ISSN 1021-4437, Russian Journal of Plant Physiology, 2009, Vol. 56, No. 1, pp. 80–84. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © I.V. Seregin, A.D. Kozhevnikova, 2009, published in Fiziologiya Rastenii, 2009, Vol. 56, No. 1, pp. 92–96.
Heavy metals (HM) are absorbed by plants mainly
via the root system. Therefore, their toxic effects are
clearly manifested in root growth inhibition. This is
widely used in the test for their presence in environ-
ment [1–6]. Growth inhibition and morphogenesis dis-
turbance depend directly on HM accumulation and spe-
ciﬁc distribution in the growing part of the root. A set
of factors determine HM uptake and accumulation.
Other ions affect greatly HM uptake in various plant
organs. Thus, ions of alkaline and alkaline earth metals
could be graded in accordance with a decrease in their
inhibitory effects on bean roots as follows: Ca
. Analogous row could be built for metal
ions suppressing Ni uptake by
It is evident from these data that calcium ions exert a
marked effect on HM uptake from the soil. As a rule,
the presence of Ca results in a great reduction in the
HM absorption by the roots of various plant species,
thus weakening HM toxicity [9–14].
However, until now it is not clear whether Ca “pro-
tective” action is universal for all plant species growing
in the presence of HM and how the presence of Ca
affects the accumulation of HM in the growing part of
the root of various plant species. This problem is not
studied properly, although it is extremely important for
practice because soil calcination is one of the widely
used approaches directed to a weakening of HM toxic-
ity [11, 15].
The main goal of this work was to elucidate whether
Ca could exert an effect on Pb- and Ni-induced growth
suppression of amaranth seedlings and to compare dis-
tribution and accumulation of these HM in the growing
root tip in the presence and absence of Ca.
MATERIALS AND METHODS
sp. L.) seeds were kindly
presented to us by Prof. G.A. Romanov. The seeds were
placed in petri dishes 150 mm in diameter on ﬁlter
paper moistened with the solutions of Pb
100, 200, 500, 700, and 1000
M) and Ni(NO
50, 70, 100, 500, and 1000
To study Ca effect on Pb and Ni toxic action, exper-
iments were performed in the presence or absence of
. To choose its concentration, amaranth seed-
lings were grown in the presence of Ca
concentration range from 0.05 to 3.0 mM. As a result
Enhancement of Nickel and Lead Accumulation and Their Toxic
Growth-Inhibitory Effects on Amaranth Seedlings
in the Presence of Calcium
I. V. Seregin and A. D. Kozhevnikova
Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, Moscow, 127276 Russia;
fax: 7 (495) 977-8018;
Received February 14, 2008
— The effects of Ni(NO
sp. L. root growth and the effect of calcium
on heavy metal (HM) accumulation in the growing root zone and root growth inhibition were studied. The seeds
were germinated in the Pb(NO
solutions at concentrations of 50, 100, 200, 500 and 700
M or Ni(NO
solutions at concentrations of 10, 50, 70, 100, and 500
M in the presence of 100
or without it.
HM toxicity was assesses in 7 days after seed sowing by the root length. Distribution of HM over the tissues of
the growing root part was examined histochemically. Ni was more toxic to root growth than Pb. In the presence
of Ca, Ni and Pb accumulation in the amaranth root growing part increased markedly, and this enhanced their
growth-inhibitory of action. A comparison of results obtained in this work and available from the literature per-
mitted a conclusion that the routes of HM penetration into the root differ in different plant species, and this
determines ambiguity of protective Ca action.
Key words: Amaranthus - lead - nickel - calcium - root - growth - distribution
: HM—heavy metals.