5 ms·

I'm confused though -- how can the plant possibly shift this?

wcoenen 6y ago
Biological light harvesting complexes[1] act as an antenna network. I guess the shape and other properties of such a complex change depending on conditions. The paper doesn't really try to explain the biological tuning mechanism. Instead, they created a model of an antenna network capable of tuning. As in, this model had a bunch of parameters describing how it captured light and tuned. Then if they optimized those parameters for stability given the light spectra that different plants are exposed to, they found that their model would reproduce the actual absorption spectra of those plants. This strongly suggest that the plants have done the same optimization by evolution. [1] https://en.wikipedia.org/wiki/Light-harvesting_complexes_of_green_plants https://en.wikipedia.org/wiki/Light-harvesting_complexes_of_...
CydeWeys 6y ago
And on what timescales does this timing occur? Are we talking seconds? Or days, i.e. accomplished by growing different structures?
- h2odragon 6y ago
  FWIW, hardening seedlings to sunlight from a greenhouse is all about switching their spectrum, and it takes 3 to 7 days depending on what plant you're talking about. Gardener's rule of thumb. 4/6/8hr exposure etc. I wonder if anyone has used RGB LEDs and tormented plants with short cycle color changes yet? There's much anecdata and debate over spectrum vs efficiency in indoor gardening, but it's faded as power density became more obviously dominant, i think.
  - CydeWeys 6y ago
    Yeah, on the orders of days is what I'd expect. So if that's right, then what kind of meaningful tuning are talking about for plants? On the order of days you can simple grow more or less of the green chlorophyll; is that not tuning enough?
- wcoenen 6y ago
  Near instantaneous. In the paper it is described as "noise-cancelling".
tantalor 6y ago
(waves hands) proteins (or something)

Biological light harvesting complexes[1] act as an antenna network. I guess the shape and other properties of such a complex change depending on conditions. The paper doesn't really try to explain the biological tuning mechanism. Instead, they created a model of an antenna network capable of tuning. As in, this model had a bunch of parameters describing how it captured light and tuned. Then if they optimized those parameters for stability given the light spectra that different plants are exposed to, they found that their model would reproduce the actual absorption spectra of those plants. This strongly suggest that the plants have done the same optimization by evolution. [1] https://en.wikipedia.org/wiki/Light-harvesting_complexes_of_green_plants https://en.wikipedia.org/wiki/Light-harvesting_complexes_of_...

CydeWeys 6y ago

And on what timescales does this timing occur? Are we talking seconds? Or days, i.e. accomplished by growing different structures?

h2odragon 6y ago
FWIW, hardening seedlings to sunlight from a greenhouse is all about switching their spectrum, and it takes 3 to 7 days depending on what plant you're talking about. Gardener's rule of thumb. 4/6/8hr exposure etc. I wonder if anyone has used RGB LEDs and tormented plants with short cycle color changes yet? There's much anecdata and debate over spectrum vs efficiency in indoor gardening, but it's faded as power density became more obviously dominant, i think.
- CydeWeys 6y ago
  Yeah, on the orders of days is what I'd expect. So if that's right, then what kind of meaningful tuning are talking about for plants? On the order of days you can simple grow more or less of the green chlorophyll; is that not tuning enough?
wcoenen 6y ago
Near instantaneous. In the paper it is described as "noise-cancelling".

tantalor 6y ago

(waves hands) proteins (or something)