Plant uptake of phosphorus from sparingly available P- sources as affected by Trichoderma asperellum T34

Abstract

The contribution of Trichoderma asperellum T34 to the plant uptake of phosphorus (P) from sparingly phytoavailable forms such as insoluble calcium (Ca) phosphates and phytates was studied. Two experiments with cucumber (Cucumis sativus L.) on siliceous sand were performed involving two factors, namely: (i) P source, viz., KH2PO4, phytate (Ins6P), and phosphate rock (PR), and (ii) inoculation with T34. Liquid pure cultures of T34 were also used. T34 increased the total content in P of cucumber roots irrespective of the particular P form and enhanced total P uptake by plants with P supplied as Ins6P or PR. The increased phytase activity observed with T34 contributes to explain its favourable influence on the uptake of P supplied as Ins6P. Solubilization of Ca phosphates from PR was favoured by the slightly acidifying effect and the increased organic anion concentration promoted by the fungus in the plant growth media. It can be concluded that T34 can improve P nutrition in plants grown on media containing phytates or insoluble Ca phosphates as dominant P forms.