Names: ________________________________ Date: _______________ Period: ____________

Lab: Producing a Paper Chromatogram of Plant Material

Purpose: 1. To understand more about the concept of a cycle. Looking at a leaf.2. To Understand environmental changes that occur seasonally.3. To learn about the term pigment.

Pigment names: Carotene = yellow orange Xanthophyll = yellowChlorophyll A = blue green Chlorophyll B = yellow-olive green

4. To understand why leaves change to different colors and fall from trees.5. To observe a chromatogram of a leaf, and leaf pigments.

Materials:- Chromatography paper (one 5 inch piece per test) - Black pen/marker- Ethanol (2 ml per test) - Pencil and tape - Radicchio leaf- Beakers/ test tubes - A coin - Spinach leaf

Procedure: Black Pen

1. Using your black pen, make a small dot about 2 cm from the end of your chromatography paper.2. Pour 2 ml of ethanol in test tube.3. Tape chromatography paper to a pencil so the bottom is just hanging down into the solution (the dot

should NOT be in the solution)4. Allow 5+ minutes for ethanol to rise. Pull out of the beaker when ethanol is 2-4 cm from the top.

Spinach and Radicchio1. Follow the procedure twice - once for each leaf with separate trials.2. Take a coin, and turn leaf upside down, place over chromatography paper and make line of leaf on the

bottom of the paper (SCRATCH MUST BE 2 CM FROM END OF PAPER)3. Pour 2 ml of ethanol in test tube. 4. Tape chromatography paper to a pencil so the bottom is just hanging down into the solution (the

scratch should NOT be in the solution).5. Allow 5+ minutes for ethanol to rise. Pull out of the beaker when ethanol is 2-4 cm from the top.

Data/Observations - Tape your dried chromatograms to the bottom of your paper!Black Pen Spinach Radicchio

Names: ________________________________ Date: _______________ Period: ____________

Lab: Producing a Paper Chromatogram of Plant Material Post-Lab

Post-Lab Questions:1. What colors are found on your paper?

2. State the name of the pigments in the leaf that were attracted to your paper.

3. What pigment was attracted to the ethanol the most?

4. Is this the correct pigment that matches the color of your leaf? Why?

5. List 3 things you learned or discovered from this lab!

Names: ________________________________ Date: _______________ Period: ____________

Lab: Producing a Paper Chromatogram of Plant Material Post-Lab

Post-Lab Questions:1. What colors are found on your paper?

2. State the name of the pigments in the leaf that were attracted to your paper.

3. What pigment was attracted to the ethanol the most?

4. Is this the correct pigment that matches the color of your leaf? Why?

5. List 3 things you learned or discovered from this lab!

Focus on Fall LeavesNot all trees change color in autumn. But for those that

do, here’s why.

Hold your breath. It looks like this fall is going to be a good one. If Mother Nature continues to provide us with sunny days and cool nights, then in a few weeks we’ll be greeted with a spectacular display of autumn colors. In the world’s northern temperate climates, the greens of summer will soon give way to fiery reds, pumpkin oranges, and golden yellows.

Suppose the blazing colors of autumn never came. Fall just wouldn't be the same for us nature lovers. But there’s more to the magic of the season than just that. Did you ever wonder why leaves change color in the Fall? Surprisingly, the colorful process by which trees get rid of leaves actually helps to keep the trees alive.

Leaves, as you probably know, are clever little food-making factories. They take basic substances (water, light, and carbon dioxide) and --- using only the energy from sunlight --- turn them into food. Green leaves make food through a process called photosynthesis. This process begins when the sun strikes chloroplasts - tiny green bodies inside the cells of a leaf that contain a green pigment (coloring substance) called chlorophyll (KLOR-o-fill).

Chlorophyll absorbs energy from the sun's rays. This energy splits the water molecules (H2O, which is supplied from the trees roots) into oxygen and hydrogen. The hydrogen combines with carbon dioxide (from the air) to form a simple sugar (glucose). This sugar is carried off to the rest of the plant and used as food for growth and other important functions.

Natures Color FactoriesBut as summer days turn cooler, deciduous trees (those that lose their leaves) make smaller

and smaller amounts of chlorophyll. This means that the leaves begin to make smaller amount of food. The tiny veins that carried water to the leaf and food to the rest of the tree become clogged with a waxy, corklike substance. This material will prevent water from escaping from the twigs once the leaves drop off. The cells connecting the leaf to the stem dissolve and separate, and the dying leaf hangs from the stem by just a few strands. When the strands break, the dead leaf drifts to the ground. But why do green leaves change color as they die?

Because green leaves aren’t “just green”. Small amounts of pigments other than chlorophyll are present in green leaves too. In the summer, the green chlorophyll overpowers these other pigments. But, in autumn, only a small amount of chlorophyll remains. This is when other pigments -- the bright reds and golds of autumn---show through.

So how does this process help a tree to survive? Leaves receive food and water from the rest of the plant by way of tiny tubes at the base of the leaves. As water evaporates from the surface of the leaves, more water comes in through the tubes. As long as the tree’s roots can absorb enough water to replace what is lost in the leaves, the tree will remain green.

But as the ground begins to harden and freeze, the tree roots cannot easily absorb water to replace what would be lost by the leaves. So, in order to protect their supply of water through the winter months, the trees get rid of their leaves.

Pigment PowerWithout enough water, the chlorophyll dries up and fades away. Once the chlorophyll begins to

fade, the other pigments can be seen. The pigments known as carotenoids, produce hues of yellow, orange, and brown. The bright crimson and purple shades come from another group of pigments known as anthocyanins. The amount of these pigments depends on how much glucose is in the leaf.

Now, even after the water is shut off from the leaf, the chlorophyll can still keep making glucose for a while --- as long as there is enough sunlight. Eventually, the chlorophyll will fade because the leaf isn't getting more water. So if the days of early autumn are sunny, the chlorophyll will make a lot of glucose. And that means more reds and purples will appear on the leaves.

But the evenings of early autumn must be cool --- around 45 F (7 C) --- for the anthocyanins (reds and purples) to be formed in large amounts. It also helps if the late summer is dry.

Most trees shed their leaves slowly (this is called abscission). In this process, minerals, carbohydrates, and other nutrients travel from the leaves to be stored in the roots and trunk of the tree over the winter. In the next spring, these substances will contribute to the new growth of buds. And the tree will “come alive” once again.

-----James A. Baggett

Name: ____________________ Date: _______________ Period: __________

Focus on Fall LeavesDirections: Read the article and answer the following questions!

1. Leaves take the basic substances (________________, light, and carbon dioxide) and using only the energy from ___________________ - turn them into _______________.

2. Photosynthesis begins when the sun strikes _________________ - tiny green bodies inside the cells of a leaf that contain a green pigment called ____________________.

3. What does Chlorophyll do?

4. Trees that lose their leaves are called __________________________ trees.5. As the days turn cooler, leaves on deciduous trees begin to make _______________

amounts of food.6. As the ground begins to _______________ and freeze, the tree roots cannot easily

absorb water to ________________ what would be _____________ by the leaves.7. So, in order to protect their supply of water through the _________________ months,

the trees _____________________________________________________.8. What is pigment? Define it

9. Chlorophyll begins to dry up when there is less water, then the other pigments _______________________________________.

10. The pigments known as carotenoids produce hues or colors of _______________, _________________, and ___________________.

11. Bright colors of ________________ and ________________ shades come from the group of pigments called ________________________.

12. If the days of early autumn are sunny, the chlorophyll will make a lot of ________________________. That means more _______________, and _______________ will appear on the leaves.

13. The evenings of early autumn must be ______________ about ____ degrees, for the reds and purples to be formed in ________ amounts.

14. Abscission means trees ______________________________________________

15. In the process of trees shedding leaves, what 3 things travel from the trees leaves to the roots?

16. In the next spring, these substances will contribute to ________________________.