Iron Translocation II. Citrate/Iron Ratios in Plant Stem Exudates

Tiffin, L. O.

doi:10.1104/pp.41.3.515

Cited by 115 publications

(73 citation statements)

References 2 publications

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“…Investigations of the forms of nutrient cations such as Fe, Cu, and Zn in leaf tissues of agronomic species (56,57) have shown these to be pr,esent as anionic complexes. Similarly, studies of the chemical forms of trace elements transported within the xylem (11,25,(37)(38)(39)(58)(59)(60)(61)(62) and phloem (63) show Ca, Fe, Ni, Mn, and Zn to be transported as organic complexes. In the case of nutrient ions, complexation may provide a basis for maintaining their mobility within the plant and allowing for their accumulation at sites of metabolic use.…”

Section: Metabolic Behavior Of Metals In Plants As Related To Tolerancementioning

confidence: 99%

Soil and plant factors influencing the accumulation of heavy metals by plants.

Cataldo¹,

Wildung²

1978

Environ Health Perspect

201

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The use of plants to monitor heavy metal pollution in the terrestrial environment must be based on a cognizance of the complicated, integrated effects of pollutant source and soil-plant variables. To be detectable in plants, pollutant sources must significantly increase the plant available metal concentration in soil. The major factor governing metal availability to plants in soils is the solubility of the metal associated with the solid phase, since in order for root uptake to occur, a soluble species must exist adjacent to the root membrane for some rinlte period. The rate of release and form of this soluble species will have a strong influence on the rate and extent of uptake and, perhaps, mobility and toxicity in the plant and consuming animals. The factors influencing solubility and form of available metal species in soil vary widely geographically and include the concentration and chemical form of the element entering soil, soil properties (endogenous metal concentration, mineralogy, particle size distribution), and soil processes (e.g., mineral weathering, microbial activity), as these influence the kinetics of sorption reactions, metal concentration in solution and the form of soluble and insoluble chemical species.The plant root represents the first barrier to the selective accumulation of ions present in soil solution. Uptake and kinetic data for nutrient ions and chemically related nonnutrient analogs suggest that metabolic processes associated with root absorption of nutrients regulate both the affinity and rate of absorption of specific nonnutrient ions. Detailed kinetic studies of Ni, Cd, and Tl uptake by intact plants demonstrate multiphasic root absorption processes over a broad concentration range, and the use of transport mechanisms in place for the nutrient ions Cu, Zn, and K. Advantages and limitations of higher plants as indicators of increased levels of metal pollution are discussed in terms of these soil and plant phenomena.The principal objectives of this review are to briefly describe the soil and plant factors influencing trace metal uptake by plants, and, with this information as a basis, illustrate some of the parameters which must be considered in using higher plants as indicators of increased levels of metals in the terrestrial environment.In order to utilize plants as monitors of metal pollution in the field, it is necessary to distinguish between uptake arising from natural metal sources and from pollutant sources. Metals from both natural and pollutant sources have the potential for being assimilated by the plant through foliar or root absorption processes. The importance of foliar absorption processes for several heavy elements has been discussed elsewhere (1, 2). Separation of the sources of metals taken up by roots is complicated by the mediating effect of soil properties and soil and plant processes. These effects may be illus-* Battelle, Pacific Northwest Laboratories, Richland, Washington, 99352. trated by examination of the concentration of metals in soil relative to po...

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Section: Metabolic Behavior Of Metals In Plants As Related To Tolerancementioning

confidence: 99%

Soil and plant factors influencing the accumulation of heavy metals by plants.

Cataldo¹,

Wildung²

1978

Environ Health Perspect

201

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“…Citric acid strongly binds Fe, anid is usually in ilmolar excess of Fe in stem exudates (11). Citrate also binds other metals (5,8) and the exudates from the 0.5 and 5.0 jM treatments contained, in most cases, enough citrate to bind (1:1) both the Fe and the competing metal.…”

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confidence: 99%

Translocation of Manganese, Iron, Cobalt, and Zinc in Tomato

Tiffin

1967

Plant Physiol.

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“…We too have found in NS 1 an increase, particularly evident for citric acid, that might be connected to the strategy done by maize for iron uptake, and therefore to the needs to produce phytosiderophores in the Fe deficiency. In this condition citric acid plays a role of a chelating agent for Fe 2+ [21,22] but also to move the cation towards vegetative apexes [23]. In NS 2 ( Fig.…”

Section: Experiments 2 (Ns 2 )mentioning

confidence: 99%

Influence of different iron availability on phosphoenolpiruvate carboxilase and malate dehydrogenase in roots of maize (Zea Mays L.) plants grown under iron deficiency

Russo

Belligno

2010

Nature Precedings

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The effect of the different nitrate availability on some enzymatic activities has been evaluated in iron deficient and iron sufficient maize plants (Zea mays L.). In order to evaluate if the induction of sensitive to pH enzymatic activities is affected by the variation of the apoplast reaction due to the different nitrate availability, two experimental tests were done on maize plants grown in nutrient solution with different NO 3 -availability and with Fe-sufficiency (+Fe) (added with 80 μM Fe(III)-EDTA) and Fe-deficiency (-Fe) (added with 0.1 μM Fe(III)-EDTA).As regards 0.4 mM NO 3 -(NS 2 ), independently of iron availability, phosphoenolpiruvate carboxilase and malate dehydrogenase inductions are higher than those recorded for the experiment with 4.0 mM NO 3 -. The two activities, for the reaction determined in citosol by NO 3 -uptake, show different responses according to Fe availability. In NS 1 the higher nitrate uptake and the contemporaneous H + incoming cause in (+Fe) plants a decrease of PEP-carboxilase activation and, during the first 24 hours, of malate dehydrogenase. The shifting of the peak of maximum activity shows that iron deficiency conditions, interfering with e -transport, determinate a slowing down of the enzyme induction, independently of nitrate availability. In NS 2 , PEPcase is higher under Fe-deficiency and malate dehydrogenase is higher under Fe-sufficiency, both during the first 24 hours.The different nitrate availability causes a different use of the acid content. In fact, in NS 1 citric content, precursor of molecules for the production of phytosiderophores, increased in (-Fe) theses. On the contrary, low nitrate availabilities determined a decrease in acid contents, mostly in (-Fe) theses. This result justifies the higher energy demand to activate membrane carriers under stress conditions for the reduced nitrate availability.

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Iron Translocation II. Citrate/Iron Ratios in Plant Stem Exudates

Cited by 115 publications

References 2 publications

Soil and plant factors influencing the accumulation of heavy metals by plants.

Soil and plant factors influencing the accumulation of heavy metals by plants.

Translocation of Manganese, Iron, Cobalt, and Zinc in Tomato

Influence of different iron availability on phosphoenolpiruvate carboxilase and malate dehydrogenase in roots of maize (Zea Mays L.) plants grown under iron deficiency

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