Chapter 31-32 Nutrition and Transport in a Flowering Plant

• Waxy cuticle
• Stomata
• Lenticels

Waxy cuticles prevent direct water loss from the surface of leaves.

Stomata controls the rate of transpiration by opening and closing.

Lenticels allows a small amount of transpiration but also allows oxygen in (for respiration) and carbon dioxide out (excretion).

Lenticels allows a small amount of transpiration but also allows oxygen in for respiration.

Lenticels allow carbon dioxide out - excretion.

Stomata are found on leaves.

On bark, woody part.

Carbon dioxide is mostly taken in from the atmosphere, but can be taken from the mitochondria in the leaf (through respiration).

Carbon dioxide can be taken in from the mitochondria in the leaf through respiration.

CO2 is mostly taken in from the atmosphere, but can be taken from the mitochondria in the leaf through respiration.

Fate of carbon dioxide- atmosphere

Sources of CO2- atmosphere + respiration.

• Plasmilised
• Opp: turgid

Turgid / turgor

• Stomata open during the day, close at night (Generally).
• High water levels: can cause stomata to open - as plant tries to rid excess water.
• Low water levels: can cause stomata to close - as plant tries to conserve water.
• Windy conditions: can cause stomata to close - as plant tries to conserve water.
• Guard cells are structures that control the opening of stomata.
• When guard cells become turgid- they curve away from each other, opening.
• When guard cells lose water (become flaccid)- they remain together, stomata closes.
• The main controlling factor of the opening/closing stomata is CO2 levels.
• High CO2 levels cause stomata to close.
• Low CO2 levels cause stomata to open.