ISSN 10214437, Russian Journal of Plant Physiology, 2012, Vol. 59, No. 3, pp. 333–338. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © E.R. Fazlieva, I.S. Kiseleva, T.V. Zhuikova, 2012, published in Fiziologiya Rastenii, 2012, Vol. 59, No. 3, pp. 369–375.
Anthropogenic influence is a mighty ecological
factor affecting the plant kingdom. It frequently
exceeds natural factors in the strength and diversity.
Environment pollution with heavy metals is an
extreme anthropogenic factor capable of plant organ
Heavy metals are known to induce ROS generation
and oxidative stress in the cells, protein denaturation,
nucleic acid damage, and lipid peroxidation (POL).
Both shortterm and chronic action of heavy metals
enhance POL. At present, it is known that POL acti
vation at stress is not only the consequence of dis
turbed homeostasis but also a component of the adap
tation process [1, 2].
Antioxidant enzymes and lowmolecular antioxi
dants play an important role in the defense against the
injurious action of free radicals and in plant adaptation
to the action of manmade pollutants. Proline is a uni
versal protector against stress in higher plants; it man
ifests diverse biological effects, obviously including
antioxidant action . A key enzyme protecting the
cell against ROS is superoxide dismutase (SOD) con
verting superoxide anionradical into hydrogen perox
ide. According to available data [4–6], many factors
elevating ROS concentration in the cell activate SOD.
Peroxidase protects the cell against hydrogen peroxide
produced as a result of superoxide reduction; peroxi
dase decomposes peroxide with the formation of
molecular oxygen and water.
Copper is one of the main pollutants on the man
disturbed territories in the Middle Urals. At the low
concentrations, copper is a micronutrient essential for
plants. However, high copper concentrations are
toxic; they activate free radical oxidation, resulting in
the disturbance of the biological membrane structure
and physiological and biochemical processes. It might
be that plants inhabiting polluted territories have bio
chemical properties providing for their tolerance to
technogenic factors, heavy metal in particular. It is
known that legume plant tolerance to elevated con
centrations of heavy metals in soil might be deter
mined by the high content in their cells of specific pro
teins and other protecting compounds permitting par
tial neutralization of heavy metal toxicity [7–9]. This
determined our choice of plant species for this study.
The objective of this work was to study separate
components of the antioxidant defense system in the
adaptation of wild plant species to copper excess in
Antioxidant Activity in the Leaves of
from ManMade Disturbed Habitats
in the Middle Urals under the Influence of Copper
E. R. Fazlieva
, I. S. Kiseleva
, and T. V. Zhuikova
Gorkii Ural State University, pr. Lenina 51, Yekaterinburg, 620083Russia;
Nizhnii Tagil State Social and Pedagogical Academy, Nizhnii Tagil
Received April 1, 2011
—Physiological mechanisms of adaptation to copperinduced stress in two widespread legume
plants, white sweet clover (
Merik.) and zigzag clover (
L.), growing in habi
tats differing in the manmade pollution. An antioxidant plant defense system was activated in response to 10
, which is a stress factor. Specific biochemical features related to adaptation to soil contamination
with copper were observed in tested plant species. Superoxide dismutase was activated in response to stress in
both species from various habitats.
from the impact zone manifested the better capacity of proline
accumulation as compared with plants from less polluted habitats.
plants from the impact zone
contained more active peroxidase. It was suggested that plants growing for a long time under stressful condi
tions manifest the greater tolerance to copper ions than plants, which did not experience stress or were sub
jected to the milder stress.
Keywords: Melilotus albus, Trifolium medium
, heavy metals, copper, proline, superoxide dismutase, peroxi
dase, peroxidation of lipids.
: POL—peroxidation of lipids; SOD—superoxide