Water transport in plants involves 3 things:
- movement through the roots
- movement through the stem
- movement through the leaves
Plants take in a lot more water than they use for photosynthesis and turgor. In fact, only about 1 percent gets used for that and the other 99 percent evaporates right out. That evaporation is called transpiration.
It’s difficult to see how plants transport by just looking at their stems. The xylem vessels the water goes through are like tiny straws that allow the water to travel through.
Even though the tubes are small, movement of water through the stem is very observable with a simple science experiment. Start by adding food coloring to jars with water in them. You can use just one color and one jar, or make several like we did.
Go to a florist and get a few white carnations. Trim the tips off of each one and then quickly place one in each jar. We decided to cut one stem lengthwise and put one half of each stem part into a different colored jar. You can see that the last flower is in a blue and a red jar.
Watch over several days and you will see that the dyed water is absorbed up the stem and appears in the flower, turning the carnation petals the color of the water.
- Find out about how plants use that 1 percent or so of water they keep and turn it into food using photosynthesis.
- Discuss why this experiment helps us to see how important it is for the soil we are growing plants in to be rich with nutrients.
- Find out what turgor pressure is. Is it possible for a plant to have too much water?
- Learn more about plant growth and what plants need to thrive by making a poster about plant growth and a terrarium.