How come sunflowers are called sunflowers? Because they look like the sun, with their petals around shaped like sunbeams? What’s more, there is this curious behavior of the plant of always keeping the flower facing the sun. Is it pagan magic or is it science?
On August 5, scientists published a study in Science magazine, in which they answer these questions. No magic indeed, pure science.
There is a scientific name for the plant’s preferential treatment to the sun and its tendency of actually moving function of it. This phenomenon is called heliotropism.
Professor Stacey Harmer (University of California, Davis) worked with colleague Nicky Creux, and Evan Brown and Austin Garner (University of Virginia). The team leader talks about their findings:
“It’s the first example of a plant’s clock modulating growth in a natural environment, and having real repercussions for the plant.”
Researchers say there is nothing surprising about the way the sunflower behaves because it is something very much like the human biological clock. The routine of the sunflower is to turn its face eastward at down, and slowly move westward by nightfall. During night time, the plant gets back to where it started at dawn, namely facing the east.
The researchers led an experiment through which they forced some of the plants to stay still, preventing them from moving and following the sun. What they observed was that the flowers prevented from performing their natural movements showed signs of more slowly evolution than the ones following their normal cycle.
Sunflowers seek the blessing of the sun because they need both light and warmth. Scientists also noted that flowers enjoying the sunbeams capture the heat, which attracts bees, or other pollinators. The small insects are a crucial factor in the plant’s growth and evolution: pollination is important for the plant to be able to reproduce.
Performing the slowly circular movement allows sunflowers to grow: the process helps the stem to stretch and get longer. Reports show that the elongating process is more likely to happen in daylight rather than at night time. Hence, the special bond between the sun and “its earthly” flower sister.
The National Science Foundation’s Plant Genome Research Program supported the financial costs of the study. Director Anne Sylvester gave her opinion on the phenomenon:
“Sunflowers, like solar panel arrays, follow the sun from east to west. These researchers tap into information in the sunflower genome to understand how and why sunflowers track the sun.”
Image source: Wikipedia