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Sistema de Información Científica
Red de Revistas Científicas de América Latina y el Caribe, España y Portugal
Contam. Ambient. 2,
63-70, 1986
TRADESCAA'TIA-MICRONUCLEUS
TEST
ON POTASSIUM DICHROMATE
RAFAEL VILLALOBOS-PIETRINI, SANDRA
GOMEZ-ARROYO, ANA Rosa FLORES-
MARQUEZ
AND
ADRIANA
CISNEROS.
Laboratorio de Citogenética y MutagCnesis Am-
bientales, Centro de Ciencias de la Atmósfeia,
Universidad Nacional Autónoma de México, Co-
yoacán
04510,
México, D.
F.
y Centro de Investi-
gación y Reproducción Animal, Universidad Au-
tónoma de Tlaxcala.
Cuttings with inflorescences of Tradescantia clone
4430
were allowed to absorb severa1
different concentrations of potassium dichromate during
6
hours and analysed
30
hours
Jater. The frequencies of micronuclei (MCNs) in tetrads were more than twice those
of the control. The relationship concentration-frequency was asymptotic.
RESUMEN
Se permitió que cortes de Tradescantia clone
4430
con inflorescencias absorbieran di-
versas concentraciones de dicromato de potasio durante seis horas y fueran analizadas
30
horas después. Las frecuencias de los micronúcleos (MCNs) observados en las tétra-
das rebasaron el doble del registro en los testigos, la relación concentración-respuesta
fue asintótica.
INTRODUCCION
Nowadays and specially due to industrial development, heavy metals have obtained
an important place among environmental pollutants and represent a pokntial health
risk due to their acute toxicity.
A
common pollutant is ch,romium, which is considered an essential micronutrient,
involved in the normal metabolism of glucose (Mertz 1969, Freund
et
al. 1979),
and as a cofactor in the increased activity of some enzymes (Mertz
1969).
It pro-
vides additivnal structural configuration and stabilization to nucleic acids and it
also serves in the maintenance of protein structure (Wacker and Vallee
1959).
Chromium is never found in the uncornbined state. Its is found in severa1 oxida-
tion states, the .most common are hexavalent (VI) and trivalent (111) forms.
Although in nature plants contain :mal1 amounts of metals (Gruskho 1948,
Gilbert 1957, Starich and Blincoe 1983), the role they play in their metabolism is
not known (Gilbert 1957). In alfalfa, an organic chromium complex of about 2600
daltons was found. In other plants this complex has a different molecular weight
(Starich and Blincoe 1983).
The extent of contamination depends mainly on soil condition, plant type (Davis
1982) and availability to the plant (Davis 1956).
Somi of the effects produced by an excess of chromium in plants are: the pre-
vention of development of oats (Hunter and Vergnano 1953), beans (Walace
et al.
1976), Rhodesian grass (Soane and Saunkr 1959), sugar beets (Pesek and
Kolsky 1967), barley (Skeffington
et
al.
1976), and rice (Kamada and Doki 1974)
;
the inhibition of infilorescence development and delay of stem growth in tobacco
(Soane and Saunder 1959)
;
the inhibition of seed germination
in
Picea abies
(Supuka 1974) and in beans (Mukherji and Kumar 1978)
;
and chlorosis in toma-
toes, sugar beets, potatoes (Hewitt 1953), tobacco (Soane and Saunder 1959),
oats (Hunter and Vergnano 1953) and rice (Verfaillie 1974).
The heavy metal effects involve several plant tisues. As an example the gametes
which develop in the inflorescences have been widely used in genetics toxi-
cology as the mother cell chromosomes of pollen grains are sensitive to physical
(Sparrow 1951, Ma
et
d.
1980, 1982, Villalobos-Pietrini and Balderas 1982) and
chemical agents (Ma
et al.
1978, 1983, 1984, 1985, Ma 1979, 1981b, Villalobos-
Pietrini and Balderas 1982). The sensitivity of the gametic cdlls to the mutagens
is related to the state of the microsporogenic cycle in which the treatment is applied.
There
is
agreement in the studies made on different plants treated with several
agents that the most sensitive state is prophase 1 (Sparrow 1951, Sparrow
et al.
1952, Ochlewsa 1964, Ma
et
al.
1978, 1980, Ma 1979, 1981a, by Villalobos-Pietrini
and Balderas 1982).
One of the most used plants to detect the damage produced by pllutants in germ
cells
is
Tradescantia,
a member of the Commelinaceae, the microsporogenic cycle
of which is well known, so for T.
reflexa
it takes 15 days (Sax and Edrnonds 1933)
and for T.
paludosa
it lasts 17 days (Taylor 1950). Among
Tradescantia
the clone
4430 has been cornmonly used because of its high sensitivity to chemical mutagens
(Van't Hof and Schairer 1982, Villalobos-Pietrini
et al.
1986). In order to evaluate
the damage produced
to
Tradescantia,
probably the easiest and most efficient
m'ethad
is
the microuclei (MCNs) in tetrads, at the end of the meiosis (Ma
et al.
1$78)
!Some responses obtained after expures are acentric fragments (Sparrow and
s!ngleton 1953, Read 1959, Schmid 1976, Ma 1979, 1981a, b), chromosomes with
inactivated centromere and isochromosomes (Gómez-Arroyo and Villalobos-Pietrini
1983, Gómez-Arroyo
et al.
1985) that are excluded from the daughter nuclei at
the end of the cell division and remain in the cytoplasm of the tetrads as MCNs
(Ma 1979, 1981a). This test system has also been used to monitor poPuted loca-
tion
in situ
(Ma
et al.
1980, 1984).
It has been shown that chromium (VI) induces mutations in
Salmonella typhi-
murium
(Petrilli and De Flora 1977, 1982, Bennicelli
et al.
1983), in
Eschefiichia
coli
(Venitt and
Levy
1974, Nakamuro
et
d.
1978, Petrikli and De Flora 1982)
and in
Schkosaccharomyces pombe
(Bonatti
et al.
1976)
;
it also produces lethality,
mitotic gene conversion and reverse mutations in
Saccharomyces cereviceae
(Kharab
and Singh 1985)
;
causes lesions to chicken embryo hepatocytes DNA (Tsapa-
kos
et
al. 1983)
;
induces chromosomal aberrations in bone marrow cells of rats
TRADESCANTIA-MICRONUCLEUS
TEST ON POTASSIUII DICHROMATL
(Bigaliev
ct
al.
1976), cmbryo cells of hamsters (Tsuda and Kato 1977) and in
mice cells in culture (Umeda and Nishimura (1979)
;
inh:bits DNA syntliesis
and decreases cdl survival in hamster fibroblasts (Lcvis
et
al. 1977, 1978). It also
produces chromosomal aberrations, sister chromatid cxchanges
(
SCE
)
and m'totic
delay in ovary cmbryos of hamsters (CI-10) (Majonc and Levis 1979)
;
SCE
in human lymphocytes
in vitro
(Gómcz-Arroyo
et al.
1981) and in rodent cell
cultures, and tran7fonnatlon of hamster cells
in vitro
(Bianchi
et d .
1983)
;
C-mitosis
in meristematic cells of
Allium cepa
(Levan 1945) and
Vicia faba
root tips (Gó-
mzz-Arroyo and Vilallobos-Pietrini 1983)
;
chromosoml aberrations (Gómez-Arroyo
and Villalobos-Pietrini 1983) and SCE in
Vicia faba
(CCmez-Arroyo
et al.
in pre-
paration)
.
Due to the fact that hexavalent forms of the chromium compounds, are the
most toxic to living organisms it is worth knowing the effects of pot~sium
dichro-
mate on gametic cells of
Tradescantia
clone 4430 using the micronuclei in tetrads
as a test system.
MATERIAL AND METHODS
The biological material used was
Tradescantia
clone 4430 which or:ginated
as
a
result of the interespec:fic cross bctween
T. Itirsutiflora
and
T. subacaulk
(Sparow
and Sparrow 1976).
The plants were reproduccd vegetatively and maintained in plastic trays with
a mixture of leaf and moldy sand (2: 1) in the greenhouse of the Centro de Cien-
cias de la Atmórfera, UNAAI. They werc irrigated twice a week.
210 plants were selected with vigorous stems and young inflorescences. They
were cut 6 cm from the top and forrned 7 groups.
-
-
Cuttings were allowed to abcorb through its normal vascular system the potassium
d'chromate solutions of 0.1, 0.2, 0.4, 0.6, 0.8 and
1.0%
ccntained in glasses. The
control was exposed to distilkd water. Al1 groups were trcated for 6 hours.
Later, cuttings wre washed with tap water and placed in glasses containing tap
water and constant aereation for 30 hours. Thc inflorescences werc fixed in ethanol-
acetic acid (3:l) and after 24 hours transfered to 70% cthanol (Ma 1981a).
By mcans of a dissecting microscope furnished with
a
micrometric objective, buds
of
2.0
-
3.5 cm were selected bccause in previous obscrvations, tetrads were found
in buds of these lengths. Buds werc dissected on slides and the anthers werc placed
in 0.5% acetocarmine and pressed in order to let the pollen mothsr cells frce and
to verify the precence of tetrads. The debris were removed before application of the
coverglass. Then the slide was heated over an alcohol flame avoiding boiling.
Gentle pressure was applied with the palm of the hand over the coverglass and some
layers of absorbent paper. Permanent slides were made following Conger and
Fairchild technique
(
1953). In order to avoid bias, slides were handled with a code.
I:or each concentration, 1500 to 3000 tetrads were observed, scoring normal tetrads
and tetrads with different numbers of MCNs, expressed at last as number of
MCNs per 100 tetrads.
To compare the mean va1lues obtained. in the treated and control groups, the
difference cf proprtion test
(Spiegel
1961) was applied. The data are thc
results of one experiment and itj replica.
RESULTS
The
Tradescantia
cuttings exposed to the lower concentrations (0.1, 0.2 and
0.4%) of potassium dichromate did not show physiological damage, but up to
0.6yc, necrotic areas in the stem and leaves were observed to reach fading in the
cuttings treated with 1.0%. In al1 cares the inflorescences were not affected. Thc
damage observed at the end of the treatment increased after 30 hours.
Table 1 shows means and standard devat'ons of MCNs per 100 tetrads for
each group. There was not a concentration-response relationship, but by statiscal
analysis the frequencies of MCNs were found significangly different from the con-
trols (P
<
0.001). The frequency of MCNs per 100 tetrads in the groups treated
exceeded double that of the control. The response
was
asymptotic to concentrations
,Table
1).
TABLE 1. MICRONUCLEI (MCNs) IN TETRADS OF TRADESCANTIA
INDUCED BY SEVERAL CONCENTRATIONS
OF POTASSIUM DICHROMATE
Conccntration
MCNs/100 tetrads
Control
o. 1
0.2
0.4
0.6
0.8
1 .o
DISCUSSION
As noted in Table 1, potassium dichromak can affect thc cliromosomes of the
pdlen mother cells in prophasc 1. The plants showed the damage 30 hours later
as MCNs which are the consequences of the production of acentric fragments
(Read 1959), chromosoms with inactivatcd centromere (Gómez-Arroyo y Villa-
lobos-Pietrini 1983, Gómez-Arroyo
et al.
1986) and isochromosomes (Schmid 1976,
GCmez-Arroyo y Villalobos-Pietrini 1983, GCmez-Arroyo et al. 1986) that are
excluded from the nuclei at the end of the meiotic division (Ma 1979, 1981a). 'The
results agEe with those of Gómez-Arroyo and Villalobos-Pietrini (1983) who found
that the same compound induced MCNs in thc meristematic root tips cells of
Vicia
faba
and that there was not a concentration-response relationship. However, Ma
et al.
(1984) treating
Tradescantta paludosa
Sax clone 03 with potassium chro-
mate, obtained negative results in the induction of MCNs.
TRADESCANTIA-MICRONUCLEUS TEST ON POTASSIUM DLCHROMATE
6 7
The effectiveness of potassium dichromate in damaging the genctic material is
shown by the production of point mutations (Bonnatti
et al.
19811, chromosomal
aberrations (Bigaliev
et al.
1976, Tsuda and Kato 1977, Nakamuro
rt
al.
1978,
Nishimura and Umeda 1978, Majone and Levis 1979, Unieda and Nish'mura
1979, Gómez-Arroyo and Villalobos-Pietrini 1983), cell transformation (Tsuda and
Kato 1977), DNA synthesis inhibition (Levk et
al.
1977, 1978) and niitotic dclay
(Majone and Levis 1979).
Plants take up chromium from the soil, accummulste it mainly in roots (90%)
and of the remainder only
2%
is translocated to leaf structures (Huffman and
Allaway 1973). In spite of the fact that the cuttings treated in this work do not
ha= roots, the whole amount of chromium probably did not reach the inflores-
cences, becausc they did not show physiologic alterations even with thc highest
concentrations.
Chromium (VI), the form contained by potassium dichromate, has an increased
biological activity because it was able to cross the cell membranes (Mertz 1969,
Taylor and Parr 1978), using the same transport xñéchanisms
to enter the cells as
other oxyanions like phosphate and sulphate (Jennette 1981). In thc cytoplasm
it is reduced by the enzyrnes composing the electron-transport cytochrome P-450
and by NADPH (nicotinamide and adenine reduced dinucleotide phosphate) to
form Cr 111 (Jennette 1981) which binds nucleic acids and nucleoproteins (Herr-
mann and Speck 1954, Levis et
al.
1977) and thus can lead to mutagenic and
carcinogenic activity (Tsapakos and Wetterhan 1983).
When Cr (VI) comes into contact with micromosomal fraction before crossing
the
Salmonella
cell membrane it is reduced to Cr (111) and thus mutagenic activity
is decreased (Lofroth 1978, Bennicelli
et al.
1983. Chelators also reduced Cr (VI)
to Cr (111) preventing entrance into the cell and decreasing or eliminating its
mutagenicity (Gentile
et al.
1981). Chromium is one of thc carchogenic heavy
metals which is consistently detected as beig mutagenic (Babich
et al.
1985).
In rats injected intravenously with potassium dichromate, thc reduction of Cr
(VI) to Cr (111) is made in the blood (Cavalleri
et
al. 1985) and the only way
the latter penetrated Qiver cells was by binding to a low-mokcular-weight substance
(Yamamoto
at al.
1981). Ormos and Mányai (1977) found that higher chromate
concentrations than normal inhibited chromate uptake in the
red
blood cells.
Tsapakos and Wetterhahn (1983) found little Cr (111) bound to DNA in the
absence of tlir complete niirrosomal rediicirig system. Meanwhilc the binding of
Cr (VI) to DNA in the ~~reseiicc
o[ niirrosonics and NADPlI was caused by a
labile intermediate chromium oxidation state, Cr (V) was produced and requircd
for the maximum binding (Jennette 1982).
Within the cell Cr (VI) a'lso damages the lycosonles, lcaving free among other
enzhes, lipases which hydrolyse tissue lipids producing epoxyaldehides that have
been related to cancer (Schoental 1975).
As can be seen in Table
1,
the frequency of MCNs in al1 the groups treated
with chromium goes beyond double the control value and is cignificantly different
(P
<
0.001). These data point out that potassium dichromate is a good inducer
of
MCNs, dthough them was not a concentration-frequency re1at;onship. Instead
the response was asymptotic to concentration. This was probably due to inhibition
of entry of chromium into the cell when high concentrations were reached (Omos
and Mányai 1977), some extracellular reduction of Cr (VI) occurred (Jennette
1981),
low translocation ,of Cr occurred in the
upper
part of the plants (Huffman
and
Allaway
1973),
or thcre was a saturation of sensitive sites of the chromosomcs.
Acknowledgements
This work was performed under contract PCCBBNA-021988 of CONACyT.
REFERENCES
Babich H., Devanas M. A. and Stotzky G.
(1985).
The mediation of mutagenicity and
clastogenicty of heavy metals by physicochemical factors. Environ. Res.
37,
253-280.
Bennicelli C., Camoirano A., Petninelli S., Zanachi P. and De Flora S.
(1983).
High sensi-
tivity of
Salmonella
TA102
in detecting hexavalent chromium mutagenicity and its reversal
by liver and lung preparations. Mutat. Res.
122,
1-5.
Bianchi V., Celotti L., Lanfranchi G., Majone F., Marin G., Montaldi A., Sponza G., Tamino
G., Venier P., Zanteschi A. and Levis A. G.
(1983).
Genetics effects of chromium com-
pounds. Mutat. Res. 117,
279-300.
Bigaliev A. B., Elemesova M. S. H. and Bigaleiva R. K.
(1976).
Chromosome aberrations in
the somatic cells of mammals evoked by chromium compounds. Tsitol. Genet. 10,
222-224.
Bmatti S., Meini H. and Abbondandolo A.
(
1976).
Genetic effects of potassium dichromate
in
Schuosaccharomyces pombc.
Mutat.
Res.
38,
147-150.
Cavalleri A., Minoia C., Richelmi P., Baldi C. and Micoli G.
(1985).
Determination of
total and hexavalent chromium in bile after intravenous administration of potassium dichro-
mate in rats. Environ. Res.
37,
490-496.
Conger A. D. and Fairchild L. M.
(1953).
A quick-freeze method for making smear slides
permanents. Stain Technol.
28,
281-283.
Davis G. K.
(1956).
Chromium in soils and animals. In:
Chromium, chemistry of chromium
and its compounds.
(M. J. Udy,
ed.)
Reinhold, New York, pp.
105-109.
Davis R. D.
(
1982).
Influence of micropollutants on vegetation. Wat. Sci. Tech.
14,
31-44.
Freund H., Atamian S. and Fisher J. E.
(
1979).
Chromium deficiency during total parenteral
nutrition. JAMA
241,
496-498.
Gentile J. M., Hyde K. and Shubert J.
(1981).
Chromium genotoxicity as influenced by
complexation and rate effects. Toxicol. Lett.
7,
439-448.
Gilbert F.
(1937).
Mineral nutrition and balance of life. Univ. Oklahoma Press.
Gómez-Arroyo S. and Villalobos-Pietrini R.
(1983).
Chromosomal alterations induced by
some chromium salts. Cytologia 48,
185-193.
,
Altamirano M. and Villaiobos-Pietrini R.
(1981).
Sister-chromatid exchanges induc-
ed by some chromium compounds in human lymphocytes in
vitro.
Mutat. Res.
90,
425-431.
,
Castillo-Ruiz P. and Villalobos-Pietrini R.
(
1986
)
.
Chromosomal alterations induced
in
Vicia faba
by different industrial solvents: thinner, toluene, benzene, n-hexane, n-heptane
and ethyl acetate. Cytologia
51,
555-564.
,
Baíza A. M., López G. and Villalobos-Pietrini R.
(
1985). A
comparative study of
the cytogenetic effects of the insecticides heptachlor, malathion, and methyl parathion in
Vicia faba.
Contam. Ambient.
1,
7-16.
Gmskho Y. M.
(1948).
Chmmium as bioelement. Biokhimiya
13,
124-126.
Hernnann H. and Speck L. B.
(1954).
Interaction of chromate witli nucleics acids in tissues.
Science 104,
426-427.
IIewitt E. J.
1953.
Metal interrelationships in plant nutrition. 1. Effects of some metal
toxicities on sugar
beet,
tomato, oat, potato and marrowstem kale grown in sand culture.
J. Exp. Bot.
4,
59-64.
Ehiffman E. and Allaway W.
(1973).
Chmmium in plants: distribution in tissues organelles,
and extracts, and availability of bean leaf Cr to animals. J. Agric. Food Chem.
21,
982-985.
Hunter
J.
G. and Vergnano 0 .
(1953).
Trace-element toxicities in oat plants. Appl. Biol.
40, 761-777.
Jennette K. W.
(1981).
The role of metals in carcinogenesis: biochemistry and metabolism.
Environ. Health Perspec.
M,
223-252.
TRADESCANTIA-MICRONUCLEUS
TEST
ON POTASSIUnI DICHROMATE
(1982). Microsomal reduction of the carcinogen chromate produces chromium (V).
J. Am. Chem. Soc.
104,
874.
Kamada K. and Doki K. (1974). Reduction of chromium (VI) in
soil
and the determina-
tion of chmmium by direct atomic absorption spectrophotoinctry. Nippon Dojo-Heryogaku
Zasshi 45, 597-599. Chem. Abstr.
83,
8253, 1975.
Kharab P. and Singh
1.
(1985). Cenotoxic effects oí potassium dicliromate, sodium nrsenite,
cobalt, chloride and lead nitrate in diploid yeast. hutat. Res. 155, 117-120.
Levan A.
(1945). Cytological reactions induced by inorganic salt solutions. Nature 156,
75 1-752.
Levis A.,
Buttignol M. and Vettorato L. (1977). Inhibition of DNA synthesis in BHK
fibroblast treared
in uitro
with potassiuni dichromate. Experientia 33, 82-84.
,
B.anclii V., 'l'amino G. and Pergoraro B. (19%). Cytotoxic effects of mammaiian
cells
in uitro.
Br.
J.
Cancer 37, 386-396.
Lofroth G. (1918). 'í'he mutagenicity of hexavalent chromium is decreased by microsomal
metabolism. Naturwissenschaften
65,
207.
Ma
T. H. (1979). Micronuclei induced by X-rays and chemical mutagens in ineiotic pollen
mother cells of
Tradescantia
a promising mutagen test system. Mutat. Res. 64, 307-313.
(
198
la).
Tradescantia
micronucleus bioassay and pollen tube chromatid aberration
test for
in situ
monitoring and mutagen screening. Environ, liealth Perspec. 37, 85-90.
(1981b).
Tradescantia
MCN-in-tetrad mutagen test for on-site monitoring and further
validation. EPA-600/S1.
,
Anderson Y. A. and Harris M. M. (1983). Mutagenicity of drinking water detected
by the
Tradescantia
micronucleus test.
Can.
J. Genet. Uytol.
27,
143-150.
---
7
9
and Bare J. L. (1983). Tradescantia-micronucleus (Trad-MCN)
test on the genotoxicity of malathion. Environ. Mutagenesis 5, 127-137.
,
Kontos G.
J.
and Anderson V. A. (1980). Stage sensitivity and dose response of
meiotic poilen mother cells of
Tradescantia
to X-rays. Environ. Expt. Bot.
20,
169.
,
Sparrow A. H., Schairer L. A. and Nauman A.
F.
(19781. Effect of 1,2-dibromo-
ethane (DBE) on meiotic chromosomes of
Tradescantia.
Mutat. Res. 58, 251-258.
,
Haris M. M., Anderson V. A., Ahmed I., Mohammad K., Bare J. L. and Lin G.
1984).
Tradescantia-micron~icleus
(Trad-MCN) test on 140 health-related agents. Mutat.
Res. 138, 157-167.
,
Tsungci F., E10 J., Chen D., Zhou R., Lin
C.,
Dai J. and Li J. (1982
)
.
Extraordinary
Iiigh micronucleus frequency induced by X-rays in a special clone of
Tradescantia seflexa.
Mutat. Res,
104,
101-103.
Majone F. and Levis A. G. (1979). Chromosomal aberrations and sister chromatid exchanges
in Cliinese hamster cells treated
in uitro
with hexavalent chromium compounds. Mutat. Res.
67, 231-238.
Mertz W. (1969). Chromium occurrence and lunction in biological systems. Physiol. Rev.
49, 163-239.
Mukherji S. and Kumar B. R. (1978). Characterization of chromium toxicity in different
plant materials. Ind. J. Exp. Biol. 16, 1017-1019.
Nakamuro K., Yoshikawa K., Sayato Y. and Kurata H. (1978). Comparative studies of
chromosomal aberration and mutagenicity of trivalent and hexavalent chromium. Mutat.
Res. 58, 175-181.
Nishimura M. and Umeda M. (1978). Mutagenic effect of some metal compounds on cul-
tured mammalian cells. Mutat. Res. 54, 246-247.
Ochlewsa M. (1974). Influence of ionizing radiation on microsporogenesis in ryc
(Secale
cereale L.)
Hodwla Rosl, Aklm. Nasienn. 18, 151-167.
Ormos C. and Mányai S. (1977). Chemical modification of erithrocytes. Effect on the velo-
city of chromate uptake. Acta Biochim. et Biophys. Acad. Sci. Hung. 2, 343-352.
Pesek F. and Kolsky V. (1967). Content of elements contaminating the edible parts of
agricultura1 crops. Content of Eeavy metals and trace clements in sugar beets from the
region of the Lovosice chemical plant. Rostl. Vyroba 13, 445-462. Chem. Abstr. 67, 52789.
Petrilli F. L. and De Flora S. (1977). Toxicity and mutagenicity of hexavalent chromium
on
Salmonella typhimurium.
Appl. Environ. Microbiol. 33, 805-809.
and
-
(1982). Interpretations on chrornium mutagenicity and carcinogenicity.
Mutagens in Our Environment.
Alan
R.
Liss, New York pp. 453-464.
Read J. (1959). Mitosis, and inhibition of mitosis by radiation. In:
Radiation bwlogy of
Vicia faba in ralation to the general problsm.
Blackwell
Scisntific
Pub. Oxford, pp. 48-69.
Sax K. and Edrnonds H. W.
(
1933). Development of the male gametophyte in
Tradescantia.
Bot. Gaz. 95, 156-163.
Schmid W. (1976). '1'lie ~nicronucleus
test for cytogenetic analysis. In:
Chemicaí Mutagens:
Principies and methods for their detection.
A. Hollaender
Ed.
Vol. 4 New York. Ylenurii
Press,
pp. 31-53.
Schoentai
R.
(1975). Chromium carcinogenesis, fonnation of epoxyaldehides and tanning.
Brit. J. Cancer
32,
403-404.
Skeffington
1<.
A., Shewrey Y.
R.
and Peterson P. J. (1976). Cliromium uptake and transport
in barley seedlings
(Hordeum vulgare
L.). Planta Berl.
132,
209-214.
Soane B. D. and Saunder D. H. (1959). Nickel and chromiurn toxicity of serpentine aoils
in Suutlicrn Hhodesia. Soil Sci. 88, 312-330.
Spwrow A. H.
(1951).
Hadiation sensitivity
af
cells during mitotic and meiotic cycles with
emphasis on possible cytochemical changes. Ann. N. Y. Acad. Sci.
51,
1508-1540.
and Singleton W. A. (1953). The use of iadiocobalt as a source of gamma rays and
some effects on chronic irradiation on growing plants. Am. Nat. 87, 29-48.
and Sparrow
R.
C. (1976). Spontaneous somatic mutation frequencies for flower
color in several
Tradescantia
species and hybrids. Environ. Exp. Bot.
16,
23-46.
,
Moses M. J. and Dubow R. J. (1952). Relationships between ionizing radiation,
chmmosome breakage and certain other nuclear disturbances. Exp. Cell Res. Suppl. 2,
305-322.
Spiegel M. R. (1970).
Statistics. Schaum's
outline series. Schaum Publishing, New York, pp.
142-193.
Starich G. H. and Blincoe C. (1983). Dietary chromium-forms and availabilities. Sci. Total
Environ. 28, 443-454.
Supuka J. (1974). Influence of the extracts of sorne iron-alloy powders on
Picea abies
(L.)
Karst. seed gennination. Biológia (Bratislava) 29, 759-767.
Taylor H. J. (1950). The duration of differentiation in utcised anthers. Amer. J. Bot. 37,
137-143.
Taylor F. G. and Parr P. D. (1978). Distribution of chromium in vegetation and small
mammals adjacent to cooling towers. J. Tenn. Acad. Sci.
53,
87-91.
Tsapakos M. J. and Wetterhahn K. E. (1983). The interaction of chromium with nucleic
acids. Chem. Biol. Interactions 46, 265-277.
,
Hampton T. H., Sinclair P. R., Sinclair J.
F.,
Bemos W. J. and Wetterhahn
K.
E.
(1983). The carcinogen chromate causes DNA darnages in inhibition drug-mediated induc-
tion of porphyrin accumulation and glucuronidation in chick embryo hepatocytes. Carcino-
genesis 4, 959-966.
Tsuda H. and Kato
K.
(1977). .Chromosornal aberrations and morphological transformation
in
hamster embryonic cells treated with potassium dichromate
in uitro.
Mutat. Res.
46,
87-94.
Umeda M. and Nishiumura M. (1979). Inducibüity of chromosomal aberrations by metal
compounds in cultured rnammalian cells. Mutat.
Res.
67, 221-229.
Van't Hof J. and Schhr L. A. (1982).
Tradescantia
assay system for gaseous mutagens.
A
report of the U:S.
Environmental Protection Agency Cene-Tox. Program. Mutat. Res. 99,
303-315.
Venitt S. and Levy L.
$.
(1974). Mutagenicity of chromates in bacteria and its relevance
to chromate carcinogenesis. Nature 250, 493-495.
Verfaillie G. R. M. (1974). Kinetics of chmmium absorption by intact rice plants. IAEA,
Vienna pp. 315-331.
Villalobos-Pietrini R. and Balderas M.
(
1982). Pollen abortion induced by gamma ,radiation
and ethanol in
Gibasis pulckella.
An. Inst. Biol. Unive. Nal. Autón. MCx. 49, Ser. Biol.
Exp. (1): 89-107.
,
Hernhnda R., Guadarrama M. A. and G4mez-Arroyo S. (1986). C,ytological detec-
tion of somatic mutations in
Tradescantia
induced by ethanol. Cytologia
51,
623-630.
Wacker W. E. C, and Vallee B. L. (1959). Nucleic acids and metals. J. Biol. Chem. 234,
3257-3261.
Wallace
A.,
Soufi S. M., Cha
J. W.
and Romrney E. M. (1976). Some effects of chromium
toxicity on bush bean plants grown in
roa.
Plant Soil 44, 471-473.
Yamarnoto A. M., Wade 0 .
and
Ono T. (1981). A low-molecular-weight chrornium binding
substance in mammals. Toxicol. Appl, Pharmacol.
59,
515-523.
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