1021-4437/05/5204- © 2005
Russian Journal of Plant Physiology, Vol. 52, No. 4, 2005, pp. 516–520. From Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 578–583.
Original English Text Copyright © 2005 by Wang, Huang, Liu, Zhan.
Plant growth and development are controlled by
hormonal and environmental signals. Unlike animals,
plants as sessile organisms are immobile and therefore
have developed mechanisms of sensing and responding
to biotic and abiotic stresses for better adaptation to
their environment. Many studies have indicated that
abscisic acid is involved in responses to biotic and abi-
otic stresses . When plants experience the stress
induced by drought, high salinity, or temperature, ABA
accumulates rapidly, leading to active plant response to
the stresses .
Exogenous ABA enhances the recovery of maize
seedlings subjected to heat shock and the survival of
suspension cells at
[3, 4]. Abass
and Rajasheker  showed that both ABA content
increased and heat tolerance enhanced to a maximum at
the same time during heat treatment of grape leaves.
[6, 7] reported that salicylic acid (SA) signif-
icantly accumulated in mustard seedlings during their
exposure to heat, and thermotolerance of seedlings also
increased. Moreover, exogenous SA could alter ther-
motolerance of mustard seedlings. However, we have
not found any reports on the relationship between ABA
and SA during plant exposure to heating.
In plant cells, one of the consequences of tempera-
ture change sensing and transduction of the perceived
signal is an increased production of ABA or SA consid-
ered as signal molecules. ABA is a sesquiterpenoid that
originates from mevalonic acid mainly via the pathway
involving carotenoid neoxanthine xanthine
ABA . Parry  and Creelman
evidence for ABA synthetic route from carotenoid to
xanthine, in which lipoxigenase (LOX) is possibly
involved. LOX is related to plant stress resistance, it can
be induced when plant is invaded by pathogen, injured
by insects, or subjected to water stress [11, 12]. It is
worth studying which pathway of ABA synthesis is
involved in plant acclimation to high temperature.
It is known that SA can alter plant resistance to abi-
otic and biotic stresses  and is regarded a signal
molecule involved in plant response to stresses . SA
rapidly accumulates in plant tissues under stress condi-
tions. However, there is no report on the changes in SA
metabolism. It is important to know whether SA and
ABA act independently to alter thermotolerance. It is
also still unknown whether plant acclimation to heat
elicits SA accumulation via the same biosynthetic path-
way as plant pathogens do. In this paper, we present the
data on the changes in ABA and SA contents and PAL
and LOX activities in heat-treated young grape plants
in an attempt to answer the above questions.
Changes in Salicylic and Abscisic Acid Contents
during Heat Treatment and Their Effect
on Thermotolerance of Grape Plants
L. J. Wang*, W. D. Huang**, Y. P. Liu**, and J. C. Zhan**
*Institute of Botany, Chinese Academy of Sciences,
20 Nanxincun, Xiangshan, Haidiar district, Beijing 100093, China;
**College of Food Science and Nutritional Engineering,
China Agricultural University, Beijing 100083, China;
Received February 24, 2004
—Heat treatment (38
C) of young grape plants (
L., cv. Jingxiu) or leaf spraying with
M salicylic acid (SA) increased leaf thermotolerance. Both treatments led to an increase in ABA content
and a decrease in lipoxygenase (LOX) activity. ABA content showed a drastic rise by one hour after treatments
and then sharply declined while LOX activity continuously decreased. In the course of heat treatment of grape
plants, endogenous SA level and phenylalanine ammonia-lyase activity rapidly increased during the ﬁrst hour,
then declined. These results showed that endogenous SA and ABA can be involved in grape plant response to
heat treatment resulted in improved thermotolerance.
Key words: Vitis vinifera - ABA - heat treatment - salicylic acid - thermotolerance
: LOX—lipoxygenase; PAL—phenylalanine
ammonia-lyase; SA—salicylic acid.
The text was submitted by the authors in English.