Plant & zo
The science of plants and more
Plants, you can find them everywhere, even on top of a mountain. Circumstances are different there, on top of the mountain, than here, below at sea level. The air, for example, is thinner. Which causes problems. Even though, plants breath CO2, oxygen is important. So important, they have a special detection system for it. But does it not sound the alarm, there on top of the mountain.
To find this out, English researchers studied an oxygen dependent process: chlorophyl production. Chlorophyl catches the light for photosynthesis. So, it is something a plant likes to have enough of, no matter the oxygen concentration. But because chlorophyl is not needed till photosynthesis starts, the last step of chlorophyl production only takes place in the light. In just germinated seedlings, that did not see any light, there is a small accumulation of pre-chlorophyl. Which is something the researchers could measure, they used it to unravel the oxygen detection system.
On top of the mountain the detection system hits the brakes later, by lower oxygen concentrations
At sea level, plants germinating in a low oxygen environment were noticed to have less pre-chlorophyl than plants germinating in a higher oxygen environment. But a mutant, that could not regulate its chlorophyl production, did not show any difference. This suggested that not the available oxygen, but the oxygen-sensing system is pushing the brake.
Al this was studied at sea level, with plants evolved to grow at sea level. What are plants doing on top of the mountain. It turned out, that just like their relatives at sea level, they have less pre-chlorophyl in low oxygen environments. But when the researchers compared the actual amounts of pre-chlorophyl of plants growing on top of a mountain with those at sea level, they did not see a difference. The oxygen-sensing system is more sensitively fine-tuned. On top of the mountain, it hits the brake by lower oxygen concentrations.
Preventing an overabundance of pre-chlorophyl. On top of the mountain, the oxygen-sensing system does not only hit the brake slower for pre-chlorophyl production. It also does this for other oxygen using processes. For plants, on top there, the air is not as thin as we like to think.
Mohamad Abbas, Gunjan Sharma, Charlene Dambire, Julietta Marquez, Carlos Alonso-Blanco, Karina Proaño & Michael J. Holdsworth (2022) An oxygen-sensing mechanism for angiosperm adaptation to altitude. Nature https://doi.org/10.1038/s41586-022-04740-y