The hydrolysis of organic P in soils is a relevant aspect contributing to the supply P to plants, which is affected by adsorbent capacity and biological properties of soils. This work aimed at studying the contribution of phytate to plant nutrition as affected by Fe oxides and phosphohydrolases releasing microorganisms in the growing medium. An experiment with cucumber and myo-inositol hexakiphosphate (myo-Ins6P) as P source was performed involving two factors: Fe oxide –ferrihydrite– rates (0, 100, 300 mg kg−1 of citrate–ascorbate extractable Fe), and microbial inoculation (Trichoderma asperellum T34, Bacillus subtilis QST713, and non-inoculated). P uptake decreased with increased Fe oxides in the growing media. Phytase activity and organic anions concentration increased with increased Fe oxides in the media. Most of the P supplied was recovered as inorganic P at the highest Fe oxide concentration. Inoculants did not improve P uptake by plants, despite B. subtilis promoted an enhanced hydrolytic activity at the highest Fe oxide concentration. An increased adsorption capacity of the growing media restricts the use of myo-Ins6P as P source by plants. This was not the result of its stabilization through adsorption or a decreased hydrolytic activity, but of the adsorption of inorganic P on Fe oxides after hydrolysis.

中文翻译：

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生长培养基的吸附能力不限制肌醇六磷酸水解，但其用作植物的磷源

土壤中有机磷的水解是促进植物磷供应的一个相关方面，受土壤吸附能力和生物特性的影响。这项工作旨在研究在生长培养基中释放微生物的 Fe 氧化物和磷酸水解酶影响植酸盐对植物营养的贡献。以黄瓜和肌醇六磷酸 (myo-Ins6P) 作为 P 源的实验涉及两个因素：氧化铁 - 水铁矿 - 比率（0、100、300 mg kg-1 柠檬酸盐 - 抗坏血酸盐可提取的 Fe）和微生物接种(Trichoderma asperellum T34, Bacillus subtilis QST713, and non-inoculated)。随着生长介质中铁氧化物的增加，磷的吸收减少。植酸酶活性和有机阴离子浓度随着介质中 Fe 氧化物的增加而增加。大部分供应的 P 以最高 Fe 氧化物浓度的无机 P 形式回收。尽管枯草芽孢杆菌在最高 Fe 氧化物浓度下促进了增强的水解活性，但接种剂并未提高植物对磷的吸收。生长介质增加的吸附能力限制了植物使用 myo-Ins6P 作为 P 源。这不是它通过吸附稳定化或水解活性降低的结果，而是水解后无机 P 吸附在 Fe 氧化物上的结果。