Principles of Biology
By
Frank H. Osborne, Ph. D.
Lab 5 - Green Plant I
Green Plants
A. The part above the ground is the shoot.
1. The shoot has a stem.
2. Leaves are attached to the stem.
3. The point of attachment is called a node.
4. The part of the stem between the two nodes is
called an internode.
5. Cotyledons from the seed used to be
attached at the node below the first pair of leaves.
Bean Plant germination
Seed Leaves
Cotyledons
Growing
Bean Plant
Apical Meristem
Trifoliate Leaf
Second Internode
First Internode
Cotyledon
Attachment
Scar
Growing
Bean Plants
Green Plants
B. Bean Plant Leaves
1. The first pair of leaves.
a. The first pair of leaves used to be part of
the embryo in the seed.
b. The embryonic leaves of the bean are
heart-shaped.
Green Plants
B. Bean Plant Leaves
2. Other leaves of the bean plant.
a. Leaves, other than the embryonic leaves
are formed by the shoot tip meristem.
b. These leaves are trifoliate and have
three leaflets.
Pigments of Leaves
A. Leaves of green plants contain pigments.
1. Carotene
a. Carotene is yellow.
b. Carotene is very soluble in organic
solvents but not very soluble in water.
Pigments of Leaves
A. Leaves of green plants contain pigments.
2. Xanthophyll
a. Xanthophyll is grey to yellow in color.
b. It is equally soluble in water and
organic solvents.
Pigments of Leaves
A. Leaves of green plants contain pigments.
3. Chlorophyll a
a. Chlorophyll a is dark blue-green.
b. Chlorophyll a is more soluble in water
than it is in organic solvents.
Pigments of Leaves
A. Leaves of green plants contain pigments.
4. Chlorophyll b
a. Chlorophyll b is light yellow-green color.
b. Chlorophyll b is more soluble in water
than it is in organic solvents.
B. Principles of
Chromatography
1. Special paper is used.
a. The paper has water in
it between the fibers
(aqueous phase)
b. A spot of concentrated
pigments is put at the
bottom of the paper.
2. The paper is placed
in solvent.
a. The solvent is the
organic phase.
b. The organic
phase (solvent) travels
up the paper and
carries the pigments
with it.
2. The paper is placed
in solvent.
a. The solvent is the
organic phase.
b. The organic
phase (solvent) travels
up the paper and
carries the pigments
with it.
3. Pigments travel at different rates depending
on their solubilities.
a. Carotene travels at the fastest rate because
it is most soluble in organic solvent.
b. Xanthophyll travels at an intermediate rate
because it is equally soluble in both water and
organic solvent.
c. Chlorophyll a and chlorophyll b travel at a
slow rate because they are more soluble in water.
d. The rate of travel is called the ratio of
fronts which is abbreviated as Rf.
Calculations
A. Mark the spot with a pencil.
B. Form the spot.
C. Run the chromatogram.
D. Mark the top and bottom of each band.
E. Measure the center of each band and mark it
with a dot.
F. Make a data table containing the distance of
each band from the spot.
G. Make another table for calculating the Rf
values.
Measuring the Chromatogram
Measuring the Chromatogram
Measuring the Chromatogram
Measuring the Chromatogram
Measuring the Chromatogram
Measuring the Chromatogram
Measuring the Chromatogram
Distances of Bands from Spot
Band
Distance of Band from Spot (cm)
Chlorophyll b
Chlorophyll a
Xanthophyll
Carotene
Front
1.2 cm
3.1 cm
7.2 cm
11.9 cm
12.2 cm
Calculation of Rf Values
Band
Chlorophyll b
Chlorophyll a
Xanthophyll
Carotene
Calculation
1.2 cm/12.2 cm
3.1 cm/12.2 cm
7.2 cm/12.2 cm
11.9 cm/12.2 cm
Rf
0.10
0.25
0.59
0.98
The End
Lab 5
Green Plant I