[Thaliana]

Checking the article again I got it from the "More Information" box at the bottom of the article. The paper is titled "In vivo evidence for a regulatory role of phosphorylation of Arabidopsis Rubisco activase at the Thr78 site" so that means A. thaliana.

The picture is certainly misleading, I guess they just grabbed a generic "plants in a rainforest" picture for evocative reasons.