A little background to start today.
Plants contain a Pi-starvation-inducible (PSI) gene expression and complex morphological, physiological, and biochemical adaptations to low phosphorus. Plants have shown to up-regulate intracellular and secreted acid phosphatases in order to catalyze the hydrolysis of Pi from various phosphate monoesters when in an acidic environment. Purple acid phosphatases (PAPs) are a specific acid phosphatase class characterized by a bimetallic active site that causes a purple color. 29 PAP genes have been identified in Arabidopsis. Both transcriptional and posttranscriptional factors have been implicated in the control of these PAPs.

Ok, so maybe I am a bit biased in this post because I work on the above PAPs. To make this post even less credible, the paper I want to discuss is written by a PhD student I know. However, the recent work that has been conducted on PAPs provides some very helpful information about how plants respond to phosphorus deficiency that cannot be ignored simply due to some predispositions.