Transcript Plant Parts and their Functions

Plant Parts and their
Functions
Leaves-Internal
Leaves-Internal
• Upper and lower epidermis-skin of the
leaf that prevents the loss of too much
moisture
• Cuticle: waxy protective coating on
outer surface
• Stomas-small openings under the leaf
for breathing or transpiration
• Guard Cells-open and close stomas
Leaves-Internal
• Air Space: CO2 & O2
• Vein: Movement of Fluid
• Xylem: transport water up
• Phloem: transport glucose
Leaves-Internal
• Chloroplasts-small green particles
that contain chlorophyll
– gives leaves their green color
– necessary for photosynthesis
Leaves-Internal
Functions of Leaves
• Photosynthesis-manufactures food
in green plants which is the
beginning of the food chain for all
living things
• Photosynthesis is the process by
which carbon dioxide and water in
the presence of light are converted
to sugar and oxygen
Functions of Leaves
• Transpiration – loss of water
through the leaves or stems of
plants
• Transpiration exchange gases as
oxygen and carbon dioxide
Stems
• Movement of Materials
• Support of the leaves and
reproductive structures
• Food storages
• Reproduction with stem cuttings or
grafting
Stems-Internal (dicot)
Stems-Internal
• Pith-dead center of stem for
support
• Heartwood-old inactive xylem
• Sapwood-new active xylem
• Cambium-thin, green, actively
growing tissue located between
bark and wood and produces all
new stem cells
• Phloem-active
• Bark-old inactive phloem
Stems-Internal
(Translocation)
• Xylem-tissue that transports water
and nutrients up from the roots to
stems and leaves
• Phloem-tissue that transports food
down from leaves to roots
Phloem
Phloem
Xylem
Stems-Internal
• Monocot : examples: corn, grasses
• Dicot: example: trees
Functions of Stems
• Translocation – move water and
minerals from roots up to leaves &
move food from leaves down to
the roots
• Xylem and phloem cells help with
this process.
Functions of Stems & Leaves
• Transpiration – plant lose water
from leaves and stems through
evaporation
• Occurs in stomas and lenticels
Root Functions
• Anchor the plant and hold it
upright
• Absorb water and minerals from
the soil and conduct them to the
stem
• Store large quantities of plant food
• Propagate or reproduce some
plants
Roots-Internal
• Much like stems in that they have
a phloem, cambium, and xylem
layer
• Phloem-the outer layer that carries
food down the root
• Xylem-the inner layer that carries
water and minerals up to the stem
Layers of Roots
• Fibrous-many branched shallow
roots
– are easier to transplant
• Tap-long root with few branched
ones
– more difficult to transplant
Functions of Roots
• Absorption-take water and
nutrients from the soil and conduct
them to the stem
• Anchor the plant and hold it
upright
• Store food for plant use
• Asexual reproduction in some
plants
Dioecious
• Male and female, imperfect flowers
on same plant
• Examples: Squash & Pumpkin
Functions of Flowers
• Produce seeds used for sexual
reproduction
• Attract insects for pollination
(Pollination is the transfer of pollen
from anther to stigma.)
• Produce fruit to protect, nourish
and carry seeds
Functions of Whole Plant
• Respiration – the process through
which plant leaves, stems and
roots consume oxygen and give of
carbon dioxide.
• Plants produce much more oxygen
through photosynthesis than they
use through respiration.