Scientists and famers can manipulate the growing conditions crops to produce the optimum quality and yield. In the Netherlands, massive greenhouses are used to grow peppers in constant light conditions, enabling farmers to reduce the growing season by four weeks.

Carbon dioxide levels on Earth have in the past been much higher. Plants evolved the capacity to use higher levels of carbon dioxide, but under modern conditions, the rate of their photosynthesis is limited. Waste carbon dioxide can be directed into greenhouses growing tomatoes. This extra carbon dioxide enables the tomatoes to photosynthesise faster, which increases sugar production, improving flavour and yield.

This clip is from:
First broadcast:
14 June 2011

This clip could be used as a lesson starter when discussing limiting factors. Students could do practical work looking at the effect of changing light intensity or carbon dioxide concentration on the rate of photosynthesis. Higher level students could develop the ideas discussed and look at the explanations for the effects seen.
Students could also examine the impact commercial plant cultivation has had on the environment. The balance between improving yield and the use of fossil fuels to generate light could be weighed up in terms of costs and benefits. The re-cycling of materials from power stations could be used to illustrate the benefits of carbon neutral technology and innovation.