plant nutrition Flashcards
photosynthesis
the process by which plants manufacture carbohydrates from raw materials using energy from light
word equation of photosynthesis
carbon dioxide + water (in presence of chlorophyll and light energy) → glucose + oxygen
balanced chemical equation of photosynthesis
6CO2 + 6H2O → C6H1206 + 6O2
chlorophyll
green pigment in chloroplasts that absorbs light for photosynthesis
uses of glucose by the plant
- energy release in respiration
- stored as starch
- used to make cellulose for cell wall
- combines with nitrates from soil to make amino acids for protein synthesis
- converted to sucrose for transportation through phloem
importance of nitrate ions
needed for protein synthesis
- deficiency = stunted growth
importance of magnesium ions
needed for chlorophyll
- deficiency = yellow leaves
limiting factor
something present in the environment in such a short supply that it restricts life processes
temperature as a limiting factor
influences activity of enzymes in chloroplasts
light intensity as a limiting factor
determines energy availability
CO2 as a limiting factor
is a raw material, so if its concentration increases there is more of it for chloroplast enzymes to use in making carbohydrates
waxy cuticle
- waterproof to prevent water loss
- transparent so allows light penetration
upper epidermis
has no chloroplast allowing light to pass through
palisade cells
- tightly packed at top to maximise light absorption
- many chloroplasts to absorb more light
chloroplasts
- contains chlorophyll
- convert glucose to starch
spongy mesophyll cells
air spaces between the cells to allow diffusion of gases throughout leaf
vascular bundle
- xylem: transports water + mineral ions
- phloem: transports sucrose + amino acids
lower epidermis
lower protective boundary
guard cells
control opening and closing of stomata
stomata
allow CO2 to enter leaf + allow O2 to leave leaf (gas exchange)
