Mode of Action of Phytotoxic Oils

Overbeek, J. van; Blondeau, René

doi:10.2307/4040131

Cited by 128 publications

(54 citation statements)

References 9 publications

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“…Permeability of mammalian gastric mucosa to H+ increases greatly when the tissue is exposed to acetate, propionate, or butyrate in acidic, but not in neutral solution (2). Van Overbeek and Blondeau found that acetic and propionic acids increased permeability of beet root disks (19). Only the undissociated molecules were toxic, and toxicity was greatest when molecular weight was lowest, as was found also in the present experiments.…”

Section: Methodssupporting

confidence: 70%

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

Jackson

Taylor

1970

Plant Physiol.

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Effects of several organic acids on ion uptake and retention and on respiration in barley roots having low and high KCI contents were assayed by measurements of K+, Na+, Ca2+, Cl-, and oxygen uptake. Organic acids with high pKa values increase the permeability of roots to ions and decrease respiration when present in sufficient concentrations at pH 5 but have no inhibitory effects at pH 7. Absence of respiratory inhibition in short times and at lower organic acid concentrations, under conditions that immediately produce a permeability increase, indicate that the permeability change is not a result of respiratory inhibition. Effects of formate, acetate, propionate, and glutarate are attributed to entry of undissociated acid molecules into the effective membranes. Lack of a permeability increase with succinate, which has lower distribution coefficients to lipid solvents than do the aliphatic acids, can be explained by failure of sufficient amounts of the hydrophilic succinic acid molecules to penetrate the membranes involved. These experiments suggest that undissociated acid in root membranes can increase permeability of the roots.Entry of weak organic acids into plants has been known for many years (1,4,18). They are generally thought to enter by distribution to the lipid-protein of the cellular membranes (see Ref. 1, for review), in part because of enhanced effects with decrease in pH. Most of these acids, however, are toxic at moderate concentrations and low pH at which inorganic salts are tolerated (7,16). Evidence that organic acids are taken up as anions by plant roots has only recently been advanced (9). Considerations of the entry of organic anions require some clarification of the nature of the interaction of the undissociated acid with roots.Measurements of salt loss from roots in the presence of several weak organic acids as shown here indicate that the limiting membranes are modified under usual experimental conditions. Changes in metabolic rates are shown to be secondary to these modifications. The conclusion is that the acid anion can enter the root without evident modification of the root membranes. The undissociated acid in sufficient concentration, however, modifies the membrane so as to alter the response toward inorganic salts and possibly toward the acid itself. MATERIALS AND METHODSThe roots were from 6-day-old seedlings of barley (Hordewn vulgare, var. Compana and var. Trebi) which had been dark grown in aerated 2 X 10-4 M CaSO4, pH 5.6 at 25 C. High KCl roots were from seedlings grown in 10-3 M KCI + 2 X 10-4 M CaSO4 at pH 5.6 for 8 hr on the 5th day. Roots were excised and rinsed several times just before use.Details of procedure and conditions for the experiments were the same as those used previously (8). Briefly, the roots were maintained in aerated organic acid salt solutions at 23 to 25 C, from which successive root samples were withdrawn periodically, rinsed with water four times, and weighed. Sampling times varied from 5 min to 24 hr. Half-gram root samples were dried in the ...

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Section: Methodssupporting

confidence: 70%

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

Jackson

Taylor

1970

Plant Physiol.

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“…Highly volatile hydrocarbons, primarily those that are small and lightweight are able to move through cell membranes easily. Small hydrocarbon molecules, which penetrate into the plant, can cause toxic effects (van Overbeek and Blondeau, 1954), which although acute, are generally short lived. Acute toxicity caused by the lighter fraction of diesel fuel may explain the delayed seed emergence and reduction in percentage germination displayed by the plants in the initial screening experiment.…”

Section: Discussionmentioning

confidence: 99%

Influence of diesel fuel on seed germination

Adam

Duncan

2002

Environmental Pollution

285

144

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The use of plant-based systems to remediate contaminated soils has become an area of intense scientific study in recent years and it is apparent that plants which grow well in contaminated soils need to be identified and screened for use in phytoremediation technologies. This study investigated the effect of diesel fuel on germination of selected plant species. Germination response varied greatly with plant species and was species specific, as members of the same plant family showed differential sensitivity to diesel fuel contamination. Differences were also seen within plant subspecies. At relatively low levels of diesel fuel contamination, delayed seed emergence and reduced percentage germination was observed for the majority of plant species investigated.Results suggest the volatile fraction of diesel fuel played an influential role in delaying seed emergence and reducing percentage germination. In addition, the remaining diesel fuel in the soil added to this inhibitory effect on germination by physically impeding water and oxygen transfer between the seed and the surrounding soil environment, thus hindering the germination response.

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“…Because early roots have yet to develop protective layers, such as a thickened epidermis and cuticle, the lipid bilayer may be more vulnerable to the presence of hydrocarbons. The lipid bilayer structure of the plasma membrane is, in essence, a colloidal micelle and as such, will follow the same principles of other colloidal micelles [45]. This includes the solubilisation when a foreign molecule is incorporated into the colloid.…”

Section: Discussionmentioning

confidence: 99%

“…As hydrocarbons are readily solubilised, they are able to move into the plasma membrane and displace fatty acids, thereby reducing the integrity of the membrane. This in turn causes the cell to become increasingly permeable, eventually leading to collapse of the cell [45]. In addition, the high tolerance of the shoots with the dicots C. muscoides and E. pendunculare to SAB-contaminated soils may be related to the epigeal germination.…”

Section: Discussionmentioning

confidence: 99%

Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants

Macoustra

King

Wasley

et al. 2015

Environ. Sci.: Processes Impacts

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. (2015). Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants. Environmental Science Processes and Impacts, 17 (7), 1238-1248. Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants AbstractSpecial Antarctic Blend (SAB) is a diesel fuel dominated by aliphatic hydrocarbons that is commonly used in Antarctic and subantarctic regions. The past and present use of SAB fuel at Australia's scientific research stations has resulted in multiple spills, contaminating soils in these pristine areas. Despite this, no soil quality guidelines or remediation targets have been developed for the region, primarily due to the lack of established indigenous test species and subsequent biological effects data. In this study, twelve plant species native to subantarctic regions were collected from Macquarie Island and evaluated to determine their suitably for use in laboratory-based toxicity testing, using germination success and seedling growth (shoot and root length) as endpoints. Two soil types (low and high organic carbon (OC)) were investigated to reflect the variable OC content found in soils on Macquarie Island. These soils were spiked with SAB fuel and aged for 14 days to generate a concentration series of SAB-contaminated soils. Exposure doses were quantified as the concentration of total petroleum hydrocarbons (TPH, nC9-nC18) on a soil dry mass basis. Seven species successfully germinated on control soils under laboratory conditions, and four of these species (Colobanthus muscoides Hook.f., Deschampsia chapmanii Petrie, Epilobium pendunculare A.Cunn. and Luzula crinita Hook.f.) showed a dose-dependent inhibition of germination when exposed to SAB-contaminated soils. Contaminated soils with low OC were generally more toxic to plants than high organic carbon soils. Increasing soil-TPH concentrations significantly inhibited shoot and root growth, and root length was identified as the most sensitive endpoint. Although the test species were tolerant to SAB-contaminated soils in germination assays, development of early life stages (up to 28 days) were generally more sensitive indicator of exposure effects, and may be more useful endpoints for future testing. Disciplines Medicine and Health Sciences | Social and Behavioral Sciences Publication DetailsMacoustra, G. K., King, C. K., Wasley, J., Robinson, S. A. & Jolley, D. F. (2015). Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants. Environmental Science Processes and Impacts, 17 (7) Keywords: total petroleum hydrocarbons, total organic carbon, monocots, dicots, germination, root and shoot growth. 2 ABSTRACTSpecial Antarctic Blend (SAB) is a diesel fuel dominated by aliphatic hydrocarbons that is commonly used in Antarctic and subantarctic regions. The past and present use of SAB fuel at Australia's scientific research stations has resulted in multiple spills, contaminating soils in these pristine areas. Despite this, no soil quality guidel...

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Mode of Action of Phytotoxic Oils

Cited by 128 publications

References 9 publications

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

Effects of Organic Acids on Ion Uptake and Retention in Barley Roots

Influence of diesel fuel on seed germination

Impact of hydrocarbons from a diesel fuel on the germination and early growth of subantarctic plants

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