The Mad Plant Scientist
January 31, 2015
As a plant scientist, some may say even a mad plant scientist, I’m interested in sharing how plants work with home gardeners. Do you know how the water gets from the roots to the top of the plant? Let’s take a look. We all know that watering is important for good plant growth. As a gardener waters plants in the garden and landscape, the movement of water from the roots through the stem occurs via a process called transpiration, where water evaporates to the atmosphere from small openings called stomata on the back of the leaves. This evaporation pulls the water from the roots to the top of the plant in tubes called xylem which act in the same fashion as a hose. We can demonstrate this process using a classic, and in my opinion fun, school science project. Great Scot Marty, you’re a genius. Placing the stems in food coloring the colored water is drawn up into the celery leaves. Another interesting effect concerning water movement in a plant happens at night when small droplets of water are seen along the edge of a leaf. Many assume this is morning dew, but actually it is the result of a process called guttation. Guttation occurs when high humidity is combined with high soil moisture. Root pressure pushes water up the plant and out special water glands called hydathodes. Fortunately, you don’t have to be a mad scientist to be a successful gardener. In my opinion, the successful gardener understands that how to grow plants is fundamentally based on knowing how plants grow. I’m horticulturist Gary Bachman for Southern Gardening.