There are two forms of phytochromes (a blue green pigment found in many plants, that regulates various developmental processes) when talking about red and blue radiation
One form absorbs the red part of radiation (600 to 700nm)and its abbreviation is PR, the other form absorbs far-red radiation (700-800nm),it's abbreviation is PFR.
The graph below shows that plants are very efficient at absorbing Red. The green line 'relative quantum efficiency' is how efficient the light is at different wavelengths for plants. The black dashed line 'luminous efficiency' is how the human eye sees light. It is important to note that both forms of Phytochromes share a common band of absorption. That means that every time that a plant receives light, both forms will be present.
PFR.
Sunlight emits both red and far-red radiation. Leaves exposed to direct sunlight absorb almost all the red light but transmit the far-red to the leaves underneath the plant canopy in a sort of filtration process. When the plants underneath the canopy receive a greater proportion of far-red, they respond with physical elongation in an attempt to capture available light. This response is called “shade avoidance”.
In the shade, plants don’t receive enough energy and so they start building processes in order to survive. As well as stem elongation, they also grow larger leaves (leaf expansion) to maximize the surface area and their chance to harvest photons. Both cases are a result of cell expansion.
Research shows that for the same artificial light intensity, under red/blue LEDs and warm-white LEDs, adding far-red light increases the quantum yield of photosystem II (one of two light reactions of plants) by an average of 6.5% and 3.5% respectively. This can potentially lead to an increase in yields. Farminc.space provides all necessary spectrums that for a plant requires in growth and blooming.
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