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1.
Atropa belladonna L. plants were grown in water culture for 8 weeks before the nutrient medium was supplemented with NiCl 2 to final concentrations of 0 (control treatment), 50, 100, 150, 200, 250, and 300 μM. After 4 days of plant growing in the
presence of nickel chloride, the content of water, proline, Ni, Fe, free polyamines, as well as lipid peroxidation rates were
measured. The addition of 100–150 μM Ni to the medium significantly reduced the fresh weight increments and water content
in comparison with these parameters for untreated plants; 200 μM Ni caused serious, although nonlethal damage to the plants,
whereas 250 and 300 μM Ni proved to be lethal. In the aboveground organs, the major part of Ni was accumulated in the apical
leaves. When the plants were treated with 200 μM Ni, the Ni content in apical leaves was 220 μg/g dry wt, while Ni content
in roots reached 1500 μg/g dry wt. The treatment of plants with proline in the presence of 200 μM Ni inhibited Ni accumulation
in tissues. The proline-treated plants exhibited elevated iron content in leaves and especially in roots and were characterized
by comparatively low rates of lipid peroxidation and by sustained leaf water status. When 200 μM Ni was applied, the content
of free putrescine decreased, while the contents of spermine and spermidine in leaves increased appreciably with respect to
the control values. The toxic effect of nickel was accompanied not only by an enhanced accumulation of high- molecular-weight
polyamines but also by their oxidative degradation, which was evident from the 14-fold increase in the content of 1,3-diaminopropane.
The protective effect of exogenous proline in the presence of high nickel concentrations was manifested in lowered lipid peroxidation
rates, alleviation of iron deficiency, and in retarded oxidative degradation of polyamines. 相似文献
2.
Summary The influence of heavy metal additions on availability and uptake of cadmium, lead, zinc, copper, manganese and iron by oat was studied. The experiments were carried out as pot experiments using sandy loam, sandy soil and organic soil. Selective extractants were used to remove metals held in different soil fractions.Lead and copper were preferently bound by organics and oxides, zinc by oxides and inorganics, and cadmium by inorganics and organics.Addition of cadmium to the soils resulted in higher cadmium concentrations in all plant parts but lower concentrations of lead, zinc, copper, manganese and iron, and the accumulation indexes of these metals were also lower when cadmium was added to the soil.Addition of cadmium plus lead, zinc and copper resulted in higher cadmium concentrations in leaves and straw of plants grown in sandy loam and sandy soil, but lower concentrations when plants were grown in organic soil as compared with the results when cadmium was added separately. The transfer of cadmium, lead, zinc and copper from soil to plant was greatest from sandy soil, and zinc and cadmium were more mobile in the plant than were lead and copper.Cadmium concentrations in leaves correlated significantly with CaCl 2 and CH 3COOH extractions in sandy loam and sandy soil and with CH 3COOH extractions in organic soil.Generally, the total metal uptake was lowest from organic soil. 相似文献
3.
A facultative halophite Mesembryanthemum crystallinum L. (the common ice plant) was shown to grow successively at the high concentrations of Cu and Zn. Although 25 μM CuSO 4 or 800 μM ZnSO 4 retarded markedly plant growth, they did not interfere with the completion of plant development and the formation of viable
seeds. In such plants, leaves accumulated more than 200 μg of Cu and 1700 μg of Zn per 1 g of dry weight. A damaging effect
of heavy metals (HMs) was manifested in a reduced content of water in leaves and proline accumulation in them. As copper is
a metal with transient valence, copper salts are more toxic than zinc salts, which was manifested in a stronger inhibition
of the chlorophyll synthesis. Both HMs induced oxidative stress, as evident from increased activities of guaiacol peroxidase
and lipoxygenase. Moderate Cu and Zn concentrations did not damage cell membranes in leaves, as evident from the absence of
their action on electrolyte leakage either under optimum conditions or after heat treatment. A capability of a substantial
HM accumulation by the common ice plant and their considerable transport to shoots (up to 50 μg of Cu and 560 μg of Zn per
plant) make it possible to consider the common ice plant as a promising phytoremediator.
__________
Translated from Fiziologiya Rastenii, Vol. 52, No. 6, 2005, pp. 848–858.
Original Russian Text Copyright ? 2005 by Kholodova, Volkov, Kuznetsov. 相似文献
4.
Summary Concentrations of Cd, Pb and Cu in the roots, stems and leaves of bulgarian bush beans ( Phaseolus vulgaris L.) were determined for plants grown in various soils of increasing levels of contamination of these metals. Most of each heavy metal absorbed by plants was retained in roots. Concentrations of Cd, Pb and Cu in roots increased in response to soil concentrations, whereas, in stems, only Cd and Pb concentrations increased and Cu concentration was relatively constant. It is thought that Cu transport to the stele was metabolically controlled, whereas Cd and Pb reached the stem by leakage across non suberised areas of the endodermis. Uptake of heavy metals was associated with a decrease in zinc content in plants and a decrease in yield. By regression analysis decrease in both zinc content and plant yield could be best related to Cd content in stems. Possible reasons for these effects are discussed. 相似文献
6.
Plants have many natural properties that make them ideally suited to clean up polluted soil, water, and air, in a process called phytoremediation. We are in the early stages of testing genetic engineering-based phytoremediation strategies for elemental pollutants like mercury and arsenic using the model plant Arabidopsis. The long-term goal is to develop and test vigorous, field-adapted plant species that can prevent elemental pollutants from entering the food-chain by extracting them to aboveground tissues, where they can be managed. To achieve this goal for arsenic and mercury, and pave the way for the remediation of other challenging elemental pollutants like lead or radionucleides, research and development on native hyperaccumulators and engineered model plants needs to proceed in at least eight focus areas: (1) Plant tolerance to toxic elementals is essential if plant roots are to penetrate and extract pollutants efficiently from heterogeneous contaminated soils. Only the roots of mercury- and arsenic-tolerant plants efficiently contact substrates heavily contaminated with these elements. (2) Plants alter their rhizosphere by secreting various enzymes and small molecules, and by adjusting pH in order to enhance extraction of both essential nutrients and toxic elements. Acidification favors greater mobility and uptake of mercury and arsenic. (3) Short distance transport systems for nutrients in roots and root hairs requires numerous endogenous transporters. It is likely that root plasma membrane transporters for iron, copper, zinc, and phosphate take up ionic mercuric ions and arsenate. (4) The electrochemical state and chemical speciation of elemental pollutants can enhance their mobility from roots up to shoots. Initial data suggest that elemental and ionic mercury and the oxyanion arsenate will be the most mobile species of these two toxic elements. (5) The long-distance transport of nutrients requires efficient xylem loading in roots, movement through the xylem up to leaves, and efficient xylem unloading aboveground. These systems can be enhanced for the movement of arsenic and mercury. (6) Aboveground control over the electrochemical state and chemical speciation of elemental pollutants will maximize their storage in leaves, stems, and vascular tissues. Our research suggests ionic Hg(II) and arsenite will be the best chemical species to trap aboveground. (7) Chemical sinks can increase the storage capacity for essential nutrients like iron, zinc, copper, sulfate, and phosphate. Organic acids and thiol-rich chelators are among the important chemical sinks that could trap maximal levels of mercury and arsenic aboveground. (8) Physical sinks such as subcellular vacuoles, epidermal trichome cells, and dead vascular elements have shown the evolutionary capacity to store large quantities of a few toxic pollutants aboveground in various native hyperaccumulators. Specific plant transporters may already recognize gluthione conjugates of Hg(II) or arsenite and pump them into vacuole. 相似文献
7.
Copper and zinc act as a cofactor of over 300 mammalian proteins. Both have same electronic configuration therefore they are
antagonist at higher individual concentration. The present study was designed with the aim to investigate the mechanisms pertaining
to toxic effects of copper on human peripheral blood mononuclear cells (PBMCs) and to evaluate the cytoprotective effect of
zinc on copper-induced cytotoxicity. The copper uptake into PBMCs was progressively increased with increasing concentration
of metal in the growth medium. However, no significant effect on copper uptake was observed in the presence of zinc. Cell
proliferation rate was decreased with increasing copper concentration. Interestingly, the proliferation rate of zinc treated
PBMCs remained nearly the same as that of control cells. LD 50 of copper (115 μM) was increased six times (710 μM) in presence of zinc for PBMCs. At higher concentrations of copper (>
100 μM) decrease level of GSH was noticed. Increased levels of metallothionein in PBMCs were observed in response to zinc.
DNA fragmentation studies also showed that copper produced DNA fragmentation at LD 50 (115 μM). Subsequently, zinc showed protection against DNA fragmentation caused by copper. Cell structure of PBMCs at LD 50 (115 μM copper) showed membrane bound cystic spaces and mitochondria having disrupted cristae and few myelin figures. In
presence of zinc at LD 50 of copper (115 μM) cells showed improvement in mitochondrial structure and membrane bound cystic spaces. Taken together,
the results of our study demonstrates that zinc play an important role in prevention of copper toxicity in peripheral blood
mononuclear cells. 相似文献
8.
盆栽实验研究了不同施Zn水平(0、300 mg/kg和600 mg/kg)下,接种丛枝菌根真菌 Glomus intraradices对枳苗生长、Zn、Cu、P、K、Ca、Mg分布的影响,并采用非损伤微测技术测定分析了菌根化与非菌根化枳根净Ca 2+、H +、NO 3-离子流动态。结果表明:(1)在不同施Zn水平下,接种菌根真菌显著提高了枳苗地上部及根部鲜重;随着施Zn水平的提高,菌根侵染率呈降低趋势,枳苗地上部与根部Zn含量呈增加趋势,且接种株根部Zn含量显著高于未接种株。(2)接种株未施Zn处理的地上部Cu、P、K、Mg和根部Cu含量、施600 mg/kg Zn处理的根部Cu及施300 mg/kg Zn处理的根部P含量均显著高于对照,而菌根真菌侵染对枳苗Ca含量并无显著性影响。(3)接种株未施Zn处理的根部距根尖端0 μm和600 μm处净Ca 2+流出速率、600 μm处净H +流入速率、2400 μm处净NO 3-流入速率均显著高于未接种株。 相似文献
9.
The effects of increase copper concentrations in medium (10–150 μM CuSO 4) on growth and viability of the roots of two-week-old soybean seedlings ( Glycine max L., cv. Dorintsa) were studied. Copper excess suppressed biomass accumulation and linear plant growth; copper affected root
growth much stronger than shoot growth. The presence of 10 μM CuSO 4 in medium suppressed accumulation of plant biomass by 40% and the root length by 70%; in the presence of 25 μM CuSO 4, these indices were equal to 80 and 90%, respectively. In the presence of 50 μM CuSO 4, roots ceased to grow but biomass and shoot length still increased slightly. 150 μM CuSO 4 was lethal for plants. The earliest sign of excessive copper toxicity was the accumulation of MDA, indicating activation
of membrane lipid peroxidation. A significant increase in MDA content was observed at plant incubation in medium with 10 μM
CuSO 4 for 1 h; in this case, the content of copper in the roots increased from 36 ±1.8 (in control) to 48 ± 2.4 μg/g dry wt. The
number of dead cells (permeable for the dye Evans Blue) was doubled in the presence of 200 μg/g dry wt within the root; this
occurred in 72 h of growth in medium with 10 μM CuSO 4, in 6 h at 25 μM CuSO 4, in 3 h at 50 μM CuSO 4, and 1 h at 150 μM CuSO 4. Toxicity of copper excess was manifested stronger in dividing and elongation cells of the root apex (root meristem and the
zone of elongation) than in more basal root regions. Copper excess resulted in the formation of breaks in the surface cell
layers of the root tips and affect root morphology. When plant grew in medium with 10 μM CuSO 4, a distance of lateral root formation zone from the root tip decreased markedly, and spherical swellings were formed on the
tips of lateral roots. The higher copper concentrations (50 and 150 μM) suppressed completely the development of lateral roots. 相似文献
10.
The levels of heavy metals copper and zinc were found to be high in the Vellar estuary. Therefore their effects on the larval
development of the abundant hermit crab Clibanarius longitarsus were studied individually and in combination from hatching till moulting to glaucothoe stage in the laboratory using freshly
hatched Artemia nauplii as food. The 96 h LC50 values found with 100 larvae each kept in 10 different concentrations of copper and zinc (350,
300, 250, 200, 150, 100, 50, 25, 10 and 5 ppb) were 50 ppb for copper and 90 ppb for zinc. Based on these 96 h LC50 values,
three sublethal concentrations were chosen for the metals copper and zinc at 50%, 25% and 10% levels of the LC50 values. With
increase in concentration of the test medium, the survival rate decreased and the time required for the completion of each
zoeal stage increased. Copper was found to be more toxic than zinc as the survival rate in copper concentrations was lower
than those in zinc concentrations. The survival rate in the mixed concentrations of metals was lower than in individual concentrations. 相似文献
11.
Three amaranth hybrids ( Amaranthus paniculatus f. cruentus (Vishnevyi dzhem), A. paniculatus (Bronzovyi vek), and A. caudatus f. iridis (Izumrud) were grown in the climate-controlled chamber on Jonson nutrient medium supplemented with 2 μM Fe 3+-EDTA. When plants developed 5–6 true leaves (six-week-old plants), NiCl 2 was added to medium to final concentrations of 0 (control), 50, 100, 150, 200, and 250 μM. In 6 days, the increment in biomass
of young and mature leaves, stems, and roots, and also the contents of Ni and Fe in them were measured. The red leaf amaranth
hybrid Vishnevyi dzhem manifested the highest phytoremediation potential. i.e., the highest capacity for Ni accumulation in
the shoots and the most pronounced symptoms of Fe deficit. In the presence of 150 and 250 μM NiCl 2 in medium, the shoots of these plants contained about 2 and 4 mg Ni/g dry wt, respectively. In experiments with Fe deficit
in plants grown for a week in the presence of NiCl 2 (0, 25, 50, 75, and 100 μM), it was established that all tested nickel concentrations suppressed iron reduction in intact
roots, which is catalyzed by ferric-chelate reductase, and this may underlie the antagonism between the two metals. In the
presence of 50 μM NiCl 2 in medium and 2 μM Fe 3+ (Fe deficit) and especially 100 μM Fe 3+ (Fe excess), the content of MDA and proline in leaves increased and superoxide dismutase was activated; this indicates a
development of oxidative stress. Leaf treatment with polyamines (putrescine or spermidine) with aminoguanidine (the inhibitor
of H 2O 2 generation at polyamine oxidation) and with 1,3-diaminopropane led to the increase in nickel accumulation in leaves but did
not result in the appearance of any signs of injury. This confirms our previous suggestion that polyamines manifest their
protectory action as Ni chelators and detoxicants. 相似文献
13.
Plants have many natural properties that make them ideally suited to clean up polluted soil, water, and air, in a process called phytoremediation. We are in the early stages of testing genetic engineering-based phytoremediation strategies for elemental pollutants like mercury and arsenic using the model plant Arabidopsis. The long-term goal is to develop and test vigorous, field-adapted plant species that can prevent elemental pollutants from entering the food-chain by extracting them to aboveground tissues, where they can be managed. To achieve this goal for arsenic and mercury, and pave the way for the remediation of other challenging elemental pollutants like lead or radionucleides, research and development on native hyperaccumulators and engineered model plants needs to proceed in at least eight focus areas: (1) Plant tolerance to toxic elementals is essential if plant roots are to penetrate and extract pollutants efficiently from heterogeneous contaminated soils. Only the roots of mercury- and arsenic-tolerant plants efficiently contact substrates heavily contaminated with these elements. (2) Plants alter their rhizosphere by secreting various enzymes and small molecules, and by adjusting pH in order to enhance extraction of both essential nutrients and toxic elements. Acidification favors greater mobility and uptake of mercury and arsenic. (3) Short distance transport systems for nutrients in roots and root hairs requires numerous endogenous transporters. It is likely that root plasma membrane transporters for iron, copper, zinc, and phosphate take up ionic mercuric ions and arsenate. (4) The electrochemical state and chemical speciation of elemental pollutants can enhance their mobility from roots up to shoots. Initial data suggest that elemental and ionic mercury and the oxyanion arsenate will be the most mobile species of these two toxic elements. (5) The long-distance transport of nutrients requires efficient xylem loading in roots, movement through the xylem up to leaves, and efficient xylem unloading aboveground. These systems can be enhanced for the movement of arsenic and mercury. (6) Aboveground control over the electrochemical state and chemical speciation of elemental pollutants will maximize their storage in leaves, stems, and vascular tissues. Our research suggests ionic Hg(II) and arsenite will be the best chemical species to trap aboveground. (7) Chemical sinks can increase the storage capacity for essential nutrients like iron, zinc, copper, sulfate, and phosphate. Organic acids and thiol-rich chelators are among the important chemical sinks that could trap maximal levels of mercury and arsenic aboveground. (8) Physical sinks such as subcellular vacuoles, epidermal trichome cells, and dead vascular elements have shown the evolutionary capacity to store large quantities of a few toxic pollutants aboveground in various native hyperaccumulators. Specific plant transporters may already recognize gluthione conjugates of Hg(II) or arsenite and pump them into vacuole. 相似文献
14.
The translocation of manganese (Mn), nickel (Ni), cobalt (Co), zinc (Zn) and cadmium (Cd) in white lupin (Lupinus albus cv. Amiga) was compared considering root-to-shoot transport, and redistribution in the root system and in the shoot, as well as the content at different stages of cluster roots and in other roots. To investigate the redistribution of these heavy metals, lupin plants were labelled via the root for 24 h with radionuclides and subsequently grown hydroponically for several weeks. 54Mn, 63Ni and 65Zn were transported via the xylem to the shoot. 63Ni and 65Zn were redistributed afterwards via the phloem from older to younger leaves, while 54Mn remained in the oldest leaves. A strong retention in the root was observed for 57Co and 109Cd. Cluster roots contained higher concentrations of all heavy metals than noncluster roots. Concentrations were generally higher at the beginning of cluster root development (juvenile and immature stages). Mature cluster roots also contained high levels of 54Mn and 57Co, but only reduced concentrations of 63Ni, 65Zn and 109Cd. 相似文献
15.
Thirty-day-old seedlings of tomato ( Lycopersicon esculentum cv. Kwangsoo) were treated with various cadmium (Cd) concentrations (0, 10, 50, 100, and 500 μM) for up to 20 days, and the
detailed distribution of absorbed Cd and its phytotoxicity in different plant parts (root, stem, and leaves) were investigated.
The accumulation of Cd in plants increased with external Cd concentrations and Cd was strongly retained by roots, with less
than 30% of the absorbed Cd being transported to shoots. Among the leaves, the lower positioned older leaves accumulated more
Cd than the younger leaves. Furthermore, Cd-exposure not only reduced the dry weight and length of both shoot and root, chlorophyll
levels in leaves, and levels of photosynthesis, but also enhanced the concentration of malondialdehyde (a lipid peroxidation
product) in all plant parts. Our results indicate that the physiological impairment of tomato seedlings exposed to toxic levels
of Cd may be related to the internal distribution of absorbed Cd, prolonged exposure, and oxidative stress in different plant
parts. 相似文献
16.
Heavy metals (HMs) are known to have negative effects on plant water status; however, the mechanisms by which plants rearrange their water relations to adapt to such conditions are poorly understood. Using the model plant Mesembryanthemum crystallinum, we studied disturbances in water status and rapid plant defence responses induced by excess copper or zinc. After a day of HM stress, reductions in root sap exudation and water deficits in leaf tissues became evident. We also observed several primary adaptive events, including a rapid decrease in the transpiration rate and progressive declines in the leaf-cell sap osmotic potential. Longer HM treatments resulted in reductions of total and relative water contents as well as proline accumulation, an increase in water retention capacity and changes in aquaporin gene expression. After 3 h of HM exposure, leaf expression of the McTIP2;2 gene, which encodes tonoplast aquaporin, was suppressed more than two-fold, thus representing one of the earliest responses to HM treatment. The expression of three additional aquaporin genes was also reduced starting at 9 h; this effect became more prominent upon longer HM exposure. These results indicate that HMs induce critical rearrangements in the water relations of M. crystallinum plants, based on the rapid suppression of transpiration flow and strong inhibition of root sap exudation. These effects then triggered an adaptive water-conserving strategy involving differential regulation of aquaporin gene expression in leaves and roots, further reductions in transpiration, and an accelerated switch to CAM photosynthesis. 相似文献
17.
Changes in cytokinin pool and cytokinin oxidase/dehydrogenase activity (CKX EC: 1.5.99.12) in response to increasing abscisic
acid (ABA) concentrations (0.5–10 μM) were assessed in the last fully expanded leaves and secondary roots of two pea ( Pisum sativum) varieties with different vegetation periods. Certain organ diversity in CKX response to exogenous ABA was observed. Treatment
provoked altered cytokinin pool in the aboveground parts of both studied cultivars. Specific CKX activity was influenced significantly
basically in roots of the treated plants. Results suggest that ABA-mediated cytokinin pool changes are leaf-specific and involve
certain root signals in which CKX activity presents an important link. This enzymatic activity most probably regulates vascular
transport of active cytokinins from roots to shoots. 相似文献
18.
Heavy metals (HMs) are toxic pollutants, which can negatively affect the physiological processes of plants; moreover, HMs
can be present in the food chain endangering people’s health. The aim of this study was to investigate the early physiological
events during HM exposure in the root tips of the food plant Pisum sativum L. Ten-day-old pea plants were treated with 100 μM CdCl 2 or CuSO 4, in nutrient solution for 48 h. We studied the rapid formation of different reactive oxygen species (hydrogen peroxide H 2O 2 and superoxide radical O 2·−) and reactive nitrogen species (nitric oxide NO· and peroxynitrite ONOO −) together with membrane damage and cell death in the meristem cells of pea roots using in vivo and in situ microscopic methods.
In our experimental system, copper and cadmium induced the formation of H 2O 2 and NO. Two hours of heavy metal treatments resulted in an increased O 2·− formation; however, later the level of this reactive molecule dramatically decreased. We found that high levels of NO were
needed for ONOO − production under HM exposure. A fast loss of membrane integrity and decreased cell viability were detected in root tips of
copper-treated plants. The effects of cadmium seemed to be slower compared to copper, but this non-essential metal also caused
cell death. We concluded that viability decreased when NO and H 2O 2 levels were simultaneously high in the same tissues. Using the NO scavenger it was also evidenced that NO generation is essential
for cell death induction under copper or cadmium stress. 相似文献
19.
The effects of cobalt on the growth and nutrient balance of mung beans were investigated. Inhibition of seedling growth occurred at 5 μ M Co and was associated with chlorosis of the younger leaves. Analysis of nutrient concentrations in root and leaf tissue of mung beans treated with 5 μ M Co showed that none of the macronutrients and only two of the micronutrients, Mn and Fe, were significantly affected. The Mn concentration in roots was reduced by 55% and the Fe concentration in the leaves by 80%. Uptake of Fe into roots was not inhibited by Co but transport of Fe to the shoot was greatly reduced. It was shown that the effect of Co on growth was additive to that of Fe deficiency, which argues against Co-induced Fe deficiency as the primary cause of growth inhibition by Co. Rather, it was considered that the high concentrations of Co in the roots and leaves compared with essential micronutrient cations can disrupt a range of metabolic processes due to competitive interactions. Comparison of the toxic effects of Co with those of other toxic trace metals Cd, Cu, Ni and Hg showed that at an applied concentration of 5 μ M , there were obvious differences in both the visual symptoms and in nutrient concentrations. The main difference between Co and the other metals was that only Co stimulated the uptake of S into the plant and its transport to the shoots, where the S concentration in the leaves was increased 2-fold. The common feature of all the trace metals examined was the strong inhibition of Fe transport to the shoot. A possible mechanism for the interaction of other trace metals with Fe transport is discussed. 相似文献
20.
The author studied the effect of different nickel concentrations (0, 0.4, 40 and 80 μM Ni) on the nitrate reductase (NR) activity
of New Zealand spinach ( Tetragonia expansa Murr.) and lettuce ( Lactuca sativa L. cv. Justyna) plants supplied with different nitrogen forms (NO 3
−–N, NH 4
+–N, NH 4NO 3). A low concentration of Ni (0.4 μM) did not cause statistically significant changes of the nitrate reductase activity in
lettuce plants supplied with nitrate nitrogen (NO 3
−–N) or mixed (NH 4NO 3) nitrogen form, but in New Zealand spinach leaves the enzyme activity decreased and increased, respectively. The introduction
of 0.4 μM Ni in the medium containing ammonium ions as a sole source of nitrogen resulted in significantly increased NR activity
in lettuce roots, and did not cause statistically significant changes of the enzyme activity in New Zealand spinach plants.
At a high nickel level (Ni 40 or 80 μM), a significant decrease in the NR activity was observed in New Zealand spinach plants
treated with nitrate or mixed nitrogen form, but it was much more marked in leaves than in roots. An exception was lack of
significant changes of the enzyme activity in spinach leaves when plants were treated with 40 μM Ni and supplied with mixed
nitrogen form, which resulted in the stronger reduction of the enzyme activity in roots than in leaves. The statistically
significant drop in the NR activity was recorded in the aboveground parts of nickel-stressed lettuce plants supplied with
NO 3
−–N or NH 4NO 3. At the same time, there were no statistically significant changes recorded in lettuce roots, except for the drop of the
enzyme activity in the roots of NO 3
−-fed plants grown in the nutrient solution containing 80 μM Ni. An addition of high nickel doses to the nutrient solution
contained ammonium nitrogen (NH 4
+–N) did not affect the NR activity in New Zealand spinach plants and caused a high increase of this enzyme in lettuce organs,
especially in roots. It should be stressed that, independently of nickel dose in New Zealand spinach plants supplied with
ammonium form, NR activity in roots was dramatically higher than that in leaves. Moreover, in New Zealand spinach plants treated
with NH 4
+–N the enzyme activity in roots was even higher than in those supplied with NO 3
−–N. 相似文献
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