ArticlePDF Available

Plant stress activated by chlorine from disinfectants prepared on the base of sodium hypochlorite

Authors:

Abstract and Figures

In this study, the phytotoxicity of disinfectants prepared on the base of sodium hypochlorite was determined. For our tests two commercial products, Savo and Dom Amor, as well as 10% NaClO solution were used. While Savo contained only NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base of NaClO are used in households for cleaning and disinfection of floors, furniture, sanitary and kitchen equipment. Savo may be used for the disinfection of drinking waters as well. Products with NaClO are also used for bacteria, algae and pathogens reduction in irrigation waters. As a subject, young seedlings of mustard
Content may be subject to copyright.
Nova Biotechnol Chim (2017) 16(2): 76-85
DOI: 10.1515/nbec-2017-0011
Corresponding author:
fargasova@fns.uniba.sk
Nova Biotechnologica et Chimica
Plant stress activated by chlorine from disinfectants prepared on the base
of sodium hypochlorite
Agáta Fargašová
Department of Environmental Ecology, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6,
Bratislava, SK-842 15, Slovak Republic
Article info
Article history:
Received: 14th July 2017
Accepted: 12th November 2017
Keywords:
Growth inhibition
Phytotoxicity
Pigment production
Sodium hypochloride
Water content
Abstract
In this study, the phytotoxicity of disinfectants prepared on the base of sodium
hypochlorite was determined. For our tests two commercial products, Savo and Dom
Amor, as well as 10% NaClO solution were used. While Savo contained only
NaClO, Dom Amor contained NaClO and earthworm enzymes. Products on the base
of NaClO are used in households for cleaning and disinfection of floors, furniture,
sanitary and kitchen equipment. Savo may be used for the disinfection of drinking
waters as well. Products with NaClO are also used for bacteria, algae and pathogens
reduction in irrigation waters. As a subject, young seedlings of mustard Sinapis
alba L. were used for the study of chronic toxicity. The observed parameters of the
inhibition of roots and shoots growth, dry (DM) and fresh (FM) mass as well as
photosynthetic pigments production (chlorophyll a, b, carotenoids) and water
content in the plants were determined. The results point out that Dom Amor was the
most toxic for S. alba seedlings growth and the rank order of the FAC contents for
both plant parts was arranged as: Dom Amor > Savo > NaClO. All disinfectants
reduced the DM and FM of roots; however, they stimulated biomass production in
the shoots. On the basis of the obtained results it could be concluded, that
disinfectants stimulated photosynthetic pigments production and reduced water
content mainly in the roots. Dom Amor did not significantly reduced the water
content in the shoots and for this parameter the following rank orders of inhibition
for roots and shoots could be arranged as NaClO > Dom Amor > Savo and NaClO >
Savo > Dom Amor, respectively. All commercial products increased chlorophyll
a (Chla) and the carotenoids (Car) content in the shoots. As significant increase was
confirmed first for Chla whose content in the presence of NaClO at concentration
24 mL/L overextended that in the control by 3.5 times. The rank orders of
stimulation for Chla and Car were NaClO > Savo > Dom Amor and Dom Amor >
NaClO > Savo, respectively.
University of SS. Cyril and Methodius in Trnava
Introduction
Chlorine is classified as a plant micronutrient
essential for proper plant growth and all crops
require it in small quantities. It is important for
photosynthesis - acts as co-factor (Hajrasuliha
1980), it is involved in the opening and closing
of stomata and plays some important role in
osmotic adjustment and plant disease suppression
(Slabu et al. 2009). It is also important for enzyme
activity regulation in the cytoplasm, acts as
a counter anion to stabilize membrane potential,
and is involved in turgor and pH regulation (Xu et
al. 2000; White and Broadley 2001). Chlorine
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
77
deficiency evokes chlorosis and necrosis. Necrosis
appears along leaves margins and tips, leaves are
smaller than usual and plant growth is also reduced
(Montero et al. 1998; Marschner and Marschner
2012). Symptoms are usually seen first on older
leaves. High chloride concentration can reduce the
yield (Albacete et al. 2008). Crops differ both in
their chloride requirements as well as in their
tolerance to chloride toxicity.
Since chloride is an anion, it does not adsorb to soil
particles and moves readily with the water in the
soil. Therefore, water quality and irrigation
management are the major factors that affect
chloride concentration in soil. Other chloride
sources in the soil are some fertilizers. Chloride
toxicity is often accompanied or complicated by
salinity or infiltration problems which appear when
salinity is low. The most common toxicity is from
chloride in irrigation water. As chloride is not
adsorbed to soil, it moves readily with the soil
water and is taken up by the crop, moves in the
transpiration steam, and accumulates in the leaves.
However, toxic symptoms appear when the
chloride content in the leaves achieves 0.3 to 1.0%
on dry weight, and sensitivity depends on crop. As
presented by Xu et al. (2000) and White and
Broadley (2001) the critical concentration for
chloride toxicity is estimated to be 4-7 mg/L for Cl-
sensitive and 15 – 50 mg/L for Cl- tolerant species.
Chloride transport and exclusion from shoots is
correlated with salt tolerance in many species. Crop
tolerance to chloride is not nearly so well
documented as crop tolerance to salinity, however,
its concentration is important for salt tolerance
(Tavakkoli et al. 2010; Teakle and Tyerman 2010).
Chlorine inputs to soils occur mainly as a result of
Cl- deposition from rainwater, fertilizer
applications (KCl), irrigation water, sea spray, dust
and air pollution. Cl- deposition from human
activity belongs mainly to irrigation and
fertilization. However, some agricultural
establishments try using water for irrigation from
reservoirs or ponds, such water recycling may
disperse plant pathogens into crops (Hong and
Moorman 2005). Bush et al. (2003) presented that
recycled irrigation water from harbors contained
substantial densities of pathogens and Hong and
Moorman (2005) reported the presence of
17 Phytophthora sp., 26 Pythium sp., 27 genera
of fungi, 8 species of bacteria, 10 viruses and
13 species of plant parasitic nematodes in irrigation
water from ponds, rivers, canals, streams, lakes,
runoff water, etc. These facts explain why chlorine
is used for disinfection of irrigation water (Cayanan
et al. 2009).
At present, it is widely used in agriculture,
chemical, paint- and lime, food, glass, paper,
pharmaceutical, synthetic and water disposal
industries. In the textile industry, it is used as
a bleacher and chlorine compounds could also be
used for electrochemical treatment of water
contaminated with dyes (Valica and Hostin 2016).
Sometimes NaClO is added to industrial waste
waters to reduce odor. Hypochlorite can be used to
prevent algae and shellfish growth in cooling
towers and in water treatment, it is used for water
disinfection. In households, it is frequently used for
the purification and disinfection of the house.
However, water with commercial sodium
hypochlorite products released into a water
environment has relatively low concentrations
enough, strong toxic effects on freshwater
invertebrates and bacteria may appear (Fargašová
2017).
By adding sodium hypochlorite to water,
hypochlorous acid (HClO) and hypochlorite ions
(ClO-) are formed. The equilibrium of these two
forms depends only on water pH (pKa for
HClO/ClO- is ~ 7.4). NaClO in water is gradually
depleted for oxidation of inorganic and organic
compounds (Mohammadi 2008). However, NaClO
is very effective and low cost biocide used for
water disinfection (Amin et al. 2013), hypochlorite
is a highly destructive, selective oxidant that reacts
easily with all biomolecules. Moreover, dissolved
chlorine dissociated into hypochlorite and
hypochlorous ions, which penetrate cell membrane,
may result in the formation of genotoxic,
mutagenic, and/or carcinogenic disinfection by-
products (DPBs) (Sapone et al. 2016) and are also
associated with adverse reproductive outcomes
(Nieuwenhuijsen et al. 2000).
As described by White and Broadley (2001),
chlorine occurs in the soil predominantly as
a Cl- anion, which does not form complexes
readily, and is repelled from predominantly
negatively charged mineral surfaces of many soil
particles. This fact changes Cl- movement in the
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
78
soil and the consequence of its slight adsorption
to soil components is not chemically altered
by soil organisms. Its movement within the soil is
largely determined by water flows. That’s why is
often used as a tracer for soil water movement.
During our study, attention was focused on free
available chlorine the FAC (mg/L) effect of
NaClO and two commercial disinfectant products,
prepared on NaClO base, on some physiological
processes in crop Sinapis alba. Chlorine enters the
plants through the roots by a symplastic pathway
and is mobile within the plant. Its fluxes across
membranes and between tissues limited growth,
water translocation in the plant and interferes with
photosynthesis through inhibition of photosynthetic
pigments production. In an effort to avoid chlorine
movement through soils and the assurance of direct
FAC effect on plant growth and physiological
activity, only water solutions of sodium
hypochlorite products were used.
Experimental
Disinfectans
The following commercial products on the base
of sodium hypochlorite (NaClO) were investigated
with regard to their phytotoxic effects Savo
(produced by Bochemie a.s., Bohumín, Czech
Republic) and Dom Amor (produced by BOOS
Biologické substancie, Košice, Slovak Republic).
Savo contained only NaClO; while Dom Amor
contained both NaClO and earthworm enzymes.
The content of effective ingredients (CEI)
of products did not exceed 5%. The toxicity
of sodium hypochlorite (NaClO) (10% solution)
was also determined. The active substance
of NaClO in water is hypochlorous acid (HClO)
and hypochlorite ions (ClO-). Fresh samples were
used for each test due to high chlorine volatility.
The concentration of free available chlorine (FAC)
of products was determined by the reaction
of the tested products with phosphate buffer
and potassium iodide, followed by titration
of thiosulphate on starch (Añasco et al. 2008).
The results of the analyses for three tested products
are presented in Table 1. However, only free active
chlorine concentrations, being the most active
and dominant form, are presented here.
Doses of the disinfectants used in the tests were
decided after preliminary experiments performed
in the laboratory according to the corresponding
guide (OECD 208 2006).
Table 1. Content of effective ingredients CEI (%)
and the concentration of free available chlorine – FAC (mg/L)
in tested substances.
CEI (%) FAC (mg/L)
Savo 5 39.90
Dom Amor 5 32.21
NaClO 10 108.86
The dissipation tests were conducted before
the experiments due to chlorine volatility.
To provide a constant chlorine level, the solutions
were replaced every 24 hours. Under these
conditions, FAC concentration at the end
of the experiments did not decrease below 90%.
The typical levels of free chlorine in drinking
water ranged from 0.2 2.0 mg/L,
though regulatory limits allow levels as high
as 4.0 mg/L.
Sinapis alba growth inhibition test
Mustard Sinapis alba L. seeds were germinated
in Petri dishes with 17-cm diameter, laboratory
filter paper No. 1 disks and plastic nets
on the bottom. Nine different concentrations from
each sample (Table 2), designed on the base
of orientation tests, were prepared in dechlorinated
tap water (80 mg/L Ca, 27 mg/L Mg, pH =
7.3±0.05). Each Petri dish contained 50 mL
of tested solution and 20 healthy looking
and similar size mustard seeds spread on the plastic
net situated on the filter paper laid down
on the bottom of the dish. As a control, only tap
water was used in the same way. Dishes were put
in a dark thermostat at 22±1°C and plastic nets
with germinated seeds were replaced every
24 hours to fresh tested solutions. After 72 hours
the roots and shoots length was measured
and IC50 concentrations were calculated
by using probit analysis (Fargašová and Lištiaková
2009).
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
79
Photosynthetic pigments and water content
determination
After 72 hours plastic nets with seedling were
transferred to hydroponic dark containers (250 mL)
with control or disinfectants solutions, situated in
laboratory box with a day-light cycle (16/8), and
the temperature was maintained at 23±2 °C.
Afterwards, the dishes were shielded from the
direct sunlight and the cultivation continued for the
next 7 days. During this period, the tested solutions
were changed every 24 hours in the same way as
was described before to provide a constant chlorine
concentration during the entire experiments. During
this cultivation shoots were not in direct contact
with the disinfectant solutions. After 10 days of
growth, the plants were harvested and the roots and
shoots were separated. Fresh mass (FM) was
weighed immediately after organ separation.
The pigment contents (chlorophyll a, b, total
Table 2. Concentrations of Savo, Dom Amore and NaClO used during the tests with S. alba seedlings expressed as the FAC
concentrations in mg/L and the volume of solution mL/L (used concentrations were selected on the base of preliminary tests).
Compound Concentration
Savo mL/L NaClO 2.0; 4.0; 6.0; 8.0; 12.0; 16.0; 24.0; 32.0;
mg/L FAC 0.08; 0.16; 0.24; 0.32; 0.48; 0.64; 0.96; 1.28;
Dom Amore mL/L NaClO 2.0; 4.0; 6.0; 8.0; 12.0; 16.0; 24.0; 32.0;
mg/L FAC 0.064; 0.13; 0.19; 0.26; 0.39; 0.52; 0.77; 1.03;
NaOCl mL/L NaClO 2.0; 4.0; 6.0; 8.0; 12.0; 16.0; 24.0; 32.0;
mg/L FAC 0.22; 0.44; 0.65; 0.87; 1.31; 1.74; 2.6; 3.48;
carotenoids) were determined in the fresh shoots
after extraction in 95% ethanol (w/v) (1 g of fresh
shoots per 6 mL of ethanol). Pigment extraction
continued until all of the homogenized plant mass
was white. After a brief centrifugation (2 min
at 2 900 x g), the pigment content was measured
spectrophotometrically at 665, 649 and 470 nm
in supernantant (Lichtenthaler and Wellburn 1983).
Photosynthetic pigments amount was calculated by
the following equations:
Chla = 13.95 (A665) – 6.88 (A649)
Chlb = 24.96 (A649) – 7.32 (A665)
Car = [1 000 (A470) – 2.05 (chl a) – 114.8 (chl b)]/245
(Chla chlorophyll a concentration,
Chlb chlorophyll b concentration, Car
carotenoids concentration; in µg/mL of plant
extract).
Afterwards plant material roots and shoots, were
separately dried at a temperature of 40 °C
to a constant mass and then weight. From the
obtained values of fresh (FM) and dry mass (DM),
the water content was calculated (Drazic and
Mihailovic 2005):
WC = (FM – DM)/DM
(WC water content, FM fresh mass, DM dry
mass) in g/g DM of S. alba seedling organs and the
effect of tested solutions on WC in the roots and
shoots was determined as a standardized values of
the reference control.
Statistical analysis
All phytotoxicity tests were carried out in triplicate,
and they included a control in tap water. Quality
control data were considered acceptable according
to control charts and other established criteria.
The ADSTAT 2.0 statistical software was used for
statistical evaluation. A T-test was used to assess
the significant difference between the controls and
other treatments.
Results and Discussion
All results obtained by the use of the above
mentioned methods were evaluated according to an
ecological risk assessment framework which
implies the examination of risks from natural,
human and industrial activities (Fargašová 2016).
Experiments with the crop S. alba confirmed that
chlorine ions are generally toxic to plants’ growth
at relatively low concentrations and may cause
irreversible damage of their development. Free
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
80
chlorine is often added to irrigation water for algae,
fungi, and bacteria destruction. Chlorination is used
mainly for surface irrigation water from rivers,
canals, reservoirs and ponds, as well as for the
prevention of clogged piping by organic material
(Cayanan et al. 2009; Parke and Fisher 2012).
As we presented before, the usage of disinfectant
prepared on the base of NaClO is very effective for
such prevention, because free chlorine levels which
destroy algae are at least 10-times lower than those
which reduced plant growth by 50% (Fargašová
2017). The inhibitory concentrations (IC) which
reduced roots and shoots growth of mustard by
50% together with their confidence intervals (CI)
are introduced in Table 3. From these results, it is
evident that the roots of S. alba were more sensitive
to disinfectants than shoots, and the commercial
product Dom Amor enriched with earthworm
Table 3. IC50 concentrations and their 95% confidence intervals (CI) for roots and shoots growth inhibition (values are
introduced as volume of compound in mL/L as well as the concentration of free available chlorine in mg/L FAC).
Compound
Roots growth Shoots growth
IC50 (CI)
(mL/L)
IC50 (CI)
(mg/L FAC)
IC50 (CI)
(mL/L)
IC50 CI)
(mg/LFAC)
Savo 12.68
(12.20 – 13.25)
0.51
(0.49 – 0.53)
19.98
(18.45 – 25.59)
0.80
(0.74 – 1.02)
Dom Amor 6.85
(6.25 – 7.33)
0.22
(0.20 – 0.24)
18.58
(17.32 – 20.38)
0.60
(0.55 – 0.65)
NaClO 5.16
(4.96 – 5.33)
0.56
(0.54 – 0.58)
8.84
(8.65 – 9.05)
0.97
(0.94 – 0.99)
enzymes had the strongest inhibitory effect on both
plant parts. For inhibition, the following rank
orders for FAC content should be arranged as so:
roots growth: Dom Amor Savo NaClO; shoots
growth: Dom Amor Savo NaClO. All tested
compounds reduced the growth more for roots than
shoots. This might be explained by Greenway and
Thomas (1965) conclusion, which assume that the
shoots initially contained no Cl- and therefore, the
toxic effects of chlorine don’t appear mainly in
young seedlings. According to the growth
responses of plants of high Cl- concentration in the
environment plants could be divided into four
categories. The differences between them are often
related to the ability to restrict Cl- transport
to shoots (White and Broadley 2001). Large
differences between the chlorine content in various
plant parts and its relation to the manifestation
toxic effects, was also confirmed (Greenway and
Munns 1980) long before. Chlorine, as an essential
element, supporting plant growth is taken into the
xylem and thereby delivered to the shoots (White
and Broadley 2001). There are two pathways for
Cl- anion intake into the xylem – the symplastic
(cytoplasmic) and the apoplastic (extracellular).
The intake process influences fluxes and
accumulation of the chlorine into the plant and its
distribution within the plant. Toxic effects
of chlorine on plants development were confirmed
also by Carrilo et al. (1996) to radish and lettuce
seedlings after the application of a commercial
dioxide product (Hallox) with 2.6 mg/L of active
chlorine. Hallox was in this case used for direct
irrigation on a soil surface at a level of 1 : 1000.
As presented by Cayanan et al. (2009) chlorine had
no phytotoxic or growth effects on all plants and
growth inhibition depends on free active chlorine
content. In addition to growth, dry and fresh mass
production could also be affected and this was also
confirmed by our experiments.
Plant growth is very closely connected with crop
production expressed as dry (DM) and fresh (FM)
mass production. Both these parameters are very
strongly influenced by chlorine fluxes and
accumulation within the roots and its translocation
into the shoots (White and Broadley 2001).
Chlorine intake is closely connected with water
uptake and translocation through plants and the
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
81
Fig.1. Water content in the roots and shoots of S. alba after 10 days’ application of Savo, Dom Amor and NaClO disinfectants
introduced as standardized values of the reference control (water content in control = 1). Statistical significance: * P < 0.05;
** P < 0.01.
results from these observations are shown
on Fig. 1. The presented results indicate that all
products in all used concentrations reduced more
water reception by the roots than its translocation
into the shoots. Plants try to supply chlorine
toxicity by its movement through water into the
upper part of the plant and in this way, attempt to
reduce chlorine toxicity in the roots which are
responsible for nutrients’ reception. As presented
by White and Broadley (2001), plants support their
growth by loading chlorine into the xylem and
thereby deliver it to the shoots. This is in
accordance with the results we obtained during the
determination of water content and dry and fresh
mass (Fig. 1, 2). These authors showed that there
are two pathways by which anions might reach the
xylem: (1) Anions enter root cells through a plasma
membrane, are then transferred from cell to cell
through plasmodesmatal connections, and are
exported across the plasma membrane of cells into
the stele (2) anions are taken extracellularly
through the cell wall and water spaces to reach the
stele – this is a relatively non-selective process
governed by the transport of water through solvent
drag. Tested compounds significantly reduced
water content only in the roots while the water
content in the shoots was stimulated or reduced
only slightly. However, Dom Amore increased the
water content in the shoots in all of the tested
concentrations; NaClO indicated a reduction which
did not exceed 64%. The following rank orders of
water content reduction could be arranged as so: for
roots NaClO Dom Amor Savo, for shoots
NaClO Savo Dom Amor.
Water reception from the solvents with NaClO,
including the two commercial disinfectant products
Savo and Dom Amor, is very closely connected
with dry (DM) and fresh (FM) production by the
roots and its translocation to upper plant parts
(Fig. 2) From the obtained results, it can be
concluded that while DM and FM production of the
roots was reduced in the presence of chlorine from
all tested compounds, DM and FM of the shoots
production was stimulated and this is in accordance
with the calculations and equations by White and
Broadley (2001), who confirmed the close relation
between the root uptake of chlorine and a plant’s
relative growth and biomass production. As was
previously presented, chlorine is an essential
micronutrient for higher plants and its minimal
requirement for crop growth is 1 g/kg DM.
However, high chlorine concentration in tissues can
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
82
Fig. 2. Roots and shoots dry (DM) and fresh (FM) mass production in the presence of tested disinfectants after 10 days’
cultivation introduced as standardized values of the reference control (water content in control = 1). Statistical significance:
* P < 0.05; ** P < 0.01.
be toxic to a crop and restrict the agriculture mainly
in saline regions. Many important cereals,
vegetables and fruit crops are susceptible to Cl-
toxicity during cultivation (Xu et al. 2000), and this
statement was confirmed also for the mustard crop
during our study.
The last observed parameter during our
experiments was the determination of
photosynthetic pigments content. These results are
presented on Fig. 3, and suggest
a significant increase of Chla content in the
presence of all disinfectants. Its production
increased with the disinfectant’s concentration, and
maximal stimulation was confirmed during NaClO
application when the Chla content in the NaClO
concentration of 24 mL/L overextended its content
in the control by 3.5 times. For this pigment
stimulation, the following rank order may be
arranged: NaClO Savo Dom Amor. However,
Chla is the most abundant pigment in plant and
absorbs red wavelengths of light; Chlb is not as
abundant and probably evolved later. In presence of
active chlorine, its concentration did not
significantly change.
Cars are a class of accessory pigments and in
plants; they contribute to the photosynthetic
machinery and protect them against photo-damage.
In the presence of all the tested disinfectants,
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
83
carotenoids concentration in the shoots were in
higher applied concentrations significantly
increased, however, did not overextend their
content in the control by to 2.5 times for Dom
Amor product. The stimulatory rank order for this
case was: Dom Amor NaClO Savo.
Chlorophyll content and fluorescence have
been used to investigate the adverse effects
of various environmental factors in experiments
under controlled conditions. As presented
by Khaleghi et al. (2012), drought is one
of the factors affecting photosynthesis and
chlorophyll content. The measurement
of chlorophyll content and fluorescence has
become established as a sensitive method for
assessing the efficiency of PSII photosynthetically,
as well as its role in environmental perturbations of
photosynthesis. Some researchers have reported
that chlorophyll content might estimate
the influence of environmental stress on growth
because these parameters were closely
correlated with the rate of carbon exchange
(Figueroa et al. 1997; Guo and Li 2000).
As presented by Khaleghi et al. (2012), Kiani et al.
(2008) and Guerfel et al. (2009), chlorophyll
content (Chla, Chlb and total chlorophyll = Chla +
Chlb) decreased under stress elicited by water
toxicity. These statements can explain why the
content of chlorophylls and carotenoids increased
in the presence of free available chlorine in the
concentrations used during our experiments with
three disinfectant products.
Chlorine is classified as a plant micronutrient and is
important for photosynthesis (Slabu et al. 2009
Marschner and Marschner 2012). In a high
concentration, chlorine reduces plant growth,
reduce yield (Albacete et al. 2008) and interfere
with photosynthesis (Harjasuliha 1980).
The critical concentration for chloride toxicity is
estimated as 4 7 mg/L FAC for sensitive plants.
In our tests, the FAC concentration which was used
was 10-times lower, and adverse effects developed
mainly in the roots. Shoots were more than two-
times less sensitive than roots and their production
of FM and DM increased. The water content in the
shoots increased or was reduced only slightly, and
Fig. 3. Disinfectants effect on the production of chlorophyll
a (Chla), chlorophyll b (Chlb) and carotenoids (Car)
in the shoots of S. alba after 10 days’ cultivation (µg/mL).
Statistical significance was in all cases at least P < 0.05.
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
84
this could explain why the photosynthetic pigment
content also increased.
Conclusions
In low concentrations chlorine is classified
as a plant micronutrient and the phytotoxic effects
of its anion begin to appear only in higher
concentrations. The obtained results confirmed that
in S. alba crop roots are more sensitive to free
active chlorine. All tested products NaClO and
the two commercial products Savo and Dom Amor,
reduced roots growth more than dry (DM) and
fresh mass (FM) production. DM and FM
production correlate also with a strong reduction
of water content (WC) in the roots. Slight shoots
growth decreases as well, since DM and FM
stimulation support photosynthetic pigments
production, mainly that of chlorophyll a (Chla).
Acknowledgement
This study was performed with the support of the Scientific
Grant Agency VEGA 1/0098/14 and KEGA 029UK-4/2016
References
Albacete A, Ghanem, ME, Martinez-Andujar C, Acosta M,
Sanchez-Bravo J, Martinez V, Lutts S, Dodd IC, Perez-
Alfocea F (2008) Hormonal changes in relation to
biomass partitioning and shoot impairment in salinized
tomato (Solanum lycopersicum L.) plants. J. Exp. Bot.
59: 4119-4131.
Amin MM, Hashemi H, Bovini AM, Hung YT (2013) A
review on wastewater disinfection. Int. J. Environ.
Health. Eng. 2: 22-30.
Añasco NC, Koyama J, Imai S, Nakamura K (2008) Toxicity
of residual chlorines from hypochlorite-treated seawater
to marine amphipod Hyale barbicornis and estuarine
fish Oryzias javanicus. Water Air Soil Pollut. 195: 129-
136.
Bush EA, Hong C, Stromberg EI (2003) Fluctuation of
Phytophthora and Phythium spp. in components of a
recycling irrigation system. Plant Dis. 87: 1500-1506.
Carrilo A, Puente ME, Bashan Y (1996) Application of
diluted chlorine dioxide to radish and lettuce nurseries
insignificantly reduced plant development. Ecotoxicol.
Environ. Saf. 35: 57-66.
Cayanan CF, Dixon M, Zheng Y, Llewellyn J (2009)
Response of container-grown nursery plants to chlorine
used to disinfest irrigation water. Hort. Sci. 44: 164-167.
Drazic G, Mihailovic N (2005) Modification of cadmium
toxicity in soybean seedlings by salicylic acid. Plant Sci.
168: 511-517.
Fargašová A (2016) Ecological risk assessment framework.
Acta Environ. Univ. Comenianae (Bratislava) 24: 10-16.
Fargašová A (2017) A test battery approach for
ecotoxicological evaluation of disinfectants prepared on
the basis on sodium hypochlorite. Monatsh. Chem. 148,
in press.
Fargašová A, Lištiaková J (2009) Cr and Ni simultaneous
phytotoxicity and mutagenicity assay. Nova Biotechnol.
Chim. 9: 107-112.
Figueroa ME, Fernández-Baco L, Luque T, Davy AJ (1997)
Chlorophyll fluorescence, stress and survival in
populations of Mediterranean grassland species.
J. Vegetation Sci. 8: 881-888.
Greenway H, Munns R (1980) Mechanisms of salt tolerance
in nonhalophytes. Ann. Rev. Plant Physiol. 31: 149-190.
Greenway H, Thomas DA (1965) Plant response to saline
substrate. V. Chloride regulation in the individual organs
of Hordeum vulgare during treatment with sodium
chloride. Aust. J. Biol. Sci. 18: 505-524.
Guerfel M, Baccouri O, Boujnah D, Chaibi W, Zarrouk M
(2009) Impact of water stress on gas exchange, water
relations, chlorophyll content and leaf structure in the
two main Tunisian olives (Olea europaea L.) cultivars.
Sci. Hort. 119: 257-263.
Guo P, Li R (2000) Effects of light nocturnal temperature on
photosynthetic organization in rice leaves. Acta Bot.
Sinica 42: 13-18.
Hajrasuliha S (1980) Accumulation and toxicity of chloride in
bean plants. Plant Soil 55: 133-138.
Hong CX, Moorman GW (2005) Plant pathogens in irrigation
water: Challenges and opportunities. Crit. Rev. Plant
Sci. 24: 189-208.
Khaleghi E, Arzani K, Moallemi N, Barzegar M. (2012)
Evaluation of chlorophyll content and chlorophyll
fluorescence parameters and relationships between
chlorophyll a, b and chlorophyll content index under
water stress in Olea europea cv. Dezful. Agric.
Biosystems Engr. 6: 636-639.
Kiani SP, Maury P, Sarrafi A, Grieu P. (2008) QTL analysis
of chlorophyll fluorescence parameters in sunflower
(Helianthus annuus L.) under well-watered and water-
stressed conditions. Plant Sci. 175: 565-573.
Lichtenthaler HK, Wellburn AR (1983) Determinations of
total carotenoids and chlorophylls a and b of leaf
extracts in different solvents. Biochem. Soc. Trans. 603:
591-592.
Marschner H, Marschner P (2012) Marschner's mineral
nutrition of higher plants, 3rd ed. Elsevier/Academic
Press, London; Waltham, MA, 672 p.
Mohammadi Z. (2008) Sodium hypochlorite in endodontics:
an update review. Int. Dental. J. 58: 329-341.
Montero E, Cabot C, Poschenrieder C, Barcelo J (1998)
Relative importance of osmotic-stress and ion specific
effects on ABA-mediated inhibition of leaf expansion
Unauthenticated
Download Date | 1/11/18 1:35 AM
Nova Biotechnol Chim (2017) 16(2): 76-85
85
growth in Phaseolus vulgaris. Plant Cell Environ. 21:
54-62.
Nieuwenhuijsen MJ, Toledano MB, Eaton NE, Fawell J,
Elliott P (2000) Chlorination disinfection byproducts in
water and their association with adverse reproductive
outcomes: a review. Occup. Environ. Med. 57: 73-85.
OECD 208: OECD guidelines for the testing of chemicals
No. 208. (2006) Terrestrial plant test: Seedling
emergence and seedling growth test. Organization for
Economic Co-operation and Development, Paris, 19 p.
Parke J, Fisher P (2012) Treating irrigation water. Digger 56:
41-45.
Sapone A, Canistro D, Vivarelli F, Paolini M (2016)
Perturbation of xenobiotic metabolism in Dreissena
polymorpha model exposed in situ to surface water
(Lake Trasimene) purified with various disinfectants.
Chemosphere 144: 548-554.
Slabu C, Zörb C, Steffens D, Schubert S. (2009) Is salt stress
of faba bean (Vicia faba) caused by Na+ or Cl
- toxicity?
J. Plant Nutr. Soil Sci. 172: 644-650.
Tavakkoli E, Rehgasamy P, McDonald GK (2010) High
concentration of Na+ and Cl
- ions in soil solution have
simultaneous detrimental effects on growth of faba been
under salinity stress. J. Exp. Bot. 61: 4449-4459.
Teakle NL, Tyerman SD (2010) Mechanisms of Cl- transport
contributing to salt tolerance. Plant Cell Environ. 33:
566-589.
Valica M, Hostin S. (2016) Electrochemical treatment of
water contaminated with methylorange. Nova
Biotechnol. Chim. 15: 55-64.
White PJ, Broadley MR (2001) Chloride in soils and its
uptake and movement within the plant: a review. Ann.
Bot. 88: 967-988.
Xu G, Magen H, Tarchitzky J, Kafkafi U (2000) Advances in
chloride nutrition of plants. Adv. Agron. 68: 97-150.
Unauthenticated
Download Date | 1/11/18 1:35 AM
... Saat ini, sangat sedikit pelaporan dan penelitian mengenai dampak yang ditimbulkan oleh disinfektan terhadap tumbuhan. Namun demikian, ada penelitian yang menunjukkan bahwa disinfektan (NaClO 10%) toksik bagi pertumbuhan semai Sinapsis alba (Fargašová, 2017b). Sementara itu, penelitian lainnya menunjukkan bahwa penggunaan natrium hipoklorit (NaClO 10%) sebagai zat kimia dengan tujuan sterilisasi menyebabkan panjang akar sorgum paling pendek dan kolonisasi akar sorgum paling sedikit (Dewi et al., 2017). ...
... Nekrosis muncul di sepanjang tepi dan ujung daun, dengan daun lebih kecil dari biasanya dan pertumbuhan tanaman juga berkurang. Gejala biasanya terlihat pertama kali pada daun yang lebih tua (Fargašová, 2017b). ...
... Sementara itu, klorin dan hipoklorit diangkut ke xylem melalui dua jalur, yakni jalur simplastik (sitoplasma) dan jalur apoplastik (ekstraseluler). Proses pemberian kedua zat ini kepada tumbuhan akan mempengaruhi fluks dan akumulasinya ke dalam tumbuhan dan distribusinya di dalam tumbuhan (Fargašová, 2017b). ...
Article
Sodium hypochlorite (NaClO) was a chemical compound commonly used as a whitening and disinfectant agent. Kiara payung (Filicium decipiens), or the ferntree, was chosen as the object of research because easily obtained, has rapid growth, and thought to respond to alien substances' stress. The main purpose of this study was to find out the response of the ferntree plant, which is given stress from sodium hypochlorite. The research method used in this study was experimentation. The independent variable in this study was Sodium Hypochlorite Concentration (X), and the dependent variable was Sodium Hypochlorite Uptake Value (Y). Phytochemical analysis was performed using the argentometry and Atomic Absorption Spectrophotometry (AAS) techniques. Correlation analysis were performed using IBM SPSS 26. This study showed that the concentration of sodium hypochlorite has a positive effect on the uptake value of sodium hypochlorite. Limitations and suggestions to this study were to check the absorption based on soil level and examine other parts of the plant in the future study. In addition, another factors to the independent variables, such as genetics and variations in sodium hypochlorite concentration should be further explored, so that correlation analysis stands more optimal. Keywords: Ferntree, Root, Sodium Hypochlorite, Stress
... In this case, a relatively low percentage of sterile and surviving microbeads was recorded. Chlorine-containing drugs often exhibit phytotoxicity [25]. The maximum effect of sterilization was achieved with the use of hydrogen peroxide in the E96H38W5 variant. ...
Article
Full-text available
Hibiscus moscheutos L. 'Berry Awesome' is a complex hybrid of the new Proven Winners Summerific series of varieties with highly ornamental characteristics. Micropropagation of highly ornamental varieties is important for mass production of planting material for commercial purposes. The traditional methods for propagating Hibiscus varieties, such as cuttings or seed propagation, however, do not guarantee high rates of production of high-quality seedlings. To solve this problem, an attempt was made to develop protocols for micropropagation of Hibiscus moscheutos L. 'Berry Awesome' in vitro on agar and liquid medium using a bioreactor system, followed by ex vitro adaptation of the regenerants. The optimal method for sterilization of nodal explants as well as the optimal composition of the initiation medium for shoot proliferation and rooting were determined. For micropropagation on a liquid medium, a rocker-type bioreactor was used, and its advantages over micropropagation on an agar medium were demonstrated. The results showed that the best sterilization method for nodal segment explants was as follows: pretreatment by rinsing with running tap water, sterile water, and distilled water for 70 min and soaking for 5 min in a mixture of solutions of ethyl alcohol (96%), hydrogen peroxide (38%), and water in a ratio of 1:1:2. In this case, live and sterile explants accounted for 62.6%. The optimal initiation medium for axillary buds in nodal segments was the Murashige and Skoog (MS) medium supplemented with 0.1 mg L −1 N-(2-chloro-4-pyridinyl)-N'-phenylurea (CPPU), which resulted in 73.3% of axillary buds being induced. The optimal solid proliferation medium was MS medium supplemented with 0.1 mg L −1 CPPU with a proliferation coefficient of 5.8. In a liquid medium, the optimal concentration of CPPU was 0.05 mg L −1 with a proliferation coefficient of 9.2. The best medium for rooting/shoots with agar and in bioreactors was MS medium with the addition of 0.1 mg L −1 indole-3-butyric acid (IBA). The highest rooting rate was 99.0% in both types of media, and the survival rate of plantlets was 88.7% in solid media and 98.7% in the bioreactor.
... An algal growth inhibition test was performed follow Table 1. Content of active ingredients -CEI (%) and concentration of free available chlorine -FAC (mg L -1 ) in tested substances (Fargašová, 2017) ing the OECD Guideline 201 (2011). The green alga, Desmodesmus subspicatus Brinkmann (SAG 86.81), was obtained from the Department of Hydrobiology, Microbiology and Toxicology of the Water Research Institute, Bratislava. ...
Article
Full-text available
The research is related to the assessment of the overall sensitivity and applicability of many bioassays representing different trophic levels for the preliminary ecotoxicological testing of commercial disinfectants marked as SA (SAVO, Bochemie a.s., Czech Republic) and DoAm (Dom Amor, BOOS – Biologické substancie, Slovak Republic). Disinfectants were prepared based on sodium hypochlorite (NaOCl). SA contains only NaOCl while earthworm enzymes enrich DoAm. In both commercial products, the NaOCl content did not exceed 5%; pure NaOCl was used as a 10% solution as well. For bioassay, water organisms ( Vibrio fischeri, Desmodesmus subspicatus, Daphnia magna and Tubifex tubifex ) situated in various trophic levels were used. All the tests were confirmed as suitable for the determination of chlorine’s adverse effects. Because the organisms’ reactions to the tested disinfectants varied, they can be arranged in the following rank order of sensitivity: V. fischeri ≥ D. subspicatus >> D. magna >> T. tubifex . The toxicity of the tested substances (NaOCl, SA, DoAm) depends on the length of exposure, the species of the organism and FAC (free available chlorine) content. The effective concentrations of the tested products ranged from 0.13 to 8.18 μL L –1 , i.e., 0.014 to 0.26 mg L –1 of FAC. However, in the tests with T. tubifex and V. fischeri the toxic effect of NaOCl was the weakest; the tests with other two organisms confirmed this compound as the most toxic. Only for T. tubifex (96 hrs) did SA have a more adverse effect than DoAm.
... The intake process influences fluxes and accumulation of the chlorine in the plants and its distribution within the plants. The fluxes across membranes and between tissues limit growth and water translocation in the plants as well as interfere with photosynthesis through inhibition of photosynthetic pigment production (Fargašová, 2017). In addition, it has been shown that a chlorine cover has been formed during hypochlorite disinfection of rice seeds and this artifact could not be eliminated simply by rinsing the seeds, even thoroughly, with sterile distilled water. ...
Article
Coconut (Cocos nucifera L.) or 'the tree of life' is one of the most important palm crops due to its versatility. Reduction in coconut productivity due to natural calamity and disease threats has raised the urgent need to develop in vitro techniques that can overcome the obstacles of the traditional breeding method. Embryo culture is one of the earliest in vitro culture techniques applied to practical problems and so far has proved itself to be of great value to breeders. However, contamination is one of the most serious problems that reduces the efficiency in in vitro culture techniques. Thus, appropriate surface sterilization treatments are highly important to in vitro culture establishment. The present study was performed to evaluate the sterilization effect of calcium hypochlorite by comparing with sodium hypochlorite. This study also examined the effects of calcium hypochlorite concentrations on plantlets morphogenesis. The findings revealed that amongst the tested treatments, 0.5% (w/v) calcium hypochlorite was the most effective treatment with the lowest rate of contamination. This treatment also significantly improved shoot and root elongation in comparison with calcium hypochlorite at higher concentrations (3% and 6%, w/v). Thus, this concentration was found to be optimal for surface sterilization of two coconut cultivars - Aromatic and Xiem Red Dwarf. Besides that, the results obtained from this study indicated that 70% (v/v) ethanol was not critical in surface sterilization protocol of coconut embryo culture. This research has provided an improved approach for surface sterilization which was previously dependent on sodium hypochlorite and ethanol.
Article
Full-text available
Chlorination is a widespread fouling control practice in water intake structures of power plants and desalination plants. Chlorine dioxide is used as an alternative to chlorine gas and sodium hypochlorite for controlling biofilms and biofouling. In this study, the physiological responses of two macroalgal species Ulva reticulata and Hypnea musciformis to chlorine dioxide treatment was studied under laboratory conditions. The algal samples were exposed to 0.05, 0.1 and 0.5 mg l⁻¹ of chlorine dioxide for 5 days. The chlorophyll-a, carotenoid content and total polyphenol levels were analysed. The algal extracts were also analysed using GC-MS to understand the changes in the biochemical profile of the algae after treated with chlorine dioxide. Results indicated an increase in chlorophyll-a, carotenoid and total polyphenol content during initial exposure duration and further treatment showed a decrease in these parameters. The chlorine dioxide treatment also affected the fatty acids composition of the macroalgae. The physiological responses observed in this study indicate that chlorine dioxide as an antifouling biocide has toxic effects on these macroalgae.
Article
Full-text available
The research is related to the assessment of the overall sensitivity and applicability of many bioassays representing different trophic levels for the preliminary ecotoxicological testing of commercial disinfectants marked as SA (SAVO, Bochemie a.s., Czech Republic) and DoAm (Dom Amor, BOOS – Biologické substancie, Slovak Republic). Disinfectants were prepared based on sodium hypochlorite (NaOCl). SA contains only NaOCl while earthworm enzymes enrich DoAm. In both commercial products, the NaOCl content did not exceed 5%; pure NaOCl was used as a 10% solution as well. For bioassay, water organisms ( Vibrio fischeri, Desmodesmus subspicatus, Daphnia magna and Tubifex tubifex ) situated in various trophic levels were used. All the tests were confirmed as suitable for the determination of chlorine’s adverse effects. Because the organisms’ reactions to the tested disinfectants varied, they can be arranged in the following rank order of sensitivity: V. fischeri ≥ D. subspicatus >> D. magna >> T. tubifex . The toxicity of the tested substances (NaOCl, SA, DoAm) depends on the length of exposure, the species of the organism and FAC (free available chlorine) content. The effective concentrations of the tested products ranged from 0.13 to 8.18 μL L –1 , i.e., 0.014 to 0.26 mg L –1 of FAC. However, in the tests with T. tubifex and V. fischeri the toxic effect of NaOCl was the weakest; the tests with other two organisms confirmed this compound as the most toxic. Only for T. tubifex (96 hrs) did SA have a more adverse effect than DoAm.
Article
Full-text available
Purpose of this paper is to draft shot information about framework for ecological risk assessment compile according Guidelines and short description of phases from which this method consists. During description of particular procedures, the meaning of used terms is introduced and explained. The framework for risk assessment is presented as a useful tool for risk management and selection of available cleanup and remedy technologies, and costs of alternative actions.
Article
Full-text available
This study examines electrochemical degradation of water artificially contaminated by azo dye Methyl Orange (MO). Degradation is based on chemical electro-oxidation of MO molecules. Graphite was used as an electrode material for electrochemical oxidation of MO. In this work, the different operative parameters (electric current, NaCl content) and their effect on effectiveness as well as the treatment time/duration of MO degradation were tested. The highest dye removal (91.0 %) was obtained during the electrolysis at current density 3.032 mA/cm
Article
Full-text available
The recycling of irrigation water may cause the dispersal of plant pathogens. Irrigation water disinfected with 2.4 mg·L-1 of free chlorine for 5 min was overhead-applied to 17 container-grown nursery plants for 11 weeks in a commercial nursery to evaluate the response of container-grown nursery plants to chlorine. No visual symptoms of injury or growth reduction were observed on the evergreen shrubs (Juniperus horizontalis, Thuja occidentalis, Buxus microphylla, Picea glauca, Rhododendron catawbiense, Taxus media, and Chamaecyparis pisifera), but there were visual injuries and/or growth reduction on some of the deciduous shrubs (Salix integra, Hydrangea paniculata, Prunus xcistena, Weigela florida, Physocarpus opulifolius). Symptoms of anthracnose were reduced on Cornus alba plants treated with chlorinated water. The chlorine treatment did not affect leaf chlorophyll content. The chlorine treatment killed all fungi and oomycetes in the irrigation water (DNA multiscan). Although there were visible leaf injuries and growth reduction on some of the deciduous plants, chlorine injury did not render them unsalable. Results suggest that irrigation water treated with 2.4 mg·L-1 free chlorine for 5 min will effectively control the dispersal of common plant pathogens without reducing the market value of container-grown plants.
Article
Full-text available
For genotoxicity study simultaneous phytotoxicity and mutagenicity assay with Vicia sativa L. var. Klára was used. For phytotoxicity the following rank orders of growth inhibition can be arranged: for roots: Ni(II) > Cr(VI) > Cr(III); for shoots: Ni(II) > Cr(VI) ≥ Cr (III). For mutagenicity assay root tips of V. sativa were used and chromosome aberrations were determined at least in 500-anatelophases. All tested metals exerted in V. sativa a significant increase of chromosomal aberration rate in applied concentrations. Maximum of aberrations invoked Cr(VI) and the rank order of aberrations fall was: Cr(VI) > Ni(II) > Cr(III). Genotoxic effects of metals were determined by analysis of micronuclei frequency in the pollen tetrads of Tradescantia plants. None of tested metal significantly stimulated micronuclei frequency and genotoxic effect was decreased in order: Cr(VI) ≥ Ni(II) > Cr(III).
Book
An understanding of the mineral nutrition of plants is of fundamental importance in both basic and applied plant sciences. The Second Edition of this book retains the aim of the first in presenting the principles of mineral nutrition in the light of current advances. This volume retains the structure of the first edition, being divided into two parts: Nutritional Physiology and Soil-Plant Relationships. In Part I, more emphasis has been placed on root-shoot interactions, stress physiology, water relations, and functions of micronutrients. In view of the worldwide increasing interest in plant-soil interactions, Part II has been considerably altered and extended, particularly on the effects of external and interal factors on root growth and chapter 15 on the root-soil interface. The second edition will be invaluable to both advanced students and researchers.
Article
The net photosynthetic rate (P-n), the apparent quantum yield (AQY), the photochemical efficiency of PS II (F-v/F-m), the quantum yield of PS II electron transport (Phi(PSII)) and the coefficient of photochemical quenching (q(p)) were decreased in rice (Oryza sativa L.) leaves under high nocturnal temperature (42 +/- 1) degrees C stress, but the relative reduction state of PS II (1 - q(p)) was increased. With the increment of stress time, the chlorophyll content and the binding degree of chlorophyll-protein complex declined gradually, the O-2(radical anion) (superoxide radical) production rate and H2O2 content in leaves elevated. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased for 2 - 3 days under high temperature stress yet decreased afterwards. The results showed that the photosynthetic efficiency declined in rice leaves under high nocturnal temperature stress with concurrent emergence of the symptom of oxidative damage. The gradual increase of the SOD, POD and CAT activities, as well as that of the ratio of P-r(photo-respiration rate) to P-r + P-n and non-photochemical quenching of chlorophyll fluorescence (NPQ) indicates that those mechanisms related to the changes of these parameters may play an important role in protecting rice leaves from oxidative damage under high nocturnal temperature stress.
Article
Sanitation is of crucial importance for the microbiological safety of drinking water. However, chlorination of water rich in organic material produces disinfection by-products (DBPs), many of which have been reported to be mutagenic and/or carcinogenic compounds such as haloacetic acids and trihalomethanes. Epidemiological studies have suggested a link between drinking water consumption and cancer. We previously observed that Cyprinus carpio fish exposed to DBPs, may be subject to epigenetic effects such as those referable to the up-regulation of cytochrome P450 (CYP) superfamily (ex. co-mutagenesis/co-carcinogenesis and oxidative stress) that has been associated to non-genotoxic carcinogenesis. Our goal was to study the xenobiotic metabolism in mollusks exposed in situ to surface water of Lake Trasimene (Central Italy) treated with several disinfectants such as the traditional chlorine dioxide (ClO2), sodium hypochlorite (NaClO) or the relatively new one peracetic acid (PAA). The freshwater bivalves (Dreissena polymorpha) being selected as biomarker, have the unique ability to accumulate pollutants. Freshwater bivalves were maintained in surface water containing each disinfectant individually (1-2 mg/L). Following an exposure period up to 20 days during the fall period, microsomes were collected from the mussels, then tested for various monooxygenases. Strong CYP inductions were observed. These data indicate that drinking water disinfection generates harmful DBP mixtures capable of determining a marked perturbation of CYP-supported reactions. This phenomenon, being associated to an increased pro-carcinogen bioactivation and persistent oxidative stress, could provide an explanation for the observational studies connecting the regular consumption of drinking water to increased risk of various cancers in humans.
Article
This is a study on the regulation of chloride concentrations in H. vulgare at the early tillering stage, when grown on media of high sodium chloride concentration. 36CI was used during certain periods to determine retranslocation.