ISSN 1021-4437, Russian Journal of Plant Physiology, 2008, Vol. 55, No. 6, pp. 782–786. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © F. Yasar, S. Ellialtioglu, K. Yildiz, 2008, published in Fiziologiya Rastenii, 2008, Vol. 55, No. 6, pp. 869–873
Salinity in soil or water is of importance for agricul-
ture because it limits a distribution of higher plants in
certain natural habitats and induces a wide range of
adverse metabolic responses in them. Although some
crops are moderately tolerant to salinity, many crops
are adversely affected by even low salt levels .
Salinity stress affects the metabolism of plant cells,
leading to severe crop damage and a loss of productiv-
When plants are subjected to environmental
stresses, reactive oxygen species (ROS) are generated
in response to stress condition . ROS can cause oxi-
dative damage to many cellular components, including
membrane lipids, proteins, nucleic acids, and chloro-
phyll . The possible ROS involvement in the mecha-
nism of damage by salt stress was already conﬁrmed on
cotton , eggplant genotypes , and melon , i.e.,
species differing in salt resistance.
To control the level of ROS and to protect the cells,
plants possess a number of low-molecular-weight anti-
This text was submitted by the authors in English.
oxidants (ascorbate, glutathione, phenolic compounds,
tocopherols) and enzymes (SOD, CAT, APX, and GR)
scavenging ROS and regenerating the active forms of
antioxidants. Under normal conditions, ROS produc-
tion and scavenging is well regulated. In this way, this
enzyme system can eliminate the damaging effects of
toxic oxygen species [8–10].
The role of antioxidant enzymes as the components
of the main tolerance mechanisms developed in
response to different environmental extremes has
already been shown. Many studies showed a correlation
between the resistance to environmental stresses and
the efﬁciency of the antioxidant system .
ROS cause chlorophyll degradation and membrane
lipid peroxidation, reducing membrane ﬂuidity and
selectivity. Chlorophyll loss, lipid peroxidation mea-
sured as MDA (malondialdehyde, a product of lipid
peroxidation) content, and electrolyte leakage are con-
sidered to be indicators of oxidative damage [12, 13].
Common bean (
) is classiﬁed as
a salt-sensitive plant . It is a species widespread in
Anatolia, but its responses to salinity stress are almost
unknown. In a previous study , we have determined
one salt-tolerant and one salt-sensitive local bean culti-
vars. In this study, we hypothesized that an increased
activity of antioxidant enzymes (CAT, APX, and GR)
Effect of Salt Stress on Antioxidant Defense Systems, Lipid
Peroxidation, and Chlorophyll Content in Green Bean
, S. Ellialtioglu
, and K. Yildiz
Department of Horticulture, Faculty of Agriculture, University of Yuzuncu Yil, Zeve Campus, Van, 65080 Turkey;
fax: 432-225-1104; e-mail: firstname.lastname@example.org
Department of Horticulture, Faculty of Agriculture, University of Ankara, Diskapi-Ankara, Turkey
Department of Horticulture, Faculty of Agriculture, University of Gazi Osman Pasa, Tokat, Turkey
Received January 18, 2007
— Salt stress-induced changes in antioxidant enzymes, such as catalase (CAT), ascorbate peroxidase
(APX), and glutathione reductase (GR), total chlorophyll content, and lipid peroxidation measured as malond-
ialdehyde (MDA) content, in leaves of a green bean genotype Gevas sirsk 57 (GS57) and cv. Fransiz 4F-89 dif-
fering in salt tolerance were investigated. Plants were subjected to three salt treatments (0, 50, and 100 mM
NaCl) under controlled climatic conditions for 7 days. The salt-sensitive cv. 4F-89 exhibited a decrease in GR
activity at all salt treatments, but the salt-tolerant genotype GS57 showed only a slight decrease in GR under
50 mM salt treatment and an increase under 100 mM salt treatment. CAT and APX activities increased with
increasing salt stress in both varieties. CAT and APX activities were higher in the salt-tolerant GS57 than salt-
sensitive cv. 4F-89. The two varieties showed an increase in MDA content with an increase in salinity, but the
increase in sensitive cv. 4F-89 under salt stress was higher than that in salt-tolerant GS57 genotype. The increas-
ing NaCl concentration caused a reduction in the chlorophyll content in cv. 4F-89 but not in GS57.
Key words: Phaseolus vulgaris - antioxidant enzymes - salt stress - oxidative stress - lipid peroxidation - chlo-
: APX—ascorbate peroxidase; CAT—catalase;
GR—glutathione reductase; MDA—malondialdehyde; ROS—
reactive oxygen species.