Which of the following would most effectively increase the rate of photosynthesis in a greenhouse?

Which of the following would most effectively increase the rate of photosynthesis in a greenhouse?

• A. Increase irrigation
• B. Increase shading
• C. Increase artificial lighting
• D. Increase soil nutrients

Answer: (C)

Light provides the energy that drives photosynthesis, so when light is limiting, boosting light intensity directly increases the rate at which leaves convert CO2 into sugars. Using artificial lighting in a greenhouse allows more photons to reach the leaves and can extend the day length, pushing the photosynthetic rate higher (up to the plant’s light-saturation point). Other factors matter, but they don’t boost the instantaneous rate as effectively when light is the bottleneck. Increasing irrigation helps only if water is limiting, shading reduces light and lowers the rate, and extra soil nutrients can support growth but don’t overcome a lack of light as efficiently as adding light does.

Light provides the energy that drives photosynthesis, so when light is limiting, boosting light intensity directly increases the rate at which leaves convert CO2 into sugars. Using artificial lighting in a greenhouse allows more photons to reach the leaves and can extend the day length, pushing the photosynthetic rate higher (up to the plant’s light-saturation point). Other factors matter, but they don’t boost the instantaneous rate as effectively when light is the bottleneck. Increasing irrigation helps only if water is limiting, shading reduces light and lowers the rate, and extra soil nutrients can support growth but don’t overcome a lack of light as efficiently as adding light does.