It's a way of saying that the R/FR ratio decreases as the plants become more
crowded. A plant preferentially absorbs red light....the far red light is
reflected and it is this increase in the proportion of far-red light (ie a
decrease in the R/FR ratio) that the neighbouring plants detect. This gives
rise to the "shade avoidance response" characterised by extented petiole
growth, early flowering, increased height etc; all attempts by the plant to
grow away from the shade.
<wjboelem at my-deja.com> wrote in message news:8k3388$lcg$1 at nnrp1.deja.com...
> I have a question regarding Walter Larcher's book, Physiological Plant
> Ecology. In it (page 41) he says" Reflection of red light plays an
> important role in communication between neighboring plants. Because the
> red/far-red ratio in the reflected light increases with increasing
> distanace from the plant reflecting it, the receiving plant, via its
> phytochrome system (Phyr/Phyfr; far-red equilibrium), is able to detect
> the presence and distance of its neighbors". How is this accomplished?
> Why does red/far-red ratio increase with distance from the plant
> reflecting it?
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