Growth patterns of bacterial communities in the rhizoplane and rhizosphere of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) in long-term pasture

Sarathchandra, S. U.; Burch, G.; Cox, N. R.

doi:10.1016/s0929-1393(97)00015-2

Cited by 73 publications

(45 citation statements)

References 13 publications

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“…However, in our study this tendency was not so well-defined. Generally, r-strategists are considered to dominate unstable environments and K-strategist are characteristic of stable environments (Sarathchandra et al 1997). These results support the fact that environmental conditions may select microorganisms belonging to r-and K-strategists (De Leij et al 1994).…”

Section: Community Structure Of Bacterial Populationsupporting

confidence: 71%

“…To evaluate the changes in the biodiversity of bacterial populations in soils the eco-physiological index (EP), a modification of the Shannon diversity index determined by the method of De Leij et al (1994), and the colony development index (CD) proposed by Sarathchandra et al (1997) were used. To calculate the EP-and CD-indices, data obtained after 1, 14 and 28 days of the experiment during enumeration of bacterial colonies on a daily basis for 10 consecutive days on 0.1 TSA were used.…”

Section: Community Biodiversity Analysismentioning

confidence: 99%

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Changes in bacterial diversity and community structure following pesticides addition to soil estimated by cultivation technique

Cycoń

Piotrowska‐Seget

2009

Ecotoxicology

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An experiment was conducted under laboratory conditions to investigate the effect of increasing concentrations of fenitrothion (2, 10 and 200 mg a.i./kg soil), diuron (1.5, 7.5 and 150 mg a.i./kg soil) and thiram (3.5, 17.5 and 350 mg a.i./kg soil) on soil respiration, bacterial counts and changes in culturable fraction of soil bacteria. To ascertain these changes, the community structure, bacterial biodiversity and process of colony formation, based on the r/K strategy concept, EP- and CD-indices and the FOR model, respectively, were determined. The results showed that the measured parameters were generally unaffected by the lowest dosages of pesticides, corresponding to the recommended field rates. The highest dosages of fenitrothion and thiram suppressed the peak SIR by 15-70% and 20-80%, respectively, while diuron increased respiration rate by 17-25% during the 28-day experiment. Also, the total numbers of bacteria increased in pesticide-treated soils. However, the reverse effect on day 1 and, in addition, in case of the highest dosages of insecticide on days 14 and 28, was observed. Analysis of the community structure revealed that in all soil treatments bacterial communities were generally dominated by K-strategists. Moreover, differences in the distribution of individual bacteria classes and the gradual domination of bacteria populations belonging to r-strategists during the experiment, as compared to control, was observed. However, on day 1, at the highest pesticide dosages, fast growing bacteria constituted only 1-10% of the total colonies number during 48 h of plate incubation, whereas in remaining samples they reached from 20 to 40% of total cfu. This effect, in case of fenitrothion, lasted till the end of the experiment. At the highest dosages of fenitrothion, diuron and at all dosages of thiram the decrease of biodiversity, as indicated by EP- and CD-indices on day 1, was found. At the next sampling time, no significant retarding or stimulating effect was detected. However, in case of CD values the higher differences were observed. The significant impact of pesticides on the physiological state of soil bacteria was not found. They were generally in dormant state (lambda < 0.5), but immediately after pesticides application, the additional reduction of frequency of bacterial cell proliferation (max. decrease of lambda value to 0.15 for thiram on day 14) and prolonged retardation time of colony appearance (max. increase of t(r) value to 1.39 for fenitrothion on day 1) on agar plates were found.

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Section: Community Structure Of Bacterial Populationsupporting

confidence: 71%

Section: Community Biodiversity Analysismentioning

confidence: 99%

Changes in bacterial diversity and community structure following pesticides addition to soil estimated by cultivation technique

Cycoń

Piotrowska‐Seget

2009

Ecotoxicology

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“…N 10 /10] 100, where N 1 , N 2 , N 3 ,…. N 10 is a proportional count of colonies grown in (Sarathchandra et al, 1997), and the ecophysiological diversity index EP = -∑(pi log pi), where pi is the number of microbial colonies from a given day divided by the total number of colonies (De Leij et al, 1993), were then calculated. Enzyme activity, similarly to the microbial count, was determined in the individual soil samples.…”

Section: Methodsmentioning

confidence: 99%

Impact of temperature on the biological properties of soil

Borowik¹,

Wyszkowska²

2016

International Agrophysics

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The aim of the study was to determine the response of soil microorganisms and enzymes to the temperature of soil. The effect of the temperatures: 5, 10, 15, 20, and 25°C on the biological properties of soil was investigated under laboratory conditions. The study was performed using four different soils differing in their granulometric composition. It was found that 15°C was the optimal temperature for the development of microorganisms in soil. Typically, in the soil, the highest activity of dehydrogenases was observed at 10-15°C, catalase and acid phosphatase – at 15°C, alkaline phosphatase at 20°C, urease and β-glucosidase at 25°C. The highest colony development index for heterotrophic bacteria was recorded in soils incubated at 25°C, while for actinomycetes and fungi at 15°C. The incubation temperature of soil only slightly changed the ecophysiological variety of the investigated groups of microorganisms. Therefore, the observed climate changes might have a limited impact on the soil microbiological activity, because of the high ability of microorganisms to adopt. The response of soil microorganisms and enzymes was more dependent on the soil granulometric composition, organic carbon, and total nitrogen than on its temperature.

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“…Water-holding capacity was determined by using the 0-bar method of saturation followed by free draining (7). Total soil bacterial counts were measured by using acridine orange staining (26), and viable counts were determined after plating on 0.1ϫ tryptone soy agar (55).…”

Section: Methodsmentioning

confidence: 99%

Soil Type Is the Primary Determinant of the Composition of the Total and Active Bacterial Communities in Arable Soils

Girvan

Bullimore

Pretty

et al. 2003

Appl Environ Microbiol

698

382

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Degradation of agricultural land and the resulting loss of soil biodiversity and productivity are of great concern. Land-use management practices can be used to ameliorate such degradation. The soil bacterial communities at three separate arable farms in eastern England, with different farm management practices, were investigated by using a polyphasic approach combining traditional soil analyses, physiological analysis, and nucleic acid profiling. Organic farming did not necessarily result in elevated organic matter levels; instead, a strong association with increased nitrate availability was apparent. Ordination of the physiological (BI-OLOG) data separated the soil bacterial communities into two clusters, determined by soil type. Denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism analyses of 16S ribosomal DNA identified three bacterial communities largely on the basis of soil type but with discrimination for pea cropping. Five fields from geographically distinct soils, with different cropping regimens, produced highly similar profiles. The active communities (16S rRNA) were further discriminated by farm location and, to some degree, by land-use practices. The results of this investigation indicated that soil type was the key factor determining bacterial community composition in these arable soils. Leguminous crops on particular soil types had a positive effect upon organic matter levels and resulted in small changes in the active bacterial population. The active population was therefore more indicative of short-term management changes.

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Growth patterns of bacterial communities in the rhizoplane and rhizosphere of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) in long-term pasture

Cited by 73 publications

References 13 publications

Changes in bacterial diversity and community structure following pesticides addition to soil estimated by cultivation technique

Changes in bacterial diversity and community structure following pesticides addition to soil estimated by cultivation technique

Impact of temperature on the biological properties of soil

Soil Type Is the Primary Determinant of the Composition of the Total and Active Bacterial Communities in Arable Soils

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