Download Plant structures

Plant structures
What does a plant need for
photosynthesis?
So what does a plant need
for photosynthesis?
 Bring in:
leaves
light
 CO2
 H2O

 Let Out:

O2
 Move Around:

stem
roots
sugars
6CO2 + 6H2O + light  C6H12O6 + 6O2
Regents Biology
energy
Organs used by plants
• All vascular plants have 3 main organs
– Roots
– Stems
– Leaves
Roots
 Functions:
 Absorb water and dissolved minerals in soil and
transport them up.
 Anchor the plant in the ground
 Storage of nutrients
Stems
• Functions:
– Produce leaves, branches & flowers
– Hold leaves up to the sunlight
– Transport substances between roots and leaves
– Storage of nutrients
Leaves
• Functions:
– Photosynthesis
• The structure of a leaf is optimized for absorbing light and
carrying out photosynthesis.
– Gas Exchange
– Transpiration
Leaf Structure
cuticle
epidermis
vascular bundle (vein)
xylem (water)
phloem (sugar)
palisades
layer
spongy
layer
epidermis
cuticle
stomate
guard
cells
Function of Leaf Structures
 Cuticle

waxy coating reduces water loss
 Epidermis

“skin” protecting leaf tissues
 Palisades layer

high concentration of chloroplasts
 collecting sun’s energy

photosynthesis
 making ATP & sugars
 Spongy layer

air spaces
 gas exchange
 CO2 in for sugar production, remove waste O2
Regents Biology
Stomata
 Openings found on underside of

leaves.
Function of stomates (openings)

Gas exchange:
 CO2 in , O2 out

Regulate water loss:
 H2O out
 Function of guard cells

open & close stomates
guard cell
stomate
Guard cells & Homeostasis
 Maintains Homeostasis
 Plenty of water / during the
day

Stomata open
 Photosynthesis can occur
 Dry / very hot / at night:

Stomata close
 Stops water loss
 Photosynthesis eventually stops
Transpiration
 As Water evaporates
from the stomata in the
leaves, water is pulled
up from roots.
 Cohesion: water sticks
to water
 Adhesion: water sticks
to sides of “tubes”
Transpiration and gas
exchange
xylem (water)
O2 H O
2
 CO2 in
 O2 out
 Regents
water
out
Biology
CO2
stomate
O2 H2O
CO2
guard
cells
Transport in plants
 Vascular Tissue: The
“bloodstream” of the plant,
transporting water and
nutrients throughout.
 Xylem: carries water

UPWARD from the roots
to every part of the plant
Phloem: Transports
products of
photosynthesis (food)
from leaves to rest of
plant.
Regents Biology