Do Plants need Light ONLY for Photosynthesis??

[niru]

Hi All

was wondering if plants need light for things other than pure photosynthesis, similar to animal world? And what for?

One sees a lot of stuff on internet about the "best" spectral tubes for plant growth & visualisation etc.. and whether even an iota of that makes sense (apart from being beyond the LCP and having enough energies to enable kicking off the photochemical reactions). If these conditions are satisfied, would using a monochromatic light do the same job as a wider spectrum tube (which could be white, blue, solar, grow, nature, etc) as far as photosynthesis is concerned, and also for the overall plant health??

Do plants get something akin to rickets (lack of vita D due to lack of sunlight) in humans 😀

cheers
niru

 

[Brenmuk]

Good question.
For plants to use light to power chemical reactions they need to capture the light using some kind of pigment. So another way of putting the question is to ask are there plant pigments that are not involved in photosynthesis. The only answer I can find is the use of plant pigments in flowers for example to attract insects - probably not that relevant to the planted tank hobby.

There has been a lot of stuff written about spectral tubes that favour plant growth over algal growth but as many on here will tell you the the spectral needs of algae and plants are almost identical so you might as well get a spectral tube that gives best viewing.

 

[ceg4048]

...was wondering if plants need light for things other than pure photosynthesis, similar to animal world?

yes...and No. Plants are autotrophs and they developed the ability to power their food production based on solar energy. Light has no relevance to a plant outside the context of food production. However...having said that...there are other processes which have nothing to do with rickets or vitamin D...

One sees a lot of stuff on internet about the "best" spectral tubes for plant growth & visualisation etc.. and whether even an iota of that makes sense (apart from being beyond the LCP and having enough energies to enable kicking off the photochemical reactions). If these conditions are satisfied, would using a monochromatic light do the same job as a wider spectrum tube (which could be white, blue, solar, grow, nature, etc) as far as photosynthesis is concerned, and also for the overall plant health??

The wavelengths of light are important in the sense that certain wavelengths trigger certain responses. The availability of certain wavelengths and their distribution in the vicinity of the light receptors tell the plant something about the environment, which then triggers certain responses and reactions. So the first priority is to obtain energy to power the photosynthetic reactions and to make food for survival. The second priority to execute programed responses and behavior using the spectral profile of the environment to determine appropriate response.

Monochromatic light will therefore work for food production but may not work as well for some programmed responses such as flowering, shape, growth patterns and so forth. Have a thorough read of the thread actinic lighting vs algae growth for further details regarding use of spectrum. In any case there are no bulbs which produce true monochromatic profile. Just as there are no bulbs which reproduce a true solar spectrum. these are all marketing illusions, so any bulb used has a few different wavelengths in it's output profile.

Cheers,