I was reading today an article about why leaves turn red in Autumn just before they fall. Seems they contain a brilliant red pigment called anthocyanin. Scientists have known it exists for a long time but weren’t clear what was happening when the leaves turned read… or why.
Seems the answer is that the pigment is there all the time but only becomes visible when chlorophyl is drained from the leaf by the plant as it prepares to close down for winter… it seems the production is a way of extending the useful life of the leaf when the weather starts to become too cold or dark for full photosynthesis and the plant slowly prepares to become dormant through the winter months.
What struck me was that this the article doesn’t address the reverse process we see in Oz… i.e. why it is that a large proportion of the native Australian trees and bushes I’ve seen produce red leaves in early spring that then darken as summer kicks in.
I doubt the phenomenon could be for the same reason… after all winter here is quite often at least as hot as summer in places like the USA and Canada where this winter reddening is most obvious. Besides… if they are right… thenh why don;t northern hemisphere trees and bushes *also* produce red leaves in order to take advantage of early sun therebye gaining an advantage over other plants unable to do this??
I think this research creates as many answers as it seems to answer.
The Eclectic Interweb 