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 waterAllows CO2 INAllows H2O OUT

• Stomate Closed – Under dry

conditionsKeeps 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

• Transport moves water from

• Roots through the Xylem

• To all parts of the plant.

• Mainly Leaves.

Food

Transport moves sugarFrom the Leaves through the Phloem To all parts of the plant Mainly Roots(storage)

Movement of Food and water

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 Respiration

Energy-Storage Energy Storage

Occurs in Chloroplast Mitochondria

Uses Sunlight, Co2, H2o o2, glucose

Makes Glucose, o2 Co2, H2o, ATP

They are Reverse reactions of each other

RESPIRATION Formula