Plant Homeostasis
Structure and Function
Flowers
• Organs of
sexual
reproduction
in plants
Roots
• Function
– Provide support
– Absorb water
– Osmosis occurs
at the root tip.
– May contain
sugars that help
the plant get
energy
Leaf Function
Contain photosynthetic cells that produce the plant’s food
(Glucose)
Stomates – small pores in the leaf’s surface
Guard Cells – control the opening and closing of the stomates.
Water Homeostasis in Plants
• Stomate Open –
When there is
sufficient water
Allows CO2 IN
Allows H2O OUT
• Stomate Closed –
Under dry
conditions
Keeps H2O in, but
doesn’t get any CO2
Stem Function
• Support the plant
• Xylem
– Long thin tubes that
transport water
• Phloem
– Long thin tubes that
transport sugars
(sap)
Water
Movement of
Food and water
• Transport moves
water from
• Roots through
the Xylem
• To all parts of
the plant.
• Mainly Leaves.
Food
Transport moves
sugar
From the Leaves
through the Phloem
To all parts of the
plant
Mainly
Roots(storage)
Movement of Food and Water
Water Movement
Transpiration -Water moves into roots by
diffusion (osmosis).
Water evaporates from the stomates
creating a suction – turgor pressure
Water flows from the roots to the leaves
to replace the lost water
Capillary Action – movement of water into
small spaces
Root Pressure – diffusion of water into
roots creates a pressure
Sugar Transport
• Pressure
flow model
Transport moves
sugar from the
leaves through the
stem to all parts of
the plant, mainly
the roots (storage)
Regulation of Plant Growth
• Photoperiodism- the response a plant has to
the light and dark hours
• Hormones- chemical messengers that
regulate plant function
• Auxins- hormones that stimulate plant growth.
Located at root tips and stems.
• Tropism- Plant growth towards a stimulus
• Phototropism- growth towards sun(leaves)
• Geotropism- growth towards earth(roots)
Plant Nutrition
• Photosynthesis- Capturing of sunlight to make
food (glucose)
• Photosynthesis is the source of most of the
oxygen in the air.
• Occurs within the Chloroplasts
Which contains Chlorophyll (green pigment)
It absorbs light energy from the sun to make glucose
• Chorophyll absorbs red & blue and reflects Green
light
Chemical Equations for Photosynthesis and Respiration
• Inorganic molecules -------------------- Organic Molecules
Comparison Chart of Photosynthesis and Respiration
Photosynthesis
Energy-Storage
Occurs in Chloroplast
Uses Sunlight, Co2, H2o
Makes Glucose, o2
They are Reverse reactions of each other
RESPIRATION
Formula
Respiration
Energy Storage
Mitochondria
o2, glucose
Co2, H2o, ATP