1021-4437/03/5002- $25.00 © 2003
Russian Journal of Plant Physiology, Vol. 50, No. 2, 2003, pp. 155–162. From Fiziologiya Rastenii, Vol. 50, No. 2, 2003, pp. 174–182.
Original English Text Copyright © 2003 by Kaﬁ, Stewart, Borland.
Plants growing in saline media may reduce internal
water deﬁcits by the absorption of inorganic ions and
the synthesis of organic solutes for osmotic adjustment.
Limited supply of essential metabolites, e.g., carbohy-
drates, could retard growth under sublethal salinity stress
[1, 2]. NaCl-stimulated accumulation of endogenous
organic osmotica is an effective mechanism for physio-
logical adaptation to salinity in nonhalophytes [3, 4].
Carbohydrates are known to be accumulated and
used for osmotic adjustment under salt stress [1, 5].
Rathert  observed a surprising uniformity in changes
in sucrose and starch with salinity in relation to salt tol-
erance of rice, soybean, and cotton. Wiemberg 
reported that sucrose rose linearly in the wheat leaves
with increasing external salinity and concluded that
sucrose might be utilized for osmotic adjustment.
Hamada and Khulaef  reported an elevation of solu-
ble carbohydrate (SC) and proline contents in leaves at
four levels of salinity (0, 50, 100, and 200 mM).
Carbohydrate accumulation in leaves in response to
salinity is thought to primarily occur as a result of
decreased export . Carbohydrate content varies con-
siderably among the plant tissues. The distribution of
carbohydrates between tissues has important implica-
tions since the suppression of photosynthesis may arise
from feedback effects of carbohydrate accumulation in
the leaf due to their reduced utilization by sinks [3, 8].
Krishnaraj and Thorpe  found that salt-tolerant
wheat cv. Kharchia-65 showed increased activities of
both the pentose phosphate pathway and glycolytic
pathway of glucose oxidation, as compared to a salt-
susceptible wheat cv. Fielder under conditions of salin-
ity. They concluded that cv. Fielder leaves incubated
C-glucose were not able to efﬁciently utilize glu-
cose under salinity conditions. Moreover, various tis-
sues may respond differently to salinity [10, 11], and,
as a result, carbohydrate distribution between organs
may be affected by salinity .
Free proline is a compatible solute, which rapidly
accumulates in order to distribute electrolytes between
cytosolic and vacuolar compartments in response to
water deﬁcit  and salinity stress [14–16]. Of the
24 amino acids analyzed, only the proline level
increased substantially in the primary root tip of
in response to 150 mM NaCl treatment
. Apart from one report , proline accumulation
following increased levels of NaCl was demonstrated
[7, 19, 20]. Proline accumulation is enhanced several-
fold, yet its role in improving resistance to salt stress
Carbohydrate and Proline Contents in Leaves, Roots, and Apices
of Salt-Tolerant and Salt-Sensitive Wheat Cultivars
M. Kafi*, W. S. Stewart**, and A. M. Borland**
*Department of Agronomy, Ferdowsi University, P. O. Box 91775-1163, Mashhad, Iran
**Department of Agricultural and Environmental Sciences, University of Newcastle Upon Tyne, NE1 7RU United Kingdom
Received December 19, 2001
—Intra-speciﬁc variations in nonstructural carbohydrates and free proline were determined in leaves,
apices, roots, and maturing seeds of two salt-tolerant cultivars (CR and Kharchia-65) and one salt-sensitive
cv. Ghods of spring wheat (
L.) grown in sand culture at various levels of salinity (0, 100, 200,
and 300 mM NaCl and CaCl
at 5 : 1 molar ratio) under controlled environmental conditions. The levels of leaf,
apex, and root ethanol-soluble carbohydrates, fructans, starch, and proline increased in line with elevating level
of salinity in all three cultivars under investigation. The contents of proline, soluble and insoluble carbohydrates
in the apex increased to levels exceeding those in the leaves and roots. Soluble carbohydrate content of salt-
sensitive cv. Ghods was higher in the leaves, apices, and roots and lower in the maturing seeds than in the other
cultivars at all levels of salinity except at 300 mM. The results show considerable variation in the amount of
soluble, insoluble sugars, and proline among plant tissues and wheat genotypes in response to salinity. Higher
soluble carbohydrates and fructan in leaves, roots and maturing seeds of stressed plants indicate that their accu-
mulation may help plant to tolerate salinity. Salt-sensitive cv. Ghods accumulated less soluble sugars in the
maturing seeds and higher soluble sugars in the apices, which might be used as an indicator in screening wheat
genotypes for salinity tolerance.
Key words: Triticum aestivum - salinity - soluble carbohydrates - proline
: SC—soluble carbohydrates; TC—total carbohy-
This article was submitted by the authors in English. It was
reported at the International Symposium “Plants and Environ-
mental Stress” (Moscow, Russia, October 2001).