Plant physiology

1. Plant Physiology
Three Main Processes:
Photosynthesis
Respiration
Transpiration

2. Photosynthesis
A plants ability to manufacture its own food
(energy)
a plant requires:
energy from sunlight,
carbon dioxide from the air
water from the soil

3. Photosynthesis
The only cells that can carry out photosynthesis
are in the mesophyll layer of leaves and stems
The green pigment, chlorophyll, that is found in
the chloroplasts of these cells traps light energy
Creates energy in the form of carbohydrates that
are stored in plant cells
This energy allows the plants to carry out
metabolic functions such as growth and
reproduction.

4. Respiration
Carbohydrates made during photosynthesis are
converted to energy.
Energy is used in the process of building new
tissues or growth of the plant.
The chemical process is called oxidation. It is
similar to the burning of wood or coal to
produce heat.

5. Photosynthesis & Respiration
Chemical reactions are opposites
Photosynthesis
Respiration
Photosynthesis is a building process
Requires energy
Respiration is a breaking down process
Releases energy

6. Comparison
Produces food
Energy is stored
Occurs in some cells
Oxygen is released
Water is used
CO2 is used
Occurs in sunlight
Uses food
Energy is released
Occurs in all cells
Oxygen is used
Water is produced
CO2 is produced
Occurs in light and dark
Photosynthesis: Respiration:

7. Transpiration
Transpiration is the process by that a plant loses
water, primarily from leaf stomata.
Transpiration involves the use of about 90% of
the water that enters the plant through the
roots.
The other 10% of the water is used in chemical
reactions and in plant tissues.
increase, transpiration increases. As humidity
decreases, transpiration increases.

8. Transpiration purpose
Transpiration is
necessary for:
Mineral transport from
the soil to the plant
parts
Cooling of plant parts
through
evaporation,
Movement of sugars
and plant chemicals,
Maintenance of turgor
pressure.