Fungi and Bacteria in the Dark-Humus Forest Soil
- PDF / 714,005 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 94 Downloads / 202 Views
BIOLOGY
Fungi and Bacteria in the Dark-Humus Forest Soil L. M. Polyanskayaa, *, D. D. Yumakova, Z. N. Tyugaya, and A. L. Stepanova aLomonosov
Moscow State University, Leninskie gory, Moscow, 119991 Russia *e-mail: [email protected]
Received January 14, 2020; revised January 17, 2020; accepted February 26, 2020
Abstract—A comparative assessment of the pools of fungal and bacterial biomass in dark humus forest soil has been performed using luminescent microscopy and cascade filtration. Cascade filtration indicates that the bacterial biomass is compatible to the fungal biomass (31–54% for bacteria and 46–69% for fungi) in the upper horizons of investigated soil. However, in the lower horizons, the bacterial biomass predominates (up to 69% at the depth of 100 cm). Thus, the cascade filtration method has made it possible to refine data on the bacterial biomass in the soil and to show for the first time that the biomass of bacteria is compatible to the biomass of fungi in the upper soil horizons and exceeds fungal biomass in the lower horizons. This method provides for a more accurate assessment of both the number and the biomass of bacteria, which allows revising the opinion of many soil microbiologists on the significant prevalence of fungal biomass in soils. Keywords: soil profile, biomass, cascade filtration method, luminescent microscopy, microbial ecology DOI: 10.1134/S1064229320090124
INTRODUCTION Assessment of the number and biomass of microorganisms in soil is one of the primary tasks of soil microbiology, because these data allow us to estimate the state of soils, the rate of organic matter transformation, and the intensity of biological cycle in soils [4]. In recent years, the number and biomass of soil microorganisms have mainly been determined with the help of luminescent microscopy. However, this method has several shortcomings. For example, the number of fungi is determined in soil suspensions of very small volume (0.04 mL under the cover glass) and, when calculating the number of fungal cells per 1 mL, it is necessary to multiply the calculated number of fungal propagules by 25 with a corresponding increase in the potential error of the estimate. A well-known method of direct counting of fungi on filters [3] somewhat underestimates the results in dependence of the soil type because of the necessity to use big aliquots (no less than 10 mL) passing through a filter and, thus, leaving a great number of soil particles on the filter, which shield fungal hyphae and spores and lead to their underestimation. However, this method is widely applied in microbiological studies, as it is easy to use; fixed preparations can be stored for a long time, so that the counting can be performed in a convenient time and for a large number of samples [9]. A new method of cascade filtration [14] demonstrated that the numbers of bacteria determined by it and by luminescent microscopy are approximately similar, whereas the estimates of the total microbial biomass differ significantly [18]. This difference is due to
the fac
Data Loading...
