Bacterial and fungal activities in soil: Separation of bacteria and fungi by a rapid fractionated centrifugation technique     

Agnete Fægri  Vigdis Lid Torsvik  J. GoksÖyr 《Soil biology & biochemistry》1977,9(2):105-112

With three natural soils from Western and Central Norway it has been shown that by homogenization and fractionated centrifugations, two fractions could be obtained, one containing 50–80% of the bacteria, and the other all the fungi together with soil debris and the rest of the bacteria. When the separation was carried out in the cold and lasting less than 3–4 h, the fractions if used immediately had constant respiratory rates for 1–2 h. The sum of the rates agreed well with that of an unfractionated soil homogenate, making it possible to calculate the ratio between bacterial and fungal respiration. Assuming that the much higher respiration in a homogenate than in intact soil is due to inhibitory conditions in the latter and that these can be analysed by separate experiments, the technique will permit estimates of the ratio between bacterial and fungal respiration in in situ soil under given conditions.The soils used had very great differences between plate and microscopic count values for bacteria. When based on plate counts, the calculated bacterial respiratory intensities became impossibly high, while they were within biologically possible limits when microscopic count values were used. The respiratory intensities for fungi when calculated from hyphal lengths and diameter measurements, were biologically possible.  相似文献