Why black (or blue, or red) plants might be the key to finding lifebeyond Earth

On 26/03/2012 12:47 PM, Chris.B wrote:
On Mar 26, 6:04 am, Sam wrote:
http://arstechnica.com/science/news/...r-blue-or-red-...

Several imaginative scientists have thought about how these two
traits of light—the number of photons and their energies—might drive
photosynthesis in other celestial contexts.

Plants on a planet orbiting a binary system need not waste energy
switching between frequency bands to match the light from the dominant
star of the moment. Many plants have the ability to produce physical
movement in response to external stimuli. (phototropism is one
example) It would not be difficult to imagine an opening mechanism to
obtain maximum exposure from one star's light. While closing down or
even going into hibernation in the presence of the other star's light.
Deciduous plants do it annually for our humble seasons. Plants on
another planet could easily do the same for their own, more complex,
ones.

True, but I find this whole scenario about dual Suns contrived. Not the
part about there possibly being dual Suns of differing energy levels,
but the part about having to switch from one to another. In what
scenario will they ever encounter where they can't see both Suns at the
same time at some point during the day? Assumedly, both Suns would be
orbiting one another in close proximity, and the life-bearing planet
would be orbiting their mutual centers of gravity. One Sun might briefly
eclipse the other, usually the bigger one will eclipse the smaller one,
but that simply means that you'll more often see the more powerful Sun,
so plants would only need to accommodate the photons from the bigger
Sun. You'll almost always be seeing both stars, except for those brief
eclipse periods, which I doubt need to be accounted for by biology,
anymore than a solar eclipse needs to be accounted for by our biology.

Actually, the plants may even have stripes, where some cells are geared
towards absorbing one Sun's photons, and beside them would be other
cells designed for the other Sun. In the macroscopic picture those
separate cells might be grouped together, and you'll see them as stripes
on the plant.

An interesting side note, what would the religion on a hypothetical
dual-Sun planet evolve into? Would they consider the two Suns as gods,
but with the bigger Sun being the husband, while the smaller one is the
wife?

Yousuf Khan