Green (~510nm) is the only color of visible light not used in photosynthesis. It’s why plants are (mostly) green: the rest of the colors of visible light are being used to produce more plant, while green just gets tossed off.
It also why dead plants turn (usually) brown: they’re no longer absorbing and using the other colors, so all of them get sent back.
This idea felt very counter-intuitive at first, as so many things are green.
But its the wal-mart greeter of colors: very visible, always letting you know it’s there, but not actually making anything work.