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Josefa María Navarro María Angeles Botella Antonio Cerd Vicente Martinez 《Journal of plant physiology》2001,158(3)
Melon seedlings (Cucumis melo L. cv.Galia) were grown hydroponically to study the effect of salinity (80 mmol/LNaCl) on phosphate (Pi) uptake and translocation at two levels of Pi (25 μmol/L and 1 mmol/L). Net uptake rates of Pi were determined by depletionof the medium and by plant content. Salinity decreased Pi uptake at low Pi (high affinity uptake mechanism), 25 μmol/L, although no specific competitive inhibition of Pi uptake by Cl− was observed. When plants were grown with high Pi (1 mmol/L), the uptake of Pi through the low affinity system was increased by 80 mmol/L NaCl. Salinity also reduced the phosphorus flux, as Pi, through the xylem. It is hypothesised that high levels of NaCl decrease the mobility of Pi stored in vacuoles, and as a result, inhibit export from this storage compartment to other parts of the plant. 相似文献
3.
Uptake of 24Mg by excised pine roots: A preliminary study 总被引:1,自引:0,他引:1
Uptake of 24Mg by excised roots of Pinus sylvestris L. during up to 4 h long incubations in 99.9 atom % 24Mg (50 M) was measured by ICP-MS. A rapid initial uptake phase (30 min) was followed by a slower uptake. This was interpreted as a shift from a phase dominated by saturable ion exchange (free space uptake), to a non-saturable phase, during which the rate of uptake was 0.077±0.0.012 mol Mg g–1 (d.wt.) h–1. The metabolic uncoupler DNP (2,4-dinitrophenol) at 50 M decreased the Mg uptake rate by 35% only, but the effect of DNP was significant (p<0.01). Several problems related to a high variability in the experimental material were encountered, and further refinement of this approach in studies of plant Mg uptake is suggested. 相似文献
4.
Contribution of an arbuscular mycorrhizal fungus to the uptake of cadmium and nickel in bean and maize plants 总被引:10,自引:2,他引:8
Two experiments were carried out in pots with three compartments, a central one for root and hyphal growth and two outer ones
which were accessible only for hyphae of the arbuscular mycorrhizal fungus, Glomus mosseae ([Nicol. and Gerd.] Gerdemann and Trappe). In the first experiment, mycorrhizal and nonmycorrhizal bean (Phaseolus vulgaris L.) plants were grown in two soils with high geogenic cadmium (Cd) or nickel (Ni) contents. In the second experiment, mycorrhizal
and nonmycorrhizal maize (Zea mays L.) or bean plants were grown in a non-contaminated soil in the central compartment, and either the Cd- or Ni-rich soil in
the outer compartments. In additional pots, mycorrhizal plants were grown without hyphal access to the outer compartments.
Root and shoot dry weight was not influenced by mycorrhizal inoculation, but plant uptake of metals was significantly different
between mycorrhizal and nonmycorrhizal plants. In the first experiment, the contribution of mycorrhizal fungi to plant uptake
accounted for up to 37% of the total Cd uptake by bean plants, for up to 33% of the total copper (Cu) uptake and up to 44%
of the total zinc (Zn) uptake. In contrast, Ni uptake in shoots and roots was not increased by mycorrhizal inoculation. In
the second experiment, up to 24% of the total Cd uptake and also up to 24% of the total Cu uptake by bean could be attributed
to mycorrhizal colonisation and delivery by hyphae from the outer compartments. In maize, the mycorrhizal colonisation and
delivery by hyphae accounted for up to 41% of the total Cd uptake and 19% of the total Cu uptake. Again, mycorrhizal colonisation
did not contribute to Ni uptake by bean or maize.
The results demonstrate that the arbuscular mycorrhizal fungus contributed substantially not only to Cu and Zn uptake, but
also to uptake of Cd (but not Ni) by plants from soils rich in these metal cations.
Deceased 21 September 1996
Deceased 21 September 1996 相似文献
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The effect of the acrodermatitis enteropathica mutation on zinc uptake in human fibroblasts 总被引:1,自引:0,他引:1
The acrodermatitis enteropathica (AE) mutation affects intestinal zinc absorption. Our goal was to determine whether the AE
mutation affects zinc uptake in human fibroblasts. Zinc uptake was determined during initial rates of uptake (10 min) following
incubation in HEPES/saline buffer. Zinc uptake (from 0.25 to 1 μM) into normal fibroblasts was significantly greater than into the AE fibroblasts (p<0.05). In order to identify factors that may alter cellular zinc uptake and be affected by the AE mutation, zinc uptake in
the presence of albumin or bicarbonate was measured. Albumin restricted zinc uptake in both normal and AE fibroblasts, whereas
bicarbonate stimulated zinc uptake in the normal fibroblasts. The effect of bicarbonate on zinc uptake in the AE fibroblasts
was significantly reduced in both the Pronase-sensitive and Pronase-resistant compartments. Following loading of the fibroblasts
with 1 μM zinc for 60 min, zinc efflux and retention were measured. The AE mutation did not affect zinc retention compared to normal
fibroblasts. We conclude that the AE mutation affects both zinc binding to the cell surface and its translocation across the
plasma membrane into the cell, possibly mediated through a defective anionic exchange mechanism. 相似文献
6.
The mechanism of zinc uptake in plants 总被引:1,自引:0,他引:1
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Wheat plants were grown at three levels of zinc nutrition in potted soil under controlled conditions. The surface soil in half of the pots was inoculated with a thin layer of milled chaff colonized byFusarium graminearum Group 1. Forty days after sowing, the plants were assessed for dry matter production and the extent of colonization by the pathogen. The concentration of zinc in the plant tissues was also determined.The zinc status of the plants ranged from severe deficiency through subclinical deficiency to sufficiency. The extent of colonization above the point of infection was decreased significantly by increasing the level of zinc supply. However, colonization of the seminal or secondary roots was not affected by zinc supply, nor was the incidence of infected plants. The unidirectional effect on resistance suggests that zinc has modified the contribution of the xylem flux to the upward spread of the pathogen. 相似文献
8.
Peanut plants (Arachis hypogaea L.) are known to absorb Ca, P and S through the fruiting organs, but information on Zn uptake pattern is lacking. Therefore, a green-house experiment was conducted to study the uptake and translocation of Zn when applied in the rooting and fruiting zones of peanut plants. To locate the pathway and distribution of radioactive Zn, autoradiographs of plants were also taken.Zinc uptake data and autoradiographs indicated that a substantial amount of65Zn was absorbed through the fruiting organs (auxillary system). Of the total65Zn in the whole plant, 55.2 per cent was absorbed through roots and remaining 44.8 per cent through fruiting organs. Zinc was translocated to all the plant parts regardless of its absorption through roots or fruiting organs. The highest zinc concentration was recorded in the kernels, followed by leaves, stem and the shell.Contribution from the Department of Soils, Haryana Agric. Univ., Hissar-India. 相似文献
9.
The mechanism(s) by which zinc is transported into cells has not been identified. Since zinc uptake is inhibited by reducing
the temperature, zinc uptake may depend on the movement of plasma membrane micoenvironments, such as endocytosis or potocytosis.
We investigated the potential role of potocytosis in cellular zinc uptake by incubating normal and acrodermatitis enteropathica
fibroblasts with nystatin, a sterol-binding drug previously shown to inhibit potocytosis. Zinc uptake was determined during
initial rates of uptake (10 min) following incubation of the fibroblasts in 50 μg nystatin/mL or 0.1% dimethyl-sulfoxide for
10 min at 37°C. The cells were then incubated with 1 to 30 μM
65zinc. Michaelis-Menten kinetics were observed for zinc uptake. Nystatin inhibited zinc uptake in both the normal and AE fibroblasts.
Reduced cellular uptake of zinc was associated with its internalization, not its external binding. In normal fibroblasts,
nystatin significantly reduced theK
m 56% and theV
max 69%. In the AE fibroblasts, nystatin treatment significantly reduced theV
max 59%, but did not significantly affect theK
m. The AE mutation alone affected theV
max for cellular zinc uptake. The control AE fibroblasts exhibited a 40% reduction inV
max compared to control normal fibroblasts. We conclude that nystatin exerts its effect on zinc uptake by reducing the velocity
at which zinc traverses the cell membrane, possibly through potocytosis. Furthermore, the AE mutation also effects zinc transport
by reducing zinc transport. 相似文献
10.
Growth of Pseudomonas aeruginosa in zinc poor environments is promoted by a nicotianamine‐related metallophore 下载免费PDF全文
Maria Chiara Mastropasqua Melania D'Orazio Mauro Cerasi Francesca Pacello Angelo Gismondi Antonella Canini Lorena Canuti Ada Consalvo Domenico Ciavardelli Barbara Chirullo Paolo Pasquali Andrea Battistoni 《Molecular microbiology》2017,106(4):543-561
11.
Chromium and its compounds may cause disturbance in the nutrient level of the plants. Iron, manganese, copper, and zinc are
essential nutrient elements and required for balanced growth and development of plants, but chromium uptake sometimes disturbed
their concentration in plants. Therefore, in the present paper, an effort has been made to observe the effect of different
levels of Cr on nutrient uptake of Phyllanthus amarus and Solanum nigrum, the medicinally important plants of indigenous systems of medicine having hepatoprotective and diuretic properties. The
study revealed that Cr causes significant changes in nutrient uptake as compared to control plants. Besides, Cr-treated plants
showed growth depression and decrease in fresh and dry weight too. With the increase in Cr supply, accumulation of Cr in roots
was increased significantly. Concentration of manganese and zinc was also increased. However, copper concentration in both
the plants seemed less affected by Cr. 相似文献
12.
B. Sathyanathan 《Journal of biosciences》1996,21(6):809-818
The typical euryhaline clamVillorita cyprinoides (Hanley) was acclimated to copper and zinc at salinity 13 × 10−3 and < 1 × 10−3 (fresh water). Acclimation enhanced the lethal tolerance, as denoted by dose-survival curves, which was more pronounced after
zinc acclimation. In fresh water copper acclimation sensitized the organisms. The copper accumulation trend was significantly
changed consequent to metal acclimation, especially after zinc acclimation, indicating some tissue metal regulatory effect.
Acclimation to copper equiped the organism to survive for longer periods with increased body burden of copper, while zinc
acclimation supressed the uptake of the more toxic ion copper. The earlier report of increased uptake of zinc by this organism
during combined exposure with copper is corelated in the present context. The role of metallothionein like protein in providing
protection against metal toxicity, the environmental implication of acclimation phenomena are indicated 相似文献
13.
Cadmium uptake and bioaccumulation in selected cultivars of durum wheat and flax as affected by soil type 总被引:4,自引:1,他引:3
G. Cieśliński K. C. J. Van Rees P. M. Huang L. M. Kozak H. P. W. Rostad D. R. Knott 《Plant and Soil》1996,182(1):115-124
Accumulation of cadmium (Cd) in crop plants is of great concern due to the potential for food chain contamination through the soil-root interface. Although Cd uptake varies considerably with plant species, the processes which determine the accumulation of Cd in plant tissues are affected by soil factors. The influence of soil type on Cd uptake by durum wheat (Triticum turgidum var. durum L.) and flax (Linum usitatissimum L.) was studied in a pot experiment under environmentally controlled growth chamber conditions. Four cultivars/lines of durum wheat (Kyle, Sceptre, DT 627, and DT 637) and three cultivars/lines of flax (Flanders, AC Emerson, and YSED 2) were grown in two Saskatchewan soils: an Orthic Gray Luvisol (low background Cd concentration; total/ABDTPA extractable Cd: 0.12/0.03 mg kg-1, respectively) and a Dark Brown Chernozem (relatively high background Cd concentration; total/ABDTPA Cd: 0.34/0.17 mg kg-1 respectively). Plant roots, stems, newly developed heads, and grain/seeds were analyzed for Cd concentration at three stages of plant growth: two and seven weeks after germination, and at plant maturity. The results showed that Cd bioaccumulation and distribution within the plants were strongly affected by both soil type and plant cultivar/line. The Cd concentration in roots leaves and stems varied at different stages of plant growth. However, all cultivars of both plant species grown in the Chernozemic soil accumulated more Cd in grain/seeds than plants grown in the Orthic Gray Luvisol soil. The different Cd accumulation pattern also corresponded to the levels of ABDTPA extractable and metal-organic complex bound soil Cd found in both soils. Large differences were found in grain Cd among the durum wheat cultivars grown in the same soil type, suggesting the importance of rhizosphere processes in Cd bioaccumulation and/or Cd transport processes within the plant. Distribution of Cd in parts of mature plants showed that durum grain contained up to 21 and 36% of the total amount of Cd taken up by the plants for the Orthic Gray Luvisol and Chernozemic soils, respectively. These results indicate the importance of studying Cd speciation, bioaccumulation and cycling in the environment for the management of agricultural soils and crops. 相似文献
14.
Summary Uptake of water and magnesium chloride solution was investigated through the outer surface of twigs of Picea abies (L.) Karst. Water uptake was determined by using pressure/volume (P/V) curves of the twigs as a basis for calculation to avoid problems of superficial extraneous water. When water was sprayed on bark and needles of 3- to 7-year-old twigs at a xylem water potential of -1.00 MPa, they absorbed as much as 80 mm3 water in 200 min/g twig dry weight as the twig water potential recovered to -0.15 MPa. With fluorescent dyes, pathways for absorption of water and solutes through the twig bark were found, particularly through the radially orientated ray tissue. In addition to uptake by mass flow, magnesium could also diffuse along a concentration gradient from the twig surface into the xylem. In the field, the magnitude of these uptake processes would depend on the concentration of elements deposited by atmospheric precipitation, the concentration gradient between the plant surface and the xylem sap, the xylem water potential and the intensity and duration of each precipitation event. 相似文献
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Cations, including calcium, magnesium, potassium, sodium, copper, iron, nickel and zinc, inhibited (up to 40%) extracellular binding and intracellular uptake of cadmium by Lemna polyrhiza in solution culture. Test plants showed a high capacity of extracellular cadmium binding which was competitively inhibited by copper, nickel and zinc; however, calcium, magnesium and potassium caused non-competitive inhibition. Iron and sodium increased K
m and decreased V
max, thereby causing mixed inhibition of extracellular binding. Intracellular cadmium uptake displayed Michaelis-Menten kinetics. It was competitively inhibited by calcium, magnesium, iron, nickel and zinc. Monovalent cations (sodium and potassium) caused non-competitive and copper caused mixed inhibition of intracellular cadmium uptake. Thus, high levels of cations and metals in the external environment should be expected to lower the cadmium accumulation efficiency of L. polyrhiza. 相似文献
17.
Discs of thallus cut from the macroalga Ulva lactuca were incubated in filtered seawater containing cadmium, zinc, copper or cobalt (30
m). The metal uptake rates differed for each metal in the order Cu > Zn > Cd > Co. Exposure of the macroalga to metals resulted in a disruption of intracellular monovalent cation composition. Intracellular potassium was irreversibly lost and sodium was accumulated by cadmium- or copper-treated U. lactuca, which was assumed to indicate irreversible disruption of the plasmalemma. Exposure to zinc caused an increase in sodium concentrations, whereas potassium concentrations were not significantly different from the controls, suggesting that the integrity of the plasmalemma had been maintained at the zinc concentration used. Intracellular magnesium was also lost from copper-treated algae, which again indicated a loss of integrity of the cell membrane. 相似文献
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Distinct mechanisms of zinc uptake at the apical and basolateral membranes of caco-2 cells. 总被引:4,自引:0,他引:4
Zinc uptake mechanisms at the apical and basolateral membrane borders of caco-2 cells were examined. This human-derived cell line possesses many morphological and functional characteristics of absorptive small intestinal cells. By day 14, confluent and well-differentiated monolayers were formed when the cells were grown on porous polycarbonate filters. Labelled zinc was placed on the apical or basal side of the monolayer and its uptake by the cells, as well as its transport across the monolayer, were measured. Zinc uptake by the cells from the apical side was found to be a saturable process (Kt = 41 microM; Vmax = 0.3 nmols/cm2/10 min) with a diffusional term at higher concentrations (1.0 sec/cm). Apical uptake was not affected by metabolic inhibitors or potential zinc ligands. Zinc uptake from the basolateral side was concentration dependent (Kd = 1.3 sec/cm) and was partially inhibited (30%) by ouabain and vanadate, suggesting that the (Na-K)-ATPase on the basolateral membrane is involved in the serosal uptake of zinc by the cell. Transport of zinc across the monolayers from the apical or basolateral compartment was concentration dependent and was not affected by metabolic inhibitors. Zinc transport from the basolateral side was greater than 2-fold greater than apical transport. Hence, separate mechanisms can be distinguished with respect to zinc uptake at the apical and basolateral membranes of caco-2 cells. 相似文献
19.
Influence of chromium on some physiological variables ofAnabaena doliolum: interaction with metabolic inhibitors 总被引:1,自引:0,他引:1
The impact of 2,4-dinitrophenol and chlorophenyl dimethylurea on ATP content carbon fixation, O2 evolution, nitrogenase activity and Cr uptake ofAnabaena doliolum has been studied. 2,4-Dinitrophenol has been found to be more toxic than chlorophenyldimethylurea for all these processes. However, when Cr toxicity to above variables was assessed in their presence the interaction was less than additive. An initial (10–15 min) concentration-dependent rapid Cr uptake, followed by a slow one, indicates a biphasic uptake. A significant inhibition of Cr uptake in the presence of both these metabolic inhibitors suggests the involvement of metabolic processes in Cr uptake. 相似文献
20.
Thomas Jahns 《Antonie van Leeuwenhoek》1992,62(3):173-179
The energy-dependent urea permease was studied in two strains ofPseudomonas aeruginosa, measuring the uptake (transport and metabolism) of14C-urea. In both strains urea uptakein vivo and urease activityin vitro differed significantly with respect to kinetic parameters, temperature and pH dependence and response to metabolic inhibitors. Ammonium strongly interfered both with the expression of the urea uptake system and its activity. The inhibition of the uptake activity by ammonium was partially relieved by hydraziniumsulfate, which prevented the translocation of ammonium into the cell, and in a methylammonium/ammonium transport-defective mutant of strain DSM 50071. Furthermore, methionine-sulfoximine, which prevented the intracellular glutamine formation from ammoniumvia inhibition of glutamine synthetase, relieved the inhibition of urea uptake by ammonium. These findings suggested that urea uptake activity inP. aeruginosa is regulated by intracellular glutamine.Abbreviations CCCP
carbonylcyanide-m-chlorphenylhydrazone
- DCCD
dicyclohexylcarbodiimide
- GS
glutamine synthetase
- MSX
methionine-sulfoximine 相似文献