Plant Structures

Original PowerPoint created by Mr. Morgan

Modified by Georgia Agriculture Education Curriculum Office

Adapted by Georgia Organics 2009

What Are primary parts of plants?LeavesStemsRootsFlowers

What are the functions of leaves?Capture lightExchange gasesProvide a site for photosynthesisSome leaves store food and waterSome form new plants and provide

support

What is photosynthesis?It is a process by which plants

combine water and carbon dioxide in the presence of chlorophyll and sunlight and produce carbohydrates and release oxygen.

Why is photosynthesis important?Light is the most important

source of energy for living things. Photosynthesis converts light into nutrients that can be used by plants and animals.

Releases oxygen

PhotosynthesisLight+6CO2+12H20-Sunlight-

> C6H1206+6O2+6H20

There are two parts of photosynthesis--the light and dark reactions.The light reactions produce

chemical energy from light.The dark reactions convert

carbon dioxide into carbohydrates.

Leaves in gas exchangeOxygen, Carbon Dioxide, and

Water exchanged from StomataPores open in day to transpire

H2O and allow gases to enterClose during dry conditions to

prevent H2O loss.

External Parts of LeavesPetiole- Stalk of leaf that

attaches to stemMidrib- Main vein of vascular

tissueBlade- Photosynthetic site of

leaf

StomataOpenings on the

epidermisallows air into leafallows H2O and oxygen

out of leaf

StemsWater and mineral transport by

capillary action and cohesion to the leaves.

Transport food to the rootsGas exchangeProduce and support new

leaves, branches, and flowers

Internal parts of stemPhloemXylemCambiumPithCortex

FunctionsPhoem-Sugar and

carbohydrates to rootsXylem- Water and nutrientsCambium- Growing part of

stem

Function Cont’Pith-Occupies the central

area of the stemCortex- Composed of

several layers of thick-walled cells

External parts of stemBudsNodesInternodes

Modified StemsRhizomes- Horizontal underground

stems(Bermuda GrassStolons- Horizontal above ground

stems(strawberries)Tubers- Greatly enlarged tip of

underground stem

Cont.Bulbs- budlike structure

consisting of a small stem (onion)

Corms- Fleshly leaves underground stems with few nodes(gladiolus)

Functions of RootsAnchor plants in soilAbsorb water and nutrientsSome store reserves for future

uses(Potato)Propagation

TaprootsAdvantagesPenetrates

deeperObtain water

from other levels

Anchor plant

DisadvantagesDifficult to

remove or harvest

do not stabilize well

FibrousAdvantagesShallower,

better for fertilization & Water

Stabilize in soil better

DisadvantageLess drought

resistantTend to get

exposed during cultivation

Primary RootsGrow down into the soil and

may branch repeatedly into lateral roots

Taproot is a primary root

Lateral RootsCalled Secondary rootsgrow horizontally away from the

primary root Some grow downward

AdventitiousCame from stems or leaves

instead of another rootProp root of corn and grapes

are examples that give support

Fibrous RootRoot structures in which the

primary and lateral roots develop equally so there is not a definite taproot.

Storage RootsAre structures such as those of

carrots and sweet potatoes which are used for food storage.

What do stems and roots have in common?

Both have xylem and phloem cells for transport.

Male flowers and their parts and functions.Stamen- has two parts- filament

and antherFilament- supports the anther

Anther- Produces pollen grains

Female parts and their functionsOvule-develops into a seedOvary- surrounds the ovule, later

becomes the fruitStyle-supports the stigmaStigma- receives the pollen grainPistil- All three female parts

together

Other parts of flowerReceptacle- enlarged part of the

flower stalk where floral part is.Sepals- outer protective parts of

budsPetals- the colored part of the

flower used to attract insects

Complete FlowerBoth have Male and Female

parts

Incomplete FlowersHave either male or female

parts but not both

MonoeciousPlants that have male and

female flower parts on separate plants

DioeciousHave both parts on the

same plant.

PollinationThe transfer of pollen from one

anther to anther stigma.Two ways- self-pollination &

Cross-pollinationBees and Wind

The End