ArticlePDF Available

Nickel: The last of the essential micronutrients

Authors:

Abstract

p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"> The knowledge about the role of Ni (Ni) in the nutrition, physiology and metabolism of the majority of crops is limited, whereas is considered to be an essential element for the higher plants starting from the 80’s of the twentieth century. The primary function of Ni in plants is defined in terms of its importance for the hydrolysis of urea; however, Ni may have an importance in other physiological processes, such as nitrogen fixation. Although the deficiencies of Ni in plants are relatively rare events, the positive response of yield and nitrogen use efficiency to applications of Ni are shown for different species. The present work summarizes the data about the essentiality of Ni and its function in plant metabolism as well as its agronomic importance for the crops. </p
Received for publicat ion: 1 December, 2010. Accepted for publication: 2 Febr uary, 2011.
1 Universidad de Ciencias Aplicadas y Ambientales –U.D.C.A. Bogota (Colombia).
2 Department of Agronomy, Agronomy Faculty, Universidad Nacional de Colombia. Bogota (Colombia).
3 Corresponding author: milopez@udca.edu.co.
Agronomía Colombiana 29(1), 49-56, 2011
Nickel: The last of the essential micronutrients
Níquel: el último de los micronutrientes esenciales
Miguel Ángel López1,3 and Stanislav Magnitskiy2
ABSTRACT RESUMEN
e knowledge about the role of Ni (Ni) in the nutrition,
physiology and metabolism of the majority of crops is lim-
ited, whereas is considered to be an essential element for the
higher plants starting from the 80’s of the twentieth century.
e primary function of Ni in plants is dened in terms of its
importa nce for the hydrolysis of urea; however, Ni may have an
importance in other physiological processes, such as nitrogen
xation. A lthough the deciencies of Ni in pla nts are relatively
rare events, the positive response of yield and nitrogen use ef-
ciency to applicat ions of Ni are shown for dierent species. e
present work summarizes the data about the essentiality of Ni
and its function in plant metabolism as well as its agronomic
importance for the crops.
El conocimiento sobre el rol del níquel (Ni) en la nutrición, -
siología y metabol ismo de la mayoría de los cultivos es li mitado;
no obstante, desde los años 80 del sig lo  este elemento se con-
sidera esencia l para las plantas superiores. La función principal
del Ni en las plantas se dene en términos de su importancia
para la hidrólisis de urea, aunque también interviene en otros
procesos siológicos como la jación de nitrógeno. Si bien las
deciencias de Ni en las plantas cultivadas son relativamente
escasas, las aplicaciones de este micronutriente presentan,
en diversas especies, respuestas positivas en el rendimiento
y la eciencia del uso de nitrógeno. El presente trabajo revisa
la esencialidad del Ni y su función en el metabolismo de las
plantas, así como su importa ncia agronómica para los cu ltivos.
Key words: mineral nutrition, essential element, mineral
deciencies, nitrogen cycle.
Palabras clave: nutrición mineral, elemento esencia l, deciencias
minerales, ciclo del nitrógeno.
Introduction
Knowledge about the role of Ni in nutrition, physiology and
metabolism of most crops is currently limited (Bai et al.,
2006). However, the evidence of essentiality of this element
for higher plants is not a new issue, but still goes back to the
70’s of the twentieth century, when a group of researchers
suggested the possible role of Ni in the metabolism of nitro-
gen through its participation in the structure of the enzy me
urease (Dixon et al., 1975). Already in the 80’s Eskew et al.
(1984a), through studies of soybeans, demonstrated the
essential role of Ni in nitrogen metabolism of leguminous
plants, a role that was independent of the form of available
nitrogen (NO3 or NH4+). e evidence generated by this
research suggested the essentiality of Ni for higher plants
(Eskew et al., 198 4b).
e lack of evidence for the role of Ni in non-leguminous
plants was caused by the fact that at that time the studies
about the essentiality were incomplete and, therefore, its
essentiality was not accepted. is gap of knowledge was
supplied by Brown et al. (1987) who established the essential
role of Ni in non-leguminous plants, specically in barley.
ese results together with those obtained previously by
Eskew et al. (1984a) led Brown et al. (1987) to propose a
more support towards the addition of Ni to the group of
micronutrients. Although these studies were, possibly, the
most signicant ones in determining the essentiality of Ni,
there also stood out the studies forwarded by Roach and
Barclay (1946) in plants of potato (Solanum tuberosum),
wheat (Triticum aestivum) and bean (Phaseolus vulgaris)
in England that indicated an increase in plant production
as a result of foliar application of Ni. Additionally, Cataldo
et al. (1978) studied the dynamics and transport of Ni in
soybean plants, while Eskew et al. (1983) founded toxic
levels of urea in the tips of soybean leaves poor in Ni, a
behavior similar to that reported by Walker et al. (1985)
in plant Vignia unguiculata.
e previous studies allowed including Ni within the
group of essential mineral nutrients (Marschner, 2002;
Taiz and Zeiger, 2004; Epstein and Bloom, 2005; Azcon-
50 Agron. Colomb. 29(1) 2011
Bieto and Talón, 2008) and, therefore, it is understood that
plants may not complete the life cycle in the absence of
this nutrient (Arnon and Stout, 1939). Recently, the De-
partment of Agriculture of the USA and the Association
of American Plant Food Control Ocials included Ni as
an essential element for plants, making it possible in the
USA the manufacture and sale of fertilizers containing
Ni (Bai et al., 2006).
Due to the fact that this mineral element is a new one in
the list of essential micronutrients, the objectives of the
present review were to illustrate the current state of re-
search on functions of Ni in plants, in particular, describe
the dynamics of Ni in non-accumulator and accumulator
species, clarify the physiological functions of Ni in plants
as well as symptoms of deciency and toxicity caused by Ni
in plants and identify plant responses to the applications.
Dynamics of nickel in soils and plants
At level of dynamics in soil, Ni is abundant metal in the
earth crust with about 3% of the composition of the earth.
In agricultural soils, typical contents of this element vary
from 3 to 1,000 mg kg-1, however, the soils derived from
basic igneous rocks can contain from 2,000 to 6,000 mg
kg-1 of Ni. Soil pH plays an important role in the avai lability
of Ni, and at pH > 6.7 Ni exists in form of poorly soluble
hydroxides, while at pH < 6.5 increases the presence of
relatively soluble compounds (Brown, 2006).
It is considered that the system of Ni+2 uptake by roots is
similar to that of Cu2+ and Zn2+, a conclusion obtained
aer conrmation of competitive inhibition in absorption
of these three nutrients. When the available concentration
of Ni+2 in the substrate is low (0.5 - 30 mkM), the process
of its absorption by roots is dependent on the expenditure
of ATP, a characteristic that indicates the presence of an
active transport of high anity (Brown, 2006).
Once Ni is absorbed by the root, its movement to the
aboveground parts of plants is closely linked to the for-
mation of organic complexes (Cataldo et al., 1978, 1988;
Bhatia et al., 2005). In general, potential ligands of metals
in plants could be grouped into three classes: oxygen donor
ligands (carboxylates: malate, citrate, malonate, succinate,
and oxalate), sulfur donor ligands (metallothioneins and
phytochelatins), and nitrogen donor ligands (amino ac-
ids) (Baker et al., 2000). In the case of Ni (Ni+2), there was
reported complex formation for its transport in the xylem
with amino acids histidine (Krämer et al., 1996; Brown,
2006) and nicotinamine (Mari et al., 2006) and organic
acids citrate, malate, and malonate (Cataldo et al., 1988;
Robinson et al., 2003; Bhatia et al., 2005), although in the
case of complex with nicotinamine, this one was reported
for the species tolerant or accumulators of Ni (Mari et al.,
2006). At the same time, Homer et al. (1995) suggested that
formation of complexes of Ni in the xylem with molecules
of high molecular weight, such as metallothioneins and
phytochelatins, is an unlikely process.
Complex formation is dependent on pH, such as at low pH
the organic acids are better chelating agents for Ni than
amino acids, whereas at high pH amino acids increase
their capacity to act as ligands (Bhatia et al., 2005). Brown
(2006) indicates that at pH below 6.5 histidine is the most
signicant ligand for Ni, while at pH < 5 citrate is the most
important chelating agent. In oak Quercus ilex, Araujo
et al. (2009) evaluated the eect of four dierent ligands
(histidine, oxalic acid, aspartic and citric acids) present in
the xylem sap on the movement of Ni+2 in the xylem. e
order of anity of ligands towards Ni+2 reported in this
research was: oxalic acid > citric acid > histidine > aspartic
acid. In contrast, the amount of Ni bound to the walls of
the xylem was higher when Ni was present as free cation,
followed by Ni-aspartic acid, Ni-histidine, Ni-citric acid,
and Ni-oxalic acid (Araujo et al., 2009).
Addition of chelating agents to soils with high contents
of Ni may be an eective practice to increase the metal
concentration in soil solution, but have a low eect on in-
creasing of Ni absorption by plants, as showed the study of
Molas and Baran (2004) in barley. is research evaluated
several Ni containing compounds: Ni-citrate, Ni-glutamate,
Ni-EDTA and NiSO4·7H2O and found that the rate of ab-
sorption of Ni by plants arranged from highest to lowest
as NiSO4·7H2O > Ni-citrate > Ni-glutamate > Ni-EDTA.
In Ni non-accumulating species, aer being absorbed and
transported, is used to ensure the functioning of urease,
and, thus, to ensure the hydrolysis of urea to produce
ammonia and carbon dioxide (Marschner, 2002; Taiz
and Zeiger, 2004). Ni in the phloem may be retraslocated
rapidly from the leaves to young tissues, especially during
reproductive growth (Ti n, 1971); this movement is associ-
ated with the formation of complexes with organic acids
and amino acids (Brown, 2006). us, Ni is considered an
element mobile in the phloem (Cataldo et al., 1978; Page
and Feller, 2005), whose mobility is higher than that of
cobalt (Zeller and Feller, 1999). In soybeans, over 70% Ni
present in the leaves could be retranslocated to the seeds
and accumulated mainly in the cotyledons (Tin, 1971;
Cataldo et al., 1978).
51López and Magnitskiy: Nickel: The last of the essential micronutrients
Nickel hyperaccumulator plants
Ni hyperaccumulator species (metallophytes), such as
Stackhousia tryonii, Hybanthus oribundus, laspi caer-
ulescens, Halimione portulacoide, Berkheya coddii, Brassica
juncea, and Typha latifolia are known to accumulate high
concentrations of Ni, among 0.1 and 3.0%, in shoots and
leaves (Ye et al., 1997; Robinson et al., 2003; Bidwell et al.,
2004; Bhatia et al., 2005; Duarte et al., 2006; Mari et al.,
2006; Hsiao et al., 2007). e latex of Sebertia acuminata
(Sapotaceae), a tree native to New Zealand, contains 25.74%
dry weight Ni (Sagner et al., 1998) as well as other cases of
exceptionally high accumulation of Ni in the aboveground
parts of plants are reported; the explanations for Ni hyper-
accumulation are related to the defense role played by high
concentrations of Ni in plant tissues against herbivores and
pathogens (Baker et al., 2000).
It is known that the members of ZIP protein families
(Zinc Regulated Transporters / Iron Regulated Transport-
ers), NRAMP (Natural Resistance Associated Macrophage
Protein), and YSL (Yellow Stripe Like) are involved in the
transport of Ni in dierent organisms. e transforma-
tion of yeasts with ZNT1 or ZNT2 partially conferred Ni
tolerance correlated with the input of Zn, which inhibits
the absorption of Ni. In contrast, transformation with
NRAMP4 conferred sensitivity to Ni in yeasts explained
by a release of Ni from the vacuole (Tejada-Jiménez et al.,
2009). In transgenic plants of Arabidopsis sp., the over-
expression of gene AtIREG2 causes increased tolerance
to high concentrations of Ni. us, it appears that the
physiological function of AtIREG2 may be accumulation
of excess of Ni accompanied by a counter ion (nitrate or
sulphate) in the vacuole to maintain the ionic balance of
cells (Schaaf et al., 2006).
Pianelli et al. (2005) suggested that, in response to elevated
contents of Ni, nicotinamine is translocated from the leaves
of hyperaccumulators to the roots, where it forms com-
plexes with Ni and facilitates its transport to the shoot. In
Arabidopsis sp., overexpression of nicotinamine synthase
confers tolerance to Ni. In addition, the tolerance of plants
to Ni also results from the chelating of Ni in the root with
histidine or organic acids, such as citrate (Tejada-Jiménez
et al., 2009).
Ni hyperaccumulator plants dier from non-accumulators
with the route of transport of this element in the root cor-
tex. e absorption of Ni via the apoplast of the roots of
corn, a non-accumulating plant, ranged from 81.3 to 88.0%,
while that of Leptoplax emarginata, a hyperaccumulator of
Ni, was from 90.6 to 95.5% (Redjala et al., 2010). e root
cell wall in both species had similar anity for the Ni but,
in hyperaccumulator plants, more Ni was absorbed via
the apoplast. is suggests, according to the authors, that
symplastic absorption is not the main factor associated
with hyperaccumulation, and the transport system of Ni
can not be similar in these two species (Redjala et al., 2010).
In hyperaccumulator species, aer absorption and trans-
port via xylem, Ni can be accumulated in vacuoles of leaf
epidermal cells (Krämer et al., 1996; Küpper et al., 2001;
Bidwell et al., 2004; Schaaf et al., 2006), in the cuticle of the
upper epidermis (Robinson et al., 2003) or remain in the
apoplast occupying certain sites in the cell wall (Krämer
et al., 1996; Bidwell et al., 2004). e accumulation of Ni
in the vacuole of epidermal cells is related to the decrease
in the concentrations of K+ and Na+ (Bidwell et al., 2004)
as a likely consequence of a competitive eect between
these cations.
Montargés-Pelletier et al. (2008) reported the carboxylic
acids (citric and malic) as the main responsible agents for
the transfer of Ni in hyperaccumulator plants Alyssum
murale and Leptoplax emarginata. In their research, citrate
was the main ligand of Ni found in stems, whereas in leaves
this function corresponded to malate. Histidine was not
detected in leaves, stems, and roots of plants under study.
In contrast, McNear et al. (2010) founded that, in Alyssum
murale, Ni was in the sap of xylem in a greater proportion
together with histidine, followed by malate and other low
molecular weight molecules. e authors based on their
results adapt a model, in which Ni is transported from
roots to leaves in complexes with histidine and then stored
in the epidermis of leaves and stem in complexes with
malate, other organic acids of low molecular weight and
counter-ions, such as sulfate SO42- (McNear et al., 2010).
Nickel functions in plants: hydrolysis of urea
Ni is chemically related to iron (Fe) and cobalt (Co).
Oxidation state of Ni in biological systems is Ni+2, but it
could also exist as Ni+ and Ni+3 (Marschner, 2002). Ni is a
functional constituent of seven enzymes, six of which are
present in bacteria and animals, while only one, urease
(urea amidohydrolase, EC 3.5.1.5), occurs in plants (Brown,
2006). Constituent participation of Ni in the structure of
urease was rst documented by Dixon et al. (1975) aer its
isolation and description from Canavalia ensiformis. Of the
seven Ni-dependent enzymes two have non-redox func-
tions (urease and glyoxylase) and the remaining ve are
involved in oxidation-reduction reactions (Ni-superoxide
52 Agron. Colomb. 29(1) 2011
dismutase, methyl coenzyme M reductase, carbon mon-
oxide dehydrogenase, acetyl coenzyme A synthase and
hydrogenase) (Brown, 2006).
Metalloenzyme urease is a ubiquitous (everywhere pres-
ent) (Malavolta and Moraes, 2007) enzyme that consists
of six identical spherical subunits, each with two atoms of
Ni (Dixon et al., 1980; Hirai et al., 1993) whose molecular
mass is reported in the range of 473-590 kDa (Fishbein
et al., 1973; Dixon et al., 1980). Within the subunits, the
union of Ni is coordinated by ligands containing N- and
O- (Marschner, 2002).
Although it is considered that Ni is not required for the
synthesis of urease, this element is an essential metal
component in the structure and catalytic function of the
enzyme (Hirai et al., 1993; Marschner, 2002). In soybean
urease, its synthesis is directed by a long chain of RNA
consisting of 3,000 to 3,500 nucleotides and their partici-
pation on the total weight of extractable seed protein is of
the order of 0.2% (Polacco and Sparks, 1982).
e role of urease is to catalyze the hydrolysis of urea
CO(NH2)2 to ammonia (NH3) and carbon dioxide (CO2),
a reaction that occurs mainly in leaves (Marschner, 2002;
Taiz and Zeiger, 2004; Malavolta and Moraes, 2007; Azcon-
Bieto and Talón, 2008). e above statement may indicate
that the functionality of Ni is restricted to those crops,
where nitrogen inputs are derived from urea, however,
this assumption is not correct; the essentiality of Ni is
due to the formation of urea interior of plants as a result
of metabolic pathways common to all plants that include
the catabolism of purines (adenine and guanine), ureides
and protein catabolism of arginine via ornithine cycle and
conversion of canavanine to canaline in certain plants
(Wa lker et al., 1985).
Other functions of nickel in plants
Ni is also involved in symbiotic nitrogen xation through
its role as an active center of hydrogenase, a process
documented in strains of nitrogen-xing bacteria Brady-
rhizobium japonicum, Bradyrhizobium sp. (Lupinus sp.),
Rhizobium tropici, Rhizobium leguminosarum, and Azo-
rhizobium caulinodans (Palacios, 1995). Hydrogenase is an
enzyme responsible for oxidizing the hydrogen produced
by nitrogenase during symbiotic nitrogen xation result-
ing in the production of ATP and, therefore, this enzyme
increases the eciency of symbiotic process, and decreases
the inhibitory activity of hydrogen in the bacteroids (Pala-
cios, 1995; Ruíz-Argueso et al., 2000). us, the low level
of Ni in agricultural soils may limit the activity of hydrog-
enase from R. leguminosarum and, therefore, the eciency
of symbiotic nitrogen xation in legumes (Ruiz-Argueso
et al., 2000; Malavolta and Moraes, 2007).
Zobiole et al. (2010) in Brazil showed that application of
glyphosate can negatively inuence symbiotic nitrogen
xation in soybeans grown in soils with low native con-
centrations of Ni in response to a decrease in the foliar
concentration of this element. In Matricaria chamomilla,
accumulation of chlorogenic acid, an important antioxi-
dant compound, was increased almost fourfold in response
to the application of 120 mkM Ni to the substrate (sand).
It is, therefore, proposed that Ni may have antioxidant
properties of phenolic metabolites (Kovacik et al., 2009).
Being similar to cation of iron, cation of Ni may have bene-
cial functions for the formation of anthocyanins that con-
tain iron or aluminum as structural elements. According
to Aziz et al. (2007), applications of Ni to soil contributed
to accumulation of anthocyanins and avones in plants of
Hibiscus sabdaria when applying 20-25 mg kg-1 Ni.
Deficiencies and toxicities of nickel in plants
Ni deciency in legumes and other dicots causes a decrease
in the activity of enzyme urease, a condition that causes
accumulation of toxic levels of urea and is manifested as
necrosis at the tip of the leaves (Eskew et al., 1983; Walker
et al., 1985; Malavolta and Moraes, 2007). In soybean,
low levels of Ni in soil reduced nodulation (Zobiole et al.,
2010) and seed yield, a phenomenon that is explained by
the involvement of Ni in hydrogenase activity of bacteroids
(Brown, 2006). At the same time, due to the relatively low
requirements of plants in Ni, the events of Ni deciencies
in the eld are few, while the toxicities caused by Ni are
more common (Mengel and Kirkby, 2001).
Decreased urease activity in non-timber species can in-
duce the deciency of nitrogen and aect the contents of
amino acid amides (asparagine and glutamine) and inter-
mediates of urea cycle (arginine, ornithine, and citrulline)
(Bai et al., 2006). In grasses, on the other hand, deciency
symptoms include intervenal chlorosis and necrotic spots
on young leaves. In general, urea accumulation in the tip
of the leaves (necrosis) of both monocotyledonous and
dicotyledonous plants is diagnostically symptom of Ni
deciency (Brown, 2006).
One of the best documented cases of the deciency of Ni
is the perennial timber pecan Carya illinoinensis. In this
53López and Magnitskiy: Nickel: The last of the essential micronutrients
species, Ni deciency is known as “mouse ear” or “little
leaf disorder” (Malavolta and Moraes, 2005; Bai et al., 2006)
and was rst proved as a deciency of Ni in 2004 by Wood
and colleagues (Malavolta and Moraes, 2007). However, the
symptom is reported in the United States since 1918 and is
characterized by the presence of round dark spots on t he tips
of new leaves and curving of leaf blade to make the appear-
ance of the ear of a mouse (Malavolta and Moraes, 2005).
In pecan, Ni deciency aects nitrogen metabolism via
ureide catabolism, amino acid metabolism and ornithine
cycle intermediates and metabolism of carbon through the
accumulation of lactic acid and oxalic acids that accumu-
late on the edges of leaf blade and would also be linked to
necrosis of the tips of the leaves (Bai et al., 2006).
Ni deciency in pecan could be corrected by foliar applica-
tion of Ni; however, the dose of Ni reported in the literature
is variable. us, Brown (2006) indicates that a dose of Ni
equal to 100 mg L-1 is sucient to correct the deciency,
while Malavolta and Moraes (2005) recommended spraying
a solution of 0.8 g L-1 Ni mixed with a dose of 4.8 g L-1 urea.
Malavolta and Moraes (2005) and Brown (2006) indi-
cated that the main factors that favor the development
of Ni deficiency are: a) excess of Cu and Zn that com-
petitively inhibits the absorption of Ni by roots, b) soil
pH > 6.5 (formation of low soluble hydroxides and Ni
oxides), c) soils with high contents of Fe, Mn, Ca, or Mg,
d) excessive doses of nitrogen or excessive liming, e)
high levels of soil phosphorus that favor the formation
of phosphates of Ni and decrease the absorption of Ni by
plants; f) inhibition of urease activity by accumulation
of Cu in plants.
In soils developed over ultrabasic rocks, high levels of Ni,
such as exceeding 250 mg kg-1 soil, may lead to Ni toxicity
in non-accumulator plants (Mengel and Kirkby, 2001).
e symptoms of Ni toxicity may resemble the symptoms
of iron deciency due to a reduced absorption of iron in
soils high in Ni (Mengel and Kirkby, 2001). e critical level
of Ni in leaves varies according to species, but generally a
suitable range is considered between 1 and 10 mg kg-1 dry
matter basis (Marschner, 2002), higher than 25 mg kg-1 lead
to Ni toxicity in non-accumulator species (Malavolta and
Moraes, 2007) through distortions in the growth of root
system and leaf buds (Brown, 2006). In wheat, the addition
of 50 and 100 mkM Ni to the growth substrate resulted
in decrease of fresh weight of shoot, the nitrate content, a
reduction in the activity of nitrate and nitrite reductase,
40 and 80% less, respectively (Gajewska and Skłodowska,
2009). In contrast, an increase in ammonium content, pro-
line concentration, and the activity of NADH-glutamate
synthase in plants treated with toxic levels of Ni was re-
ported (Gajewska and Skłodowska, 2009). e toxicity of
Ni in plants may be alleviated by liming or application of
phosphate fertilizers that reduce availability of Ni to the
plants (Mengel and Kirkby, 2001).
Plant yield response to applications of nickel
e response of plants to applications of Ni is wide and
includes eects on nitrogen xation, seed germination and
disease suppression. However, a much higher eect could
be seen when nitrogen is provided in the form of urea or
symbiotically xed (Brown, 2006).
e rst evidence of the y ield response to Ni was document-
ed by Roach and Barclay (1946), who reported a signicant
increase in crop yields of potato (Solanum tuberosum),
wheat (Triticum aestivum) and bean (Phaseolus vulgaris)
as a result of foliar application of Ni from dilute solutions.
In soybean, it was found that the addition of 40 g ha-1
Ni increases nodulation and crop yield (Malavolta and
Moraes, 2007), an eect attributed to the proper function-
ing of the symbiosis between soybean and Rhizobium sp.
(Brown, 2006). In parsley (Petroselinum crispum) growing
in plastic containers with clay, the addition of 50 mg kg-1
soil Ni from NiSO4 source increases the yield and qual-
ity of leaves, reduces the accumulation of NO3- and NH4+
and increases the accumulation of essential oil aroma
constituents (Atta-Aly, 1999). On the other hand, in Brazil
the application of 0.03 mg L-1 Ni in nutrient solution of
umbu seedlings (Spondias tuberosa) increased dry mass
production by 81.52% compared to untreated control
(Caires et al., 2007).
In rose of Jamaica (Hibiscus sabdaria), Aziz et al. (2007)
found that a joint application of cobalt and Ni in doses of
20 and 25 mg kg-1 soil, respectively, increases the total mass
of the plants, branch number and dry weight and fresh
weight of owers. In addition, these applications promoted
an increase in the concentration of N, P, K, Co, Ni, Mn,
Zn, and Cu, both in leaves and owers of the plants (Aziz
et al., 2007).
Gad et al. (2007) in tomato (Lycopersicon esculentum)
grown in sand found that the addition of 30 mg kg-1 sand
Ni signicantly increased the total mass of the plant,
54 Agron. Colomb. 29(1) 2011
number of branches, leaf area, root length, contents of
auxins and gibberellins. Similarly, the addition of Ni in
the aforementioned doses improved fruit quality variables
such as size, fresh weight, diameter, dry weight, contents
of vitamin C, total soluble solids, and soluble sugars. In
addition, the application of Ni caused the decrease in the
contents of NO3- and NH4- as well as acidity, favorable
characteristics for consumer health (Gad et al., 2007).
Finally, it has been shown a benecial eect of Ni in the
management of agents causing fungal diseases, such as
rust of cereal crops (Brown, 2006; Malavolta and Moraes,
2007). e benecial eect is attributed to the alleged role
of this element in reactions involving enzymes, such as
superoxide dismutase, changes in nitrogen metabolism
due to the contribution of Ni (Brown, 2006) and the
possible toxicity of Ni to the pathogen (Malavolta and
Moraes, 2007).
Changes in nitrogen metabolism may involve the decrease
in amount of free amino acids, a substrate used by most
pathogens for growth and proliferation (Strengbom et
al., 2002). e accumulation of free amino acids, such
as valine, leucine, isoleucine, tyrosine, tryptophan, and
arginine, in response to Ni deciency was reported by
Bai et al. (2006). In practical terms, the eciency of foliar
sprays of urea in dierent crops can be improved by their
joint application with Ni (NiSO4) at levels not exceeding
40 g ha-1 of Ni for crop cycle.
e application of Ni may have positive eects on nitrogen
use eciency in crops that extract high content of this
mineral nutrient from soil and where nitrogen fertilizers
are applied using urea as the main source, such as in case
of rice. However, such eects could only be veried by
conducting a research involving Ni as a case study.
Conclusions
e current state of research dedicated to physiology of Ni
in plants illustrates the essentiality of this micronutrient for
plants, in par ticular, its importance for the processes related
to the metabolism of nitrogen. e primary function of Ni
is dened in terms of its importance for the hydrolisis of
urea; however Ni may have an importance in other physi-
ological processes, such as nitrogen xation and synthesis
of anthocyanins. Although the deciencies of Ni in plants
are relatively rare events, the positive response of crop yield
and nitrogen use eciency to applications of Ni are shown
for dierent species.
Literature cited
Araujo, G.C.L ., S.G. Lemos and C. Naba is. 2009. Ni sorption cap acity
of ground xylem of Quercus ilex trees and eects of selected
ligands present in the x ylem sap. J. Plant Physiol. 166, 270-277.
Arnon, D.I. and P.R. Stout. 1939. e essentia lity of certa in elements
in minute qua ntity for plants with special reference to copper.
Plant Physiol. 14, 371-375.
Atta-Aly, M.A. 1999. Eect of Ni addition on the yield and quality
of parsley leaves. Scientia Hort. 82, 9-24.
Azcon-Bieto, J. and M. Talón. 2008. Fundamentos de siología
vegetal. 2nd ed. Mc Graw Hill Interamericana, Barcelona,
Spain. pp. 83-97.
Aziz , E., N. Gad and N. Badra n. 2007. Eect of cobalt and Ni on pla nt
growth, yield and avonoids content of Hibiscus sabdaria L.
Aust. J. Basic Appl. Sci. 1, 73-78.
Bai, C., C. Reilly and B.W. Wood. 2006. Ni deciency disrupts me-
tabolism of ureides, amino acids, and organic acids of young
pecan foliage. Plant Physiol. 140, 433-443.
Baker, A.J.M., S.P. McGrath, R.D. Reeves and J.A.C. Smith. 2000.
Metal hyperaccumulator plants: A review of the ecology and
physiology of a biochemical resource for phytoremediation of
metal-pol luted soils. pp. 85-107. E n: Terry, N., G. Bañuelos a nd
J. Vangronsveld (eds.). Phytoremediation of conta minated soil
and water. Boca Raton, FL.
Bidwell, S.D., S.A. Crawford, I.E. Woodrow, S. Knudsen and A.T.
Marsha ll. 2004. Sub -cellular loca lization of Ni in t he hyperac-
cu mu lator, Hybanthus oribundus (Lindley) F. Muell. Plant
Cell Environ. 27, 705-716.
Bhatia, N.P., K.B. Walsh and A.J.M. Baker. 2005. Detection and
quantication of ligands involved in Ni detoxication in a
herbaceous Ni hyperaccumulator Stackhousia tryonii B ailey.
J. Exp. Bot. 56, 1343-1349.
Brown, P.H., R.M. Welch and E.E. Cary. 1987. Ni: A micronutrient
essential for higher plants. Plant Physiol. 85, 801-803.
Br o w n , P. H . 2006. Ni. pp. 329-350. En: Barker, A.V. and D.J. Pil-
beam (eds.). Handbook of plant nutrition. CRC Press, Boca
Raton, FL.
Caíres, O.S., E.V. de Oliveira, J.G. de Carvalho and C.R. Fonseca.
2007. Adição de níquel na solução nutritiva para o cultivo de
mudas de umbuzeiro. Rev. Bras. Ci. Solo. 31, 485-490.
Cataldo, DA., T.R. Garland, R.E. Wildung and H. Drucker, 1978.
Ni in plants. II. Distribution and chemical form in soybean
plants. Plant Physiol. 62, 566-570.
Cataldo, DA., T.R. Mc Fadden, T.R. Garl and and R.E. Wi ldung. 1988.
Organic constituents and complexation of Ni (II), cadmium
(II) and plutonium (IV) in soybean xylem exudates. Plant
Physiol. 56, 734-739.
Dixon, N.E., C. Gazzola, R.L. Blakeley and R. Zerner. 1975. Jack
bean urease. A metalloenzyme. A simple biological role for
Ni. J. Am. Chem. Soc. 97, 4131-4133.
Dixon, N.E., R.L. Blakeley and R. Zerner. 1980. Jack-Bean urease
(EC 3.5.1.5.3.). III. e involvement of active site Ni ion in
inhibition by b-mercaptoethanol and phosphoramidate, and
uoride. Can. J. Biochem. 58, 481-488.
55López and Magnitskiy: Nickel: The last of the essential micronutrients
Duarte, B., M. Delgado and I. Caçador. 2007. e role of citric acid
in cadmium and Ni uptake and translocation, in Halimione
portulacoides. Chemosphere 69, 836-840.
Epstein, E. and A. Bloom. 2005. Mineral nutrition of plant: prin-
ciples and perspectives. Sinauer Associates, Inc. Publishers.
Sunderland, MA.
Eskew, D.L., R.M. Welch and E.E. Cary. 1983. Ni an essential mi-
cronutrient for legumes and possibly all higher plants. Sci.
222, 621-623.
Eskew, D.L., R.M. Welch and E.E Cary. 1984a. A simple plant nu-
trient solution purication method for eective removal of
trace metals using controlled pore glass-8 hydroxyquinoline
chelation colum n chromatography. Plant Physiol. 76, 103-105.
Eskew, D.L., R. M. Welch and W.A. Norvell. 1984 b. Ni in higher plants:
fur ther evidence for an es sential role. Plant Physiol. 76, 691-693.
Fishbein, W.N., K. Nagarajan and W. Scurzi. 1973. Urease catalysis
and str ucture. IX. e ha lf-unt and hempolymers of jack be an
urease. J. Biol. Chem. 248, 7870-7877.
Gad, N., M.H. El-Sherif and N.H.M. El-Gereendly. 2007. Inuence
of Ni on some physiological aspects of tomato plants. Aust. J.
Basic Appl. Sci. 1, 286-293.
Gajewska, E. and M. Skłodowska. 2009. Ni-induced changes in
nitrogen metabolism in wheat shoots. J. Plant Physiol. 166,
1034-104 4.
Hirai, M., R. Kawai-Hirai, T. Hirai and T. Ueki. 1993. Structural
change of jack bean urease induced by addition of surfactants
studied w ith synchrotron-rad iation small-ang le X-r ay scatter-
ing. Eur. J. Biochem. 215, 55-61.
Homer, F.A., R.D. Reeves and R.R. Brooks. 1995. e possible
involvement of amino acids in Ni chelation in some Ni-accu-
mulating plants. Curr. Topics Phytochem. 14, 31-37.
Hsiao, K.H., P.H. Kao and Z.Y. Hseu. 2007. Eects of chelators on
chromium a nd Ni uptake by Brassica junc ea on serpentine m ine
tailings for phytoextraction. J. Hazard. Materials 148, 366-376.
Kovácik, J., B. K lejdus and M. Backor. 2009. Phenolic met abolism of
Matricaria chamomilla plants exposed to Ni. J. Plant Physiol.
166 , 1460 -1464 .
Krämer, U., J.D. Cotter-Howells, J.M. Charnock, A.J.M. Baker and
J.A.C. Smith. 1996. Free histidine as a metal chelator in plants
that accumulate Ni. Nature 379, 635-638.
Küpper, H., E. Lombi, F.J. Zhao, G. Wiesha mmer and S.P. McGrath.
2001. Cellular compartmentation of Ni in the hyperaccu-
mulators Alyssum lesbiacum, Alyssum bertolonii and laspi
goesingense. J. Experim. Bot. 52, 2291-2300.
Malavolta, E. and M.F. Moraes. 2005. Niquel: “Orelha de raton”.
Informações Agronômicas 112, 2.
Malavolta, E. and M.F. Moraes. 2007. Ni – from toxic a nutrient
essential. Better crops with plant food 91, 26-27.
Marschner, H. 2002. Mineral nutrition of higher plants. 2nd ed.,
Academic Press, London, 889 p.
Mari, S., D. Gendre, K. Pia nelli, L. Ouerda ne, R. Lobinsk i, J.F. Briat,
M. Lebrun and P. Czernic. 2006. Root-to-shoot long-distance
circulation of nicotianamine and nicotianamine–Ni chelates
in the metal hyperaccumulator laspi caerulescens. J. Exp.
Bot. 57, 4111-4122.
McNear, D.H., R.L. Chaney and D.L. Sparks. 2010. e hyperac-
cumulator Alyssum murale uses complexation with nitrogen
and oxygen donor ligands for Ni transport and storage. Phy-
tochem. 71, 188-200.
Mengel y Kirkby, 2001. Principles of plant nutrition. 5th ed., IPI,
Bern, 687 p.
Molas, J. and S. Baran. 2004. Relationship between the chemical
form of Ni applied to the soil and its uptake and toxicity to
barley plants (Hordeum vulgare L.). Geoderma 122, 247-255.
Montargés-Pelletier, E., V. Chardot, G. Echevarria, L.J. Michot, A.
Bauer and J.L. Morel. 2008. Identication of Ni chelators in
three hy peraccumulat ing plants: An X-ray spect roscopic study.
Phytochem. 69, 1695-1709.
Page, V. and U. Feller. 2005. Selective t ransport of zinc, manganese,
Ni, cobalt and cadmium in the root system and transfer to t he
leaves in young wheat plants. Annals Bot. 96, 425-434.
Palacios , J.M. 1995. Sistema de oxidación de h idrogeno de Rhizobium
leguminosarum: control de la expresión génica por NiFe y
FnRn. En : Universidad Politéc nica de Madrid. htt p://wwwedu-
micro.usal.es/sen/Palacios.html, consulta: mayo de 2009.
Pianelli, K., S. Mari, L. Marques, M. Lebrun and P. Czernic. 2005.
Nicotianamine over-accumulation confers resistance to Ni in
Arabidopsis thaliana. Transg. Res. 14, 739-748.
Polacco, J.C. and R.B. Sparks. 1982. Patterns of urease synthesis in
developing soybeans. Plant Physiol. 70, 189-194.
Redjala, T., T. Sterckeman, S. Skiker and G. Echevarria. 2010. Con-
tribution of apoplast and symplast to short term Ni uptake by
maize and Leptoplax emarginata roots. Environ. Exper. Bot.
68, 99-106.
Roach, W.A. and C. Barclay. 1946. Ni and multiple trace-element
deciencies in agricultural crops. Nature 157, 696.
Robinson, B.H., E . Lombi, F.J. Zhao and S.P. McGrath. 2003. Uptak e
and dist ribution of Ni and other meta ls in the hyperac cumula-
tor Berkheya coddii. New Phytol. 158, 279-285.
Ruíz-Argueso, T., J. Imperial and J.M. Palácios. 2000. Prokaryotic
nitrogen  xation. pp. 489-507. En: Triplett, E .W. (ed.). Horizon
Scientic Press, Wymondham, U.K.
Sagner, S., R. K neer, G. Wanner, J.P. Cosson, B. Deus -Neuman n and
M.H. Zen k. 1998. Hypera ccumulation, complex ation and dis-
tribution of Ni i n Sebertia acuminata. Phytochem. 41, 339-347.
Schaa f, G., A. Honsbein, A.R. Me da, S. Kirchner t, D. Wipf and N. von
Wiren. 2006. AtIREG2 encodes a tonoplast transport protein
involved in iron-dependent Ni detoxication in Arabidopsis
thaliana roots. J. Biol. Chem. 281, 25532-25540.
Strengbom, J., A. Nord in, T. Näsholm and T. Ericson. 2 002. Parasitic
fungus mediates change in nitrogen-exposed boreal forest
vegetation. J. Ecol. 90, 61-67.
Taiz, L. and E. Zeiger. 2004. Plant physiology. 3th ed. Sunderland:
Sinauer Associates. 723 p.
Tejada-Jiménez, M., A. Galván, E. Fernández and Á. Llamas. 2009.
Homeostasis of t he micronutrients Ni, Mo and Cl w ith specic
biochemical functions. Curr. Opinion Plant Biol. 12, 358-363.
Tin, L.O. 1971. Translocation of Ni in xylem exudates of plants.
Plant Physiol. 48, 273-277.
56 Agron. Colomb. 29(1) 2011
Walker, CD., R.D. Graham, J.T. Madison, E. E. Cary and R .M. Welch.
1985. Eects of Ni deciency on some nitrogen metabolites in
cowp eas (Vigna unguiculata L. Walp.). Plant Physiol. 79, 474-479.
Ye, Z.H., A.J.M. Baker, M.H. Wong and A.J. Willis. 1997. Copper
and Ni uptake, accumulation and tolerance in Typha latifolia
with a nd without iron plaque on the root sur face. New Phytol.
136, 481-488.
Zeller, S. and U. Feller. 1999. Long-distance transport of cobalt and
Ni in maturing wheat. Europ. J. Agron. 10, 91-98.
Zobiole, L.H .S., R.S. Ol iveira, R.J. Kremer, J. Consta ntin, T. Yamada, C .
Castro, F.A. Ol iveira and A. Oliveira. 2010. Eect of gly phosate
on symbiotic N2 xation and Ni concentration in glyphosate-
resistant soybeans. Appl. Soil Ecol. 44, 176-180.
... Ni, a component of the plant, soil, and aquatic environment, is an essential micronutrient in low concentrations, which is required for plants, such as cotton (Gossypium hirsutum L.), wheat (Triticum aestivum L.), potato (Solanum tuberosum L.), tomato (Solanum Lycopersicon L.), and other plant species, to complete their growth cycles [11]. Ni is a vital component of urease and is also a constituent of several metalloenzymes, such as Ni-Fe hydrogenase, methyl-coenzyme M reductase, acetyl coenzyme-A synthase, RNase-A, and superoxide dismutase [12]. Ni toxicity decreases the nitrogen concentration, inhibits nitrate uptake, and negatively influences nitrogen assimilation-related enzymes. ...
Article
Full-text available
The excessive use of nickel (Ni) in manufacturing and various industries has made Ni a serious pollutant in the past few decades. As a micronutrient, Ni is crucial for plant growth at low concentrations, but at higher concentrations, it can hamper growth. We evaluated the effects of Ni concentrations on nitrate (NO3−) and ammonium (NH4+) concentrations, and nitrogen metabolism enzyme activity in rice seedlings grown in hydroponic systems, using different Ni concentrations. A Ni concentration of 200 μM significantly decreased the NO3− concentration in rice leaves, as well as the activities of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthetase (GOGAT), respectively, when compared to the control. By contrast, the NH4+ concentration and glutamate dehydrogenase (GDH) activity both increased markedly by 48% and 46%, respectively, compared with the control. Furthermore, the activity of most active aminotransferases, including glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT), was inhibited by 48% and 36%, respectively, in comparison with the control. The results indicate that Ni toxicity causes the enzymes involved in N assimilation to desynchronize, ultimately negatively impacting the overall plant growth.
... Reduced hydrogenase activity in symbiotic Rhizobium leguminosarum affects the symbiotic N 2 fixation is also reported due to nickeldeficiency (Ureta, 2005;Zobiole et al., 2009). Nickel in stress amount augments the growth and yield of plants and vital for the biosynthesis of anthocyanins (Ragsdale, 1998;Lopez and Magnitskiy, 2011). It can persuade plant resistance to disease through the controlling of the creation of secondary plant metabolites resulting in increased productivity (Wood and Reilly, 2007). ...
Article
Full-text available
Nickel pollutant, one of the important widespread heavy metal pollutants starts from natural as well as anthropogenic sources. At present, it is a fact that nickel is an essential element vital for the healthy growth of plants. It plays a crucial responsibility for the activities of certain enzymes, for substantiating proper redox state of a cell and many other physiological, biochemical and growth responses. The use of nickel in modern technology is gradually increasing that result in hastening consumption of nickel-containing product. Nickel compounds arrive in the environment during its manufacturing as well as its use. Their rapid accumulation in different locations of the earth is responsible for widespread nickel pollution. This review presents an analysis of the existing situation related to essentiality, effect and mechanism of nickel toxicity in plants. The investigation of the current scenario is extremely crucial for the realization of the extent of the crisis linked to nickel as an environmental toxicant.
... Copper and nickel are essential micronutrient for plants (López and Magnitski, 2011) but becomes toxic above a certain threshold (McBride, 1994;Adriano, 2001). One useful agent in reducing metal bioavailability in acidic contaminated soils is lime (Pardo et al., 2018), which acts either by forming new solid phases (through metal precipitation or co-precipitation) or by promoting metal adsorption (McBride, 1994;Ma et al., 2006). ...
... Nickel is a component of urease that metabolizes urea nitrogen in plants to useable ammonia within the plant. The shortage of Ni in plants are infrequent events, the positive response of yield and nitrogen use efficiency to applications of Ni are shown for different species (Lopez & Magnitski, 2011). In higher concentrations, Ni is toxic and has a negative effect on many physiological and biochemical processes, such as photosynthesis, transpiration, and mineral nutrition (Shahzad et al., 2018). ...
Article
Heavy metals (HMs) are among the main environmental pollutants that can enter the soil, water bodies, and the atmosphere as a result of natural processes (weathering of rocks, volcanic activity), and also as a result of human activities (mining, metallurgical and chemical industries, transport, application of mineral fertilizers). Plants counteract the HMs stresses through morphological and physiological adaptations, which are imparted through well‐coordinated molecular mechanisms. New approaches, which include transcriptomics, genomics, proteomics, and metabolomics analyses, have opened the paths to understand such complex networks. This review sheds light on molecular mechanisms included in plant adaptive and defense responses during metal stress. It is focused on the entry of HMs into plants, its transport and accumulation, effects on the main physiological processes, gene expressions included in plant adaptive and defense responses during HM stress. Analysis of new data allowed the authors to conclude that the most important mechanism of HM tolerance is extracellular and intracellular HM sequestration. Organic anions (malate, oxalate, etc.) provide extracellular sequestration of HM ions. Intracellular HM sequestration depends not only on a direct binding mechanism with different polymers (pectin, lignin, cellulose, hemicellulose, etc.) or organic anions but also on the action of cellular receptors and transmembrane transporters. We focused on the functioning chloroplasts, mitochondria, and the Golgi complex under HM stress. The currently known molecular mechanisms of plant tolerance to the toxic effects of HMs are analyzed.
... Nickel, a lustrous, silvery white-hard metal, is present all over the world in different soil types with various oxidation states (López and Magnitski 2011;He et al. 2012;Tsadilas et al. 2019). Nowadays, Ni pollution is a serious concern all over the world because its concentration has increased considerably, exceeding the permissible limit in the soil (Poonkothai and Vijayavathi 2012;Sreekanth et al. 2013;Emamverdian et al. 2015). ...
Article
Full-text available
Nickel (Ni), an essential micronutrient and a prime component of the plant enzyme urease, has an indispensable role in plants. Triacontanol (TRIA) is a conspicuous plant growth regulator in agriculture, which proved advantageous in enhancing the overall production of plants. Therefore, an experiment was laid down to understand the effects of Ni toxicity on the menthol mint (Mentha arvensis L.) and its mitigation by exogenously applied TRIA. The different treatments applied to the plants were 0 (control), TRIA (10 −6 M), Ni (60 mg kg −1), Ni (80 mg kg −1), TRIA (10 −6 M) + Ni (60 mg kg −1), and TRIA (10 −6 M) + Ni (80 mg kg −1). This work was evaluated on the basis of various growth, biochemical, physiological, yield and quality parameters. Nickel applied at 80 mg kg −1 of soil exhibited maximum inhibition in the parameters studied. Application of TRIA improved all the growth parameters such as plant height, fresh and dry weights as well as herbage yield under non stress and stressed conditions. The levels of carbonic anhydrase (CA) activity, photosynthetic parameters (chlorophyll and carotenoids), and chlorophyll fluorescence of the plants were also stimulated by TRIA under Ni stress. Exogenous TRIA also displayed positive effects on the cellular antioxidant defense mechanism of Ni-affected plants as it increased the levels of proline (PRO), electrolytic leakage (EL), and activities of antioxidant enzymes, viz. superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX), therefore, restrained the triggering of the oxidative burst (reactive oxygen species) in the plant cells. Moreover, TRIA improved the overall production (in terms of yield and content) of EO in the plants and maintained the leaf ultrastructure and root morphology under Ni treatment. GC-MS analysis revealed that TRIA upregulated the level of menthone and menthyl acetate over their respective controls and under Ni-stressed condition.
Article
The potential use of zero-valent iron (ZVI) nanoparticles (i.e., <100 nm in size) for the remediation of metal-contaminated soils has sparked a flurry of research in recent years. However, even reading a large number of these papers cannot completely dispel doubts that ZVI nanoparticles are indeed superior to ZVI microparticles (e.g., iron powder or grit) in immobilizing metals and metalloids in soils. Our primary objective was to compare the adsorption properties of iron-based amendments (ZVI micro- and nanoparticles, natural iron oxides) supplied in a biochar matrix in soils contaminated by a copper-nickel (Cu/Ni) smelter on the Kola Peninsula in Russia. The following iron-containing amendments were added to the studied soil: a composite of ZVI nanoparticles and biochar (synthesized by pyrolysis of iron-impregnated biochar), a mixture of iron powder (i.e., ZVI microparticles) with biochar, and a mixture of iron oxides (from natural ferromanganese nodules) with biochar. Perennial ryegrass (Lolium perenne L.) was grown in pots on untreated and amended soils for 21 days under laboratory conditions. In our time-limited study, ZVI nanoparticles did not prove superior to ZVI microparticles or natural iron oxides at immobilizing metals in copper- and nickel-contaminated soil. In other words, ZVI particles size was irrelevant under the experimental setup of this study in its effects on exchangeable metal concentrations, foliar elemental concentrations, and plant growth.
Article
Full-text available
Lime is one of the effective agents for reducing the phytoavailability of metals in contaminated acidic soils. However, previous studies have shown that lime alone cannot reduce metal phytotoxicity to the desired extent in such soils. The goal of this study was to evaluate the effect of different amendment combinations (lime with and without Feand/or Mn-based amendments) on plant growth. A sample of Histosol (0-5 cm) was collected around a Cu/Ni smelter near Monchegorsk, Murmansk region, exhibiting total Cu and Ni concentrations in the soil of 6418 and 2293 mg kg-1, respectively. Likewise, a sample of forest litter (0-15 cm) was collected around a Cu smelter near Revda, Sverdlovsk region, exhibiting total Cu concentration in the soil of 5704 mg kg-1. Fe-Mn oxides were sourced from ferromanganese nodules in the Gulf of Finland, and iron powder was used as a precursor for iron oxides. Perennial ryegrass was grown in pots for 21 days under controlled laboratory conditions. Two dolomite doses were tested: 5% w/w (giving a soil pH of 6.5) and 20% w/w (giving a soil pH of 7.4). Over-liming stunted plant growth; therefore, the dolomite dose was set at 5% in the further experiments of the study. Importantly, the addition of 0.5% and 1% of Fe-Mn-oxides or iron powder did not improve the efficacy of the lime amendment in promoting plant growth in the soils. Therefore, the issue of reducing plant exposure to metals remained unresolved in the soils under study.
Article
Full-text available
Nickel toxicity in agricultural crops is one of the most common problems in recent years. However, few studies have been conducted on the effect of iron oxides on the reduction of nickel toxicity in crops. The goals of this research were to investigate the effects of non-stabilized and Na carboxymethylcellulose (Na-CMC)-stabilized hematite on mobility reduction and phytoavailability of nickel and to study their effects on some agronomic traits, concentrations of phosphorus, potassium, iron, zinc and nickel in maize. For this purpose, a factorial experiment was conducted using a completely randomized design with three replications. The experimental factors were types and dosages of adsorbents; two types of adsorbents including non-stabilized (H) and Na-CMC-stabilized hematite (H-CMC) at four levels (0, 0.25, 0.5 and 1%) and different levels of soil total Ni (25, 75, 125, 175 and 325 mg kg-1). The results showed that with increasing total soil nickel concentration, shoot height, shoot and root dry weight and concentrations of potassium, phosphorus, iron and zinc in the shoot of maize were decreased and nickel concentration increased. At the contaminated level of 325 mg/kg nickel, concentrations of potassium, phosphorus, iron and zinc were decreased about 43.56, 47.98, 73.79 and 86.03%, respectively, and shoot height and dry weight were decreased about 36.86 and 42.56% respectively as compared to control treatment. The results also showed that the application of adsorbents in soil increased the concentration of K, P, Fe and Zn and decreased the concentration of nickel in maize. By applying 0.5% H-CMC, the concentration of nickel in the shoot and root of maize decreased by 52.61 and 46.84% respectively, followed by the concentration of potassium, phosphorus, iron and zinc in the shoot increased about 20.55, 18.68, 61.66 and 48.81% respectively, as compared to control treatment.
Chapter
Elements essentially required for the proper functioning of plants are termed as “essential nutrients” that are classified into macro (H, O, C, P, K, N, Ca, Mg, S) and micro (B, Fe, Cu, Mn, Zn, Ni, Mo, Cl) nutrients. Micronutrients though required in minute quantity are an integral part of plant nutrition, and their absence from the system significantly affects plant growth and biochemical functioning. Metallic micronutrient availability in soil being dependent upon soil pH and redox potential has become an issue for alkaline soils. In general, all micronutrients are bioavailable in acidic to neutral soil pH except Mo. Thus, making the nonsignificant supply of these nutrients in alkaline soil a constraint for sustainable agriculture. Besides soil chemical properties, soil biota and rhizosphere root chemistry and plant symbiotic associations also affect micronutrient solubilization and uptake by plants. Modification of rhizosphere chemistry, the introduction of mycorrhizal association and biofertilizers can be an option for increasing bioavailability of these nutrients in alkaline soils. Using biofertilizers and screening, enrichment and incorporation of Fe, Zn, Cu, and Mn solubilizing, and S reducing bacteria are only useful if we can sustain proper microbial count per gram of soil. Application of different inorganic and organic amendments, fertigation of synthetic nutrient formulation, and foliar application of micronutrient products are acceptable and economical options for tackling this issue in alkaline soils. This chapter is an effort to summarize all issues associated with the availability of micronutrients in alkaline soils and possible options for enhancement of bioavailable fraction, uptake and assimilation of these nutrients by various crop plants.
Article
Soil management using fertilizers can modify soil chemical, biochemical and biological properties, including the concentration of trace-elements as cadmium (Cd), chromium (Cd) and nickel (Ni). Bacterial isolates from Cd, Cr, and Ni-contaminated soil were evaluated for some characteristics for their use in bioremediation. Isolates (592) were obtained from soil samples (19) of three areas used in three maize cultivation systems: no-tillage and conventional tillage with the application of mineral fertilizers; minimum tillage with the application of sewage sludge. Four isolates were resistant to Cr 3þ (3.06 mmol dm À 3) and Cd 2þ (2.92 mmol dm À 3). One isolate was resistant to the three metals at 0.95 mmol dm À 3. All isolates developed in a medium of Cd 2þ , Cr 3þ and Ni 2þ at 0.5 mmol dm À 3 , and removed Cd 2þ (17-33%) and Cr 6þ (60-70%). They were identified by sequencing of the gene 16S rRNA, as bacteria of the genera Paenibacillus, Burkholderia, Ensifer, and two Cupriavidus. One of the Cupriavidus isolate was able to remove 60% of Cr6+ from the culture medium and showed high indole acetic acid production capacity. We evaluated it in a microbe-plant system that could potentially be deployed in bioremediation by removing toxic metals from contaminated soil.
Article
Full-text available
In this work the influence of four different ligands present in the xylem sap of Quercus ilex (histidine, citric, oxalic and aspartic acids) on Ni(II) adsorption by xylem was investigated. Grinded xylem was trapped in acrylic columns and solutions of Ni(II), in the absence and presence of the four ligands prepared in KNO(3) 0.1molL(-1) at pH 5.5, were percolated through the column. Aliquots of solutions were recovered in the column end for Ni determination by graphite furnace atomic absorption spectrometry (GFAAS). The experimental data to describe Ni sorption by xylem in both the presence and absence of ligands was better explained by the Freundlich isotherm model. The decreasing affinity order of ligands for Ni was: oxalic acid>citric acid>histidine>aspartic acid. On the other hand, the Ni(II) adsorption by xylem increased following the inverse sequence of ligands. Potentiometric titrations of acidic groups were carried out to elucidate the sorption site groups available in Q. ilex xylem. The potentiometric titration has shown three sorption sites: pK(a) 2.6 (57.7% of the sorption sites), related to monobasic aliphatic carboxylic acids or nitrogen aromatic bases, pK(a) 8.1 (9.6%) and pK(a) 9.9 (32.7%), related to phenolic groups.
Article
Full-text available
Com o objetivo de avaliar a influência da adição de Ni na solução nutritiva de Hoagland & Arnon sobre o crescimento e a nutrição mineral de mudas de umbuzeiro, realizou-se este trabalho. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições e seis doses de Ni (0; 0,0005; 0,05; 0,1; 0,5 e 1,0 mmol L-1). Observou-se que o Ni, em pequenas concentrações, estimula o crescimento de mudas de umbuzeiro em solução nutritiva; para o cultivo destas em solução nutritiva de Hoagland & Arnon, recomenda-se a adição de 0,03 mmol L-1 de Ni.This study evaluated the influence of Ni addition to Hoagland - Arnon nutrient solution on the growth and mineral nutrition of Umbu (Spondias tuberose) tree seedlings. The experiment was in a completely randomized design with four replications and six Ni doses (0; 0.0005; 0.05; 0.1; 0.5; and 1.0 mmol L-1). Low Ni concentrations in the nutrient solution stimulated Umbu seedlings growth. The application of 0.03 mmol L-1 of Ni is recommended for the cultivation of Umbu seedlings in Hoagland - Arnon nutrient solution.