plants - interactive board

8/6/2019 Plants - Interactive Board

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Earth is green because of plants.

They help in maintaining ourenvironment by absorbing

carbon dioxide from the air and

releasing oxygen.

Our Earth looks beautifulbecause its green. Lets all help

to keep it green. Conserve trees!


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In this lesson we will learn about

Classification of Plants

Parts of a plant

Root System

Shoot System

Stem

Leaf

Flowers and Fruits

Getting to know Plants


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Classification according to size andstructure:

HerbsSmall plants with green and soft

stem < 1 m in height.

Grass

MustardCabbageCorianderWheat


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Classification according to size and structure:

Shrubs Medium sized with hard and thin stem(1 - 3 m in height).They have branches

starting from just above the ground.

Lemon Rose Karonda Bougainvillea


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Classification according to size and structure:

TreesTall and large plants with hard and woodystem (> 3 m in height).They have one main

stem called the trunk which supportsbranches at a certain height.


Mango Neem Coconut


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Creepers & Climbers

Some plants are

different from herbs,

shrubs and trees. As

their stems are weak,they cannot stand

upright and spread on

the ground. These are

creepers.

Some plants take the

support of

neighbouring plats to

climb up as theirstems are weak .

These are called

climbers.

Pumpkin

Green

Peas


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Annual, Biennial & Perennial

PlantsPlants are also divided into types according to their lifecycle:

Annual plants(generally herbs) life cycle from seed

germination to fruit formation is completed in one seasonor year- like Wheat, Paddy, Moong, Gram etc.

Biennial Plants(generally herbs & rarely shrubs) taketwo seasons or years to complete their biological lifecycle like potato,radish, carrot etc.

Perennial Plants(generally trees) live for more thantwo years like Neem, Guava etc.


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Parts of a PlantPlants consist of many partsthat have specific roles.

Most plants have two

systems:

Flower

Fruit

Seed

Leaf

Stem

Primary Root

Secondary Root

Shoot System The part of

the plant above the ground.

Root System The part of

the plant below the ground.


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Root System

The non-green part of the plant that remains andgrows underground is called the root system. Rootsdevelop from the radicle (the part that emerges firstfrom the seed) of the seed and grows towards soil and

water.Types ofRoots

Taproot The main root from whichmany branching roots grow sideways

like Radish, Neem, Mango etc.

Fibrous Root a cluster of thin fibre

like roots that spread out in the soil

like Wheat, Maize, Grass etc.


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Functions ofRoots

Roots hold the plant firmly in the soil. Inother words, roots are said to anchor theplant to the soil.

Roots absorb water and minerals fromthe soil and send them to the other parts ofthe plant which help them to grow.

Roots prevent soil erosion by holding thesoil together.


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Stem

The stem is the link between the roots and the leavesand flowers. The shape, size and nature of stem differ

from plant to plant like thick & woody stems and

thin & weak stems.

Stem of a tree is called

the trunk.Most of the tree trunks are covered

with an outer layer called the

bark.


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The Stem of a Plant

Node The point fromwhere a leaf grows.

Axilliary Bud Budthat gives rise to

branches

Internode Theportion of the stem

between two nodes.

Apical Bud Bud at theterminal end of the stem.

The stem grows at this

bud.


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Functions of a Stem

Conduction of water

and minerals- carrieswater & minerals from

root to different parts of

the plant.

Conduction of foodmade by leaves- carriesfood made by leaves to

different parts of the

plant.

As a physical support supports branches,

leaves, flowers and fruits

of the tree.

Modified Stem

Some modifiedstems can store

food stem growsunderground and

stores food made bythe leaves, like in

Ginger, Potato and

Onion.

Some modifiedstems can make

foodand performall the functions of

a leaf, like Cactus

and Prickly Pear.


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LeafA leaf is a thin expanded outgrowth from the node of thestem. The green colour is due to the presence of a greenpigment called chlorophyll.

Leaf blade or

Lamina- flatgreen part ofthe

leaf

Petiole- short stalk

that attaches the

leafto the stem

Midrib- is the

continuation ofthe

petiole in the leaf.Veins- branch out from the

midrib.

v

Leaf Venation-

design made by the

veins in a leaf.

Reticulate

Venation thedesign is net-like on

both sides of the

midrib.

Parallel Venation-

the veins areparallel to each

other as in a maize

leaf.


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Leaf - Layers

The lower most layer is called

stomata. The leaf breathes

through the stomata.

Under theskin there are

many layers

of cells. These

cells are tiny

bag-like

structurescontaining

water and

small packets

of chlorophyll.

A leaf has a

transparent

layer at the top.

An open stomata


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Modified LeavesIn certain plants, leaves are modified in a natural

way. These are modified leaves like spines &

tendrils.

Additional Functions:

Reduce loss of water such

as in dessert plants.

Protect plants from animals.

Thread-like tendrils help the

plants to climb.


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Flowers & Fruits


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Structure of a Flower

Sepals most important part in an open

flower, sepals are the outermost green-leafy

structures in a flower. They protect the flower

at the bud stage.

Stamenslittle stalks with swollen

tops around the centre of the flower.They are the male parts of the flower.

The stamen has two parts filament

& anther (carries pollen grains

which take part in reproduction.


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Structure of a Flower

Petals leaf-like

coloured part next tothe sepal. The colour

and fragrance of the

petals attract insects

that help plants inreproduction.

Lower broader part ofthe pistil is the ovarywhich contains

female cells calledovules.

Stigma is the stickyend at the top of the

style.

Upper narrow part of

the pistil is the style

Pistil (or carpel) a

flask shaped

structure at the

centre. This is thefemale part of the

flower.


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Fruits

Flowers are developed intofruits.

They form seeds by theprocess ofpollination thetransfer of pollen fromanther to stigma.

After pollination the ovules

change into seeds and theovary of the flower growsand develops into a fruit.


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Functions of a Flower

Flowers are the reproductive organs of the

plant.They are the source

of perfumes,flavouring foods

and medicines.

Nectar from flowersis used by honey

bees to prepare

honey.


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Save plants & trees.Save the earth.

plants - interactive board

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