Positive feedback between acidification and organic phosphate mineralization in the rhizosphere of maize (Zea mays L.).

Ding, X.; Fu, L.; Liu, C.; Chen, F.; Hoffland, E.; Shen, J.; Zhang, F.; Feng, G.


Abstract To test the hypothesis that rhizosphere acidification would enhance the hydrolyzation of organic phosphates by increasing phosphatase activity. A Petri dish experiment with sterile agar and a pot experiment with a low P soil were used. In the Petri dish experiment, roots of each plant were cultured in two compartments, each of which contained agar with one of three nitrogen combinations: NH4 +/N0 (N0 = nitrogen free), NH4 +/NO3 -, and NO3-/N0. Phytin was supplied as the sole phosphorus (P) source to all compartments. In the pot experiment, the soil in each pot was treated with N0, KNO3, or (NH4)2SO4) together with 0 or 75 mg kg-1 phytin-P. Dry weight, P concentration, and P content of roots were highest in the NH4 + compartments in the Petri dish experiment. In the pot experiment, dry weight, P concentration, and