Ch. 15 &16: Plant Physiology

Major parts of a flower

Plant Cell

How plants produce food

• Photosynthesis – a series of processes in which light energy is converted to a simple sugar.

• Chlorophyll – green material inside the leaves and stems of the plant that gives the plant its green color.

• Chloroplasts – small, membrane-bound bodies inside cells that contain the green chlorophyll pigments.

• These are the sites of the actual conversion of solar energy into stored energy.

Photosynthesis

6CO2 + 6H2O >> C6H12O6 + 6O2

Respiration

• Exchange of oxygen and carbon dioxide

C6H12O6 + 6O2 >> 6CO2 + 6H2O +HEAT

Transpiration

• Process by which the plant gives up water vapor to the atmosphere.– Most plants transpire about 90% of the water

they take in.

What causes plants to wilt?

• Lack of turgor pressure, caused from not having enough water.

• Turgor pressure – swollen or stiffened condition as a result of plant cells being full of water.

Purpose of soil

• Soil provides a natural environment for roots. It supplies air, water, and nutrients for the plant.

Plant nutrition

• There are sixteen essential elements for normal plant growth. – Macronutrients – elements used in relatively

large amounts.– Micronutrients – elements used in small, or

trace amounts.

Macronutrients

• C – carbon

• H – hydrogen

• O - oxygen

Obtained from the atmosphere

N – nitrogen Ca - calcium

P – phosphorus Mg - magnesium

K – potassium S – sulfur

Micronutrients

• B – boron

• Cu – copper

• Cl – chlorine

• Fe – iron

• Mn – manganese

• Mo – molybdenum

• Zn - zinc

Soil pH• pH – acidity level.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Acidic Alkaline (base)

Neutral

Optimum range for most plants