Plant nutrition Method of nutrition used by plants is: photosynthesis. Raw materials needed: CO2 and H2O Conditions present: chlorophyll and sunlight~ GEP WeeSC

Leaf Structure GEP WeeSC

To show presence of stomata GEP WeeSC

Section of leaf GEP WeeSC

Structure of Stomata GEP WeeSC

Stomata: open and close GEP WeeSC

Photosynthesis Summary equation: CO2 + H2O C6H12O6 + O2 Products of photosynthesis: 1 sugar (built up to starch for storage) 2 oxygen. Light, chlorophyll GEP WeeSC

How to show that plant is photosynthesising Test for presence of starch . Photosynthesis is the only way a plant can produce this. How to test for starch? Use iodine solution. GEP WeeSC

To test a leaf for starch Boil leaf in water. Boil leaf in alcohol to remove chlorophyll Wash in water . Why must the leaf be boiled in water? To allow I2 solution to penetrate cells. Why must the leaf be decolorised? To allow blue black colour to show up. Why must the leaf be washed in water? To soften it. GEP WeeSC

To show that chlorophyll is needed 1 Destarch a potted plant with variegated leaf by: 2 placing the plant in the light for 48 hrs. 3 Remove a leaf & test for starch. 4 Only the green parts of the leaf give a dark blue (blue- black) colour with I2 solution. GEP WeeSC

To show that light is needed Destarch 2 potted plants. Leave 1 in the dark (experimental). Put one in the light (control). All other conditions must be the same. Leave the 2 plants for 48 hrs. Take a leaf from each plant to test for starch In which plant will starch be present? GEP WeeSC

To show that CO2 is needed for photosynthesis Destarch 2 potted plants. Place 1 plant in a bell jar with a dish of soda lime to absorb CO2. Place the other in a bell jar without CO2 (Which plant is the control?) All other conditions should be the same for both plants. Leave the plants for 48 hrs, then test the leaf for starch (with I2 solution). In which plant will starch be present? GEP WeeSC

To show that O2 is given off during photosynthesis Place some water plants eg hydrilla under an inverted filter funnel in a beaker of H2O. Dissolve some NaHCO3 in the H2O ( to provide CO2 to the plant. Place the apparatus in sunlight for 6 hrs. Set up a control in the same way, but left in the dark. Gas bubbles will only be released from the plant placed in sunlight. This gas rekindles a glowing splint. GEP WeeSC

What happens to sugar formed in photosynthesis 1 Broken down in respiration. 2 Built up into starch for storage. 3 Turned into fats for storage & other uses. 4 Combined with N2 to form proteins. 5 Moved to other parts of the plant. GEP WeeSC

photosynthesis GEP WeeSC

To test for presence of starch using I2 solution GEP WeeSC

To show that CO2 is needed for photosynthesis GEP WeeSC

To show that chlorophyll is needed. Use variegated leaf. GEP WeeSC

To show that O2 is given off GEP WeeSC

To show that O2 is given off. Glowing splint rekindles. GEP WeeSC