Physiological action of humic substances on microbial cells

Visser, S. A.

doi:10.1016/0038-0717(85)90009-4

Cited by 143 publications

(54 citation statements)

References 6 publications

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“…The mechanism of HA action in promoting plant growth is not completely known. Several explanations have been given such as: (1) increase in cell membrane permeability (Hewitt 1952, Hernando 1968, Visser 1985; (2) increase in oxygen uptake, respiration and photosynthesis (Aitken, Acock and Senn, 1964;Hernando, 1968;1975); (3) increase in phosphorus uptake (Jelenic et al 1966); (4) increased root and cell elongation (Aso andYamaguchi 1971, Schnitzer andPoapst 1971;Vaugham 1974); (5) increased ion transport (Cacco and Civelli 1973); and (6) acting as cytokinin-like substances (Cacco and Dell'Agnolla 1984). There are other hypotheses about the function of humic'acids but these represent the current consensus.…”

Section: The Components Of Our Organic Biostimulantmentioning

confidence: 99%

The Use of Organic Biostimulants to Help Low Input Sustainable Agriculture

Russo¹,

Berlyn²

1991

Journal of Sustainable Agriculture

186

113

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ABSTRACT. The use of biostimulant compounds in forestry and agriculture offers significant opportuni for farmers, according to findings from current university researc ! and field trials. Improved root and shoot growth, better stress resistance, better root growth potential, and reduction in nitrogen levels of fertilization are some of the possibilities that these compounds connote to sustainable agriculture.

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Section: The Components Of Our Organic Biostimulantmentioning

confidence: 99%

The Use of Organic Biostimulants to Help Low Input Sustainable Agriculture

Russo¹,

Berlyn²

1991

Journal of Sustainable Agriculture

186

113

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“…, Swift, 1976;Visser, 1985). However, microorganisms have extremely limited capacities for movement and may thus remain for long periods in inactive resting stages because they are physically separated from their food resources or lack suitable microenvironment conditions.…”

Section: Biological Systems Of Regulation and Soil Fertilitymentioning

confidence: 99%

Impact of Soil Fauna on the Properties of Soils in the Humid Tropics

Lavelle

Blanchart

Martin

et al. 2015

SSSA Special Publications

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“…This hypothesis implies that the biological effects of HS are connected to membrane activity (12,44,56). Sorption of HS onto cells is the best documented phenomenon; numerous studies include phytoplankton (7,15,36,57), isolated fish gill cells (7), bacteria (13,14,27,57), fungi (60), and plants (12,31,44). This suggests that the sorption of HS onto biological membranes is a general process, but very few quantitative estimates are available (13,36).…”

mentioning

confidence: 99%

Estimation of Uptake of Humic Substances from Different Sources by Escherichia coli Cells under Optimum and Salt Stress Conditions by Use of Tritium-Labeled Humic Materials

Куликова

Perminova

Badun

et al. 2010

Appl Environ Microbiol

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The primary goal of this paper is to demonstrate potential strengths of the use of tritium-labeled humic substances (HS) to quantify their interaction with living cells under various conditions. A novel approach was taken to study the interaction between a model microorganism and the labeled humic material. The bacterium Escherichia coli was used as a model microorganism. Salt stress was used to study interactions of HS with living cells under nonoptimum conditions. Six tritium-labeled samples of HS originating from coal, peat, and soil were examined. To quantify their interaction with E. coli cells, bioconcentration factors (BCF) were calculated and the amount of HS that penetrated into the cell interior was determined, and the liquid scintillation counting technique was used as well. The BCF values under optimum conditions varied from 0.9 to 13.1 liters kg ؊1 of cell biomass, whereas under salt stress conditions the range of corresponding values increased substantially and accounted for 0.2 to 130 liters kg ؊1 . The measured amounts of HS that penetrated into the cells were 23 to 167 mg and 25 to 465 mg HS per kg of cell biomass under optimum and salt stress conditions, respectively. This finding indicated increased penetration of HS into E. coli cells under salt stress.Humic substances (HS) are natural organic compounds comprising 50 to 90% of the organic matter of peat, coal, and sapropel (i.e., sludge that accumulates at the bottom of lakes), as well as of the nonliving organic matter of soil and water ecosystems (9,34,53). Being the products of stochastic synthesis, HS are characterized as polydispersed substances having elemental compositions that are nonstoichiometric and structures which are irregular and heterogeneous. Thus, it is not possible to assign an exact structure to HS. Instead, they are operationally defined using a model structure predicated on available compositional, structural, functional, and behavioral data: a model structure containing all the same basic structural units and types of reactive functional groups (46). HS have been demonstrated to contain a large amount of residues resembling the original building blocks (aromatic subunits, amino acids, carbohydrates, etc.) (51) as well as polyphenolic components with nonhydrolyzable C-C and ether bonds (51, 16). Since humic matter is a complex mixture of organic substances, HS yield extremely high polydispersity values (i.e., the ratio of weight-average molecular weight to the number-average molecular weight [M w /M n ]), which vary within the range of 1.64 to 4.40 (38). These extremely high polydispersity values mean that even though they yield relatively high values of molecular weight, HS contain a low-molecular-weight fraction.HS are known to play important roles in protecting microorganisms and higher plants from climatic and technogenic stresses, such as pollution, draught, UV irradiation, and pathogen and viral infections (2, 22, 31). However, mechanisms underlying protective functions of these natural systems are still poorly und...

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Physiological action of humic substances on microbial cells

Cited by 143 publications

References 6 publications

The Use of Organic Biostimulants to Help Low Input Sustainable Agriculture

The Use of Organic Biostimulants to Help Low Input Sustainable Agriculture

Impact of Soil Fauna on the Properties of Soils in the Humid Tropics

Estimation of Uptake of Humic Substances from Different Sources by Escherichia coli Cells under Optimum and Salt Stress Conditions by Use of Tritium-Labeled Humic Materials

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