Topic C: Plant Nutrition Flashcards
importance of autotrophs
produce organic molecules from CO2 & other inorganic molecules
photosynthesis
the fundamental process by which plants manufacture carbohydrates from raw materials using energy from light
limiting factors
a factor that is at its minimum level at a certain time for a specific plant
Ex: plant Y at 8pm => light and temp
-> the limiting factor for plant Y at 8pm is light (and temp)
leaf structure
waxy cuticle upper epidermis palisade mesophyll spongy mesophyll guard cells stoma lower epidermis waxy cuticle xylem phloem air space
autotrophs
sustain themselves without eating anything from other organisms
waxy cuticle
non-cellular, prevents water loss
upper epidermis
one layer of flattened cells, allows max light to pass through, no chloroplasts, tightly packed
palisade mesophyll
one or two layers of column-shaped cells, packed with chloroplasts, main photosynthesis tissue, narrow air spaces to allow circulation
spongy mesophyll
loosely packed, free circulation of air, easy evaporation of water for transpiration, fewer chloroplasts
guard cells
pair of modified epidermal cells, contain chloroplasts, can change shape to alter size of the stomata, control transpiration, allow gas exchanes
stoma
hole usually on lower epidermis as less direct heat energy, allows transpiration, allows gas exchange between atmosphere and air space
lower epidermis
single layer of flattened cells, no chloroplasts
waxy cuticle
thinner as there is less heat energy, prevents water loss from the leaf surface
xylem
transports water and mineral salts to leaf, thickened cell walls support leaf
phloem
transports sugars and other organic molecules away from leaf
air space
allows free circulation of air in leaf to promote gas exchange with photosynthesising cells
effect of temperature on photosynthesis
enzymes are involved in photosynthesis and after the optimum temperature, enzymes are denatured the rate of photosynthesis goes down
effect of light intensity on photosynthesis
at low-to-medium light intensity, the photosynthesis the rate increases; at high light intensity, the rate of photosynthesis reaches a plateau
effect of O2 on photosynthesis
at really low concentration, photosynthesis does not occur but as the concentration starts to increase, it’s positively correlated and at very high concentration the rate plateaus because enzymes are used up
