| Purpose - |
This demonstration shows
the way that stem function to move water up a plant |
|
| Nature - |
Demonstration |
| Materials - |
long stemmed white
carnation (or other white flower such as chrysanthemum) , scalpel, 2
x 50 ml flasks, water, red and blue food colouring, stand |
| Method - |
- Trim about 5 centimetres of stem
from the bottom.
- Using the scalpel split the stem
length wise from about 10 centimetres down to the bottom
- Half fill the two vials with water
and add a few drops of red food colouring to one, and a few
drops of blue to the other.
- Using the stand, arrange the flower
so that half the split carnation stem sits in the red solution
and half in the blue.
- Within an hour
or so you will see the white petals starting to take on a slight
coloured tinge. By the next day the flower will be as
strongly coloured as the ones in the photos.
|
| Safety - |
Be careful with the
scalpel. |
| Explanation - |
Water is drawn up a plant
stem through vessels called xylem. The coloured water moves
through them up into the cells of the flower petals, colouring the
flower. |
| Notes - |
- Soil minerals that have
dissolved in ground water are carried through the plant to the
leaves in the same way the food colouring was.
- For something a
bit different try very carefully quartering the stem and sitting in
four different coloured test tubes (pictures on right)
|
|
