1021-4437/01/4801- $25.00 © 2001
Russian Journal of Plant Physiology, Vol. 48, No. 1, 2001, pp. 100–103. Translated from Fiziologiya Rastenii, Vol. 48, No. 1, 2001, pp. 119–123.
Original Russian Text Copyright © 2001 by Talanova, Titov, Boeva.
All other things being equal, the sudden strong
inﬂuence of a speciﬁc stress factor or a slow, gradual
increase in its action differently affect plant tolerance.
For example, it was established that, during a gradual
increase or decrease in temperature from hardening to
injuring ranges, plants had time to adapt to this factor.
Subsequently, such plants were able to tolerate extreme
temperatures that would injure unhardened plants
[1, 2]. There is similar evidence as regards salt toler-
ance. Pretreatment of sorghum plants with low concen-
trations of NaCl increased their tolerance to higher salt
concentrations that would be lethal for nonpretreated
plants . Thus, a gradual increase in the dose of a
stress factor (high and low temperature, salt) results in
the development of tolerance that is considerably
higher than that formed by a factor of constant inten-
It is still unknown whether this conclusion can be
applied to other stress factors, in particular, to heavy
metals, because this problem remains little investigated
[4, 5]. Therefore, taking into account a continuous
increase in the industrial heavy-metal pollution of the
environment, we have studied the responses of plants to
increasing concentrations of lead and cadmium salts.
MATERIALS AND METHODS
L., cv. Otra) and wheat
L., cv. Mironovskaya 808) seedlings
were used in the experiments. The seedlings were
grown for 3 days in ﬁlter-paper rolls on a half-strength
Knop solution, pH 6.2–6.4, without air bubbling, at a
relative humidity of 60–70%, an illuminance of 10 klx,
a 14-h photoperiod, and 22–25
The seedlings were incubated for 1, 4, or 7 days on
dilute (0.001–0.005 mM} solutions of lead nitrate or
cadmium bromide or on distilled water as a control.
This was followed by 7-day-long treatments with more
concentrated (0.05–10 mM) solutions of the same salts.
These high concentrations of lead and cadmium salts
were shown earlier to inhibit plant growth, and, after
more prolonged treatment, to induce plant injury and
death . Throughout the experiment, some of the
seedlings were treated with solutions of lead or cad-
mium salts of constant (low or high) concentrations.
Other experimental conditions were kept constant.
Reagent grade salts of heavy metals produced in Russia
The responses of seedlings to the treatments were
evaluated by the alterations in fresh and dry weights
and the survival rate.
Three experiments were performed. Each treatment
included ﬁve groups of four seedlings. Arithmetic
means from three independent experiments and their
standard errors are presented in the ﬁgures and the
Treatment of barley seedlings with 1 mM lead
nitrate for 7 days resulted in a signiﬁcant inhibition of
fresh and dry matter accumulation (Figs. 1a and 1c).
Drastic retardation of growth to the point of total inhi-
bition was observed regardless of the time of the onset
Effect of Increasing Concentrations of Heavy Metals
on the Growth of Barley and Wheat Seedlings
V. V. Talanova, A. F. Titov, and N. P. Boeva
Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya ul. 11, Petrozavodsk, 185610 Russia;
fax: 7 (814) 277-9810; e-mail: email@example.com
Received November 16, 1999
—The tolerance to increasing doses of lead and cadmium salts on the growth and survival of barley
L.) and wheat (
L.) seedlings were studied. Seedlings grown under con-
trolled conditions were treated with dilute (0.001–0.005 mM) solutions of either lead nitrate or cadmium bro-
mide for 1, 4, or 7 days. Subsequently, they were incubated for 7 days in solutions of the same compounds, but
at sublethal or lethal concentrations (0.05–10 mM). Plant pretreatment with low concentrations of heavy metals
induced an increase in their tolerance to the metals, because pretreated plants could tolerate heavy metals at
high concentrations. It is concluded that plant tolerance to increasing concentrations of heavy metals is related
to the activation of protective and adaptive processes in their tissues.
Key words: Hordeum vulgare - Triticum aestivum - lead - cadmium - growth - tolerance