Chromatography High School Science Fair Projects

Name: Megan
Age: 15 - Home School
Texas, USA
Science Category: Biology - Botany

Project Research

Autumn is a second spring where every leaf is a flower. – Albert Camus

I’ve always been fascinated by the seemly magical transformation that leaves go through during the autumn. Between the magic and my curiosity, it seemed natural to do a science fair project investigating this change of color.

Through research I learned that leaves have pigment-containing chloroplasts in specialized organelles found in plant cells. These chloroplasts make it possible for them to use photosynthesis as a process to provide the plant with energy and food. The chloroplasts, which are in the leaf cells, contain different pigments that give the leaf its color. The pigment we see in most leaves is chlorophyll, which is green.

But leaves contain other pigments. These pigments include xanthophylls (yellow), carotenoids (yellow, orange), and anthocyanins (red). These colors are normally hidden by the chlorophyll, except for when the chlorophyll begins to break down during the autumn season. This is when you can then see the yellow, orange, and red pigments.

Having lived in South Dakota where trees burned with color, I’ve noticed some trees and bushes in Texas never change colors nor lose their leaves during the fall. I learned from our county extension agent, John Begnaud, that seed producing plants are called Angiosperms and that the trees and bushes I was interested in were either deciduous (lose leaves-normally in winter)or broadleaf evergreens (keep leaves all year).

I thought that both broadleaf evergreen plants and deciduous plants would show the green chlorophyll when I did pigment testing, because I could see the green chlorophyll. But I wanted to know if broadleaf evergreen plants (those Angiosperms which do not lose their leaves in the winter) showed xanthophylls, carotenoids, and anthocyanins pigmentation like deciduous plants (those Angiosperms which lose their leaves in the winter).

Hypothesis

I believe that the leaves from both the broadleaf evergreens and the deciduous will contain all the pigments. These include the chlorophyll, xanthophylls, carotenoids, and anthocyanins. Because all the leaves are visibly green, they will definitely contain the pigment chlorophyll which I believe will be the most prominent of the pigments.

Carotenoids, anthocyanins, and xanthophylls all work as accessory pigments which work with chlorophyll to help absorb light.

Therefore, I believe that both deciduous and broadleaf evergreens will contain the pigments xanthophylls, carotenoids, and anthocyanins, but with these pigments being less intense in the broadleaf evergreens than in the deciduous.

Materials
Camera
Notebook
Pen
Plastic baggies
Pencils
9” X 13” pan for hot tap water
Viva Paper Towels
Coffee filters
Drawing Paper
Permanent marker
Tape
16 ounce Glass jars with covers
Isopropyl Alcohol—91%

To see Megan's experiment and data (page 2) chromatography high school science experiment.