Light & Plant Growth

Light is obviously a limiting factor on photosynthesis: without it plants cannot take up carbon dioxide to form energy.  

The three main attributes of light that concern plants are

1. The Quality: Including wavelength (colour) 

2. The Quantity: How much exposure they receive (intensity)

3.The Duration: How long each period of light exposure goes for

Activity 1: Photosynthesis and light availability 

Watch the video below and see how availability of light (winter vs summer) limits the photosynthetic activity of plants (darker shades of green). In turn, reflect on how this must impact the overall food web and ecosystem of an area. 

ACTIVITY 2: PLANT GROWTH AND LIGHT
Watch this video The Effect of Light on Plant Growth.
Dot point list (in your book) a quick summary of some of the ways that light impacts plant growth

ACTIVITY 3: PHOTOSYNTHESIS AND WAVELENGTH

Plant Growth and Wavelength Virtual Lab (requires Flash)

What to Do:
1.  Run the simulator using the different coloured wavelengths.
2.  Use the ruler (at the bottom of the sim) to measure the height of the plants
3.  Record your results using the table function (bottom left hand corner)
4.  When you've finished the table click 'Print' and then 'Save to PDF'

Questions: (In your book pls)

1. According to the simulator, which wavelength of light provides the best growing conditions?  What were the results which support this?

2.  Do your results support a) Your hypothesis and b) The video (Activity 2) findings?

Background Reading:

• Gowing Plants & Light (bbc video)
• Light & Plant Growth Arizona University (webpage)
• Effects of Wavelength (colour) on plant growth Heliospectra page (webpage)
• Effect of Colour on Plant Growth Michigan University (webpage)
• Effects of Colour on Plant Growth (webpage)