Transcript Parts of the plant and their functions

Parts of the Plant and
Their Functions
By: Ita Rodríguez
3rd Grade
Importance of plants
• Without plants
life on earth
would not exist
Plants
• Primary source of
food for people and
animals
• Produce oxygen
• Help keep us cool
• Renew (filter) the
air
Plants
• Slow wind speed
• Provide a home for
wildlife
• Beautify
surroundings
• Perfume the air
• Provide building
materials and fuel
Plants
•
•
•
•
Need nutrients
Soil
Water
Sunlight
Plant Photosynethesis
• Photosynthesis is the
process by which plants
make food (sugar or
glucose)
– Sunlight provides
energy
– The air provides
carbon dioxide
– Nutrients and water
are absorbed by the
roots
– Photosynthesis occurs
in the chloroplast in
the leaves
Carbon dioxide enters the leaves through
stomata (tiny holes) in the leaves. Oxygen
leaves the same way.
Soil Nutrients
Nitrogen – growth, photosynthesis
Phosphorus – photosynthesis, flowering
Potassium – build proteins, prevent disease
Calcium – strong cells
Magnesium – photosynthesis
Sulfur - build proteins and produce food
Parts of a Plant
• Four basic parts
– leaves
– stems
– roots
– flowers
Leaves
• Definition: flattened
outgrowth of stem
• Used for:
photosynthesis,
respiration, and
transpiration
• Produces food
used by the plant
and also store it for
later use
Shape and Size of Leaves
• Vary among plants
• Used for identification of plants
Leaves: Their Basic Parts
•Leaf Base
•Petiole
•Lamina (blade)
•Midrib
•Veins
•Margins (edges)
EXTERNAL ANATOMY
Leaf Base
•Part attached to the stem or branch
•Protects a bud in its axil
Petiole
• Part of leaf that connects the lamina with
the stem (leaf stalk)
•Some time a leaf may not have a petiole,
such leaves are called – Sessile
Lamina (blade)
•The flat, expended, and broad part of leaf
•Most important part of the leaf (food
manufacturer)
• Has veins
• Forms structural
framework of
the leaf
Midrib
• Large center vein
from which all
other leaf veins
extend
Veins
• Systems of tubes
(xylem and phloem)
for the transport of
nutrients and water
– Xylem: ducts that bring
water and minerals
from the roots into the
leaf
– Phloem: ducts that
usually move sap, with
dissolved sucrose,
produced by
photosynthesis in the
leaf, out of the leaf
Venation Types
Netted or Reticulate
Venation
Margins
• Edges of leaves
• Assists in plant identification
Leaf Arrangement
• Alternate
• Opposite
• Whorled
– arranged in a
circle around the
stem
Leaf Types
• Simple leaf:
undivided blade
with a single
axillary bud at the
base of its petiole
Leaf Types
• Compound leaf:
 blade divided into leaflets
 has a single bud at the base of its petiole
– pinnate
-- palmate
Leaf Types
• Peltate leaves: petioles
that are attached to the
middle of the blade
• Perfoliate leaves: sessile
leaves that surround and
are pierced by stems
Specialized or Modified Leaves
•
•
•
•
•
•
•
•
•
•
•
Cotyledons
Tendrils
Shade leaves
Drought-resistant leaves
Prickles and thorn
Storage leaves
Reproductive leaves
Insect-trapping leaves
Bracts
Window leaves
Flower pot leaves
Cotyledons or “Seed Leaves”
•First leaves produced by a germinating
seed
•Often contains a store of food to help the
seedling become established
Tendrils
Garden Pea
•Leaflets are reduced in
size
•Allows plant to cling to
other objects
Leaves: Needles and Spines
Drought
Resistant
leaves
Leaves: Colorful Bracts
Petal-like leaves
Internal Leaf Structure
• Epidermis
–skin of the leaf
–single layer of cells
–protects leaf from loss of too
much moisture
Internal Leaf Structure
Stomata
• Small hole
• Opened and
closed by 2
guard cells
• Allows the plant
to breathe and
transpire
– gives off
moisture
open
closed
Stomata Function: gas exchange
in the leaf
Guard
cell
oxygen
When a plant is
photosynthesising
Carbon
dioxide
Leaf Cell (Palisade)
Chloroplasts
• Contains
chlorophyll
• Located inside
the food making
cells
Photosynthesis
• Process by which
CO2 and H2O in
the presence of
sunlight are
converted to sugar
and oxygen
• This makes the
plants' food
Respiration
• Plants respire 24 hours a day
• They consume O2 and nutrients and
give off CO2 and water
Stems
• Have two main
functions
– movement of
water and
minerals from
the roots upward
– movement of
manufactured
food down
Stem Functions
• Support of leaves
and reproductive
structures
Stem Functions
• Used for food storage
and reproduction of
plants involving
cuttings
• Green stems
manufacture food just
as leaves do
External Stem Structure
• Lenticels:
breathing pores
• Bud scale scars:
indicate where
terminal bud has
been located
previous year
Leaf Scars
• Show where leaf
was attached
• Distance between
the two represents
one year of growth
Internal Stem Structure
• Phloem- bark, carries manufactured foods down
• Xylem- wood, carries water and minerals up
• Cambium- separates the 2 and produces all new
cells
Roots
• Underground or
above ground
• Functions:
– anchor plant and
hold upright
– absorb water
and minerals
form soil and
conduct to stem
– store food
External
• Root Cap
– produces new cells
– protects roots as they
push through soil
• Root Hair
– increases surface area
of roots
– facilitate the
absorption of water
and nutrients
Root Structure
• Internal
– similar to stems
– older roots have xylem, phloem and
cambian
Type of Root Systems
• Fibrous Roots:
– easier
transplanting
– shorter, smaller,
more compact
Examples of plants
with this root
system are
 Banana
 Coconut
 Rice
 Corn
 Sugar Cane
All grasses
Type of Root Systems
• Tap Roots:
– large central
roots with
shorter,
branching roots
Examples of plants
with this root
system are
Mango
Avocado
Carrots
Tomatoes
Peppers
Type of Root Systems
• Aerial Roots:
– hang down in
mid-air and
absorb water
from rainfall
Examples of plants
with this root
system are
Some mangroves
Wild Pine
Orchids
Specialized Root Systems
• Stilt Roots:
– grow down from
lateral branches,
branching in the
soil
Specialized Root Systems
• Adventitious Roots:
– Grow from
unusual places
on plants such
as stems, leaves
and even fruits
Flowers
• Definition: the seed-bearing part of a
plant, consisting of reproductive organs
(stamens and carpels) that are typically
surrounded by a brightly colored corolla
(petals) and a green calyx (sepals)
• Vary in size, shape, and colors
• Flowering plants are called
angiosperms
Flower Structure
• Petals
• Stamen and pistil:
reproductive
organs
• Anther and ovary
• Calyx (sepal):
green leaf-like part
that covers and
protects bud before
opening
Petals
• Are actually leaves
• Usually bright colors to attract
pollinating insects
Stamen
• Stamens
– male part of
flower
– has two parts
1.filament
2.anther
Anther
Filament
Pistil
• Stamens
– female part of flower
– has three parts
1.stigma
2.style
3.ovary
Anther
• Anther: sac-like structure on top of
filament, contains pollen
Ovary
• Egg cells develop here
• Grows to become fruit
or seedcoat
Animals: A Simbiotic Relationship
• Pollination: color of
flower attracts insects
to fertilize flower
– beginning of fruit
and seed formation
• Fruits and seed are
attractive to birds who
eat and spread seeds
– reproduces plant
– some seeds carried
on animals coats
Types of Flowers
• Complete contains 4 main parts
• Incomplete does not have all 4 main
parts
Flower Classification
• Monoecious
– stamens and pistils are found in separate
flowers on the same plant
– ex: Corn
Flower Classification
• Dioecious
– stamens and pistils are
found in separate flowers
on separate plant
– ex: Holly
Gymnosperms
• Group of non-flowering,
seed-producing plants:
– conifers, cycads, Ginkgo,
and Gnetales
– comes from the Greek
word gymnospermos,
meaning "naked seeds"
– seeds develop either on
the surface of scales or
leaves, often modified to
form cones, or at the end
of short stalks
Pteridophyta
• Primitive plant
• Do not produce flowers
or seeds
• Reproduce by spores
• Have xylem and phloem
(making them vascular
plants)
• Have stems, leaves, and
roots
Seeds
A seed is an embryonic plant enclosed
in a protective outer covering called
the seed coat, usually with some
stored food
External Seed Structure
Seed Coat
Seed Coat Texture
• Cactus seed under a powerful
Internal Seed Structure
Different Types of Seeds
GERMINATION
Steps:
 Seed coat breaks
 Radicle becomes
root
 Hypocotyl and
epicotyl become
the stem
 First leaves grow
and
photosynthesis
begins
First leaves
Watch the following video https://www.youtube.com/watch?v=oYzXToyEzBU
Life Cycle
THE END