Composition - Nice find for this challenge. I think the colors are pretty good for this challenge. The framing going corner to corner is exactly the way I would've done it (which doesn't make it right by no means). And I really think you found the right leaf for the shot. The biggest problem with this photo methinks is the left side of the leaf is too washed out. There is just too much light IMO to make this come out as good as it could. Which leads me to the next part.
Technical - I would've made the exposure a little shorter. It would've naturally saturated the colors more and also let more of the color show on the left side. Its pretty well focused and I do like the framing. DOF is not a factor in a 2-dimensional pic like this. The focus looks to be a pinch soft on the upper left side and I think that this could be fixed post. Overall its pretty well taken.
Overall - A pretty good shot, but not up to its potential. A faster shutter or a higher F number to cut the exposure value down a little would've been very helpful. I think in shooting 2 dimensional shots like this, I would'nt mess with the Aperture priority mode. I'd have stuck with the Shutter priority or done it manually. There is definitely something here to build on though. Nice work. - Bob
Wow, very nice way to handle the focus of the challenge, and nice close-up shot. Is this a Coleus leaf? I like the orientation of the color change as well.
interesting hue shift - makes it very painterly - I like the deep color on right, it is a little washed out in the left. I might have cropped the left hand side about half way, it would be more abstract, but that goes with the colors!
wow - are these the real colours ? The grainyness just adds to the great textures and patterns in this. Cool shot, though I feel it should point up to the right rather than the left - have you tried rotating it around to see how it looks at different angles ? (9) revised - 10