Why do certain species of aquatic plant colour up under intense light? That they do is something we often observe in all well lighted planted tanks. That this change in colouration becomes more prominent with the intensity of light is also a common observation. I will concede that some specie of aquatic plants will not show any perceptible change in their colouration and some others do not need very intense light to be other than green.
There are and always had been nutritional factors which can change the colouration of plants – but those need not be addressed here.
As I see it, when a plant does change its colour under lights, it does not stop reflecting the green part of the light spectrum it normally did, but is now reflecting an additional part of the spectrum, and this causes the change in colouration. Conversely this means that the plant is reducing the range of the light spectrum it was absorbing. Therefore it follows that the plant is reducing its energy absorption from those parts which are in more intense light. Why?
Additional energy when there is no lack of nutrients for the plant to increase synthesis of its growth substances should have been an advantage to the plant; still the plant is opting to reduce it energy absorption. Nature never induces curtailment of any action (or omission) which is of advantage to any specie; then why is such an advantage to the plant being curtailed? The answer must be that behind the obvious advantage lies some hidden disadvantage.
Reflecting over the question, it suddenly struck me the answer must be oxygen. Oxygen is synonymous with life, as we know it, but it is a dangerous poison. Man regularly uses oxygen and oxidising agents to kill living organisms. The most abundant byproduct of photosynthesis is oxygen. Therefore the plants that change colour with more intense light must have a limited capacity to handle the byproduct oxygen in its photosynthetic action. The change of colour is a defensive mechanism to reduce the quantum of the byproduct – oxygen.
I am no scientist, but I do like my queries answered. So I put questions to myself and try to find logical answers to them, not all my beliefs are true but this time I think I am on the right track.
Nature does nothing without reason. The propensity to change colour must have a purpose, especially as synthesising those pigments need effort and expense of nutrient elements of these plant specie. No plant would evolve such an unnecessary and costly (extravagant) behaviour.
Genetically the threshold of different plants in handling of oxygen or the mechanism by which different specie control the threshold may differ. The explanation why some plants do not change colour would be there.
The range of the spectrum chosen by the plant would naturally be fixed by their genetic evolution.
Even if the trigger for additional pigments is linked to the byproduct oxygen from photosynthesis only; it would explain nutritional deficiencies and/or availabilities causing colour change in plants.
Any nutritional deficiency which affects the plants efficiency in handling the oxygen – or a nutritional excess of any element that increases the plants photosynthesis; can and will cause a change of the colour of the plant, when the threshold is breached.
There are and always had been nutritional factors which can change the colouration of plants – but those need not be addressed here.
As I see it, when a plant does change its colour under lights, it does not stop reflecting the green part of the light spectrum it normally did, but is now reflecting an additional part of the spectrum, and this causes the change in colouration. Conversely this means that the plant is reducing the range of the light spectrum it was absorbing. Therefore it follows that the plant is reducing its energy absorption from those parts which are in more intense light. Why?
Additional energy when there is no lack of nutrients for the plant to increase synthesis of its growth substances should have been an advantage to the plant; still the plant is opting to reduce it energy absorption. Nature never induces curtailment of any action (or omission) which is of advantage to any specie; then why is such an advantage to the plant being curtailed? The answer must be that behind the obvious advantage lies some hidden disadvantage.
Reflecting over the question, it suddenly struck me the answer must be oxygen. Oxygen is synonymous with life, as we know it, but it is a dangerous poison. Man regularly uses oxygen and oxidising agents to kill living organisms. The most abundant byproduct of photosynthesis is oxygen. Therefore the plants that change colour with more intense light must have a limited capacity to handle the byproduct oxygen in its photosynthetic action. The change of colour is a defensive mechanism to reduce the quantum of the byproduct – oxygen.
I am no scientist, but I do like my queries answered. So I put questions to myself and try to find logical answers to them, not all my beliefs are true but this time I think I am on the right track.
Nature does nothing without reason. The propensity to change colour must have a purpose, especially as synthesising those pigments need effort and expense of nutrient elements of these plant specie. No plant would evolve such an unnecessary and costly (extravagant) behaviour.
Genetically the threshold of different plants in handling of oxygen or the mechanism by which different specie control the threshold may differ. The explanation why some plants do not change colour would be there.
The range of the spectrum chosen by the plant would naturally be fixed by their genetic evolution.
Even if the trigger for additional pigments is linked to the byproduct oxygen from photosynthesis only; it would explain nutritional deficiencies and/or availabilities causing colour change in plants.
Any nutritional deficiency which affects the plants efficiency in handling the oxygen – or a nutritional excess of any element that increases the plants photosynthesis; can and will cause a change of the colour of the plant, when the threshold is breached.
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