Plant Nutrition II Flashcards
Photosynthesis Equation:
carbon dioxide + water -> (+ light and chlorophyll) glucose + oxygen
During photosynthesis light energy is absorbed by …
a pigment called chlorophyll, which can be found in the chloroplast of plant cells.
The light energy absorbed by chlorophyll is then used to ….
convert water from the soil and carbon dioxide from the air into a simple sugar called glucose. As a by-product of photosynthesis oxygen is made.
The glucose made by photosynthesis is stored in plants in the form of ….
starch (and which is a large molecule made of thousands of glucose molecules)
The production of starch can be tested using
iodine solution, which turns from brown to blue/black
Testing for the requirement of light:
We can test for the requirement of light by covering part of the lead with foil of card. No light should be produced in this area and so this area will remain brown when tested with iodine.
Testing for the requirement of chlorophyll :
We can test for the requirement of light by using variegated leaves have no chlorophyll in the white areas. No chlorophyll should be produced in this area and so this area will remain brown when tested with iodine.
Testing for the production of oxygen :
We can test for the production of oxygen using a water plant such as elodea. As photosynthesis takes place oxygen gas becomes visible. These can be collected in a test tube and tested for oxygen with a glowing splint.
Testing for the requirement of carbon dioxide
We can test for the need for carbon dioxide using soda lime. This traps the carbon dioxide from the air so that it is no longer available for photosynthesis. Leaves in presence of soda lime, should not turn black when tested for starch using iodine.
Leaf Structure : Waxy Cuticle
• Waterproof
• Reduces water loss
Reduces infection by fungi and bacteria
Leaf Structure : Upper Epidermis
• Protection
• No chloroplast
Absorbs harmful light but allows light for photosynthesis to pass through
Leaf Structure : Palisade Cells
- Tightly packed, elongated (long) cells
- Lots of chloroplasts
- Higher rate of photosynthesis
Leaf Structure : Spongy cells
• Loosely packed with air space between cells
• Some chloroplasts
Some photosynthesis
Leaf Structure : Air spaces
- Between spongy cells
* Providing air channels through leaf allowing gas exchange
Leaf Structure : Xylem
- Rigid vessels in lignin
* Carry water and minerals from roots to stem and leaves
Leaf Structure :Phloem
- Vessels of living cells
- Sieve tube cells form vessels
- Carry dissolved sugar around plants to places where the glucose is used and stored as starch
Leaf Structure : Guard Cells
- Guard cells change shape depending on the amount of water inside
- Controls opening and closing of stomata (pores on the underside of leaves)
Leaf Structure : Stomata
- Spaces between the guard
* Controls gad exchange (movement of oxygen and carbon dioxide)and water loss from leaf
How does the leaf import raw materials for photosynthesis (water and CO2 needed)
water and CO2 enters through stomata by diffusion
How does the leaf get rid of waste products?
stomata controls gas exchange
How does the leaf export sugar from photosynthesis to parts of plants that need them (glucose)?
phloem carries sucrose to rest of plant
Glucose Use:
Substrate for respiration
Glucose : Elements
C, H, O
Sucrose : Use
Main sugar carries in phloem, also in nectar
Sucrose : Elements
C, H, O
Starch : Use
Storage carbohydrate
Starch : Elements
C, H, O
Lipids : Use
Components of cell membranes + long-term energy store (seeds)
Lipids : Structure
C, H, O
Cellulose : Use
Components of cell walls
Cellulose : Structure
C, H, O
Amino Acids : Use
Components of proteins
Amino Acids : Structure
C, H, O, N
Nucleotides : Use
Components of DNA
Nucleotides : Structure
C, H, O, N, P
Chlorophyll : Use
Absorption of light in photosynthesis
Chlorophyll : Structure
C, H, O, Mg
Mineral required by plants : Nitrogen
Nitrogen is need for making amino acids. These contain the element: C, H, O and N. Plants need amino acids to make proteins, which are required for plants growth. If a plant lacks nitrogen, it’s growth is stunted. The plant may also have yellow leaves.