1021-4437/01/4801- $25.00 © 2001
Russian Journal of Plant Physiology, Vol. 48, No. 1, 2001, pp. 111–115. Translated from Fiziologiya Rastenii, Vol. 48, No. 1, 2001, pp. 132–136.
Original Russian Text Copyright © 2001 by Zhukov, Lebedeva, Vereshchagin.
In recent years, an increase in the proportion of
cereal crops in total cultivated area brought about a
wide-spread propagation of helminthosporic root rot of
wheat, which causes seedling sparseness, inhibition of
plant growth, a decrease in grain yield, and an
enhanced accumulation of infection in seeds . At
present, the varieties of cereals resistant to the disease
are practically nonexistent , and, therefore, physio-
logical and biochemical investigations of tolerance for
infection stress are very urgently needed.
According to the now generally recognized mem-
brane theory of stress (“membrane homeostasis theory”
), the survival of plants in a state of stress depends
primarily on their ability to recover the initial mem-
brane structure upset by a stress [3, 4]. The changes in
the content of membrane lipids play a signiﬁcant role in
stress-induced metabolic disturbances . Thus, the
shifts in this parameter caused by an infection stress are
most important for determining the role of membranes
in the adaptation to stress.
Changes in the plant lipid content caused by fungal
infection have been studied by numerous authors [6–8].
However, there is only fragmentary evidence with
respect to the changes brought about by helminthos-
poric root rot infection [9, 10], and there are apparently
no data at all on the effect of the agent of wheat root rot,
. Therefore, the
present work was devoted to investigating the inﬂuence
of the wheat root rot on the content of acyl lipids in the
shoots and roots of wheat seedlings.
MATERIALS AND METHODS
The culture of the pathogenic fun-
(Sacc.) Shoemaker, an
aggressive strain H-21 , obtained from the Institute
of Phytopathology, Russian Academy of Agricultural
Sciences, was grown in a stationary culture for 12 days
in ﬁve test-tubes in a liquid Capek medium. To isolate
fungal conidia, 4 ml water were added to each test tube,
the contents were mixed, and the suspension thus
obtained was ﬁltered through two layers of gauze. This
operation was carried out three more times to yield a
suspension with a total volume of 80 ml. The number of
conidia was determined in a Fuchs–Rosenthal hemocy-
tometer using a microscope, and the suspension was
diluted to a concentration equal to 8000 conidia/ml.
Elite seeds of Saratovskaya 55, a root rot-suscepti-
ble cultivar of spring wheat (
obtained from the Saratov Research Station, Russian
Academy of Agricultural Sciences, were sterilized for
15 min with a 1% sodium hypochlorite solution and
then washed with tap water for 1 h. Trays for seed ger-
mination were treated with ethanol, and ﬁlter paper and
coarse calico were autoclaved at 100
C and 172 kPa for
1 h. Slightly drained seeds were arranged 2.0–2.5 cm
apart on a glass wrapped with a moistened coarse calico
and placed in a 44
34 cm tray. The surface of this tis-
sue in the tray containing 225 seeds was uniformly cov-
ered with a dilute suspension of conidia (28.1 ml), with
Effect of Helminthosporic Root Rot
on the Lipid Content in Wheat Seedlings
A. V. Zhukov, N. I. Lebedeva, and A. G. Vereshchagin
Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya ul. 35, Moscow, 127276 Russia;
fax: 7 (095) 977-8018; e-mail: firstname.lastname@example.org
Received October 25, 1999
—The concentration of dry matter and the content of esteriﬁed fatty acids in total lipids of roots and
etiolated shoots of 3- to 10-day-old seedlings of wheat (
L.) infected with
(Sacc.) Schoemaker, the agent of helminthosporic root rot, were determined in the course of germination.
At the onset of germination, fungal infection caused a considerable increase in the dry matter concentration in
both roots and shoots due to the enhanced mobilization of seed reserves. However, after the 7th day of germi-
nation, dry matter concentration fell below the level of noninfected control seedlings as a result of infection.
The content of total lipids rose immediately after infection and always exceeded the control index up to the end
of germination, in spite of a continuous decrease in this index in both control and infected seedling. It is con-
cluded that an increase in the content of cellular lipids is a characteristic response of both shoots and roots to
the root rot infection of wheat seedlings.
Key words: Bipolaris sorokiniana - Triticum aestivum - esteriﬁed fatty acids - fungal infection - total lipids
: FA—fatty acids.