Sunflowers are known to return “facing” the Sun as it crosses the sky. But exactly how sunflowers “see” the Sun in order to follow it remained unknown.
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A new study by American scientists from the University of California at Davis has shown that sunflowers use an unexpected natural mechanism for this, reports EurekAlert.
This was an absolute surprise for us,” the researchers note.
Most plants exhibit phototropism – the ability to grow towards a light source.
Sunflowers swing their head, growing a little more on the east side of the stem – pushing the head west – during the day and a little more on the west side at night, so the head turns back to the east.
Scientists hypothesized that sunflowers’ heliotropism—the ability to follow the sun—was based on the same basic mechanism, which is controlled by a molecule called phototropin and responds to light at the blue end of the spectrum.
This, in particular, was confirmed by experiments carried out on sunflowers grown in special laboratory chambers: indoors, sunflowers grew directly towards the light, activating genes associated with phototropin
However, plants grown outdoors showed a very different pattern of switching on the relevant genes—there was no obvious difference in phototropin between one side of the stem and the other.
Researchers have not yet identified the genes involved in heliotropism.
We seem to have ruled out the phototropin pathway, but have not found clear evidence. – the researchers emphasize.
Blocking blue, ultraviolet, or infrared had no effect on the heliotropism response.
“This suggests that there are likely multiple pathways that respond to different wavelengths of light to achieve the same goal,” the paper notes.
Scientists have also found that sunflowers learn quickly.
When lab-grown plants were moved outdoors, they began tracking the sun on the first day. This behavior was accompanied by a burst of gene expression on the shaded side of the plant, which was not repeated in subsequent days, the researchers noted. – This indicates that some kind of “reflashing” is taking place.
Scientists note that in addition to identifying previously unknown pathways of light perception and plant growth, this discovery has broader implications.
What you determine in a controlled environment such as a growth chamber may not work in the real world, the researchers note.
Source: EurekAlert
Scientists have discovered an unexpected feature of plants
Source: Racurs
I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.