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以一株分离于植物根际土壤且有较强溶磷能力的真菌研究其对磷矿石的风化作用。对该菌株的ITS序列进行PCR扩增及序列测定后,再结合该菌株的形态特征对其进行鉴定,结果为黑曲霉(Aspergillus niger)。用ICP-OES测定培养液中的Ca2+浓度,磷钼比色法测定可溶性磷的含量,电子探针、透射电镜和能谱仪分析菌株作用后的残留物。培养液中的Ca2+浓度由第3天的10.02mg/L增加到第30天的217.61mg/L,可溶性磷的浓度由第3天的5.37mg/L增加到第30天的921.37mg/L;风化过程中形成了大量的次生矿物草酸钙,大分子有机物形成的生物膜以及菌丝体穿插破坏矿物颗粒促进磷矿石的风化。表明该菌株对磷矿石有较强的风化能力,黑曲霉生长产生的生物物理破坏作用和胞外分泌物的生化降解作用是引起磷矿石风化的主要因素。
The fungal species isolated from the plant rhizosphere soil and having strong ability to dissolve phosphorus were used to study the weathering effect on phosphate rock. The ITS sequence of the strain was amplified by PCR and sequenced, and then the strain was identified by its morphological characteristics. The result was Aspergillus niger. The content of Ca2 + in the culture solution was determined by ICP-OES, the content of soluble phosphorus was determined by phosphorus molybdenum colorimetry, and the residue after the strain was analyzed by electron probe, transmission electron microscopy and energy dispersive spectroscopy. The concentration of Ca2 + in culture medium increased from 10.02mg / L on the third day to 217.61mg / L on the 30th day, and the soluble phosphorus concentration increased from 5.37mg / L on the third day to 921.37mg / L on the 30th day. In the process of weathering, a large amount of secondary minerals such as calcium oxalate, biofilm formed by macromolecular organic compounds and mycelium interspersed destroy mineral particles to promote the weathering of phosphate rock. The results showed that the strain has strong weathering ability to phosphate rock. The biophysical destruction caused by Aspergillus niger and the biodegradation of extracellular secretions are the main factors causing the weathering of phosphate rock.