Plant Nutrition Flashcards
(24 cards)
What are the parts of a leaf?
- margin
- lamina (leaf blades)
- vein
- midrib
- leaf stalk (petiole)
Functions of lamina, vein and petiole
Lamina - large flat surface, allows absorption of sunlight
Vein - carry manufactured food to other parts of plant
Petiole - holds leaf away from stem to obtain sunlight
Cross section of leaf
Waxy cuticle
Upper epidermis
Palisade mesophyll
Spongy mesophyll
Vascular bundle
Lower epidermis
Guard cell
Function of cross section of leaf
Waxy cuticle: prevents evaporation
Upper epidermis: transparent to allow sunlight in palisade
Palisade mesophyll: packed with chloroplast
Spongy mesophyll: increase internal space for gas exchange
Vascular bundle: stores xylem and phloem
Guard cell: regulate size of stomata
Name five uses of glucose in a plant
- make sucrose for fruits and nectar
- make fats and oil for seed and storage
- make starch for storage
- make cellulose for cell wall
- used for respiration for energy release
- combine with nitrate to produce amino acid for growth and repair
- combine with magnesium to produce chlorophyll
What are the limiting factors for photosynthesis?
- light intensity
- temperature
- CO2 concentration
- stomata
What is the definition of limiting factor for photosynthesis?
Anything in short supply that prevents photosynthesis occurring at max rate
What is photosynthesis?
The process of plant manufacturing carbohydrate from raw materials using energy from sunlight
Function of chlorophyll
- traps sunlight for photosynthesis
- light energy combines CO2 and H2O to produce carbohydrate
Equation for photosynthesis
Carbon dioxide + water –> glucose + oxygen
6CO2 + 6H2O –> C6H12O6 + 6O2
What does a perfect condition for photosynthesis consist of?
- optimum amounts of water
- optimum sunlight
- optimum carbon dioxide concentration
How does temperature affect rate of photosynthesis?
Low temp = low ROP
High temp = low ROP
Optimum temp = high ROP (diff plant has diff optimum temp)
What happens when stomata is turgid and how is it caused?
Water from other epidermal cell coil are absorbed by guard cell, turgid stomata opens; caused by good amount of sunlight
What happens when stomata is flaccid and how is it caused?
Stomata loses water, cells become flaccid and stomata closes; caused by high temperature
What are the effects of mineral deficiency in a plant?
Magnesium deficient - yellowing between veins
Nitrate deficient - yellowing of whole leaf
What is the purpose of testing starch in leaf?
To prove sunlight is important for photosynthesis
How does destarching work?
Plant is placed in a dark room for at least 24hrs to remove all starch
Steps for testing starch in leaf
- Place plant in dark room for at least 24hrs
- Boil leaf until soft to stop all chemical reactions
- Remove chlorophyll by placing boiled leaf into a test tube with ethanol
- Place test tube into water bath (by now leaf should be pale/white)
- Rinse leaf
- Add iodine solution
- Leaf should turn from yellow brown to blue black
How does colour change by adding iodine solution onto a leaf work?
Leaf is partially covered by iodine; area covered with iodine turns yellow brown and the area with no iodine turns blue black
How is oxygen tested?
Put glowing wooden splint over test tube, the splint reignites/rekindles
Function of xylem
Transport water and minerals
Function of phloem
Transport nutrients (sucrose and amino acids)
Function of companion cell
- help in loading and unloading
- monitor substances exiting and entering the phloem
- facilitate in active transport
Differences between xylem and phloem vessels
Xylem - one way flow, no end walls between cells, thick walls stiffened with lignin
Phloem - two way flow, cells have end walls with perforations
