Chlorophyll & Photosynthesis Surviving in hot environments and - PowerPoint PPT Presentation

Plant adaptations, Chlorophyll & Photosynthesis Surviving in hot environments and making the most of light

What we are going to do today … Visit the Faculty Experimental grounds – look at plant adaptations to their environments and collect your experimental plants and leaves Experiments: 1) Heat tolerance in different leaves – which plants are best suited to surviving hot environments? 2) Chlorophyll – making the most of light a) How do plants manage in the shade ? Or…… b) How do variegated leaves manage to survive?

1) Heat tolerance in different leaves: which plants are best suited to surviving hot environments? • Different plants have different ability to tolerate high temps. • Heat stress affects photosynthesis • Measure the heat tolerance using a “Plant stress meter” (FluoroPen)

2) Making the most of light: How do plants manage in shade? www.saps.org.uk http://www.controlledenvironments.org

• Chlorophyll absorbs the red and blue light - appears green. Two main types chlorophyll a and chlorophyll b. • Carotenoids absorb the blue-green and blue light - appears yellow or yellow-orange. • Anthocyanins absorb blue, blue-green and green light- appear red or purple to our eyes. http://www.sidthomas.net/SenEssence/Evolution/pigments.htm

More chl b than chl a in shade ..lower a/b ratio Antennae Reaction Excitation Centres energy Photon of SUN SHADE light 1. Shade plants can invest in more light capturing structures (antennae) than in light ‘using’ structures (reaction centres). 2. Also increase the number of photosystems, so higher total chl content 3. Often have larger, thinner leaves and longer petioles.

2) Making the most of light: How do variegated plants manage to survive? Some leaves are purple, red or variegated. • But do the non-green parts have chlorophyll as well? • Extract anthocyanin using baby oil? "Coleus-1" by Aftabbanoori - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons -

Chlorophyll content and a/b ratio Measure the chlorophyll content using scanning spectrophotometer

What now? Quick visit to our experimental grounds to select our leaves and pick our samples and variegated plants. Equipment: take zip lock bags and damp tissue paper