Pigments in Leaves

Objectives

•	Plotting of leaf reflectance on graph paper, based on the pigments present.
•	Identify pigments present based on leaf reflectance.

Materials

•	Colour photographs of leaves
•	Empty graph charts (at the end of the worksheet)

Procedure

1)	Use the empty graph charts at the end of the worksheet to plot the spectral reflectance of leaves containing chlorophylls, xanthophylls, carotenoids and anthocyanins. Bear in mind that the amount of energy each pigment absorbs (at an average concentration) is:
	BLUE	GREEN	RED	
Chlorophylls	40%	-	40%	
Xanthophylls	40%	-	-	
Carotenoids	-	20%	40%	
Anthocyanins	-	30%	-	

The leaves in question contain:
Leaf #1: Chlorophylls & xanthophylls
Leaf #2: Carotenoids & anthocyanins
Leaf #3: Chlorophylls, xanthophylls & carotenoids
Leaf #4: Xanthophylls & anthocyanins
Leaf #5: Chlorophyll, carotenoids & anthocyanins
Leaf #6: Xanthophylls, carotenoids & anthocyanins
Leaf #7: All four pigments.
2)	
Look at the following colour photographs and try to guess how much energy is absorbed in the blue, green and red regions in each case. You don’t have to be very specific, just estimate if the absorption is high (above 40%), average (between 20 and 40%) or low (20% or less): 
A

A

Blue Reflectance	:

Green Reflectance	:

Red Reflectance	:

B

C

B
Blue Reflectance	:

Green Reflectance	:

Red Reflectance	:

C
Blue Reflectance	:

Green Reflectance	:

Red Reflectance	:
Now look at the table of question #1. Using the information there, can you guess which pigments are present in each of cases A, B and C?

	Leaf #	Leaf #

	Leaf #	Leaf #
	Leaf #	Leaf #
	Leaf #	Leaf #