Categories: Technology

Study Reveals Mechanism By Which They Detect Light Sources

Plants are able to differentiate between the different amounts of light they receive and how their cells respond to it. Until now, a clear explanation for this phenomenon has not been found.

Don’t let appearances deceive you There is much more to the fascinating world of plants than meets the eye.To. And speaking of “vision,” although plants do not have eyes in the sense that we know them, they do exist. They have the ability to detect where light is coming from. But how do they do it?

This secret was revealed by researchers from University of Lausanne (UNIL) and Federal Polytechnic School of Lausanne (EPFL) in Switzerland. Research has shown that plants have light-sensitive tissue in their stems that uses optical properties to control their growth.

The plant “sees” thanks to air channels

Unlike other living organisms, plants do not have a visual organ comparable to the eyes. However, his amazing ability to determine the origin of a light source.

Sensing a light source is especially important for plants, which use this information to determine the position of their organs as they grow, a phenomenon known as phototropism.

It turns out that Plant stems have something amazing called “air ducts.”. These are spaces between cells that not only facilitate the passage of air, but also limit the amount of light passing through They are like little curtains of light inside the plants!

The secret is in the optics

The study used a popular plant model in plant biology known as Arabidopsis Talianaspecifically the mutant version with the stem is “surprisingly transparent“The lead researcher said in a press release.

“We discovered that the natural milky appearance of the stems of young wild plants is actually due to the presence of air in precisely positioned intercellular channels in various tissues. “In mutant individuals, the air is replaced by a watery liquid, giving them a translucent appearance.”

Christian Fankhauser, Director of the Center for Integrative Genomics, Faculty of Biology and Medicine, UNIL

These channels increase light diffusion, especially in the hypocotyls – the part of the plant that grows from the seed – the seedlings. This has an impressive effect creating the light gradient needed for an efficient growth responseit’s like an indoor light show on every floor!

Water and air in the right proportions

As detailed in the study, the photosensitive fabric uses optical properties of the air-water interface to create a “visible” light gradient for the plant.

The refractive index is a measure that describes how much light slows down when passing through a material compared to its speed in a vacuum.

“Air and water have very different refractive indices. This causes light to diffuse as it passes through the hypocotyl of the seedling. We have all observed this phenomenon while admiring a rainbow,” explained Martina Legris, co-author of the study.

The research also allowed us to better understand the formation of intercellular air-filled channels, which serve various functions in plants, such as promoting gas exchange and providing resistance to hypoxia (decreased oxygen) in the event of flooding.

Comparing mutant and wild plants allowed the researchers to conclude that the composition of the internal tissue (water or air) is responsible for mechanism that allows a plant to determine the direction of light.

Research like this provides new insight how plant biology workspresenting us with a botanical spectacle of molecular mechanisms that deserves green and bright applause.

Link to news:
Fankhauser K, Legris M. Air channels create a directional light signal to regulate hypocotyl phototropism. Science (2023)

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