Research Institute Ital, Wageningen, The Netherlands.
Microb Ecol. 1990 Mar;19(2):149-61. doi: 10.1007/BF02012096.
The hypothesis that the population size of introduced bacteria is affected by habitable pore space was studied by varying moisture content and bulk density in sterilized, as well as in natural loamy sand and silt loam. The soils were inoculated withRhizobium leguminosarum biovartrifolii and established and maintained at soil water potentials between -5 and -20 kPa (pF 1.7 and 2.3). Rhizobial cells were enumerated when population sizes were expected to be more or less stable. In sterilized soils, the rhizobial numbers were not affected or decreased only slightly when water potentials increased from -20 to -5 kPa. In natural soils, the decrease in rhizobial numbers with increasing water potentials was more pronounced. Bulk density had only minor effects on the population sizes of rhizobia or total bacteria. Soil water retention curves of both soils were used to calculate volume and surface area of pores from different diameter classes, and an estimation of the habitable pore space was made. Combining these values of the theoretical habitable pore space with the measured rhizobial numbers showed that only 0.37 and 0.44% of the habitable pore space was occupied in the sterilized loamy sand and silt loam, respectively. The situation in natural soil is more complicated, since a whole variety of microorganisms is present. Nevertheless, it was suggested that, in general, pore space does not limit proliferation and growth of soil microorganisms.
研究了引入细菌的种群大小是否受可居住孔隙空间影响的假设，通过改变灭菌土壤以及自然壤土和粉壤土中的含水量和体积密度来实现。将 Rhizobium leguminosarum biovartrifolii 接种到土壤中，并将其维持在 -5 到 -20 kPa（pF 1.7 和 2.3）的土壤水势下。当种群大小预计更加稳定或略有减少时，对根瘤菌细胞进行计数。在灭菌土壤中，当水势从-20 增加到-5 kPa 时，根瘤菌数量没有受到影响或仅略有减少。在自然土壤中，随着水势的增加，根瘤菌数量的减少更为明显。体积密度对根瘤菌或总细菌的种群大小只有较小的影响。两种土壤的土壤水分保持曲线都用于计算不同直径类别的孔隙体积和表面积，并对可居住的孔隙空间进行了估计。将这些理论可居住孔隙空间的值与测量的根瘤菌数量结合起来表明，灭菌壤土和粉壤土中的可居住孔隙空间分别仅占 0.37%和 0.44%。自然土壤的情况更为复杂，因为存在各种各样的微生物。尽管如此，仍有人认为，一般来说，孔隙空间不会限制土壤微生物的增殖和生长。
