Abstract—

In a model experiment, the transformation of microbial complexes of cultivated saprotrophic bacteria and yeasts during freezing-thawing was studied in various natural substrates that are used to create soil constructions for urban landscaping and for growing herbaceous plants. The number of saprotrophic bacteria and yeasts depended both on the type of substrate and on temperature changes during freezing-thawing. At the stage of freezing of peat and soil (arable horizon) to 0 and –5°C and at the subsequent stage of thawing to 0°C, a significant increase in yeast number was registered. The maximum number of yeasts in soil and peat was 5.1 log (CFU/g). In contrast to the number of yeasts, number of saprotrophic bacteria in soil and peat was characterized by a sharp decrease when the substrate temperature was negative and peaked at 19–22 and 10°C, respectively. The maximum bacterial number in soil and peat was 7.5 and 8.0 log (CFU/g), respectively. In sand, number of both saprotrophic bacteria and yeasts did not depend on the temperature and was 5.0 log (CFU/g) for bacteria and 3.4 log(CFU/g) for yeasts at all stages of the freezing-thawing cycles. In total, 15 saprotrophic bacterial species and 29 yeast species were isolated from different components of soil constructions. At the maximum temperature of freezing in the cycles (–5°C), three bacterial species with psychrophilic properties (Flavobacterium psychrophilum) and the ability to form endospores resistant to various adverse effects (Bacillus subtilis, B. megaterium) were isolated from soil and peat. Among the yeasts isolated from soil and peat at negative temperature and also having psychrophilic properties were Candida sake, Rhodotorula glutinis, Rh. mucilaginosa, and Solicoccozyma terricola. Bacteria with psychrophilic properties, F. psychrophilum and Pseudomonas fluorescens, as well as two species of bacilli, Bacillus subtilis and B. megaterium were revealed in sand at negative temperatures. Only one yeast species, Debaryomyces hansenii, capable of surviving stress conditions in the form of ascospores, was isolated from sand at –5°C. The effect of short-term temperature drops on the microbial communities’ number and diversity dynamics in soil constructions in a model experiment showed that specialized soil constructions were able to “tolerate” short-term temperature stress drops typical of the spring and autumn period, restoring the number of initial populations after cessation of the negative impacts. This also indicates development of the soil constructions in the process of functioning, rather than their rapid degradation.

中文翻译：

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冻融过程中不同来源（土壤，泥炭，沙土）土壤结构组分中微生物复合物的转化

摘要—

在一个模型实验中，研究了在各种自然基质中冻融过程中培养的腐生细菌和酵母菌的微生物复合物的转化，这些基质用于创建用于城市园林绿化和种植草本植物的土壤结构。腐生细菌和酵母的数量既取决于底物的类型，也取决于冷冻-解冻过程中的温度变化。在泥炭和土壤的冷冻阶段（可耕层）至0和–5°C，在随后的融化至0°C阶段，酵母数量显着增加。土壤和泥炭中酵母的最大数量为5.1 log（CFU / g）。与酵母的数量相比，土壤和泥炭中腐生细菌的数量以底物温度为负值并在19-22和10°C达到峰值时急剧下降的特征为特征，分别。土壤和泥炭中的最大细菌数分别为7.5和8.0 log（CFU / g）。在沙土中，腐养细菌和酵母菌的数量均不依赖于温度，在冻融循环的所有阶段，细菌的细菌数均为5.0 log（CFU / g），酵母菌的细菌数为3.4 log（CFU / g）。总共从土壤结构的不同组成部分中分离出15种腐生细菌和29种酵母。在循环的最高冻结温度（–5°C）下，三种具有嗜冷特性的细菌（总共从土壤结构的不同组成部分中分离出15种腐生细菌和29种酵母。在循环的最高冻结温度（–5°C）下，三种具有嗜冷特性的细菌（总共从土壤结构的不同组成部分中分离出15种腐生细菌和29种酵母。在循环的最高冻结温度（–5°C）下，三种具有嗜冷特性的细菌（从土壤和泥炭中分离出了黄杆菌（Flavobacterium psychrophilum）和形成对各种不良作用（枯草芽孢杆菌，巨大芽孢杆菌）产生抗性的内生孢子的能力。在负温度下从土壤和泥炭中分离并具有嗜冷特性的酵母中，有假丝酵母，Rhodotorula glutinis，Rh。mucilaginosa，并Solicoccozyma孢。在负温度下，在沙子中发现了具有嗜冷性的细菌，嗜热链球菌和荧光假单胞菌，以及两种细菌，枯草芽孢杆菌和巨大芽孢杆菌。只有一种酵母在–5°C下从沙子中分离出能抵抗子囊孢子形式的胁迫条件的汉逊Debaryomyces hansenii。在模型实验中，短期温度下降对土壤结构中微生物群落数量和多样性动态的影响表明，特殊的土壤结构能够“忍受”春季和秋季典型的短期温度应力下降，从而恢复消除负面影响后的初始人口数量。这也表明了土壤结构在运转过程中的发展，而不是迅速退化。