• Photosynthetic
• Leafless
• Coiled structure
• Possess adhesive glands for fixation

 

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B. Green Plant with Flat Stem, No Leaves, Covered by Soft Spines

Structure Observed: Phylloclade Definition: A modification of the

steminto a

leaf-like photosynthetic organ. Characteristics:

• Thick, fleshy, and succulent
• Contains

  mucilage for retaining water

• True leaves are reducedto spines or scales
• Performs photosynthesis

Form: Flat and leaf-like in appearance Example:

Opuntia Purpose:

Xerophytic adaptationfor survival in arid conditions

 

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C. Many Obliquely Produced Roots from Lower Nodes

Structure Observed: Stilt roots Definition: Specialized roots arising from the

lower nodes of the stem. Characteristics:

• Grow obliquely downward

  into the soil

• Helppenetrate the soil

  effectively

Function

: Provide

mechanical supportto the plant

Occurrence: Particularly common in monocots and weak-stemmed plants Significance: Allow the plant to remain stable on soft or unstable ground.

 

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D. Many Plants in Marshy Region with Upwardly Growing Roots (Visible During Low Tide)

Structure Observed: Pneumatophores (Respiratory Roots) Definition: Specialized roots produced by

halophytes(plants growing in marshy places or saline swamps).

Characteristics:

• Negatively geotropic(grow vertically upwards)
• Conical projections

  around main trunk

• Possesslenticels

  (minute pores for gaseous exchange)

Function

:

• Obtain sufficient air for respiration
• Overcome the problem of waterlogged soil

Problem Solved: In waterlogged soil, the main root system doesn't get sufficient oxygen, affecting mineral absorption Examples:

Rhizophora,Avicennia,

Sonneratia,Heritiera

(var. sundri)

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E. Plant with Leaves Having Long Leaf Apex Curling Around Support Structure Observed: Leaf tendril

Specific Type:Leaf tip tendril

Definition:Thin, green, wiry, coiled structures

derived from themodification of a leaf part.

Origin: Modification of leaf (or leaflet or leaf tip) Characteristics:

• Thin and wiry
• Green color (photosynthetic)
• Coiled structure
• Highly sensitive to touch

Function: Help theplant climb

by coiling around nearby supports

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F. Plant Growing on Another Plant (Not a Parasite) with Two Types of Roots Structure Observed: Epiphytic plant (e.g., Orchid)

Examples:Vanda,

Dendrobium Definition: Plants that

grow on treesbut are

NOT parasites(they don't absorb nutrients from the host).

Types of Roots: 1. Regular Roots

• Absorb moisture from the air

2. Epiphytic Roots (Specialized)

• Hang in the airwithout entering soil
• Covered with

  velamen tissue(spongy membranous covering)

• Velamen tissue characteristics:
• Absorb moisture from air
• Hygroscopic (water-absorbing)
• Possess porous walls
• Often silvery white or green
• Without root cap

Habitat: Dense rain forests where soil moisture is unavailable

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G. Onion Slices Served for Lunch Structure Consumed:

Fleshy leaves of the bulb What is the Bulb?

• Underground stem modification
• Highly reduced and discoid stem
• Bears a

  whorl of fleshy scale leaves

• Food storage organ

Structure of Onion Bulb:

Botanical Classification:Tunicated or layered bulb

with concentric arrangement of fleshy leaves

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H. Marigold Flower (Not One Flower)

Structure Observed:Inflorescence

What the Teacher Meant:

• The structure is NOT a single flower
• It is an

  inflorescence- a

  specialized axisover which

  many flowers (florets) are borne

• The structure is composed ofmultiple individual flowers

  clustered together

Composition

:

• Ray florets

  (outer): Unisexual neuter flowers (lack both reproductive whorls)

• Disc florets(inner): Bisexual flowers

Scientific Name:Tagetus

(Marigold) Significance: This clustering makes the plant more attractive to pollinators and increases pollination efficiency.

 

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I. Papaya Fruit with Seeds Attached to Sides

Structure Observed:Parietal placentation

Observation: All seeds areattached to the sides

(inner walls) of the fruit Placentation Type:

Parietal Placentation Characteristics:

• Ovules are placed on the

  inner wallof the

  unilocular ovary

• Ovary has only one chamber
• Develops inmulticarpellary syncarpous gynoecium

How Seeds Form: When ovules mature after fertilization, they become seeds attached to the inner wall where the ovules were attached Example: Papaya is listed as a plant exhibiting parietal placentation

 

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6. Match the Following

Types of Placentation with Figure Index

 

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7. Observe the Following Figures and Label the Different Parts

Left Figure (Seed/Ovule Structure)

Important Parts of a Seed:

 

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Right Figure (Anther/Stamen Structure)

Important Parts of a Stamen:

Note: In most flowers, the anther isbilobed

(2 lobes), but in some plants likeHibiscus, it may be

monothecous(single lobe).

 

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8. Differentiate with Diagrammatic Representation

A. Racemose and Cymose Inflorescence

Visual Difference:

• Racemose: Single main elongated axis with flowers arranged along its length
• Cymose: Branched axis with central flower and lateral flowers around it

 

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B. Reticulate and Parallel Venation

Functional Difference

:

• Reticulate: Better for broad leaves requiring support from multiple directions
• Parallel: Better for long, narrow leaves requiring linear support

 

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C. Tap Root and Adventitious Roots

Key Differences Summary:

• Tap Root: Single main root | Deep soil penetration | Dicots | Hierarchical branching
• Adventitious Roots: Multiple roots from stem base | Superficial growth | Monocots | Similar-sized roots | Fibrous appearance