Plants ‘see’ underground by channelling light to their roots

A light-bulb moment? Plants seem to pipe sunlight directly down into underground roots to help them grow.

More…

Maybe some plants are better than others for transmitting light down to their roots.

CrazyNeutrino said:

Plants ‘see’ underground by channelling light to their roots

A light-bulb moment? Plants seem to pipe sunlight directly down into underground roots to help them grow.

More…

“They found that the plant stem acts like a fibre-optic cable, conducting light down to receptors in the roots known as phytochromes. These trigger the production of a protein called HY5, which promotes healthy root growth.”

Starting.

CrazyNeutrino said:

Plants ‘see’ underground by channelling light to their roots

A light-bulb moment? Plants seem to pipe sunlight directly down into underground roots to help them grow.

More…

“Red light was found to move most efficiently through the plants. The long wavelengths of such light may be favourable because they can travel further than shorter blue and green wavelengths”.

Is that unexpected?

Blue light travels further than red light underwater, and plant conduits are mostly water, so thinking about it one way you’d expect to see blue light travel more efficiently to the roots than red light. But thinking about it another way, blue light is more easily scattered by small molecules than red light (Rayleigh scattering) so you’d expect blue light to be lost from the plant conduits while red light travel through. Two opposite ways of thinking give opposite expectations.

Thinking further, the light approaching a plant contains a much larger red component if the sun is shining directly on the plant than when it is only lit by the blue sky.

mollwollfumble said:

CrazyNeutrino said:

Plants ‘see’ underground by channelling light to their roots

A light-bulb moment? Plants seem to pipe sunlight directly down into underground roots to help them grow.

More…

“Red light was found to move most efficiently through the plants. The long wavelengths of such light may be favourable because they can travel further than shorter blue and green wavelengths”.

Is that unexpected?

No.
mollwollfumble said:

Blue light travels further than red light underwater, and plant conduits are mostly water, so thinking about it one way you’d expect to see blue light travel more efficiently to the roots than red light. But thinking about it another way, blue light is more easily scattered by small molecules than red light (Rayleigh scattering) so you’d expect blue light to be lost from the plant conduits while red light travel through. Two opposite ways of thinking give opposite expectations.

Thinking further, the light approaching a plant contains a much larger red component if the sun is shining directly on the plant than when it is only lit by the blue sky.

The plants use the blue and red differently. If you feed them light only red then photosynthesis suffers.

glad i read the article sometimes cos if i relied on a correct interpretation on here i would be mislead.

It would be interesting to see if plants could grow under the light of the sun on Mars, under a pressure dome obviously as it has to have an atmosphere but not using growing lighst but just whatever sunlight is available.

Cymek said:

It would be interesting to see if plants could grow under the light of the sun on Mars, under a pressure dome obviously as it has to have an atmosphere but not using growing lighst but just whatever sunlight is available.

In equatorial Mars the total insolation is similar to that in northern Scotland.

Cymek said:

It would be interesting to see if plants could grow under the light of the sun on Mars, under a pressure dome obviously as it has to have an atmosphere but not using growing lighst but just whatever sunlight is available.

That’s exactly what a recent experiment on the International Space Station set out to test. The experiment was fixed to the outside of the ISS and a large number of organisms were subjected to soil, atmosphere and lighting conditions likely to be found on Mars.

roughbarked said:

mollwollfumble said:

CrazyNeutrino said:

Plants ‘see’ underground by channelling light to their roots

A light-bulb moment? Plants seem to pipe sunlight directly down into underground roots to help them grow.

More…

“Red light was found to move most efficiently through the plants. The long wavelengths of such light may be favourable because they can travel further than shorter blue and green wavelengths”.

Is that unexpected?

No.
mollwollfumble said:

Blue light travels further than red light underwater, and plant conduits are mostly water, so thinking about it one way you’d expect to see blue light travel more efficiently to the roots than red light. But thinking about it another way, blue light is more easily scattered by small molecules than red light (Rayleigh scattering) so you’d expect blue light to be lost from the plant conduits while red light travel through. Two opposite ways of thinking give opposite expectations.

Thinking further, the light approaching a plant contains a much larger red component if the sun is shining directly on the plant than when it is only lit by the blue sky.

The plants use the blue and red differently. If you feed them light only red then photosynthesis suffers.

Chlorophyll A has two absorption peaks, one in the blue and one in the red. Not absorbed is green, which is why plants are green. Plants use red and blue light the same way. But you’re right that photosynthesis suffers if only red light is used, because the absorption peak for Chlorophyll A at the red end of the spectrum is smaller than that at the blue end of the spectrum.