2.18-2.23 plant nutrition Flashcards
Photosynthesis definition
the process by which plants manufacture carbohydrates from raw materials using energy from light
Photosynthesis symbol equation
6CO2 + 6H20 –> C6H1206 + 6O2
Photosynthesis word equation
carbon dioxide + water –> glucose
+ oxygen
Which factors affect the rate of photosynthesis
light intensity- the more the higher rate (levels off eventually)
carbon dioxide concentration- the more the higher rate (levels off eventually)
temperature- the closer to optimum the higher rate (decreases at higher temperatures)
chloroplasts- the more the higher the rate (can be affected by loss of leaves, deficiencies and diseases)
Waxy cuticle
protective layer on top of the leaf, prevents water from evaporating
Upper epidermis
thin and transparent to allow light to enter the palisade cell layer beneath it
Palisade mesophyll
column shaped cells packed tightly with chloroplasts to absorb more light maxamising photosynthesis
Spongy mesophyll
contains internal air spaces increasing the surface area to volume ratio for the diffusion of gases (mainly co2)
Lower epidermis
Contains guard cells and stomata
Guard cells
absorbs and loses water to open an close the stomata to allow co2 in and o2 out
Stomata
Where gas exchange takes place; opens during the day and closes during the night. Evaporation of water takes place here. In most plants found in greater concentration under the leaf to reduce water loss
Vascular bundle
contains xylem and phloem to transport substances to and from the leaf
Xylem
transports water for mesophyll cells to use during photosynthesis and minerals
Phloem
transports sucrose and amino acids around the plant
What do plants need mineral ions for?
Growth
What are the four mineral ions
nitrogen, phosporous, potassium, magnessium
What is nitrogen used for and what will leaves suffer incase of deficiency?
-making proteins for growth
-in deficiency, upper leaves pale green lower leaves yellow or dead
What is phosphorus used for and what will leaves suffer incase of deficiency?
-make flowers and fruit
-in deficiency discolored purple leaves and small roots
What is potassium used for and what will leaves suffer incase of deficiency?
-making roots
-in deficiency poor flower and fruit growth, yellow leaves with dead spots
What is magnesium used for and what will leaves suffer incase of deficiency?
-making chlorophyll
-in deficiency normal upper leaves but yellow lower leaves
test to see if CO2 is nescasarry for photosynthesis
-place a plant inside a sealed jar with lime soda and leave for 24 hours
-leave another plant in a co2 rich environment for 24 hours
-test each for starch using iodine
-if color goes from orange/brown to blue black starch is present
test to see how light intensity affects photosynthesis
-use a water plant and place in a beaker
-place a lamp infront of the beaker moving the lamp away 10 cm each time and leave for 60 seconds at each interval
-count the bubbles produced
-more bubbles = more photosynthesis
test to see for starch in a leaf
-boil a variegated leaf to denature the enzymes
-place the leaf in warm ethanol to remove chlorophyll (green pigment)
-rinse the leaf to remove the ethanol
-pat leaf dry and place a couple drops of iodine (iodine should go from brown/orange to blue/black if starch is present)
test to see how light affects photosynthesis
-place one plant in the dark for 24 hours
-place another plant in the light for 24 hours
-provide both with otherwise perfect conditions (water, CO2 ect.)
-after 24 test both for starch
