Influence of Complexation on the Uptake by Plants of Iron, Manganese, Copper and Zinc

Laurie, Stuart H.; Tancock, N.P.; McGrath, Steve P.; Sanders, J. Roger

doi:10.1093/jxb/42.4.515

Cited by 45 publications

(30 citation statements)

References 9 publications

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“…According to Laurie et al (1991b), there are two possible pathways of metal uptake into root. The first path consists in the dissociation of complex (MeL) in diffusion layer (solution phase) after which the released free ion metal (Me) may be transported to cell root across plasmalemma.…”

Section: Discussionmentioning

confidence: 99%

“…On the contrary, complexation of Ni by histidine increased its phytoassimilation, but decreased its phytotoxicity (Krämer et al, 1996). According to investigations carried out by Laurie et al (1991b), Von Wiren et al (1996) and Molas (1997), the absorption of metal chelates by plants and their phytotoxicity, including Ni chelates, depends on the chemical nature of the chelating agent as well as on the stability constant of the chelate.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between the chemical form of nickel applied to the soil and its uptake and toxicity to barley plants (Hordeum vulgare L.)

Molas¹,

Baran²

2004

Geoderma

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relationship between the chemical form of nickel applied to the soil and its uptake and toxicity to barley plants (Hordeum vulgare L.)

Molas¹,

Baran²

2004

Geoderma

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“…-10.6 for tomato, which is quite similar to values reported for maize (Zea mays L.) grown in DTPA-containing nutrient solutions (Halvorson and Lindsay, 1977), and for barley (Hordeum vulgare L.) reared in solutions buffered with HEDTA (N-[2-hydroxyethyl] ethyelenedinitrilotriacetate) (Norvell, 1991 ). Laurie et al (1991) also reported Zn deficiency in barley at computed log (Zn 2+) values of ca.…”

Section: Zinc-phosphorus Interactions In Tomato 173mentioning

confidence: 90%

Zinc-phosphorus interactions in two cultivars of tomato (Lycopersicon esculentum L.) grown in chelator-buffered nutrient solutions

1992

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Zinc-phosphorus interactions have been frequently studied using a diverse number of crop species, but attainment of reproducible Zn deficiencies, especially severe ones, has been hampered by the use of conventional hydroponic solutions wherein contaminating levels of Zn are often near-adequate for normal growth. We utilized novel, chelator-buffered nutrient solutions for precise imposition of Zn deficiencies. Tomato (Lycopersicon esculentum L. cv. Jackpot or Celebrity) seedlings were grown for 15 to 18 d in nutrient solutions containing 200, 600, or 1200/xM P, and 0 to 91/zM total Zn. Computed free Zn 2÷ activities were buffered at ~< 10 -l°3 M by inclusion of a 100-/zM excess (above the sum of the micronutrient metal concentrations) of the chelator DTPA. At total added Zn = 0, acute Zn deficiency resulted in zero growth after seedling transfer, and plant death prior to termination. Free Zn 2* activities ~< 10-1°6 M resulted in Zn deficiencies ranging from mild to severe, but activities <~ 10-~2 were required to cause hyperaccumulation of shoot P to potentially toxic levels. Despite severe Zn deficiency (i.e. ca. 20% of control growth), tissue Zn levels were usually much higher than the widely reported critical value of 20 mg kg-~, which may be an artifact of the selection of DTPA for buffering free Zn 2÷. Across Zn treatments, increasing solution P depressed growth slightly, especially in Celebrity, but corresponding increases in tissue P (indicative of enhanced P toxicity) or decreases in tissue Zn (P-induced Zn deficiency) were not observed. The depressive effect of P was also not explained by reductions in the water-soluble Zn fraction. Within 40 h, restoration of Zn supply did not ameliorate high leakage rates (as measured by K + efflux) of Zn-deficient roots. Similarly, transfer of Zn-sufficient plants to deficient solutions did not induce leakiness within 40 h. Foliar sprays of ZnSO 4 almost completely corrected both Zn deficiency and membrane leakiness of plants grown in low-Zn solutions. Hence, maintenance of root membrane integrity appears to depend on the overall Zn nutritional status of the plant, and not on the presence of certain free Zn 2÷ levels in the root apoplasm.

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“…Similarly, the potential for the supply of metal in the bulk solution to limit rootmetal binding was assessed by comparing the total amount of metal in the bulk exposure solution with the total amount of metal that was sorbed by the root in response to the Me 2+ exposure. Special consideration was given to the potential secondary effects of NTA, which include enhanced metal accumulation via selective and non-selective uptake of the intact metal-chelate complex (Bell et al, 1991(Bell et al, , 2003Laurie et al, 1991) and phytotoxicity (Vassil et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

The effect of metal diffusion and supply limitations on conditional stability constants determined for durum wheat roots

Antunes

Hale

2006

Plant Soil

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Conditional stability constants (log K), and binding site densities (G max ) for dissolved metals and biota are important input parameters for the Biotic Ligand Model. However, determination of these binding parameters is likely to be influenced by solution kinetics because roots have a large metal-binding capacity and can accumulate metals rapidly. The aim of this study was to determine if the rate of free metal ion diffusion to the root surface, and amount of metal in the bulk solution, is sufficient to accommodate the maximum root-metal accumulation capacity. The extent to which these kinetic limitations affect the magnitude of log K and G max values was also assessed. Seven day old hydroponically grown durum wheat (Triticum turgidum L. var durum, cv 'Arcola') were exposed to solutions with p{Cu 2+ }s ranging from 10.54 to 2.26 (~20°C, pH=6.0, ionic strength=0.03 M). Exposure solutions were prepared with and without the metal buffer nitrilotriacetic acid (NTA) so that the total amount of metal in the exposure solution, and net flux of metal to the root, could be varied. The results demonstrate that NTA enhances Cu accumulation at exposure p{Cu 2+ }s between 10 and 6. Comparison of the diffusive flux to the root with the metal flux into the root, for ()NTA) and (+NTA) Cu exposures, showed that the flux of the un-buffered free metal ion to the root was not large enough to accommodate the maximum Cu binding capacity between 10 and 6 p{Cu 2+ } in solution. The total amount of Cu in solution may have limited uptake for exposure p{Cu 2+ }s of 10.01 and 9.01, but the background concentrations of Cu in the control plants prevented definitive conclusions from being made within this exposure range. Similar results were found for Mn and Ni. For Cd, which had lower background concentrations in the roots, the amount of metal in solution did not limit uptake until a p{Cd 2+ } of 10.01. Limiting the supply of Cu 2+ to the root (i.e. low {Cu 2+ }s with no NTA) caused only a moderate bias in G max values, but suppressed the log K value by 3.44 log units. The log K values for Cd, Mn and Ni, in the absence of NTA, were more similar than expected, which suggests that the kinetics of free ion re-supply to the root surface limited metal uptake, as it did for Cu.

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Influence of Complexation on the Uptake by Plants of Iron, Manganese, Copper and Zinc

Cited by 45 publications

References 9 publications

Relationship between the chemical form of nickel applied to the soil and its uptake and toxicity to barley plants (Hordeum vulgare L.)

Relationship between the chemical form of nickel applied to the soil and its uptake and toxicity to barley plants (Hordeum vulgare L.)

Zinc-phosphorus interactions in two cultivars of tomato (Lycopersicon esculentum L.) grown in chelator-buffered nutrient solutions

The effect of metal diffusion and supply limitations on conditional stability constants determined for durum wheat roots

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