Number Of Saprophytes Research Articles

Ecological Assessment of Drilling Sludge and Development of a Method for their Bioremediation in Western Siberia

The article considers the issue of bioremediation of drilling sludge. The aim of the research is studying of the microbiological processes occurring in soils based on drilling sludge, with their subsequent application for the biological stage of reclamation of disturbed lands. Microbiological characteristics of drilling sludge and four samples of soils based on it with the addition of diatomite, dolomite flour, peat, gypsum, glauconite, humic preparation Rostock in different proportions were studied. Crops were shown on agarized medium: meat-peptone agar (MPA), starch-ammonia agar (SAA), Munz medium, Chapek medium, depending on the determined group of microorganisms. The total number of microflora, the number of saprophytes, microorganisms growing on starch-ammonia agar (SAA), hydrocarbon-oxidizing bacteria (PSB), micromycetes and actinomycetes were estimated. The mineralization coefficient is calculated. The total number of microflora in the samples ranged from 51 to 271 million CFU/g. The share of saprophytes was 16.724.8% of the total amount of microflora. The proportion of microorganisms growing on SAA was 15.6-36.6%. The minimum number of PSB was 2.0 million CFU/g of soil; the maximum was 22.0 million CFU/g. The mineralization coefficient varies from 0.81 to 1.63, which indicates different rates of mineralization processes. The number of micromycetes determined on the Chapek medium ranged from 0.01 to 3.33 million CFU/g, on SAA from 0.03 to 10.4 million CFU/g. At the same time, the number of micromycetes is much lower than the number of bacteria, which is normal for soils. The number of actinomycetes varied from 0.2 to 7.3 million CFU/g. The largest number of actinomycetes was noted when peat and humic preparation Rostock were introduced. The share of actinomycetes in the total number of microflora on the SAA ranged from 0.6 to 14%. There is a development of the total number of microflora, an increase in the diversity of microbocenosis, which indicates a decrease in the concentrations of water-soluble salts, petroleum products and the presence of an additional food source in the form of peat. Based on the data obtained, a conclusion was made about the possibility of using soils based on drilling sludge with the addition of peat and humic preparation Rostock for the reclamation of disturbed lands.

Aphid honeydew, a potential stimulant of Cochliobolus sativus and Septoria nodorum and the competitive role of saprophytic mycoflora

The effect of aphid honeydew on fungal leaf saprophytes and pathogens was studied on wheat under controlled environmental conditions. When honeydew was added to the inoculum, the colonization of flag leaves by a mixed population of Sporobolomyces roseus, Cryptococcus laurentii var. flavescens, Aureobasidium pullulons and Cladosporium cladosporioides was highly stimulated. After an exponential growth period of about 6 days, the population densities of all showed a tenfold increase in the presence of honeydew. Honeydew added to the inoculum of Septoria nodorum or Cochliobolus sativus enhanced the degree of infection of wheat leaves by these pathogens 2.5–4 times. During the prepenetration development of C. sativus, honeydew stimulated spore germination, the formation of two germ-tubes per conidium and germ-tube growth. Addition of saprophytes to the inoculum, enriched with honeydew, reduced the stimulation of infection in one experiment only where high population densities were reached within one day, but application of honeydew 4–5 days before inoculation, always resulted in an abundant population of naturally occurring saprophytes which completely neutralized the honeydew effect. Carbohydrate determinations of washings from leaves treated with artificial honeydew, revealed a decrease in washable carbohydrates from 450 to 40 μg ‘glucose’ cm−2 leaf within 7 days, with a simultaneous increase in the number of saprophytes from less than 104 to 4.106 C.F.U. cm−2. The implications of these results for the interpretation of secondary effects of aphids on the yield of wheat are discussed.

The mycoflora associated with Halimione portulacoides: III. fungi on green and moribund leaves

Studies on the phylloplane fungi associated with Halimione leaves have shown that three groups of fungi may be delimited. These comprise the fungi present only as propagules on the leaves, those growing actively and sporing on the leaves, and thirdly a group which only produces vegetative mycelium whilst the leaves remain green. At the onset of leaf senescence, fungi in the latter group may sporulate and the leaf is also invaded by a number of saprophytes not actively associated with the phylloplane.