Botanical Studies (2006) 47: 239-250.

*

Corresponding author: E-mail: ashrafm@fsd.paknet.com.

pk; Phone: 92-41-9200312; Fax: 92-41-9200764.

INTRODUCTION

Salt stress-induced imbalance in the hormonal levels

of plants is well known (Debez et al., 2001; Wang et al.,

2001). Abscisic acid (ABA) generally increases in re-

sponse to salinity, and auxins decline (Zhang and Zhang,

1994; Wang et al., 2001). Recent studies show that SA

is involved in the plant responses to salt and osmotic

stress by playing a role in the reactive oxygen species-

mediated damage caused by high salt and osmotic condi-

tions (Borsani et al., 2001) possibly through signalling

and gene regulation. Therefore, SA-diminished changes

in phytohormone levels are suggested to be responsible

for salt tolerance in some crop species (Shakirova et

al., 2003). Moreover, the inhibitory effect of salt stress

on plant growth involves an array of cellular processes,

and all of these may be regulated by an altered hormone

homeostasis under salt stress (Xiong and Zhu, 2002). For

example, elevations in endogenous ABA levels could act

as an internal inhibitor of shoot growth in some plants

(Lee et al., 1996). However, adequate levels of ABA could

regulate the export of organic substances from the leaf and

presumably participate in the regulation of the metabolism

of transportable assimilates (Kiseleva and Kaminskaya,

2002).

Polyamines (PAs), such as Spd and Spm and their

obligate precursor Put, are polybasic amines that are

implicated in many physiological processes in plants

(Smith, 1985; Tiburcio et al., 1993; Galston and Kaur-

Sawhney, 1995; Kumar et al., 1997). Because of their

polycationic nature at a physiological pH, PAs occur

PHYSIOLOGY

Does polyamine seed pretreatment modulate growth

and levels of some plant growth regulators in hexaploid

wheat (Triticum aestivum L.) plants under salt stress.

Muhammad IQBAL

1

, Muhammad ASHRAF

1,

*, Shafiq-Ur-REHMAN

2

, and Eui Shik RHA

3

1

Department of Botany, University of Agriculture, Faisalabad 38040, Pakistan

2

Faculty of Biological Resources Science, College of Agriculture, Chonbuk National University, Chonju 561-756, Republic

of Korea

3

Life Resources Science, Plant Genetics & Breeding, Sunchon National University, Sunchon, 540-742, Republic of Korea

(Received July 12, 2005; Accepted December 19, 2005)

ABSTRACT.

The effect of seed presowing treatment with polyamines (2.5 mM putrescine, 5.0 mM

spermidine and 2.5 mM spermine) on growth and internal levels of different plant growth regulators in two

spring wheat (Triticum aestivum L.) cultivars MH-97 and Inqlab-91 was studied. The primed seeds of each

treatment and non-primed seeds were sown in a field in which NaCl salinity of 15 dS m

-1

was developed.

Although all three polyamines were effective in improving grain yield in both cultivars under saline

conditions, the effect of spermine (Spm) was more pronounced. All priming agents reduced leaf free abscisic

acid (ABA) levels in MH-97 as compared with untreated plants under saline conditions, but putrescine

(Put) priming caused a maximum increase in leaf ABA concentration in MH-97 under saline conditions. In

contrast, in Inqlab-91, Put proved to be very effective in increasing free indoleacetic acid (IAA) concentration

under saline conditions. Spermidine (Spd) and Spm were very effective in enhancing salicylic acid (SA)

concentration in both MH-97 and Inqlab-91 under saline conditions. Leaf free Put concentration was higher

in plants of MH-97 raised from seeds treated with Spd under saline conditions. In contrast, all priming agents

decreased leaf Put concentration compared with non-priming in Inqlab-91 under saline conditions. Plants

of both cultivars raised from seeds treated with Put had the maximum Spm levels under saline conditions.

Overall, the beneficial effects of priming agents (polyamines) were cultivar specific. Physiologically, the

beneficial effect of pre-sowing treatment with Spm on grain yield in both cultivars may be attributed to altered

hormonal balance.

Keywords: Hormone priming; Plant hormones; Pre-sowing treatment; Salinity; Salt tolerance.

240

Botanical Studies, Vol. 47, 2006

in plant cells not only as free forms, but also as bound

forms. The intracellular free PA pool depends on several

processes including a) PA synthesis, b) PA degradation,

c) PA conjugation, d) PA transport (Tiburcio et al., 1990;

Slocum, 1991; Bagni and Torrigiani, 1992; Tiburcio et al.,

1997) and e) interaction with other hormones like ABA

(Lee et al., 1997). Recent molecular genetic analyses have

shown that altered polyamine levels have profound effects

on plant growth and development (Fritze et al., 1995;

Kumar et al., 1996; Masgrau et al., 1997; Watson and

Malmberg, 1998). Polyamines, being cationic in nature,

can associate with anionic components of the membrane

such as phospholipids thereby stabilizing the bilayer

surface and retarding membrane deterioration (Roberts et

al., 1986; Galston and Kaur-Sawhney, 1987; Kramer and

Wang, 1989; Basra et al., 1994). It has been shown that

PAs in chloroplasts can covalently bound to chlorophyll-

protein complexes in thylakoids and Rubisco in the

stroma (Del Duca et al., 1994). These ionic interactions

are considered to increase stabilization of the subcellular

compounds and membranes under stress (Roberts et al.,

1986).

Interest is growing in the possible involvement of PAs

in the defense reactions of plants to various environmental

stresses (Flores, 1990; Kumar et al., 1997; Bouchereau et

al., 1999; Shen et al., 2000; Galston, 2001; He et al., 2002;

Maiale et al., 2004). Many reports have indicated that the

stress tolerance of plants is correlated with their capacity to

enhance the synthesis of PAs upon encountering the stress

(Evans and Malmberg, 1989; Chattopadhyay et al., 1997;

Bouchereau et al., 1999; Mo and Pau, 2002; Kasinathan

and Wingler, 2004; Kasukabe et al., 2004). Which of

the three PAs plays central roles in stress responses of

plants may depend on the plant species and the types

of stress (Kasukabe et al., 2004). In many, but not all,

cases, however, Spd is more closely associated with stress

tolerance of plants than Put and Spm (Bouchereau et al.,

1999; Li and Chen, 2000; Shen et al., 2000; He et al.,

2002; Martinez-Tellez et al., 2002; Maiale et al., 2004).

For example, salinity greatly enhanced the accumulation

of Spm and Spd associated with a decrease in Put content

in wheat cultivars (El-Shintinawy, 2000). Lefevre and

Lutts (2000) observed that an ionic rather than osmotic

component of salt stress is involved in the initial steps of

PAs accumulation in rice. Lin and Kao (1995) showed

contrasting results that increasing NaCl levels led to a

decrease in free putrescine levels, but an increase in Spd

levels in a salt-sensitive rice cultivar, cv. Taichung Native

1. In pea (Anderson and Martin, 1973) and barley (Smith,

1973), neither Put nor Spd accumulated when exposed to

increasing salinity. Salt stress increased the levels of Put

and decreased the concentration of Spm in wheat (Simon-

Sarkadi et al., 2002).

Even if PAs accumulate, this does not prove their

involvement in stress protection, especially as the role of

PAs may depend on their cellular localization and whether

they are free, bound to proteins, or conjugated to phenolic

acids (Bouchereau et al., 1999). However, a correlation

between stress tolerance and polyamine levels has been

demonstrated in a number of studies using a variety of

plant materials, but the physiological rationale for stress-

induced polyamine accumulation remains unknown. The

function of PAs is presumed to be protective, with a role

in scavenging free radicals being a favoured hypothesis

(Mansour, 2000). These reports indicate that the individual

PAs may have different roles during the response of plants

to salt stress. Seed priming with appropriate concentrations

of PAs has also been shown to be beneficial under salt

stress in some crops (Mansour et al., 2002; Mishra and

Sharma, 1994; Ali, 2000). Moreover, hydropriming is also

known to be effective under saline conditions (Twitchell,

1955; Zheng et al., 1998; Roy and Srivastava, 1999;

Junmin et al., 2000; Cassaro-Silva, 2002).

All these reports led us to hypothesize that pre-sowing

seed treatment with PAs could alleviate the adverse

effects of salt stress on the growth of spring wheat. Thus,

the primary objective of the present study was to assess

that up to what extent PAs applied as per-sowing seed

treatment could ameliorate the effect of salt stress on two

wheat cultivars differing in salt tolerance. In addition, it

was determined that how far pre-sowing seed treatment

with PAs can regulate the internal levels of PAs and other

plant growth regulators in two genetically diverse wheat

cultivars subjected to salt stress.

MATERIALS AND METHODS

The seeds of two moderately salt tolerant spring wheat

cultivars, MH-97 and Inqlab-91, were obtained from the

Wheat Section, Ayub Agricultural Research Institute,

Faisalabad, Pakistan. Solutions of 2.5 mM, 5.0 mM and

2.5 mM each of Put, Spd and Spm were used for seed

priming, respectively, following Mansour et al. (2002).

Distilled water was also used for priming and as a control.

Healthy wheat seeds (17 g for each treatment) were

primed separately in 100 mL of solutions of PAs as well

as in distilled water (DW) for 12 h at room temperature in

plastic cups (250 mL). After presoaking, the seeds were

surface dried on filter paper and then allowed to air-dry for

12 h at room temperature. The air-dried seeds were used

for field experiments.

A field experiment was conducted at the Botanic

Garden, University of Agriculture, Faisalabad (UAF)

during winter 2003-2004. Eight blocks having a length,

width and depth of 1097, 137 and 46 cm, respectively, and

lined with polythene sheets were filled with thoroughly

mixed sandy loam soil (pH = 7.56; electrical conductivity

of the saturation paste = 2.84 dS m

-1

; saturation percentage

= 25.5). In order to develop 15 dS m

-1

NaCl salinity,

the calculated amount of NaCl was dissolved in water

required for complete saturation of the soil in four blocks

(replicates). Thus, the soil was completely saturated with

salt solution (150 mM) so as to homogenize soil salinity.

The other four blocks served as control (2.84 dS m

-1

).

After three weeks, when the moisture contents were

suitable for germination, the primed seeds (P-seeds) of

IQBAL et al. — Does polyamine-priming modulate growth under salt stress.

241

each treatment and non-primed seeds (NP-seeds) were

sown in rows keeping row to row spacing at 15 cm. All

pre-sowing seed treatments were randomized in each

block. The experiment was laid out in a split split plot

design.

At the boot stage, 12 plants from each treatment (three

plants replicate

-1

) were uprooted and washed. After being

dried with filter paper, roots were carefully removed, and

data for fresh weights of shoots were recorded. Samples

were dried in an oven at 65oC for two weeks, and shoot

dry weights were recorded. At maturity, grain yield plant

-1

(g) was recorded.

Determination of hormones (Auxins, Abscisic

acid) and Salicylic acid

Fresh leaves (3

rd

leaf from top) were harvested

from each treatment. Two grams of fresh leaves were

finely chopped in 30 mL of 80% cold (-70oC) aqueous

methanol (4:1, v/v) supplemented with 20 mg L

-1

butylated hydroxytoluene (BHT) and stored at -70oC

or -20oC. Fresh leaves already frozen and stored were

ground with a mortar and pestle using aqueous 80%

methanol supplemented with BHT (MeOH-BHT) as

extracting solvent. To check recoveries during extraction

and purification, 191.6 ng of IAA, 300 ng NAA, 287.4

ng salicylic acid (SA), and 191.6 ng abscisic acid

(ABA) were used as internal standards and were added

before homogenization in each sample and blank. The

homogenate was vortexed for 10 min and filtered with

suction through Whatman #42 paper (Whatman Shanghai,

China). The residues in the flask and on the filter were

rinsed thrice with 10-mL aliquots of extracting solvent

and twice with 100% MeOH. The extracts were combined

and mixed and then divided into two equal samples

(Kusaba et al., 1998). One sample was used for IAA

and ABA analyses and the other for SA analysis. The

extract was concentrated to an aqueous residue by rotary

flask evaporation (RFE) at 35oC. The sublimation losses

were reduced by adding phosphate buffer (pH 7). The

aqueous fraction was transferred to 50-mL polypropylene

centrifuge tubes. The flask, used for RFE, was rinsed with

10 mL of hexane to extract chlorophylls and lipids from

the aqueous residue. Similarly, the aqueous fraction was

partitioned three times against hexane after adjusting the

pH to 8. The pH of the aqueous residue was adjusted to 3

with HCl and again partitioned three times with hexane.

The hexane fractions were then discarded. The pH was

then adjusted to 2.8, and the samples were centrifuged

for 15 min at 13,000 g to remove any precipitate. The

supernatant fractions were decanted into clean centrifuge

tubes and partitioned thrice against 10-mL portions of cold

diethylether-BHT so as to extract any traces of hormones.

Each 10-mL portion of ether was partitioned, in turn,

against a 10-mL portion of 1 mM HCl. The same 10 mL of

1 mM HCl was used for all three 10-mL portions of ether.

All three ether fractions were combined and evaporated

by RFE to dryness in vacuo. The residue was immediately

dissolved into 500 μL of 80% ice-cold MeOH-BHT in a

1.5-mL Eppendorf microcentrifuge tube. These samples

were kept overnight at -70oC and then centrifuged (25,000

g) for 10 min at -10oC. (A lower temperature helped to

remove any residues easily.) Standards were also prepared

following the same procedure. The supernatant was

filtered and subjected to HPLC (high performance liquid

chromatography) analysis.

Analysis of IAA, SA, and ABA was performed by

HPLC system (Sykam GmbH, Kleinostheim, Germany),

equipped with S-1121 dual piston solvent delivery

system and S-3210 UV/VIS detector. Following Guinn

et al. (1986) with some modifications, the elution system

consisted of 100% methanol: 1% acetic acid (52:48 v/v)

as solvent, run isocratically with a flow rate of 1.10 mL

min

-1

at 40oC. Twenty microliters of filtered extracts (using

a Whatman nylon membrane filter of 0.45 μm pore size,

Whatman Int. Ltd., Maldstone, England) were injected

into a Hypersil ODS reverse-phase (C

18

) column (4.6 ×

250 mm, 5-

μ

m particle size: Thermo Hypersil GmbH,

Germany). Detection of different hormones was performed

at 280 nm by co-chromatography with authentic standards.

The peak areas were recorded and calculated by a

computer with SRI peak simple chromatography data

acquisition and integration software (SRI Instruments,

Torrance, California, USA). All values were corrected on

internal standards with known concentrations of different

hormones.

Determination of polyamines

Fresh leaves (3

rd

leaf from top) were harvested from

plants of each treatment. Two grams of fresh leaves were

finely chopped in 20 mL of cold 5% aqueous perchloric

acid and were stored at -70oC.

For polyamine extraction and HPLC analysis, the

benzoylation method was performed as described

previously (Flores and Galston, 1982) with some

modifications. Leaf tissue (2 g fresh weight) was

homogenized in 20 mL of cold 5% perchloric acid

with a mortar and a pestle containing 200 nmol of 1,

6-hexanediamine as an internal standard. The homogenates

were incubated at 4oC for 30 min and then centrifuged

at 13,000 g for 20 min. Aliquots of 1 mL of supernatant

were added to 1 mL of 4 M NaOH with 10

μ

L of benzoyl

chloride. The mixture was vigorously vortexed for 30 s

and then incubated for 30 min at room temperature. The

reaction was terminated by adding 2 mL of saturated

NaCl. The benzoyl-polyamines were extracted with 3 mL

of cold diethyl ether for 30 min. Then the samples were

centrifuged at 2,500 g for 5 min, and the ether phase was

collected and dried under N

2

flow. The residues were

redissolved in 500

μ

L of methanol in a 1.5-mL Eppendorf

microcentrifuge tube. Polyamine standards (Sigma, USA)

were prepared similarly to plant samples. These samples

were filtered and stored at -20oC for HPLC analysis.

The polyamine contents were analyzed by HPLC

(Sykam GmbH, Kleinostheim, Germany) equipped

242

Botanical Studies, Vol. 47, 2006

in the grain yield of both cultivars. An exception was in

the plants of Inqlab-91, raised from seeds treated with Put

under saline conditions.

Saline substrate significantly altered the leaf free IAA

contents of both wheat cultivars (P . 0.001; Table 3).

Cultivars also differed significantly from one another.

However, different priming agents altered leaf IAA

concentrations differently in both cultivars. For example,

distilled water proved to be the priming agent most

effective at increasing free IAA concentration in MH-97

under saline conditions. In contrast, in Inqlab-91, Put,

and Spd proved to be very effective at increasing the free

IAA concentration under saline conditions and non-saline

control, respectively (Table 4). Overall, the increase in

free IAA concentration in MH-97 due to different priming

agents was higher than that in Inqlab-91 under both saline

and non-saline conditions.

Leaf free ABA concentrations of both cultivars

changed significantly under salt stress. The effects of

priming agents differed significantly in altering leaf ABA

concentration of both cultivars (P . 0.001; Table 3).

Except hydropriming, all priming agents reduced leaf free

ABA levels in MH-97 as compared with untreated plants

under saline conditions. However, Put priming increased

leaf ABA concentrations the most in MH-97 under saline

conditions.

Salt stress significantly changed the leaf free SA

concentrations of both cultivars (P . 0.001; Table 3).

Priming agents also showed different effects on free SA

concentration in leaves of both cultivars (P . 0.001). The

pattern of increase or decrease in leaf SA concentration in

both cultivars due to salt stress was not consistent (Table

4). However, Spd was a very effective priming agent

in enhancing SA concentration in MH-97 under saline

conditions. In contrast, pre-treatment with Spm slightly

with S-1121 dual piston solvent delivery system and

S-3210 UV/VIS detector. The elution system consisted of

methanol: water (65:35 v/v) as solvent, run isocratically

with a flow rate of 0.70 mL min

-1

at 50oC. Twenty

microliters of benzoylated extracts were injected into a

Hypersil ODS reverse-phase (C

18

) column (4.6 × 250 mm,

5-

μ

m particle size: Thermo Hypersil GmbH, Germany)

and detected at 254 nm. The peak areas were recorded

and calculated by a computer with SRI peak simple

chromatography data acquisition and integration software

(SRI Instruments, Torrance, California, USA).

Data analysis

Analysis of variance (ANOVA) of data for all attributes

was computed using a COSTAT computer package

(CoHort Software, 2003, Monterey, California). The

comparisons of means were done by COSTAT computer

package, using Duncan’s New Multiple Range (DMR)

test.

RESULTS

Saline growth medium caused a significant reduction

in fresh weights of shoots of plants of both cultivars (P

. 0.001; Table 1). Plants derived from seeds treated with

different priming agents did not improve shoot fresh

weight in either cultivar.

Salt stress imposed in the growth medium caused a

significant reduction in the grain yield of both cultivars

(P . 0.01; Table 1). However, different priming agents

caused a significant increase in grain yield (P . 0.001). Of

the priming agents used, Spm was found very effective

in enhancing the grain yield of both cultivars under salt

stress (Table 2). Overall, in comparison with non-priming,

all priming treatments caused a significant improvement

Table 1. Mean squares from analysis of variance of data for shoot fresh mass and grain yield per plant of two cultivars of hexaploid

wheat raised from seeds primed with different polyamines.

Source of variation

Degrees of freedom

Shoot fresh mass

Grain yield plant

-1

Salinity (S)

1

3721.1***

26.90**

Main plot error

3

14.09

0.276

Cultivars (C)

1

6.045ns

0.121ns

C x S

1

0.559ns

0.319*

Subplot error

6

16.72

0.039

Treatments (T)

4

31.74*

0.578***

T x S

4

10.961ns

0.061**

T x C

4

25.44*

0.137***

T x C x S

4

26.86*

0.129***

Error

48

9.469

0.016

*, **, *** = significant at 0.05, 0.01, and 0.001 levels, respectively.

ns = non-significant.

IQBAL et al. — Does polyamine-priming modulate growth under salt stress.

243

Table 2. Shoot fresh mass and grain yield per plant of two cultivars of hexaploid wheat at 2.84 dS m

-1

(control) or 15 dS m

-1

NaCl

(salt) when the seeds were primed with solutions of different polyamines. Values in parentheses are SE of means (based on four

replicates).

Pre-sowing seed

treatments

MH-97

Inqlab-91

2.84 dS m

-1

15 dS m

-1

2.84 dS m

-1

15 dS m

-1

Shoot fresh biomass (g plant

-1

)

Put (2.5 mM)

27.72 (1.56)

14.51 (2.94)

29.79 (0.89)

18.39 (0.87)

Spd (5.0 mM)

27.29 (1.87)

14.97 (2.21)

29.05 (0.77)

15.79 (0.81)

Spm (2.5 mM)

31.23 (0.53)

14.84 (2.61)

31.13 (0.82)

14.87 (0.76)

Distilled water

29.82 (0.25)

15.98 (1.71)

24.66 (0.80)

16.43 (0.56)

Untreated

27.14 (0.47)

15.28 (0.89)

28.95 (0.89)

14.64 (0.73)

LSD 5%

4.375

Grain yield (g dry weight plant

-1

)

Put (2.5 mM)

3.55 (0.144)

2.66 (0.059)

3.75 (0.150)

2.24 (0.094)

Spd (5.0 mM)

3.98 (0.112)

2.93 (0.103)

3.75 (0.083)

2.50 (0.017)

Spm (2.5 mM)

3.69 (0.108)

3.05 (0.074)

3.84 (0.078)

2.56 (0.021)

Distilled water

3.60 (0.044)

2.25 (0.137)

3.58 (0.025)

2.52 (0.029)

Untreated

3.43 (0.059)

2.12 (0.150)

3.57 (0.094)

2.25 (0.049)

LSD 5%

0.178

Table 3. Mean squares from analysis of variance of data for IAA, ABA, and SA and polyamine concentrations of two cultivars of

hexaploid wheat raised from seeds primed with different polyamines.

Source of variation Degrees of freedom

IAA

ABA

SA

Salinity (S)

1

792614.2***

100509.1***

8461635.1***

Main plot error

3

421.2

548.2

9414.9

Cultivars (C)

1

19438.5*

50605.4***

12246589.0***

C x S

1

73564.6**

94511.6***

5254614.9***

Subplot error

6

2821.9

12.7

39618.8

Treatments (T)

4

52291.8***

11815.3***

5132013.4***

T x S

4

78157.3***

9782.8***

1312861.3***

T x C

4

76262.8***

19010.7***

2249342.3***

T x C x S

4

87476.9***

23998.0***

1849103.4***

Error

48

1327.4

649.8

40559.5

Putrescine

Spermidine

Spermine

Salinity (S)

1

4450.3**

385946.6***

3081.3ns

Main plot error

3

46.8

118.4

574.9

Cultivars (C)

1

133.6ns

3027.8ns

188.2ns

C x S

1

705.4**

26786.5*

2513.1**

Subplot error

6

38.3

2609.3

96.6

Treatments (T)

4

635.7***

25959.7***

2191.4***

T x S

4

902.5***

31620.2***

2628.6***

T x C

4

1238.4***

5230.5ns

1547.7***

T x C x S

4

809.4***

8347.2ns

549.6ns

Error

48

19.8

3251.5

271.3

*, **, *** = significant at 0.05, 0.01, and 0.001 levels, respectively; ns = non-significant.

IAA, indoleacetic acid; ABA, abscisic acid; SA, salicylic acid.

244

Botanical Studies, Vol. 47, 2006

increased leaf SA concentration in Inqlab-91 under saline

conditions.

Salt stress of the growth medium significantly affected

leaf Put concentration of both cultivars, but the cultivars

also did not differ significantly (Table 3). However, the

priming agents differed significantly in altering the Put

levels in both wheat cultivars (P . 0.01). Leaf free Put

concentration was higher in plants of MH-97 raised from

seeds treated with Spd under saline conditions (Table

5). Of all priming agents, Put was the most effective at

increasing leaf Put concentration in Inqlab-91 under saline

conditions. In contrast, the remaining priming agents

decreased leaf Put content compared with non-priming in

Inqlab-91 under saline conditions.

Different priming agents altered leaf free Spd

concentration under both saline and non-saline conditions,

but cultivars also did not differ significantly. Similarly, the

difference among priming agents in altering the Spd levels

of plants of both cultivars was also insignificant (Tables 3

and 5).

Salt stress imposed in the growth medium had no

significant effect on leaf spermine (Spm) concentration in

either cultivar, and neither cultivar differed significantly

from the other. However, priming agents differed

significantly in altering free Spm concentration in both

cultivars (Tables 3 and 5). For example, plants of both

cultivars raised from seeds treated with Put had the

maximum Spm levels under saline conditions.

DISCUSSION

It should now be evident that growth regulator balance

can be changed at high salinities, and this effect can

be partially alleviated with application of exogenous

growth promoter substances (Gadallah, 1999; Khan

et al., 2000; Debez et al., 2001). In the present study,

priming with Put alleviated the adverse effects of salt

stress on hormonal balance in the plants of Inqlab-91.

For example, put pre-treatment considerably increased

leaf ABA and IAA concentrations in Inqlab-91 under

saline conditions. In contrast, in MH-97, it decreased free

ABA levels compared with the untreated plants under

saline conditions. The increased ABA levels can regulate

the pathways of photoassimilate utilization in leaves by

partitioning carbon flows either to the synthesis of high

molecular weight compounds (cellulose, hemicellulose,

and proteins), used for cell growth in leaves, or to

Table 4. IAA, ABA and SA concentrations (ng g

-1

fresh weight) of two cultivars of hexaploid wheat at 2.84 dS m

-1

(control) or 15

dS m

-1

NaCl (salt) when the seeds were primed with solutions of different polyamines. Values in parentheses are SE of means (based

on four replicates).

Pre-sowing seed

treatments

MH-97

Inqlab-91

2.84 dS m

-1

15 dS m

-1

2.84 dS m

-1

15 dS m

-1

Free IAA

Put (2.5 mM)

209.2 (2.51)

164.1 (26.54)

121.9 (4.74)

182.9 (10.37)

Spd (5.0 mM)

85.4 (0.11)

125.1 (13.13)

633.2 (12.19)

94.8 (6.97)

Spm (2.5 mM)

231.2 (4.74)

119.6 (15.43)

273.7 (8.45)

112.9 (6.70)

Distilled water

421.8 (18.83)

180.9 (18.79)

561.4 (49.02)

88.2 (1.05)

Untreated

472.5 (19.29)

138.1 (35.93)

288.9 (21.48)

101.5 (1.74)

LSD 5%

51.79

Free ABA

Put (2.5 mM)

183.6 (16.82)

231.5 (12.80)

59.5 (19.78)

187.1 (7.59)

Spd (5.0 mM)

31.5 (0.88)

178.5 (2.38)

173.8 (1.34)

110.7 (0.37)

Spm (2.5 mM)

116.9 (9.91)

137.9 (9.40)

145.2 (18.85)

122.6 (10.60)

Distilled water

119.3 (0.90)

329.4 (13.94)

93.3 (3.47)

102.9 (5.91)

Untreated

96.5 (9.53)

368.5 (21.15)

168.1 (19.50)

127.3 (5.56)

LSD 5%

36.24

Free SA

Put (2.5 mM)

1588.4 (10.4)

1634.6 (31.0)

1524.9 (117.9)

1572.1 (34.7)

Spd (5.0 mM)

1851.5 (74.3)

2851.5 (39.7)

3929.5 (204.7)

1959.6 (62.2)

Spm (2.5 mM)

2434.3 (51.6)

1668.8 (128.2)

4744.4 (90.9)

2574.5 (71.2)

Distilled water

2331.5 (63.2)

1147.2 (81.0)

2332.6 (207.6)

1659.5 (57.7)

Untreated

919.6 (90.1)

1133.8 (108.9)

3069.3 (61.5)

2019.9 (63.1)

LSD 5%

286.3

IQBAL et al. — Does polyamine-priming modulate growth under salt stress.

245

the synthesis of transportable forms of carbohydrates

(Kiseleva and Kaminskaya, 2002). Similarly, auxins

play a critical role in the regulation of plant growth and

development, including cell division and differentiation

(Thimann, 1977; Dietz et al., 1990; Normanly, 1997;

Davies, 1995; Pospi.ilova, 2003). Thus, the improvement

in growth only in Inqlab-91 due to priming with Put seems

to have been due to increased leaf ABA and IAA levels

under salt stress.

Generally, salinity caused a marked increase in Put

levels in both cultivars. Both arginine decarboxylase

(ADC) and ornithine decarboxylase (ODC) are responsible

for salt (NaCl) induced increase in Put biosynthesis

(Friedman et al., 1989; Lee and Chen, 1998). However,

plants show diverse responses to high saline conditions

with respect to PA biosynthesis: some systems show

increased PA levels while others show smaller increases or

even decreases (Krishnamurthy and Bhagwat, 1989; Lin

and Kao, 1995; Lee and Chen, 1998). In the present study,

in comparison with plants raised from untreated seeds,

pre-treatment with Put increased endogenous free Put

levels only in Inqlab-91 under saline conditions. Serrano

et al. (1997, 1998) have hypothesized that the increase in

PAs levels in response to stress is immediate, indicating

it is a consequence of stress rather than a protective

mechanism. After a period of time, even if the stress

situation continues, PA levels decrease and resemble those

from non-stressed plants. However, many contrasting

reports have suggested the change in PAs under salt

stressed conditions to be a protective mechanism (Roberts

et al., 1986; Kramer and Wang, 1989; Basra et al., 1994;

Basra et al., 1997; Kasukabe et al., 2004).

Pre-sowing seed treatment with Spd also improved

the grain yield of both cultivars under saline conditions.

However, the salinity induced decrease in leaf free IAA

was not alleviated by pre-sowing treatment with Spd

in either cultivar. It also caused a decrease in leaf ABA

levels and an increase in SA levels in both cultivars except

Inqlab-91, in which pre-sowing treatment with Spd did not

ameliorate salt-induced reduction in leaf SA levels under

saline conditions. SA is an endogenous growth regulator

which controls plant growth and development (Schettel

and Balke, 1983), photosynthesis and transpiration rates

(Pancheva et al., 1996), and ion uptake and transport

(Harper and Balke, 1981; Uzunova and Popova, 2000).

SA is also known to reverse salt stress-induced decreases

Table 5. Polyamine concentrations (μg g

-1

fresh weight) of two cultivars of hexaploid wheat at 2.84 dS m

-1

(control) or 15 dS m

-1

NaCl (salt) when the seeds were primed with solutions of different polyamines. Values in parentheses are SE of means (based on

four replicates).

Pre-sowing seed

treatments

MH-97

Inqlab-91

2.84 dS m

-1

15 dS m

-1

2.84 dS m

-1

15 dS m

-1

Putrescine

Put (2.5 mM)

8.66 (0.35)

22.37 (0.92)

10.52 (1.14)

24.24 (6.77)

Spd (5.0 mM)

28.16 (1.32)

35.71 (3.69)

15.17 (2.07)

17.99 (0.36)

Spm (2.5 mM)

15.88 (0.82)

23.87 (4.36)

8.04 (0.30)

15.14 (0.28)

Distilled water

10.72 (0.85)

16.48 (0.66)

13.40 (1.51)

21.60 (4.09)

Untreated

9.18 (0.20)

19.06 (0.50)

8.70 (1.44)

81.14 (2.77)

LSD 5%

6.32

Spermidine

Put (2.5 mM)

43.9 (15.5)

308.9 (24.8)

58.5 (4.35)

355.1 (80.1)

Spd (5.0 mM)

108.1 (0.37)

228.3 (27.7)

61.6 (17.6)

182.7 (18.7)

Spm (2.5 mM)

67.9 (3.91)

303.2 (66.5)

141.7 (24.6)

169.5 (71.6)

Distilled water

79.1 (11.3)

145.6 (18.9)

134.4 (12.6)

136.2 (15.2)

Untreated

151.5 (0.46)

342.2 (5.00)

175.7 (6.59)

240.1 (27.9)

LSD 5%

(S x V x T) = ns

Spermine

Put (2.5 mM)

6.31 (1.35)

44.47 (8.51)

4.19 (0.06)

25.42 (5.81)

Spd (5.0 mM)

6.80 (0.58)

12.53 (0.23)

2.80 (0.13)

5.89 (1.28)

Spm (2.5 mM)

6.54 (0.21)

17.73 (3.33)

8.72 (0.28)

9.13 (0.32)

Distilled water

5.63 (0.21)

7.40 (0.39)

14.46 (1.96)

6.38 (1.01)

Untreated

6.86 (0.38)

18.13 (0.36)

20.19 (6.48)

26.06 (2.74)

LSD 5%

(S x V x T) = ns

246

Botanical Studies, Vol. 47, 2006

in total and reducing sugar contents by providing a pool

of compatible osmolytes in the presence of sodium (Tari

et al., 2002). In the present study, the greater improvement

in grain yield in MH-97 could be attributed to increased

accumulation of SA under saline conditions. Furthermore,

the pattern of accumulation of PAs was not consistent in

both cultivars due to pre-sowing treatment with Spd under

saline conditions. For example, Spd proved to be the most

effective of all priming agents in accumulating leaf free

Put levels in MH-97 while it failed to cause accumulation

of leaf Put contents in Inqlab-91 under saline conditions.

Pre-sowing seed treatment with Spd did not affect leaf

free Spd and Spm levels in either cultivar under saline

conditions. This contravenes the findings reported in

some earlier studies, e.g., salt-tolerant rice cultivars

(Krishnamurthy and Bhagwat, 1989), Limonium sp.

(Bouchereau et al., 1999) and Bromus spp. (Santa-Cruz et

al., 1997). It may be possible that high levels of binding of

Put and Spd to proteins in actively dividing young tissues

and lower levels in mature non-dividing tissues might

have resulted in lower leaf free Put levels in Inqlab-91 and

non-significant levels of Spd and Spm in both cultivars

under saline conditions. Such accumulation and non-

accumulation of Spd and Spm has already been reported

in tissues of Chrysanthemum (Aribaud et al., 1995).

Spm was the most effective of all the polyamines

for seed priming because it maximized improvement in

grain yield in both cultivars under both saline and non-

saline conditions. Priming of seeds of Inqlab-91 with Spm

proved to be effective in reducing the drastic effect of salt

stress on plant hormonal balance. For example, salinity-

induced reduction in SA was alleviated by Spm priming

of Inqlab-91 under saline conditions. However, leaf free

ABA and SA levels in MH-97 were not affected by pre-

soaking with Spm under saline conditions. Thus, the

increase in grain yield is probably due to the increased rate

of translocation of photosynthates from leaves to grains

caused by pre-sowing Spm treatment. Such increases in

grain yield following hormone pre-treatments has already

been found in wheat (Lovell, 1971; Dewdeny and Mcwha,

1978; Ray and Choudhuri, 1981; Aldesuquy and Ibrahim,

2001).

Hydro-priming did not show a pronounced effect

on shoot growth or grain yield in either cultivar under

saline conditions, except for Inqlab-91, which showed

improved grain yield. Failure of hydro-priming to

improve germination and growth has already been

reported in wheat (Chaudhri and Wiebe, 1968) and

Kentucky bluegrass (Poa pratensis) (Pill and Necker,

2001). However, some reports do exhibit the considerable

effectiveness of hydro-priming on germination and

later growth in different plant species under both saline

and non-saline conditions, e.g., wheat (Kamboh et al.,

2000), and Acacia tortilis (Rehman et al., 1998). Hydro-

priming also failed to show a consistent effect on hormone

homeostasis in both cultivars. For example, it increased

leaf free IAA in MH-97, but decreased it in Inqlab-91,

under saline conditions. Moreover, the decrease or

increase in leaf free ABA and SA due to hydropriming was

not pronounced in either cultivar under saline conditions.

In conclusion, of the different priming agents used

in this study, Spm was most effective at alleviating the

adverse effect of salt stress on grain yield in both wheat

cultivars. Although all other priming agents were also

effective in inducing salt tolerance in wheat cultivars, the

beneficial effects of these priming agents were cultivar

specific. Physiologically, the beneficial effect of pre-

sowing treatment with Spm on grain yield in both cultivars

may be attributed to altered hormonal balance.

LITERATURE CITED

Aldesuquy, H.S . and A.H. Ibrahim. 2001. Wat er rela tions ,

abscisic acid and yield of wheat plants in relation to the

interactive effect of seawater and growth bioregulators. J.

Agron. Crop Sci. 187: 97-104.

Ali, R.M. 2000. Role of putrescine in salt tolerance of Atropa

belladonna plant. Plant Sci. 152: 173-179.

Anders on, J .N. and R.O. Mart in. 1973. Ide ntifi cat ion of

cadaverine in Pisum sativum. Phytochemistry 12: 443-446.

A ri ba u d, M ., M. C a rre , a n d J . M a rt i n- Ta ng uy. 19 95 .

Tra ns glutam inas e like activity in Chrysanthemum leaf

explants cultivated in vitro in relation to cell growth and

hormone treatment. Plant Growth Regul. 16: 11-17.

Bagni, N. and P. Torrigiani. 1992. Polyamines: A new clas s

of growth s ubs tances . In C.M. Ka rs se n and Loon va n

Vreugdenhil (eds.), P rogress in Plant Growth Regulation.

Kluwer Academic Publishers, Dordrecht, pp. 264-275.

Basra, A.S., B. Singh, and C.P. Malik. 1994. Priming-induced

changes in polyamine levels in relation to vigor of aged

onion seeds. Bot. Bull. Acad. Sin. 35: 19-23.

Basra, R.K., A.S. Basra, C.P. Malik, and I.S . Grover. 1997.

Are polyamines involved in the heat-shock protection of

mungbean seedlings. Bot. Bull. Acad. Sin. 38: 165-169.

Borsani, O., V. Valpuesta, and M.A. Botella. 2001. Evidence for

a role of salicylic acid in the oxidative damage generated

by NaCl and osmotic stress in Arabidopsis seedlings. Plant

Physiol. 126: 1024-1030.

Bouchereau, A., A. Az iz, F. Larher, and J. Marti n-Ta nguy.

1999. Polyamines and environmental challenges: Recent

development. Plant Sci. 140: 103-125.

C as s aro-S il va, M . 2002. P re -hydra tion and de hydra ti on

effect on Senna macranthera (Co llad ) Irwi n et Ba rn

(Caesalpiniaceae) seed germination under saline stres s.

Revista de Agricultura (Piracicaba) 77: 231-242.

Chattopadhyay, M.K., S. Gupta, D.N. Sengupta, and B. Ghosh.

1997. Expression or arginine decarboxylase in seedlings of

indica rice (Oryza sativa L.) cultivars as affected by salinity

stress. Plant Mol. Biol. 34: 477-483.

Chaudhri, M. and H.H. Wiebe. 1968. Influence of calcium

pretreatment on wheat germination on saline media. Plant

Soil. 18: 208-216.

IQBAL et al. — Does polyamine-priming modulate growth under salt stress.

247

Davies, P.J. 1995. Plant Hormones: P hysiology, Biochemistry

and Molecular Biology. Kluwer Academ ic Publis hers ,

Dordrecht.

Debez, A., W. Chaibi, and S. Bouzid. 2001. Effect of NaCl and

growth regulators on germination of Atriplex halimus L.

Cahiers Agriculturae 10: 135-138.

Del Duca, S., V. Tidu, R. Bassi, C. Esposito, and D. Serafini-

Fracassini. 1994. Identification of chlorophyll a/b proteins

as subs trate s of tra nsglut ami nas e act ivity in i sola ted

chloroplasts of Helianthus tuberosus L. Planta 193:

283-289.

Dewdeny, S.J. and J .A. Mcwha. 1978. The metabolism and

transport of abscisic acid during grain filling in wheat. J.

Exp. Bot. 29: 1299-1308.

Di e tz , A., U . Ku ts ch e ra , a n d P.M . Ra y. 19 9 0. A ux i n

enhancement of mRNAs in epidermis and internal tissue of

the pea stem and its significance for control of elongation.

Plant Physiol. 93: 432-438.

El-Shintinawy, F. 2000. Photosynthesis in two wheat cultivars

differing in salt susceptibility. Photosynthetica 38: 615-620.

Evans, P.T. and R.L. Malmberg. 1989. Do polyamines have roles

in plant development. Annu. Rev. Plant Physiol. Plant Mol.

Biol. 40: 235-269.

Flores, H.E. and A.W. Galston. 1982. Analysis of polyamines in

higher plants by high performance liquid chromatography.

Plant Physiol. 69: 701-706.

Flores, H.E. 1990. Polyamines and plant stress. In R.G. Alscher

and J.R. Cum ming (eds .), S tress Responses in Pl ants:

Adaptation and Acclimation Mechanism. Wiley-Liss, New

York, pp. 17-239.

Friedman, R., A. Altman, and N. Levin. 1989. The effect of salt

stress on polyamine biosynthesis and content in mungbean

plants and in halophytes. Physiol. Plant. 76: 295-302.

Fritze, K., I. Czaja, and R. Walden. 1995. T-DNA tagging of

genes influence polyamine metabolism: Isolation of mutant

plant lines and rescue of DNA promoting growth in the

presence of a polyamine biosynthetic inhibitor. Plant J. 7:

61-71.

Gadallah, M.A.A. 1999. Effects of kinetin on growth, grain

yield and some mineral elements in wheat plants growing

under excess salinity and oxygen deficiency. Plant Growth

Regul. 27: 63-74.

Galston, A.W. and R. Kaur-Sawhney. 1995. Polyamines as

endogenous growth regulators. In P.J. Davies (ed.), P lant

Horm ones: Phys iology, Biochem is try, and Mol ecula r

Biology. Kluwer Academic Publishers, pp. 158-178.

Gal st on, A.W. an d R. Kaur-S a whney. 1987. P ol yam ine s

as e ndoge nous growth regula tor. In P.J. Davies (ed.),

Pl ant Ho rmone s a nd the ir Ro le i n Pl ant Gro wt h and

Development. Martinus Nijhoff, Boston, pp. 208-295.

Galston, A.W. 2001. Plant biology: Retros pect and prospect.

Curr. Sci. 80: 143-152.

Guinn, G.D., D.L. Brummett, and R.C. Beier. 1986. Purification

and measurement of abscisic acid and indole acetic acid by

high performance liquid chromatography. Plant Physiol. 81:

997-1002.

Harper, J.R. and N.E. Balke. 1981

.

Characterization of the

inhibition of K

+

absorbtion in oats roots by salicylic acid.

Plant Physiol.

68: 1349-1353.

He , L ., K. N a da , a nd S . T ac h i ba n a . 2 0 02 . E ffe c t s of

spermidine pretreatment through the roots on growth and

photosynthesis of chilled cucumber plants (Cucumis sativus

L.). J. Jap. Soci. Hort. Sci. 71

:

490-498.

Junmin, H., S. Xiaoping, and Z. Jian. 2000. Mitigative effects

of hydration-dehydration treatment on salt stress-induced

injuries to tomato seed germination. Acta Hort. S in. 27

:

123-126.

Kamboh, M.A., Y. Oki, and T. Adachi. 2000. Effect of pre-

sowing seed treatments on germination and early seedling

growth of wheat varieties under saline conditions. Soil Sci.

Plant Nutr. 46

:

249-255.

Kasinathan, V. and A. Wingler. 2004. Effect of reduced arginine

decarboxylase activity on salt tolerance and on polyamine

format ion during sa lt s tres s i n A rabi dopsis thali ana.

Physiol. Plant. 121

:

101-107.

Kas uka be, Y., L . He, K. Nada, S. Misawa, I. Ihara, and S.

Tachibana. 2004. Overexpression of spermidine synthase

enhances tolerance to multiple environmental stresses and

up-regulates the expres sion of various s tres s-regulated

genes in transgenic Arabidopsis thaliana. P lant Cell

Physiol. 45

:

712-722.

Khan, M.A., I.A. Ungar, and A.M. Showalter. 2000. The effect

of salinity on the growth, water status, and ion content of

a leaf succulent perennial halophyte, Suaeda fruticosa (L.)

Forssk. J. Arid Environ. 45

:

73-84.

Kiseleva, I.S. and O.A. Kaminskaya. 2002. Hormonal regulation

of a ssim ilate utilization in barley lea ves in relation to

the development of their s ource function. Russ. J. Plant

Physiol. 49

:

534-540.

Kramer, G.F. and C.Y. Wang. 1989. Correlation of reduced

chilling injury with increas ed s permidine and s permine

levels in zucchini squash. Physiol. Plant. 76

:

479-482.

Krishnamurthy, R. and K.A. Bhagwat. 1989

.

Polyamines as

modulators of salt tolerance in rice cultivars.

Plant Physiol.

91: 500-504.

Kumar, A., T. Altabella, M.A. Taylor, and A.F. Tiburcio. 1997.

Recent advances in polyamine research. Trends Plant Sci. 2

:

124-130.

Kuma r, A., M.A. Ta ylor, S .A.M. Ari f, and H.V. Dav ies .

1996 . P ota to pla nts e xpre s si ng a nti s ens e and s ens e

S-adenosylmethionine decarboxylase (SAMDC) transgenes

show altered levels of polyamines and ethylene: Antisense

plants display abnormal phenotypes. Plant J. 9

:

147-158.

Kusaba, S ., Y. Kano-Murakami, M. Matsuoka, M. Tamaoki,

T. S akamoto, I. Yama guchi, and M. F ukumoto. 1998.

Alteration of hormone levels in transgenic tobacco plants

overexpres s ing the ric e homeobox ge ne OSH1. P lant

Physiol. 116

:

471-476.

248

Botanical Studies, Vol. 47, 2006

Lee, T.-M., Y.-J. Shieh, and C.-H. Chou. 1996. Abscis ic acid

inhibits shoot elongation of Scirpus mucronatus. P hysiol.

Plant. 97: 1-4.

Lee, T.-M., H.-S. Lur, and C. Chu. 1997. Role of abscisic acid

in chilling tolerance of rice (Oriza sativa L.) seedlings. II.

Modulation of free polyamine levels. Plant Sci. 126: 1-10.

L ee , T.-M. a nd M.H. Ch en. 1998 . Hypo s al ine e ffec t o f

polyamine accumulation in Ulva fasciata (Ul val es ,

Chlorophyta). Bot. Bull. Acad. Sin. 39

:

167-174.

Lefevre, I. and S. Lutts. 2000. Effects of salt and osmotic stress

on free polyamine accumulation in moderately salt resistant

rice cultivar AIW 4. Int. Rice Res. Note 25

:

36-37.

Li, Z.Y. and S.Y. Chen. 2000. Differential accumulation of the

S-adenosylmethionine dec arboxylas e transcript in rice

seedlings in response to salt and drought stress. Theo. Appl.

Gene. 100

:

782-788.

Lin, C.C. and C.H. Kao. 1995. Levels of endogenous polyamines

and NaCl inhibited growth of rice seedlings. Plant Growth

Regul. 17

:

15-20.

Lovell, P.H. 1971. Translocation of photosynthates in tall and

dwarf varieties of pea Pisum sativum. Physiol. Plant. 25

:

382-385.

Maiale, S., D.H. Sanchez, A. Guirado, A. Vidal, and O.A. Ruiz.

2004. Spermine accumulation under salt stress. J. Plant

Physiol. 161: 35-42.

Mansour, M.M.F., K.H.A. Salama, M.M. Al-Mutawa, and A.F.A.

Hadid. 2002. Effect of NaCl and polyamines on plasma

membrane lipids of wheat roots. Biol. Plant. 45: 235-239.

Mansour, M.M.F., M.M. Al-Mutawa, K.H.A. Salama, A.F.A.

Hadid. 2002. S alt a cclim ation of wheat s alt s ens itive

cultivar by polyam ines . In Ahmad, R. and K.A. Ma lik

(eds.), P rospects for Saline Agriculture. Springer Verlag,

Berlin, Germany, pp. 155-160.

Mansour, M.M.F. 2000. Nitrogen containing compounds and

adaptation of plants to salinity s tres s. Biol. Plant. 43:

491-500.

Martinez-Tellez, M.A., M.G. Ramos-Clamont, A.A. Gardea, and

I. Vargas-Arispuro. 2002. Effect of infiltrated polyamines

on polygal acturona se a cti vity and inj ury re spons e in

zucchini squash (Cucurbita pepo L.). Biochem. Biophy.

Res. Commun. 295: 98-101.

Masgrau, C., T. Altabella, R. Farras, D. Flores, A.J. Thompson,

R. T. B e s fo rd , a n d A.F. Ti b urc i o. 1 997 . In duc i bl e

overexpression of oat arginine decarboxylase in transgenic

tobacco plants. Plant J. 11

:

465-473.

Mishra, S.M. and I. Sharma. 1994. P utres cine as a growth

inducer and as a source of nitrogen for mustard seedlings

under sodium chloride s alinity. Indian J. Exp. Biol. 32

:

916-918.

Mo, H. a nd E .C . P ua . 2 002 . Up -re gul at io n o f a rgin in e

dec arboxyl as e ge ne exp res si on and a ccum ula tion of

polyamines in mustard (Br assica juncea) in respons e to

stress. Physiol. Plant. 114

:

439-449.

Norm anly, J. 1997. Auxin metabolism . P hysiol. Plant. 100

:

431-442.

Pancheva, T.V., L.P. Popova, and A.N. Uzunova. 1996

.

Effects

of salicylic acid on growth and photosynthesis in barley

plants.

J.

Plant Physiol.

149: 57-63.

Pill, W.G. and A.D. Necker. 2001. The effects of seed treatments

on germination and establis hment of Kentucky bluegrass

(Poa pratensis L.). Seed Sci. Technol. 29

:

65-72.

P os pi.ilova, J. 2003. P articipation of phytohormones in the

stomatal regulation of gas exchange during water stress.

Biol. Plant. 46

:

491-506.

Ray, S. and M. A. Choudhuri. 1981. Effect of growth regulators

on grain filling and yield of rice (Oryza sativa L.). Ann.

Bot. 47

:

755-758.

Rehman, S., P.J.C. Harris, and W.F. Bourne. 1998. Effects of

pre-sowing treatment with calcium salts, potassium salts, or

water on germination and salt tolerance of Acacia seeds. J.

Plant Nut. 21

:

277-285.

Roberts , D.R., E.B. Dum broff, a nd J.E. Thomps on. 1986.

Exogenous polyamines alter membrane fluidity in bean

leaves: A basis for potential misinterpretation of their true

physiological role. Planta 167

:

395-401.

Roy, N.K. and A.K. Srivastava. 1999. Effect of presoaking seed

treatment on germination and amylase activity of wheat

(Triticum aestivum L.) under salt stress conditions. Rachis

18

:

46-51.

Santa-Cruz, A., M. Acosta, F. Perez-Alfocia, and M.C. Bola-

rin. 1997. Changes in free polyamine levels induced by

salt stress in leaves of cultivated and wild tomato species.

Physiol. Plant. 101

:

341-346.

Schettel, N.L. and N.E. Balke. 1983

.

Plant growth response to

several allelopathic chemicals. Weed

Sci.

31: 293-298.

S e rra no, M., M.C. Ma rt yne z-Ma dri d, F. R ique lm e , an d

F. Romo jaro. 1997. Modi fied a tmos phe re pac kagi ng

minimizes increases in putrescine and abscisic acid levels

caused by chilling injury in pepper fruit. J . Agric. F ood

Chem. 45

:

1668-1672.

Serrano, M., M.T. Pretel, M.C. Martynez-Madrid, F. Romojaro,

and F. Riquelme. 1998. CO

2

treatment of zucchini squash

reduces chilling-induced physiological changes. J. Agric.

Food Chem. 46

:

2465-2468.

Shakirova, F.M., A.R. Sakhabutdinova, M.V. Bezrukova, R.A.

Fatkhutdinova, and D.R. Fatkhutdinova. 2003. Changes in

the hormonal status of wheat seedlings induced by salicylic

acid and salinity. Plant Sci. 164: 317-322.

Shen, W.Y., K. Nada, and S. Tachibana. 2000. Involvement in

polyamines in the chilling tolerance in cucumber cultivars.

Plant Physiol. 124

:

431-439.

Simon-Sarkadi, L., G. Kocsy, and Z. Sebes tyen. 2002. Effect

of salt stress on free amino acid and polyamine content in

cereals. Acta Biologica Szegediensis 46

:

73-75.

S loc um, R.D. 1991. P olyam ine bios ynthes is in plants . In

R.D. Slocum and H.D. F lores (eds .), Biochem is try and

P hysiology of P olyam ines in Plants. CRC Pres s, Boca

Raton, FL, pp. 23-40.

IQBAL et al. — Does polyamine-priming modulate growth under salt stress.

249

Smith, T.A. 1985. Polyamines. Annu. Rev. Plant Physiol. 36

:

117-143.

Smith, T.A. 1973. Amine levels in mineral deficient Hordeum

vulgaris leaves. Phytochemistry 12

:

2093-2100.

Tari, I., J. Csiszar, G. Szalai, F. Horvath, A. Pecsvaradi, G. Kiss,

A. Szepesi, M. Szabo, and L. Erdei. 2002. Acclimation of

tomato plants to salinity stress after a salicylic acid pre-

treatment. Acta Biologica Szegediensis 46

:

55-56.

Thimann, K.V. 1977. Hormone Action in the Whole Life of

Plants. Amherst: University Massachusetts Press.

Tiburcio, A.F., T. Altabella, A. Borrell, and C. Masgrau. 1997.

Polyamine metabolism and its regulation. Physiol. Plant.

100

:

664-674.

Tiburcio, A.F., J.L. Campos, X. Figueras , and R.T. Besford.

1993. Recent advances in the understanding of polyamine

functions during plant development. Plant Growth Regul.

12

:

331-340.

Tiburcio, A.F., R. Kaur-S awhney, and A.W. Galston. 1990.

Polyamine metabolism. In B.J. Miflin and P.J. Lea (eds.),

T he B ioc hem is tr y of P la nts : Inte rme dia ry Nit roge n

Metabolism. Academic Press, New York, pp. 283-325.

Twitchell, L.T. 1955. Germination of fourwing saltbush seed

as affected by s oaking and chloride removal. J. Range

Manage. 8

:

218-220.

Uzunova, A.N. and L.P. Popova. 2000

.

Effect of salicylic acid

on leaf anatomy and chloroplast ultrastructure of barley

plants. Photosynthetica 38: 243-250.

Wang H., L.G. Ma, J.M. Li, Y.H. Zhao, and X.W. Deng. 2001.

Direct interaction of Arabidopsis cryptochromes with COP

1

in light control development. Science 294: 154-158.

Watson, M.B. and R.L. Malmberg. 1998. Arginine decarboxylase

(polyamine synthes is ) mutants of Arabidops is thaliana

exhibit altered root growth. Plant J. 13

:

231-239.

Xiong, L. and J.K. Zhu. 2002. Molecular and genetic aspects of

plant responses to osmotic stress. Plant Cell Environ. 25:

131-139.

Zhang J. and X. Zhang. 1994. Can early wilting of old leaves

account for much of the ABA accumulation in flooded pea

plants. J. Exp. Bot. 45: 1335-1342.

Zheng, Z., Z. Jin, K. Xia, X. Zhou, and C. Ma. 1998. An ABA

binding prot ein with nucleic acid-binding properties .

Science in China. Series C, Life sciences/Chinese Academy

of Sci. 41

:

209-216.

250

Botanical Studies, Vol. 47, 2006

以多元胺預先處理種子能否½節發芽後處於鹽逆境六倍體小

麥之生長及若干植物生長½節物½之含量高低？

Muhammad IQBAL, Muhammad ASHRAF, Shafiq-Ur-REHMAN, and Eui Shik

RHA

1

Department of Botany, University of Agriculture Faisalabad 38040, Pakistan

2

Faculty of Biological Resources Science, College of Agriculture

Chonbuk National University, Chonju 561-756, Republic of Korea

3

Life Resources Science, Plant Genetics & Breeding, Sunchon National University

Sunchon, 540-742, Republic of Korea

　　種子發芽前，分別以多元胺 (2.5 mM putrescine, 5.0 mM spermidine 及 2.5 mM spermine) 預先處理

對之後幼苗之生長及內在生長½節物½之量的影響以兩種春小麥 (Triticum aestivum L.) 品系 MH-97 及

Inqlab-91 測試。實驗組及對照組之種子均種在鹽度為 15 dS m

-1

之實驗田。雖然對兩種供試小麥之½

粒產量受鹽害之減低情形，三種多元胺均可改善；spermine 之效果最好。三種多元胺均對 MH-97 葉內

自由型離層酸 (ABA) 之減少 (實驗組比對對照組) 均有所改善，但以 putrescine 之效果最佳。相對地，

putrescine 在品系 Inqlab-91 內則最有效地增加葉內自由型 indoleacetic acid, spermidine 及 spermine 則在

兩種供試品系處於鹽逆境下有效地增強葉中之水楊酸 (salicylic acid) 含量。以 spermidine 預處理之種

子，之後在鹽逆境下葉中自由型之 putrescine 則以 MH-97 較對照組為高。相反地，在品系 Inqlab-91 所

有三種多元胺之種子處理均導致之後發芽幼苗在鹽逆境下均比對照組有較低之葉中自由型 putrescine，

兩種品系之種子經 putrescine 預處理後，之後發芽之植物體在鹽逆境下均有最大量之葉中自由型

spermidine。整體而言，多元胺之種子預處理其好處依品種而異。自生理觀點而言，種子以 spermine 預

處理之所以在鹽逆境下能改善兩種供試品種之½粒產量，可能歸因於植物激素的平衡之改變。

關鍵詞：植物生長½節物½預處理；植物生長½節物½；發芽前之預處理；鹽度；高鹽耐受性。