1.
Parts of the Plant and
Their Functions
By: Ita Rodríguez
3rd Grade

2.
Importance of plants
• Without plants
life on earth
would not exist

3.
Plants
• Primary source of
food for people and
animals
• Produce oxygen
• Help keep us cool
• Renew (filter) the
air

4.
Plants
• Slow wind speed
• Provide a home for
wildlife
• Beautify
surroundings
• Perfume the air
• Provide building
materials and fuel

5.
Plants
• Need nutrients
• Soil
• Water
• Sunlight

6.
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
– Sugars are made as food for
the plant and oxygen is
released
Carbon dioxide enters the leaves through
stomata (tiny holes) in the leaves. Oxygen
leaves the same way.

7.
Soil Nutrients
Nitrogen – growth, photosynthesis
Phosphorus – photosynthesis, flowering
Potassium – build proteins, prevent disease
Calcium – strong cells
Magnesium – photosynthesis
Sulfur - build proteins and produce food

8.
Parts of a Plant
• Four basic parts
– leaves
– stems
– roots
– flowers

9.
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

10.
Shape and Size of Leaves
• Vary among plants
• Used for identification of plants

11.
Leaves: Their Basic Parts
•Leaf Base
•Petiole
•Lamina (blade)
•Midrib
•Veins
•Margins (edges)

12.
EXTERNAL ANATOMY

13.
Leaf Base
•Part attached to the stem or branch
•Protects a bud in its axil

14.
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

15.
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

16.
Midrib
• Large center vein
from which all
other leaf veins
extend

17.
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

18.
Venation Types
Netted or Reticulate
Venation

19.
Margins
• Edges of leaves
• Assists in plant identification

20.
Leaf Arrangement
• Alternate
• Opposite
• Whorled
– arranged in a
circle around the
stem

21.
Leaf Types
• Simple leaf:
undivided blade
with a single
axillary bud at the
base of its petiole

22.
Leaf Types
• Compound leaf:
blade divided into leaflets
has a single bud at the base of its petiole
– pinnate -- palmate

23.
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

24.
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

25.
Cotyledons or “Seed Leaves”
•First leaves produced by a germinating
seed
•Often contains a store of food to help the
seedling become established

26.
Tendrils
Garden Pea
•Leaflets are reduced in
size
•Allows plant to cling to
other objects

27.
Leaves: Needles and Spines
Drought
Resistant
leaves

28.
Leaves: Colorful Bracts
Petal-like leaves

29.
Internal Leaf Structure
• Epidermis
–skin of the leaf
–single layer of cells
–protects leaf from loss of too
much moisture

30.
Internal Leaf Structure

31.
Stoma
• Small hole
• Opened and
closed by 2
guard cells
• Allows the plant
to breathe and
transpire
– gives off
moisture
open closed

32.
Stoma Function: gas exchange in
the leaf
Guard oxygen
cell
When a plant is
photosynthesising
Carbon
dioxide

33.
Leaf Cell (Palisade)

34.
Chloroplasts
• Contains
chlorophyll
• Located inside
the food making
cells

35.
Photosynthesis
• Process by which
CO2 and H2O in
the presence of
sunlight are
converted to sugar
and oxygen
• This makes the
plants' food

36.
Respiration
• Plants respire 24 hours a day
• They consume O2 and nutrients and
give off CO2 and water

37.
Stems
• Have two main
functions
–movement of
water and
minerals from
the roots upward
–movement of
manufactured
food down

38.
Stem Functions
• Support of leaves
and reproductive
structures

39.
Stem Functions
• Used for food storage
and reproduction of
plants involving
cuttings
• Green stems
manufacture food just
as leaves do

40.
External Stem Structure
• Lenticels:
breathing pores
• Bud scale scars:
indicate where
terminal bud has
been located
previous year

41.
Leaf Scars
• Show where leaf
was attached
• Distance between
the two represents
one year of growth

42.
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

43.
Roots
• Underground or
above ground
• Functions:
– anchor plant and
hold upright
– absorb water
and minerals
form soil and
conduct to stem
– store food

44.
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

45.
Root Structure
• Internal
– similar to stems
– older roots have xylem, phloem and
cambian

46.
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

47.
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

48.
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

49.
Specialized Root Systems
• Stilt Roots:
– grow down from
lateral branches,
branching in the
soil

50.
Specialized Root Systems
• Adventitious Roots:
– Grow from
unusual places
on plants such
as stems, leaves
and even fruits

51.
Specialized Root Systems
• Stilt Roots:
– grow down from
lateral branches,
branching in the
soil

52.
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

53.
Flower Structure
• Petals
• Stamen and pistil:
reproductive
organs
• Anther and ovary
• Calyx (sepal):
green leaf-like part
that covers and
protects bud before
opening

54.
Petals
• Are actually leaves
• Usually bright colors to attract
pollinating insects

55.
Stamen
• Stamens
–male part of
flower
– has two parts
1.filament
2.anther
Anther
Filament

56.
Pistil
• Stamens
– female part of flower
– has three parts
1.stigma
2.style
3.ovary

57.
Anther
• Anther: sac-like structure on top of
filament, contains pollen

58.
Ovary
• Egg cells develop here
• Grows to become fruit
or seedcoat

59.
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

60.
Types of Flowers
• Complete contains 4 main parts
• Incomplete does not have all 4 main
parts

61.
Flower Classification
• Monoecious
– stamens and pistils are found in separate
flowers on the same plant
– ex: Corn

62.
Flower Classification
• Dioecious
– stamens and pistils are
found in separate flowers
on separate plant
– ex: Holly

63.
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

64.
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

65.
SSeeeeddss
A seed is an embryonic plant
enclosed
in a protective outer covering called
the seed coat, usually with some
stored food

66.
EExxtteerrnnaall SSeeeedd SSttrruuccttuurree
Seed Coat

67.
SSeeeedd CCooaatt TTeexxttuurree
• Cactus seed under a powerful microscope

68.
IInntteerrnnaall SSeeeedd SSttrruuccttuurree

69.
Different Types of Seeds

70.
GGEERRMMIINNAATTIIOONN
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

71.
LLiiffee CCyyccllee

72.
THE END