Photosynthesis

  - Introduction
  - The Leaf Structure
  - The Process
  - Pigments
  - Photosynthesis Rate

- Photosynthesis Test
- Links

Transpiration

Thinkquest Team 22016
Andrew Griffiths
Tim Sindle
Ben Harper

Factors affecting the rate of photosynthesis

It can be affected by many things, including:

1)Sunlight - its Intensity & wavelength.
2)Temperature
3)CO₂ and O₂ - availability
4)Any factor that influences the production of chlorophyll, enzymes, or energy carriers(ATP and NADPH).

The rate of photosynthesis will always corrospond to that factor which is in least supply. Its rate will only increae when its supply is increated.

Sunlight

Generally the more light there is, the more photosynthesis occurs. This is true up to a point, where the plant has reached maximum photosynthesis levels, and so any increase in light intensity will not affect the plant further.

Temperature

Generally higher temperatures are better than cold temperatures for photosynthesis. However if it is humid, and the air is saturated with water vapour, photosynthesis is limited. This is because the water vapour being expelled cannot leave and go into the air, as there isn't a concernation difference for it to diffuse across. So the water vapour sits in the leaf, stopping photosynthesis.

CO₂ Basically the more CO₂ in the air, the better the rate of photosynthesis. Of course CO₂ is taken in during the daytime, and if its content was less that normal, photosynthesis couldn't happen normally. Fertilisers increase the number of soil fungi and bacteria, thus increasing the levels of CO₂ from their respiration and decomposition processes. So fertilisers are good news for plants.

Water and CO₂

Plants need water for photosynthesis. If they lack it, they wilt. When they have a deficiency of water, their stomata close, so CO₂ cannot diffuse into the leaves. So CO₂ is also the limiting factor, although it is as a result of lack of water.