4.4 factors that affect the rate of photosynthesis

effect of light availability

• as light intensity increases, so does the rate of photosynthesis until it reaches the light saturation point and plateaus

• different pigments absorb coloured light differently

effect of water availability

• as water availability increases, so does the rate of photosynthesis until the soil becomes waterlogged and the rate decreases

• if there is not enough water, the plant closes the stomata, and prevents carbon dioxide uptake

• if there is too much water in the soil the lack of oxygen prevents water uptake

effect of temperature

• as temperature increases, so does the rate of photosynthesis (due to collisions between reactants and enzymes) until it reaches a maximal point and decreases due to the denaturation of enzymes

  

effect of carbon dioxide concentration

• as carbon dioxide concentration increases, so does the rate of photosynthesis until all the enzymes become saturated with carbon dioxide and the rate of reaction plateaus

interrelationship between photosynthetic factors

various factors (light availability, water availability, temperature, carbon dioxide concentration) work together to influence the rate of photosynthesis

• light intensity combined with carbon dioxide concentration or temperature have different influences on the rate of photosynthesis