SCI/P/4: PLANT LIFE P.4

The course for studying Plant Life. This course is taken in Primary Four in Ugandan Syllabus.

Types of plants.

  1. Flowering plants
  2. Non-flowering plants.

Non- flowering plants

These are plants which do not produce or bear flowers.

Examples of non-flowering plants:

  1. Pines
  2. Ferns mosses
  • Eucalyptus
  1. Mosses

WATCH THE VIDEO BELOW TO LEARN ABOUT HOW SEEDS GERMINATE

Difference between plants and animals.

  1. Plants make their own food while animals feed on plants and other animals.

Flowering plants:

These are plants that produce or bear flowers.

Examples of flowering plants:

  1. mangoes                               6. cotton
  2. maize                                    7. Oranges
  3. pawpaws                               8. Jackfruit. etc
  4. peas
  5. coffee

Structure of a flowering plant.

Flowering Plant

 

Week two lesson two.

Systems of a flowering plant:

  1. Shoot system.
  2. Root system

Shoot system.

  1. The system of the plant above the ground level.
  2. It develops from the plumule of the seed.

Parts of the shoot system.

  1. Leaves
  2. Fruits
  3. Node
  4. Terminal bud
  5. Stem
  6. Flower
  7. Internode
  8. Auxiliary bud

 

Leaves:

Parts of a leaf:

 Simple Leaf

 

 

 

 

 

 

 

Functions of each part:

Leaf stalk ( petiole ):

To supply water to the leaf from the branch or stem.

 

Leaf base:

Attaches the leaf on to the stem.

 

Midrib / midvein:

Transports water and nutrients from the leaf stalk to other parts of the leaf.

 

Veins.

-Supply water and minerals from the mid vein to all parts of the leaf.

-Collects manufactured food from all parts of the leaf to the mid vein.

 

Stomata.

-For breathing.

– For transpiration.

 

Lamina ( leaf blade )

-For making food / photosynthesis.

 

Week two lesson three.

Leaf venation.

This is the arrangement of veins in a leaf.                                     

Types of leaf venation:

  1. Network leaf venation
  2. Parallel leaf venation.

Parallel leaf venation.

 Parallel Leaf Venation

 

 

 

 

Examples of plants with parallel leaf venation:

  1. All cereals eg maize, millet, wheat etc.
  2. Grass.
  3. Sugar cane.

Network leaf venation:

Network Leaf Venation 

                

 

 

 

 

 

 

 

 

 

 

 

Examples of plants with network leaf venation:

  1. All legumes eg beans, soya beans, peas, ground nuts.
  2. Jack fruit.
  3. Mango plant.
  4. Coffee plant. 

Type of leaves.

  1. Simple leaves
  2. Compound leaves.

Simple leaves:

They are leaves with one leaflet on the stalk.

Characteristics of simple leaves.

  1. They have one leaflet on the stalk.
  2. They have one margin.

 Week two lesson five.

Examples of simple leaves:

Simple entire.

Simple Entire

 

 

 

 

 

Plants with simple entire leaves:

  1. Mango
  2. Jack fruit
  3. Avocado

 

Simple serrated.

Simple serated

 

 

 

 

 

 

Examples:

  1. Black jack
  2. Lantana camara.

 

Simple lobbed leaf

Simple Lobbed

 

 

 

 

 

 

 

 

 

 

Simple palmate.

Simple Palmate

 

 

 

 

 

 

 

 

 

 

Example

Pawpaw leaf.

 

Simple lanceolate.

Parallel Leaf Venation

 

 

 

 

 

Examples

  1. Maize
  2. Sugar cane
  3. Sorghum.

Compound leaves;

They are leaves with many leaflets on one stalk.

Characteristics of compound leaves:

They have many leaflets on a leaf stalk.

Examples of compound leaves:

Compound pinnate leaves eg acacia.

Compound Pinnate

 

 

 

 

 

 

 

 

Compound bi-pinnate leaves eg jacaranda.

Compound Bi-pinnate

 

 

 

 

 

 Compound trifoliate leaves eg beans.

 Commpound Trifoliate

Compound digitate.

 Compound Digitate

 

 

 

 

 

Week two lesson Six

Uses of leaves to people:

 

  • Some leaves are eaten as food eg cabbages, onions etc
  • For sale
  • For thatching houses.
  • For making decorations eg palm leaves
  • For beverage eg tea leaves
  • For herbal medicine eg mango leaves, guava leaves etc
  • For feeding domestic animals.
  • For making mats.
  • For study purposes.

Uses of leaves to a plant.

  • For making food ( photosynthesis )
  • For breathing.
  • For transpiration.
  • Some store food for the plant eg onions and cabbages
  • Some are used for propagation eg bryophyllum

The onion bulb.

onion-bulb
 

 

 

 

 

 

 

 

Functions of parts of the onion.

Foliage leaves: make food for the onion.

Fleshy leaves; store food for the onion.

Scaly leaves; protect the inner parts of the bulb.

Axillary bud; grows into a new plant / shoot system.

Stem; –holds the leaves together 

-passage for water and mineral salts from the soil to the leaves.

– produces leaves, roots and buds. 

Transpiration.

It is the process by which plants lose water inform of vapour to the atmosphere.

  • It cools the plant
  • It helps the plant to suck more water from the soil. ( increases osmosis)

Importance of transpiration in the environment.

  • It helps in rain formation.

An illustration to show how transpiration occurs

Process of transpiration

 

 

 

 

 

 

How plants control the rate of transpiration.

  • By shedding their leaves.
  • Some plants have small leaves.
  • Some plants have thick leaves with few stomata.
  • Some plants have wax on their leaves.
  • Some plants have thorns instead of leaves.

Factors affecting the rate of transpiration.

  • Size of the leaf: the larger the leaves, the higher the rate of transpiration.
  • Temperature; the higher the temperature, the higher the rate of transpiration.
  • Humidity; the higher the humidity, the lower the rate of transpiration.

Photosynthesis.

It is the process by which plants make their own food.

Photo means light.

Synthesis means to make, manufacture or build.

Conditions for photosynthesis.

Chlorophyll; traps sunlight energy.

Sunlight; provides energy required for photosynthesis.     

Carbondioxide and water; are raw materials for photosynthesis

NB: the byproducts of photosynthesis are oxygen and water vapour.

Stems  

Uses of stems to people and other animals.

  • Some stems are eaten.
  • Some stems are used as firewood.
  • For herbal medicine.
  • For making timber.
  • For sale.
  • For study purposes.
  • some are habitats for some animals eg ants and birds

uses of stems to a plant.

  • Transports water and mineral salts from the roots to the leaves.
  • Transports food from the leaves to other parts of the plant.
  • Some stems are used for breathing.
  • Some stems are used for propagation eg cassava and sugar cane.
  • Stems support leaves and branches of a plant.
  • Some stems store food for the plant eg irish potatoes and sugar 

Types of stems.

Upright stem ( erect stem ) eg mango stem, orange stem, maize stem etc.

 Upright Stem

Climbing stems eg cucumber, coco yam, pea plants, morning glory etc

 Climbing Stems

 

 

 

 

 

 

 

Underground stems.  

Stem Tubers: They are swollen underground stems with stored food eg irish potatoes and coco yams.

Stem Tuber

 

 

 

 

 

 

 

 

 

Creeping stems eg sweet potatoes

Creeping Stems

 

 

 

 

 

 

NB: sugar cane is not a stem tuber because its stem is not found underground.

 

Ways plants climb others.

Using tendrils eg passion fruits, cucumber, peas, pumpkins etc.

 Passion Fruit

 

 

 

 

 

 

 

Using hooks or thorns eg bougainvillea

 Climbing Plants using thorns

 

 

 

 

 By twinning (clasping) eg morning glory, some beans and spang.

 Climbing Stems

 

 

 

 

 

 

 

Why some plants climb others.

  • For support
  • To get enough sunlight energy. 

Root system:

It is the part of a plant below the ground level.

Tap root system.

 Tap Root System

 

 

 

 

 

Examples of plants with tap root system.

  • Mango plant
  • Bean plant
  • Jack fruit plant
  • Orange plant

Main root: Holds the plant firmly in the ground.

Lateral roots: Holds the plant firmly in the ground.

Root hairs: Suck water and mineral salts from the soil.

Root cap: Protects the growing tip of the roots.

Fibrous root system.

The roots grow from one point at the base of the stem.

 Fibrous roots

 

 

 

 

 

 

 

 

 

 

 

 

Examples of plants with fibrous root system.

  • Maize plant
  • Sorghum plant
  • Millet plant
  • Rice plant.

NB: all cereal have fibrous root system.

 

Types of roots;

  • Primary roots
  • Secondary roots.

Examples of secondary roots.

  • Prop roots
  • Adventitious roots
  • Breathing roots
  • Clasping roots
  • Buttress roots
  • Stilt roots.

Prop roots: they are commonly found on cereals.

Their main purpose is to give extra support to the plant.

Examples of plants with prop roots

  • Maize plant
  • Sugar cane plant
  • Sorghum plant
  • Barley plant

 Adventitious roots

Adventitious roots.

They develop from the stems of the plant.

Examples of plants with adventitious roots.

  • Onion plant
  • Banana plant
  • Pumpkin plant
  • Pineapple plant. 

Uses of roots to people.

  • Some roots are eaten
  • Some are for herbal medicine.
  • Some are sold for money
  • For study purposes.

Uses of roots to plants.

  • Roots hold the plant firmly in the soil.
  • They suck water and mineral salts from the soil.
  • Some are used for breathing
  • Some store food for the plant eg cassava root, sweet potato root and carrots.
  • Some roots have root nodule which nitrogen fixing bacteria.

Root tubers.

These are plants with swollen underground roots with stored food.

Examples are;

  • Sweet potato plant
  • Cassava plant
  • Carrot plant. 

Flowers.

A flower is the reproductive part of a plant.

Uses of flowers to plants.

They are used for reproduction.

 

Uses of flowers to people.

  • For decoration
  • For showing love
  • For sale
  • For making perfume
  • Used as wreaths
  • Some flowers are eaten.
  • They are used as a sign of welcome.

Use of flowers to other animals.

Some collect nectar from flowers eg bees, humming birds, sun birds. 

The structure of a flower:

 Flower

 

 

 

 

Functions of each part:

Flower stalk: holds the flower onto the stem.

Sepals: protect the flower when it is still young (bud stage).

They make food for the plant since they have chlorophyll.

Petals: they are brightly coloured to attract pollinators.

Ovary; develops into a fruit after fertilization.

Ovules: develop into seeds after fertilization.

Anther head: produces pollen grains.

Stigma: receives pollen grains.

Style: holds the stigma in position.

Filament: holds the anther head in position.

 

Pistil:

This is the female part of a flower.

It is made up of ; stigma, style, ovary and ovules.

 Pistil

 

 

 

 

 

 

 

 

Stamen:

This is the male part of a flower.

It is made up of the anther head and the filament.

Stamen

 

 

 

 

 

 

 

 

 

NB: – A group of sepals is called calyx.

-A group of petals is called corolla. 

Pollination:

It is the transfer of pollen grains from the anthers to the stigma of a flower.

Types of pollination:

  • Self pollination
  • Cross pollination

Self pollination;

It is the transfer of pollen grains from the anthers to the stigma on the same flower.

Movement of pollen grains in self pollination

 Pollination

 

 

 

 

 

Plants which carry out self pollination:

  • Tomato plant
  • Wild magrigold

 Cross pollination:

It is the transfer of pollen grains from the anthers of one flower to the stigma of another flower but of the same kind.

Cross pollination

 

 

 

 

 

 

Plants which carry out cross pollination:

  • Maize plant.
  • Coco nut plant.
  • Pawpaw plant.
  • Cow pea plant.
  • Passion fruit plant.

 

Difference between self and cross pollinated flowers:

 

Self pollinated Cross pollinated
-filaments are longer than styles -Styles longer than filaments
-Pistils and stamen On same flower -Pistils and stamens on different flowers
-Produce large amounts of pollen grains -Produce small amounts of pollen grains.
-Anthers higher than stigmas -Stigmas higher than anthers 

Agents of pollination:

An agent of pollination is anything that carries pollen grains from the anthers to the stigma.

Some agents of pollination:

  • Insects like bees, butterflies, moths, beetles.
  • Birds like sunbirds, humming birds.
  • Wind
  • Animals like man.

Difference between wind and insect pollinated flowers.

Insect pollinated Wind pollinated
Have brightly coloured petals Have dull coloured petals
Have large petals Have small petals
Produce scent Produce no scent
Produce nectar Produce no nectar
Produce few pollen grains Produce a lot of pollen grains
Have sticky stigma Have hairy stigma
Have heavier pollen Have lighter pollen grains

Changes which occur after fertilization:

  • Ovules develop into seeds.
  • Ovary develops into a fruit.
  • Petals dry and fall off.

Seeds.

A seed is a developed ovule.

Types of seeds:

  • Monocotyledonous seeds.
  • Dicotyledonous seeds.

Monocotyledonous seeds:

These are seeds with one cotyledon.

Examples include:

  • Rice seeds
  • Sorghum
  • Wheat
  • Maize
  • Oats
  • Barley

Characteristics of monocotyledonous seeds.

  • They have one cotyledon.
  • They store food in the endosperm.
  • They undergo hypogeal germination.
  • The plants have parallel leaf venation.
  • The plants have fibrous root system.

External parts of a maize grain.

Internal parts of a maize grain:

 Part of a maize seed

Functions of each part;

Endosperm: stores food for the grain.

Cotyledon; suck food from the endosperm to the embryo.

Plumule sheath: protects the plumule .

Plumule; develops into a shoot system.

Radicle  sheath: protects the radicle.

Radicle: develops into a root system.

Embryo: this is made up of the plumule and radicle.

It develops into a new plant.

Testa (seed coat): protects the inside parts of the grain.

Dicotyledonous seeds:

These are seeds with two cotyledons.

Examples of dicotyledonous seeds:

  • Coffee
  • Beans
  • Soya
  • groundnuts

Characteristics of dicotyledonous seeds:

  • The plants have two cotyledons
  • The plants have tap root system
  • They store food in the cotyledon
  • The plants have network leaf venation
  • They undergo epigeal germination

External parts of a bean seed:

Internal parts of a bean seed:

Internal Parts of a been seed

 

 

 

 

 

 

 

Functions of each part:

Cotyledons: store food for the embryo.

Testa/ seed coat: protects the inside parts of a seed.

Radicle: develops into the root system.

Plumule: develops into the shoot system.

Embryo: grows into a new plant.

Scar/ hilum: it is where the seed is attached to the pod.

Seed germination:

  • It is the growing of a seed into a seedling.
  • A seedling is a young plant.

Conditions for germination:

  • Water
  • Warmth
  • Oxygen

Importance of each condition;

Water: –it softena the testa for the embryo to pass.

-water dissolves the stored food in the cotyledon.

Oxygen: it is used for respiration.

Warmth: provides the right temperature for germination.

The process of germination:

  • Water enters the seed through the micropyle.
  • The testa softens, swells and allows the radicle to pass through.
  • The cotyledon can either remain in the ground or come out of the ground according to the type of germination.

Types of germination:

  • Epigeal germination.
  • Hypogeal germination.

 

Epigeal germination;

The type of germination where the cotyledon comes out of the ground/ soil.

Epigeal Germination

 

 

 

 

 

 

 

Plants with epigeal germination:

  • Bean plant
  • Soya plant
  • Pea plant
  • Groundnut plant

 

Hypogeal germination:

It is the type of germination where the cotyledon remains in the  soil.

Plants with hypogeal germination:

  • Maize plant
  • Wheat plant
  • Sorghum plant
  • Millet plant
  • Oat plant

Uses of seeds to people and other animals:

  • Some seeds are eaten
  • Some are sold
  • For feeding poultry
  • For decoration
  • For planting.

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ASSIGNMENT : Plant Life assignment MARKS : 10  DURATION : 1 week, 3 days

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