I know many of you are just dying to start modelling alien worlds and I have been meaning to start a discussion about it for a while. I will add links to useful resources as I find them.
So starting with plants: This page has information about how alien plant life may look: http://solstation.com/life/a-plants.htm
So looks like its basic black for plants on low light worlds.
Plant-like life forms under a bluer and brighter star than the Sun may reflect the less useful or abundant red and yellow
light, so appearing in autumn tones.