So what is phototropism? It is an organism’s directional growth toward stimulus such as light. Most often observed in plants, growth toward light also can occur in fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs.
In our home gardens, we can see that flowers, shrubs and trees prefer to face the sun, seeking light for optimal growth. Sun-loving plants especially, will stretch and contort to reach sunlight – a possible sign of poor plant placement.
Over the plant’s lifetime, placement in relation to light determines its growth pattern, sending branches in unwanted directions. A wayward branch might be aesthetically displeasing or annoyingly in the way. Certainly proper plant location minimizes odd growth patterns, but gardens are ever evolving and many long-lived plants, especially trees succumb to wayward growth. Proper pruning can be one straight-forward resolution. Interestingly, the Portland Japanese Garden, renown for stunning Japanese Maples (acer palmatum) has alternative shaping and regulation techniques. Observing the trees’ phototropic properties, trees are regularly rotated in situ, allowing each side to grow towards light. Although, this year’s Workshop: Maple Pruning is sold out, visit http://japanesegarden.com and marvel the art and science of the garden.
Observation is a powerful learning tool as well as the foundation for continuing scientific discovery - there are abundant observation opportunities in a garden. For budding garden scientists - a fun and easy project from the Texas Junior Master Gardener program.
One really interesting thing about plants is that they are phototropic. That means they will bend toward light. Try building this plant maze to see how they do it.
Cut a square in one end of the box. Cut a square in each piece of cardboard, at a different place on each piece. Place your plant in one end of the box, and space the cardboard pieces in the box. Put the lid on the box. The plant will grow throught the maze to the hole at the other end of the box. Draw a picture of what your plant maze looks like and how the plant grew.