微生物溶解磷矿粉能力与pH及分泌有机酸的关系

从玉米根际和非根际土壤中分离得到的 74株溶解磷矿粉的微生物 ,发现它们的溶磷能力差异很大 ,主要决定于菌株本身的特性 ,与其来源无关 ,真菌普遍比细菌要强。真菌的溶磷能力与其培养介质的 pH之间呈显著的负相关 ,但细菌的这种关系非常弱。二者都产生多种有机酸 ,真菌主要分泌草酸、丙二酸和乳酸 ,而细菌主要分泌草酸、酒石酸、丙二酸、乳酸和乙酸 ,不同菌株分泌有机酸的数量和种类差异很大 ,但溶磷量与有机酸总量或单个有机酸浓度之间 ,没有发现显著的相关性 ,唯独柠檬酸与真菌的溶磷量之间存在显著的相关性。说明不同菌株有完全不同的溶磷机理 ,可能多种机理并存。

The Relationship Between Rock Phosphate Solubilization and pH and Organic Acid Production of Microorganisms

Seventy-four phosphate-dissolving microorganisms were isolated from corn rhizosphere and nonrhizosphere soils. It was found that these microorganisms had complete capacity to solubilize the rock phosphate. This capacity depended upon only the isolates' characteristics, but not their origin. The fungi normally had much higher capacity than the bacteria. The capacity of the fungi was closely correlated to pH in the culture solution. However, the relationship was weak for the bacteria. Both the fungi and bacteria produced many diffirent kinds of organic acids. The total quantity and constituents of the organic acids were quite different for each isolate. The fungi mainly produced oxalic acid, malonic acid and lactic acid. The bacteria mainly produced oxalic acid, tartaric acid, malonic acid, lactic acid and acetic acid. There was not significant relationship between the rock phosphate solubilization capacity and the total and single quantity of the organic acids. Only the citric acid concentration in the culture solution was closely related to the capacity. It was suggested that each isolate had different mechanisms in solubilizing the rock.Probably, one isolate had more than two mechanisms in dissolving rock phosphate.;