In germinating seedlings, phytases hydrolyze phytic acid to release inorganic P for plant utiliz- ation (Duff et al., 1994). A recent study (Li et al., 1997) showed a strong correlation between P- deficiency and release of phytases by several plant species. Many other intracellular acid phosphatases exist in plants, with specific and non-specific sub- strates, but whether these hydrolases are released into root exudates has not yet been reported. The discovery that root border cells release extracellular enzymes, nod-gene-inducing compounds, signals con- trolling gene expression and substrate for mycorrhizal development (Hawes et al., 1998; Zhu et al., 1998) clearly suggest that they may also play a major role in nutrient acquisition in the rhizosphere. However, ex- periments involving the incubation of root border cells with poorly soluble nutrient compounds are needed to provide direct evidence of this function.