While school is out this summer, let’s experiment with some plant science! Botany is the name for the science of plants. This fun project takes only a few minutes to set up.
Do you ever wonder why we water flowers and gardens? Water is as essential for plants as it is for people. If plants don’t get enough water, they could die, just like people would without water. But how does the water you put in the ground around a plant feed its leaves and flowers?
Water is an important ingredient in photosynthesis—the process plants use to make food! Plants use energy from sunlight to make glucose (a type of sugar) from water, minerals, and carbon dioxide in the air.
Plants have roots, stems, leaves, and flowers that make fruits and seeds. Inside plant stems are two types of tubes called phloem and xylem. Phloem is the smaller outer part of the stem, inside the protective skin or epidermis. Xylem is thicker and makes up most of the stem. Each tube has its own job.
How do water, minerals, and food get to the leaves and flowers?
The tubes in the plant stem act like roads, only instead of cars and trucks, they carry water and nutrients. Phloem moves food (glucose) all through the plant, up and down the stem between the roots and the leaves and flowers. Xylem carries the water and minerals in only one direction: from roots to the leaves and flowers.
The experiment: Seeing water move
To see how water moves up a stem and into a flower, you’ll need:
- White flower(s)
- Clear glass or vase
- Food coloring
Cut flowers stems right before you are ready to put them in water. Be sure to ask permission before picking flowers from a garden!
- Put water in your glass or vase.
- Add several drops of food coloring to the water.
Caution: Food coloring is a dye, so ask for help and be careful not to get any on your clothes or other surfaces.
- Put your flower in the colored water.
- Wait and watch.
The stem will absorb the water, the xylem will carry it up to the flower, and eventually the white flower petals will turn the color of the dye in the water. It may take several hours for the dye to reach the flowers, though!
Try this with several different types of flowers, different food colors, and different amounts of coloring. White flowers will always work best to show the dye, but maybe one flower type is faster to take up the coloring than another. You could keep track of how long it takes to reach the petals. Real scientists always take notes and record their experiences.
Article written by Nancy Good, Extension Master Gardener Volunteer.