Photosynthesis reactivity to different light

[MolecularMan14]

I've heard somewhere that plants react differently to different spectrums of light (visible light). Which is more affective for photosynthesis? Red, or blue light? Why does it matter? How does the light actually affect the process?

[5614]

light is the process, photosyn. works on light, light is the input. no light = no photosyn

[5614]

red and blue is best, view top graph for the question, more info in the 2nd graph, a, b, c and d are different plants

[swansont]

red and blue is best

 

Hence plants being green - they absorb the red and blue best.

[MolecularMan14]

light is the process, photosyn. works on light, light is the input. no light = no photosyn

 

I know that but what exactly does the wavelength have to do with the process. (btw-thanks for the graphs, really good )

[coquina]

Leaves turn red and gold in the fall because the chloroplasts die. The cells that contain the carotinoids are left. They are there all the time, but during the warm months, there are many more chloroplasts, so one cannot see them.

 

I wonder if the carotinoids are more effective with dealing with photons that are hitting the earth at a greater angle, as happens when winter approaches. I'm sure the answer is on the net somewhere, but I'm to tired to look it up at the moment. Someone else want to give it a go?

[Skye]

I know that but what exactly does the wavelength have to do with the process. (btw-thanks for the graphs, really good )

The wavelengths correspond to the energy required to kick an electron up to a higher energy state. This breaks a double bond in the molecule. This allows the molecule to change from one isomer to another, more stable one (cis to trans). The molecule is jammed into a protein. When the molecule changes shape, it pushes on the protein and so it changes shape too. The protein, with a couple of others, then hydrolyses the molecule cyclic GMP (guanine like in your DNA). The GMP is then no longer cyclic, and this molecule then acts as the signal to open up the Na+ ion channels which leads to a nerve impulse into your noggin.