Telechargé par Khabtane Hamid

PUB 1

publicité
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
AENSI Journals
Advances in Environmental Biology
ISSN-1995-0756
EISSN-1998-1066
Journal home page: http://www.aensiweb.com/AEB/
Heat shock effects on chlorophyll fluorescence, membrane stability, and
metabolites accumulation in durum wheat (Triticum turgidum L. var. durum)
seedlings and relationships with yield stress tolerance indices
1,2Sofia
3Mouna
Hamli, 3Mostapha Labhilili, 2Kenza kadi, 2Abd El Hamid Khabthan, 3Meryem Alyadini,
Tagouti, 3Rajae Manzeri, 3Fatima Gaboun and 1Hmenna Bouzerzour
1
Valorization of Biological Natural Resources Laboratory, Faculty of Life and Natural Sciences, Setif-1 University, 19000, Algeria
Department of Agronomy, Faculty of Life and Natural Sciences, Khenchela University, 40000, Algeria
3
Center Regional of Agricultural Research, Biotechnology Unit, P.O. Box 415, Rabat, Morocco
2
ARTICLE INFO
Article history:
Received 28 January 2015 Accepted
25 February 2015 Available online 6
March 2015
Keywords:
Triticum durum, RWC, Proline,
Fluorescence, P index, heat shock,
seedling
ABSTRACT
Physiological traits are receiving increasing attention as screening tools for stress
resistance to enhance both yield potential and yield stability under stressful conditions.
This study was undertaken to investigate the discriminating ability of bioassays applied
to durum wheat lines subjected to heat shock at the seedling growth stage and to study
their relationships with grain yield stress tolerance indices. Sufficient amount of
variability was observed in the responses of the eight durum wheat genotypes
evaluated. Heat shock increased proline, soluble sugars and damage to cell membrane
and decreased Fv/Fm ratio, relative water content and chlorophyll content. Genotype
responses varied according to stress intensity. Different genotypes were declared as
tolerant to stress based on different parameters. Base on proline and soluble sugars
results Korifla was identified as stress tolerant. Bousselam was declared stress tolerant
based on membrane stability, relative water and chlorophyll contents results. Waha was
tolerant based on Fv/Fm ratio. P index identified three varieties as stable and high
yielding. Correlations study indicated that the relationships between bioassays
parameters and with tolerance indices varied according to stress levels, suggesting that
these physiological traits could not be recommended to replace grain yield field testing,
under the Algerian conditions of durum production.
© 2015AENSI Publisher All rights reserved.
To Cite This Article: Sofia Hamli, Mostapha Labhilili, Kenza kadi, Abd El Hamid Khabthan, Meryem Alyadini, Mouna Tagouti, Rajae
Manzeri, Fatima Gaboun and Hmenna Bouzerzour., Heat shock effects on chlorophyll fluorescence, membrane stability, and metabolites
accumulation in durum wheat (Triticum turgidum L. var. durum) seedlings and relationships with yield stress tolerance indices. Adv.
Environ. Biol., 9(8), 116-125, 2015
INTRODUCTION
High temperature adversely affects wheat productivity in arid and semi-arid regions. This stress decreases
photosynthesis, impairs respiration, inactivates enzymes and disrupts membranes, suppressing growth. This type
of stress poses a challenge that can only be addressed through development of tolerant cultivars. The limited
success in developing heat tolerant cultivars is imposed by the complex nature of heat stress effects on plant and
the difficulty to separate the effects of this type of stress from the effects of other stresses [1]. Selection of high
yielding and stress tolerant genotypes is an important objective in these stressful environments, where breeding
relies on direct selection for yield and few alternatives to direct selection have been adopted. To develop stress
tolerant genotypes, reliable and efficient techniques must be made available to assess the plant response to the
targeted stress.
Lack of appropriate traits, to use in place of or along with grain yield, as selection criteria, prevents yield
improvement in these environments. However examples of traits, correlated with stress tolerance, and which
have been efficient in wheat breeding, are reported in the literature [2]. Chlorophyll fluorescence, proline, water
soluble sugars, relative water and chlorophyll contents and membrane stability, have been proposed as selection
criteria to improve stress tolerance [3, 4, 5, 6, 7]. These traits, which had the capacity to discriminate between
tolerant and sensitive genotypes, under stress conditions, would enable breeders to identify superior genotypes
and devise breeding strategies for the improvement of heat tolerance. Heat stress causes chlorophyll breakdown
Corresponding Author: Sofia Hamli, Deparment of Agronomy, Faculty of nature science and life, Khenchela University
40000, Algeria.
E-mail: [email protected]
117
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
in sensitive genotypes and alters chlorophyll fluorescence pattern [8, 9]. Fv/Fm ratio is an indicator of
photoinhibition under heat stress and as such it was found useful for screening wheat for chlorophyll stability [8,
10, 11].
Proline and water soluble sugars play an active role in the protection of plants by acting as cellular osmotic
regulators between cytoplasm and vacuole [12]. Heat stress leads to drastic change in the cell membrane
stability whose structural properties are altered, allowing electrolyte leakage. The relative level of membrane
injury can be estimated by the amount of leaked electrolyte following heat stress treatment. The membrane
thermo-sensitivity assay has been used as a technique to screen for heat tolerance in various crops [13, 14].
Stress tolerance has been also approached, with some success, by developing tolerant varieties through
traditional plant breeding techniques using field evaluation. Grain yield of tested cultivars is evaluated under
both stress and stress free growth conditions, enabling a direct comparison of the performance and stability.
Several indices were proposed to describe such yield variation for a given genotype [15, 16]. Fischer and
Maurer [17] proposed a stress susceptibility index (S) based on the minimization of yield reduction from
favorable to unfavorable environments. Lin and Binns [18] proposed an index (P) for comparing yield
performances of genotypes across environments, where the highest-yielding genotype within each environment
is taken as the reference. The objective of this study was to assess the discriminating ability of physiological
screening tests applied to durum wheat lines subjected to heat shock at the seedling growth stage and to evaluate
their relative utility as predictor of stress tolerance expressed under the form of grain yield index.
MATERIALS AND METHODS
Eight durum wheat (Triticum turgidum L. var. durum) genotypes namely Bousselam, Gaviota durum,
Korifla, Mrb3, Ofanto, Tajdid, Vitron and Waha were used as plant material. The pedigrees of these varieties
and cross origin were reported by Nouar et al., [19]. Seeds were first cleaned and a uniform seed size lot of
each genotype was obtained by sieving. Seeds were surface sterilized by immersion in a hypochlorite solution
(1% available chlorine) for 2 minutes and then rinsed thoroughly with distilled water. Enough seeds per
genotype were placed in Petri dishes on a germination paper moistened with distilled water, and germinated in
an incubator for 6 days at 25°C. Germinated seeds were transferred to plastic pots filled with 1/3 soil and 2/3
sand (v/v) and irrigated daily. Sets of 3-leaf seedlings were up rooted, gently washed with distilled water and
immersed in a water bath at 40°C for 0, 30 and 60 minutes. The following traits were measured.
Chlorophyll content:
Chlorophyll content measurements were made on the emerged blade of two seedlings per treatment. Total
chlorophyll pigments were extracted from leaf samples of 0.1g fresh weight in 10 ml of 85% acetone.
Absorbance of the extract was measured, at 645 and 663 nm, on a Sontays Techtron 635 spectrophotometer, and
samples chlorophyll concentration deduced using the following equation due to Arnon [20]: Chl (mg/g FW) =
20.2 A645 – 8.02 A663
Relative leaf water content:
Harvested leaf-samples were weighted to obtain the fresh weight (FW) and immersed in glass test tubes
containing 10 ml of distilled water and stored in a cold room, overnight, to allow for rehydration. Leaf-samples
were re-weighted for turgid weight (TW) determination, then were dried at 65°C for 24 hours and weighted to
get dry weight (DW). Relative water content was determined using the following formulae reported by
Azimzadeh and Azimzadeh [21]: RWC (%) = 100 x [(FW-DW)/(TW-DW)].
Membrane thermo stability:
Blade leaf-samples were collected from each treatment, rinsed twice in deionized water and cut into
segment, 1 cm long. Five segments per treatment were immersed in glass test tubes containing 10 ml of double
deionized water. The test tubes were tightly capped and held overnight at room temperature, then an initial
reading (T1) was done with a conductivity meter. The test tubes were immersed in water bath at 100°C
temperature for 60 minutes, let to stand overnight, and a second reading was taken (T2). Membrane thermo
stability was expressed in percentage units of the relative leakage, according to Ibrahim and Quick [13]: %
injury = 100 x (T1/T2).
Proline accumulation:
A second experiment, similar to the one described here above, was conducted to obtain enough plant
material for the determination of the accumulated proline, according to the method of Bates et al., [22], and
water soluble sugars, using the anthrone colorimetric assay [23]. Proline was extracted from 0.5 g leaf samples
tissue mixed with 1mL of 3% 5-sulfosalicylic acid (w/v) in test tubes and stirred for 20 minutes. One hundred
μL aliquots were pipetted into test tubes and adjusted to 1mL with double-deionized water. One mL acid
118
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
ninhydrin (prepared by mixing 1.25 g ninhydrin + 30 mL glacial acetic acid+ 13.8 mL 85% phosphoric acid +
6.2 mL double deionized water) and 1.0mL glacial acetic acid were added to the test tubes. Test tubes were
stirred for 1 minute and incubated in a water bath for 60 minutes at 100°C.
The reaction was stopped after incubation by placing tubes in ice bath. Tubes were removed from the ice
bath and 4 mL of toluene was added to each test tube. Tubes were again stirred for 1 minute and allowed to
settle down for 5 minutes for phase separation. Three mL of the upper phase, containing toluene, were pipetted
into cuvette and absorbance was read at 520 nm in a spectrophotometer (Sontays Techtron 635 spectrophotometer) using toluene as blank. A standard curve was prepared using known concentrations of proline. A
calibration series, incremented by10 µg/mL from 10 to 100 µg/mL of proline, was run, and the standard curve
plotted. The concentration of the unknown samples was estimated by referring to the standard curve and
expressed on fresh weight basis.
Sugars accumulation:
Water soluble sugars were determined from 100 mg of plant material, extracted in 80% ethanol solution.
The extract was incubated for 6 hours at 60°C. Anthrone reagent was prepared by dissolving 150 mg anthrone in
72% H2SO4 solution. Plant extract was pipetted in glass test tubes, and 6 ml of the anthrone reagent were added
to each sample, heated in a water bath at 100°C for 10 minutes. The test tubes were ice cooled for 10 minutes
and to settle at room temperature for another 30 minutes. Optical density was read at 625nm on a Sontays
Techtron 635 spectrophotometer. Samples water soluble sugar concentrations were estimated by referring to the
sugar standard curve and expressed on fresh weight basis.
Leaf chlorophyll fluorescence:
Fluorescence measurements were done on attached leaf blades using a portable fluorimeter (Opti-Science
30). Three measurements were done per treatment on the leaf adaxial side. Fluorescence signals were used to
provide estimates of Fv/Fm ratio [24]. The experiments were conducted at the plant physiology laboratory,
Faculty of life and natural sciences, Khenchela University (Algeria). The chlorophyll fluorescence experiment
was conducted at the Biotechnology Unit of the Regional Center of Agricultural Research (CRRA, INRA,
Rabat, Morocco), during a stay of the first author in December 2012 and January 2013.
Stress tolerance indices:
Two stress tolerance indices, the stress susceptibility index (S) [17] and the genotypic superiority index (P)
[18], were derived from grain yield data collected from field trials carried out during the 2009-10 cropping
season at five locations [19]. The S index was calculated for each genotype as follows: S = (1-ys/yns)/(1-Ȳs/Ȳns),
where ys is the stressed and yns is the non-stressed genotype grain yield. Ȳs is the stressed and Ȳns is the nonstressed location mean yield. The P index was calculated for each genotype (i) as follows: Pi = [Σ (Xij-Mj)²]/2n,
where n is the number of locations, Xij est the yield of the ith genotype in the jth location, and Mj is the yield of
the best performing genotype in the j th location.
Statistical analysis:
A two-way analysis of variance with 3 replications was used to test the main effects and the interaction
[25]. When appropriate a heat shock susceptibility index (HSSI), similar to the salinity susceptibility index
reported by Jiang et al., [26] was calculated for each variety as: HSSI (%) = [(100Ys/Yc) -100], where Ys is the
mean value of the parameter measured under heat shock conditions and Yc is the mean value of the same
parameter measured in the absence of heat shock (control). Linear correlation analysis was used to determine the
relationships between the measured traits. Data were analyzed using the free software Cropstat 7.2. 3 [27].
RESULTS AND DISCUSSIONS
Heat shock effect on the measured parameters:
The analysis of variance indicated significant heat shock main effect and genotype x heat shock interaction
of the measured traits (Table 1). Mean values of the measured traits, average over varieties, are indicated in
table 2. Proline, sugars and ion-leakage increased; while relative water and chlorophyll contents and Fv/Fm ratio
decreased under heat shock treatments (Table 2). The heat shock-induced increase, over control value, observed
under 60 min heat-treatment, was 107.8%, 95.1% and 214.3%, for proline, water soluble sugars and ion-leakage,
respectively. The control mean values of these traits were 26.03µg/ml proline, 50.79µg/ml water soluble sugars
and 11.12% injury. The heat shock-induced decline, observed under 60 min treatment, was 15.40% for relative
water content, 9.10% for chlorophyll content and 20.27% for the Fv/Fm ratio. The control mean values of these
characters were 88.64% relative water content, 3.98 mg/g FW chlorophyll content and 0.74 Fv/Fm ratio (Table
2).
119
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
In the absence of heat stress (check treatment), the tested varieties showed inherent differences in the
expression of the measured traits (Table 3). Waha accumulated significantly more proline (35.83µg/ml) and
sugars (61.21µg/ml). Korifla accumulated significantly less proline (12.90 µg/ml) and sugars (30.47µg/ml).
Ofanto had the highest mean values of electrolyte leakage (14.00%), relative water (91.40%) and chlorophyll
(7.40 mg/g FW) contents. Gta durum had the lowest relative water content (82.07%) and Vitron exhibited the
lowest chlorophyll content (2.30 mg/g FW). Values of the Fv/Fm ratio were not significantly different among
the tested varieties (Table 3). The analysis of the relative changes in accumulated proline, under heat shock
treatments, indicated that Korifla and Mrb3 were more sensitive to heat shock, and Tajdid and Waha were less
responsive. The 60 min treatment was more discriminating among genotypes which clustered into three groups:
high (Korifla and Mrb3), intermediate (Vitron and Ofanto) and low accumulating genotypes (Figure 1A).
Korifla accumulated, relatively, more water soluble sugars compared to Ofanto which accumulated less. The 60
min treatment discriminated best among the tested genotypes which grouped into four clusters, with an averaged
sugar HSSI of 293.2% (Korifla), 212.0% (Mrb3, Tajdid, Vitron, Bousselam), 177.6% (Waha, Gaviota durum),
and 119.6% (Ofanto) (Figure 1B).
Table 1: Analysis of variance mean squares of Fv/Fm ratio, proline, water soluble sugars, % injury to cell membrane, relative water and
chlorophyll contents of eight durum wheat genotypes subjected to heat shock stress at 40°C during 0, 30 and 60 minutes at the
seedling stage.
Sources of variation
Heat shock (HS)
Rep/HS
Genotype (G)
G x HS
Error
Ddl
2
6
7
14
42
Fv/Fm
0.14476*
0.00595
0.01972ns
0.01531**
0.00173
Pro (µg/ml)
3627.6**
17.5
696.8ns
486.4**
10.9
Suc (µg/ml)
14052.9**
89.9
1331.1*
380.9**
153.1
Chl (mg/g FW)
25.5**
0.1
12.1*
2.8**
0.1
Inj (%)
3415.5**
9.8
44.4ns
35.3**
6.0
RWC (%)
1198.4**
4.5
9.5ns
31.3**
6.1
Fv/Fm = quantum yield; Proc = proline, µg/ml; Suc = Soluble sugars, µg/ml; Inj= injury to cell membrane, %; RWC= relative water content,
%; Chl= Chlorophyll content, mg/g FW. ns,* = non-significant and significant effect at 5% probability level, respectively.
Table 2: Heat shock main effect of accumulated proline, soluble sugars, % injury to cell membrane, relative water and chlorophyll contents
of eight durum wheat genotypes subjected to heat shock stress at 40°C during 0, 30 and 60 minutes at the seedling stage.
Heat shock duration at 40°C
Parameters
0
30
60
Lsd5%
Fv/Fm
0.74
0.68
0.59
0.05
Chl (mg/g FW)
3.98
2.81
1.92
0.18
RWC (%)
88.64
84.94
74.97
1.50
Pro (µg/ml)
26.03
39.25
54.09
2.95
Sug (µg/ml)
50.79
73.19
99.15
6.69
Inj (%)
11.12
23.82
34.96
2.21
Fv/Fm = quantum yield; Proc = proline, µg/ml; Sug = Soluble sugars, µg/ml; Inj= injury to cell membrane, %; RWC= relative water content,
%; Chl= Chlorophyll content, mg/g FW.
Relative water content was less affected by heat shock treatment in Bousselam (100.0 and 91.0%) and
Gaviota durum (100.0 and 95.5%) than in Tajdid (90.8 and 78.8%) and Vitron (93.2 and 76.9µ), under both 30
and 60 min treatments, which ranked differently Ofanto and Korifla. No clear clustering of the studied varieties
appeared for this trait which exhibited a large range under 60 min treatment (Figure 2A). Heat shock treatments
classified differently the tested genotypes for ion-leakage. Vitron expressed high increase in ion-leakage
(305.9%), under 30 min treatment, but under 60 min heat stress treatment, it is Korifla (385.0%) which
exhibited the highest ion-leakage. Bousselam (140.0%), under 30 min treatment, and Ofanto (256.0%), under 60
min treatment, had the lowest % injury index (Figure 2B).
120
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
450
BOU
A
GTA
Kori
400
Mrb
OFA
350
Proline HSSI (%)
TAJ
Vit
300
WAH
250
200
150
100
0
30
Heat shock duration ( min)
BOU
350
60
B
GTA
Sugars HSSI (%)
Kori
Mrb
300
OFA
TAJ
Vit
250
WAH
200
150
100
0
30
Heat shock duration (min)
60
Fig. 1: Proline (A) and water soluble sugars (B) HSSI (%) of eight durum wheat genotypes subjected to heat
shock stress at 40°C during 0, 30 and 60 min at the seedling stage.
Table 3: Check mean value of proline (Proc, µg/ml); water soluble sugars (Sug, µg/ml); injury to cell membrane (Inj, %); relative water
content (Rwc,%) ; Chlorophyll content (Chl, mg/g FW) and Fv/Fm ratio of eight durum wheat genotypes subjected to heat shock
stress at 40°C during 0, 30 and 60 minutes at the seedling stage.
Genotype
Pro
Sug
% Inj
Rwc
Chl
Fv/Fm
Bousselam
24.84
60.60
12.50
85.00
2.37
0.775
Gta durum
34.85
53.13
11.50
82.07
2.50
0.740
Korifla
12.90
30.47
10.00
88.87
6.22
0.730
Mrb3
14.87
37.20
11.00
88.33
4.72
0.747
Ofanto
35.29
58.76
14.00
91.40
7.40
0.732
Tajdid
28.60
57.28
11.50
92.00
2.67
0.759
Vitron
20.43
47.73
9.00
92.53
2.30
0.720
Waha
35.83
61.21
9.50
88.93
3.67
0.716
Lsd5%
5.5
20.4
4.0
4.1
0.5
0.07
Fv/Fm = quantum yield; Proc = proline, µg/ml; Sug = Soluble sugars, µg/ml; Inj= injury to cell membrane, %; RWC= relative water content,
%; Chl= Chlorophyll content, mg/g FW.
121
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
Decline in chlorophyll content, at 30 min heat shock treatment, varied from 7.0% (Bousselam) to 54.1%
(Ofanto), and from 22.8% (Mrb3) to 80.9% (Ofanto), at 60 min heat shock treatment. Bousselam, with a low
initial chlorophyll content of 2.4 mg/g FW, was the least affected, expressing a relative decline of 7.0% and
26.8% under both stress treatments, while Ofanto, with a high inherent chlorophyll content of 7.4 mg/g FW, was
the most affected by the stress. Chlorophyll content bioassay clustered the tested varieties into three groups:
Bousselam and Mrb3, the least affected group, with an average chlorophyll decline of 24.5%, Gta durum,
Korifla, Tajdid, Vitron and Waha, intermediate group, with an average chlorophyll reduction of 48.9%, and
Ofanto, forms the sensitive group with a chlorophyll content reduction of 80.9%, under 60 min heat treatment
(Figure 3).
105
A
100
RWC HSSI (%)
95
90
85
BOU
GTA
Kori
Mrb
OFA
TAJ
Vit
WAH
80
75
70
0
20
40
60
Heat shock duration (min)
450
400
BOU
GTA
Kori
Mrb
OFA
TAJ
Vit
WAH
B
350
Inj HSSI (%)
300
250
200
150
100
50
0
0
10
20
30
40
50
60
Heat shock duration (min)
Fig. 2: Relative water content (A) and ion-leakage (B) HSSI (%) of eight durum wheat genotypes subjected to
heat shock stress at 40°C during 0, 30 and 60 min at the seedling stage.
122
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
0
-10
-20
HSSI Chl (%)
-30
BOU
GTA
Kori
Mrb
OFA
TAJ
Vit
WAH
-40
-50
-60
-70
-80
-90
0
30
60
heat shock duration min
Fig. 3: Chlorophyll content HSSI (%) of eight durum wheat genotypes subjected to heat shock stress at 40°C
during 0, 30 and 60 min at the seedling stage.
Concerning the decline in chlorophyll content under heat stress, the results of the present study corroborate
those reported by Dash and Mohanty [28] who analyzed the responsiveness of bread wheat cultivars to growth
at 40°C for 60 h and the potential of the heat stressed -seedlings to recover during 24 h post-stress growth at 25
°C. These authors mentioned that chlorophyll content in heat stressed-seedlings declined to 76% in HD-2643
cultivar and between 50 to 57% in HD-2327 and HD-2307 cultivars. The Fv/Fm genotype x heat shock
interaction analysis suggested the high tolerance of Waha which showed no significant decline in its Fv/Fm ratio
under both heat stress treatments. In comparison, Vitron and Korifla exhibited a significant reduction in the
Fv/Fm ratio which declined by 7.0%, at 30 min, and by 45.0% at 60 min heat shock treatments. Bousselam and
Gaviota durum maintained a constant Fv/Fm ratio at both treatments, showed an averaged decrease of 7.87 and
6.36%, at 30 and 60 minutes heat shock treatments, respectively. The 60 minutes heat shock treatment was the
most discriminant between varieties, grouping them into three clusters: tolerant (Waha), moderately tolerant
(Mrb3, Ofanto, Tajdid, Bousselam and Gaviota durum), and susceptible genotypes (Vitron and Korifla) (Figure
4). Concerning the variation in the decline of the Fv/Fm ratio, among genotypes, similar results to those of the
present study were reported by Dash and Mohanty [28]. These researchers analyzed the Fv/Fm ratio of control
and heat stressed-seedlings, and found that heat-stress induced maximal decrease in the Fv/Fm ratio of PBN51
and HD-2643 cultivars and that among the studied cultivars, the Fv/Fm ratio was significantly reduced in C306,
HD-2402, and HD-1553, but not in HD-2307cultivars.
110
Wah
100
Fv/Fm HSSI (%)
Mrb
90
80
Bou
Gta
Of
Tajd
70
Vit
60
Kor
50
0
10
20Heat shock 30
40
50
60
duration (min)
Fig. 4: Fv/Fm HSSI (%) of eight durum wheat genotypes subjected to heat shock stress at 40°C during 0, 30 and
60 min at the seedling stage.
123
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
In general, the results of the present study corroborate those reported by Araus et al., [8] who found that the
Fv/Fm ratio, chlorophyll and relative water contents declined from the unstressed (irrigated) to the stressed
(rainfed) environments. The reduction in the Fv/Fm ratio was interpreted as the occurrence of photo-damage
rather than photoprotection. Similarly, Balochi [29] mentioned that stress decreased chlorophyll and relative
water contents and Fv/Fm ratio, in all the tested varieties and that genetic variation was observed for the
measured traits among varieties under stress conditions.
Grain yield stress tolerance indices:
Grain yield ranged from 1.05 t/ha, yield of Tajdid, expressed at HAR location to 5.59 t/ha, yield of the same
genotype observed at KH location (Table 4). On average, Mrb 3, Bousselam and Waha were among the top grain
yielding entries. P index values varied from 0.05 for Mrb 3 to 0.65 for Ofanto. Based on this index Mrb 3,
Bousselam and to a lesser extent Waha are classified as stable and high yielding. While Ofanto, Vitron and
Gaviota durum are classified as unstable and low yielding (Table 4). S index values varied from 0.92 for Ofanto
to 1.11 for Tajdid. Since values of this index, less than unity, are suggestive, according to Fisher and Maurer
[17], of tolerance to stress, then Ofanto, Gaviota durum, Vitron and Bousselam are tolerant to stress. These
results suggested that Bousselam cumulates, both, above average grain yield and stress tolerance, while Ofanto,
Gaviota durum and Vitron are stress tolerant and low yielding (Table 4). These results indicated that P index is
best suited to select for higher and stable yield under both stressed and unstressed conditions. This index
identified three genotypes as stable and high yielding among which two (Bousselam and Waha) have been
released as cultivars [19].
Table 4: Average grain yield per location and stress tolerance indices of the eight durum wheat genotypes
Grain yield (t/ha) / location
Génotype
SET
KH
HAR
SBA
SAI
Average
Bousselam
4.37
5.01
1.47
2.71
3.68
3.45
Gaviota durum
3.55
4.26
1.33
2.29
4.10
3.10
Korifla
3.97
5.13
1.23
2.31
3.33
3.19
Mrb3
4.61
4.98
1.32
2.97
3.78
3.53
Ofanto
2.84
4.15
1.37
2.06
3.42
2.77
Tajdid
3.69
5.59
1.05
2.50
2.96
3.15
Vitron
3.22
4.53
1.37
1.95
4.16
3.05
Waha
3.82
5.04
1.25
2.78
3.76
3.33
Locations: SET= Setif, KH= Khroub, HAR= Harrouch, SBA= Sidi Bel Abbes, SAI= Saïda.
Stress index
P
S
0.06
0.97
0.34
0.94
0.17
1.04
0.05
1.01
0.65
0.92
0.25
1.11
0.41
0.95
0.11
1.03
Relationships between tests parameters and grain yield stress tolerance indices:
Using the relative values of the assays parameters, expressed as heat shock susceptibility index (HSSI), the
analysis of the spearman's rank correlation indicated that under 30 minutes exposure at 40°C, soluble sugars
were positively correlated with % damage to cell membrane (r= 0.881, P=0.007), and with Fv/Fm ratio (r=
0.762, P=0.037). Per cent damage to cell membrane was positively and significantly correlated with Fv/Fm ratio
(r= 0.762, P=0.037) and negatively with relative water content, at 10% probability level (r= -0.643, P=0.083).
Chlorophyll content showed a negative correlation with P index (r= -0.714, P=0.058). Under 60 minutes
exposure to heat shock stress, soluble sugars were positively correlated with % damage to cell membrane (r=
0.850, P=0.011), but not with Fv/Fm ratio, as it was observed under 30 minutes exposure to heat shock stress.
However soluble sugars showed significant correlation, negative with P index (r= -0.659, P=0.084), and positive
with S index (r= 0.716, P=0.052). These relationships were not observed under 30 min exposure. These results
indicated the inconsistency of the relationships between physiological tests. The relationships with stress indices
appeared to be dependent on stress severity. These laboratory tests do not predict the genotypic response to
stress experienced in the field. As such, they could not be recommended to replace field testing based on grain
yield as screening tools for identification of tolerant genotypes to be used in crossing programs or applied
directly to segregating populations. The results of the present study do not corroborate those of Talebi [30] who
reported a significant correlation between chlorophyll content and S index, under moisture-stressed conditions,
suggesting the potential of this index for selecting drought tolerant genotypes. Cseuz [31] reported that water
retention capability, assimilates translocation and canopy temperature tests were closely correlated, in drier
years, with multi-location yield tests, and suggested them as screening tools.
Conclusion:
The various laboratory tests assessed in this study indicated sufficient amount of variability in the
responses of the seedling of the eight durum wheat genotypes evaluated. Heat shock affected significantly the
measured parameters, increasing proline, soluble sugars and damage to cell membrane and decreasing Fv/Fm
ratio, relative water content, and chlorophyll content. Genotype responses varied according to genetic
background and stress intensity and could be grouped into tolerant and sensitive, based test results. P index
appeared to be best suited to select for higher and stable yield under both stressed and unstressed field
124
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
conditions. This index suggested Mrb3, Bousselam and Waha as stable and high yielding. Spearman's rank
correlations indicated that the relationships between bioassays results and with stress tolerance indices varied
according to stress levels. As such, the laboratory tests assessed in the present study could not be recommended
to replace grain yield field testing, under the conditions of the Algerian durum wheat production.
ACKNOWLEDGEMENT
The authors thank the staffs of the ITGC-Agricultural Research Stations of Guelma, Khroub, Setif, Sidi Bel
Abbes and Saïda for their technical assistance in the management of the field trials, particularly MM Tahar
Hazmoune, Hocine Zerargui and Abdelkader Menad. MM Mostapha Kamar for his assistance in the Center
Regional of Agricultural Research, Rabat, Morocco.
REFERENCES
[1] Slafer, G.A., J.L. Araus, C. Royo, L. Garcia Del Moral, 2005. Promising eco-physiological traits for genetic
improvement of cereal yields in Mediterranean environments. Annals of Applied Biology, 146: 61-70.
[2] Reynolds, M.P., R.P. Singh, A. Ibrahim, O.A.A. Ageeb, A. Larque Saavedra, J.S. Quick, 1998. Evaluating
physiological traits to complement empirical selection for wheat in warm environments. Euphytica, 100:
84-95.
[3] Bajji, M., J.M. Kinet, S. Lutts, 2002. The use of the electrolyte leakage method for assessing cell membrane
stability as a water stress tolerance test in durum wheat. Plant Growth Reg, 36: 61-70.
[4] Araus, J.L., G.A. Slafer, M.P. Reynolds, C. Royo, 2002. Plant breeding and drought in C3 cereals: What
should we breed for? Ann. Bot, 89: 925-940.
[5] Sayar, R., H. Khemira, A. Kameli, M. Mosbahi, 2008. Physiological tests as predictive appreciation for
drought tolerance in durum wheat (T. durum Desf.). Agronomy research, 6: 79-90.
[6] Pinto, R.S., M.P. Reynolds, K.L. Mathews, C.L. Mc Intyre, J.J. Olivares-Villegas, S.C. Chapman, 2010.
Heat and drought adaptive QTL in a wheat population designed to minimize confounding agronomic
effects. Theor. Appl Genet, 121: 1001-1021.
[7] Cossani, C.M., M.P. Reynolds, 2012. Physiological traits for improving heat tolerance in wheat. Plant
Physiology, 160: 1710-1718.
[8] Araus, J.L., T. Amaro, j. Voltas, H. Nakkoul, M.M. Nachit, 1998. Chlorophyll fluorescence as a selection
criterion for grain yield in durum wheat under Mediterranean conditions. Field Crops Research, 55: 209223.
[9] Guo, R.W.P. Hao, D.Z. Gong, X.L. Zhong, F.X. Gu, 2013. Effects of water stress on germination and
growth of wheat, photosynthetic efficiency and accumulation of metabolites. Chap book. 13. InTech., 367380.
[10] Teng, S., Q. Qian, D. Zeng, Y. Kunihiro, K. Fujimoto, D. Huang, L. Zhu, 2004. QTL analysis of leaf
photosynthetic rate and related physiological traits in rice (Oryza sativa L.). Euphytica, 135: 1-7.
[11] Baker, N.R., 2008. Chlorophyll fluorescence: A probe of photosynthesis in vivo Annu. Rev. Plant Biol., 59:
89-113.
[12] Rizhsky, L., H. Liang, J. Shuman, V. Shulaev, S. Davletova, R. Mittler, 2004. When defense pathways
collide: The response of Arabidopsis to a combination of drought and heat stress. Plant Physiology, 134:
1683-1696
[13] Ibrahim, A.M.H., J.S. Quick, 2001. Genetic control of high temperature tolerance in wheat as measured by
membrane thermostability. Crop Sci., 41: 1405-1407.
[14] Gholami, M., M. Rahemi, S. Rastegar, 2012. Use of rapid screening methods for detecting drought tolerant
cultivars of fig (Ficus carica L.). Scientia Horticulturae, 143: 7-14.
[15] Najaphy, A., M. Geravandi, 2011. Assessment of indices to identify wheat genotypes adapted to irrigated
and rainfed environments. Advances in Environmental Biology, 5: 3212-3218.
[16] Nouri, A., A. Etminan, J.A. Teixeira da Silva, R. Mohammadi, 2011. Assessment of yield, yield-related
traits and drought tolerance of durum wheat genotypes (Triticum turgidum var. durum Desf.) Aust. J. Crop
Sci., 5: 8-16.
[17] Fischer, R.A., R. Maurer, 1978. Drought resistance in spring wheat cultivars. I. Grain yield response. Aust.
J .Agric. Res., 29: 897-907.
[18] Lin, C.S., M.R. Binns, 1988. A superiority measure of cultivar performance for cultivar x location data.
Can. J. Plant Sci., 68: 193-198.
125
Sofia Hamli et al, 2015
Advances in Environmental Biology, 9(8) May 2015, Pages: 116-125
[19] Nouar, H., H. Bouzerzour, L. Haddad, A. Menad, T. Hazmoune, H. Zerargui, 2012. Genotype x
environment interaction assessment in durum wheat (Triticum durum Desf.) using AMMI and GGE
Models. Advances in Environmental Biology, 6: 3007-3015.
[20] Arnon, D.I., 1949. Copper enzymes in isolated chloroplasts. Polyphenol oxidase in Beta vulgaris. Plant
Physiology, 24: 1-15.
[21] Azimzadeh, S.M., S.J. Azimzadeh, 2011. Study on drought tolerance of twelve varieties of bread wheat
(Triticum aestivum L.) in east part of Iran. Advances in Environmental Biology, 5: 3256-3262.
[22] Bates, L.S., R.P. Waldrem, I.D. Teare, 1973. Rapid determination of free proline for water stress studies.
Plant and Soil, 39: 205-208.
[23] Yemm, E.W., A.J. Willis, 1954. The estimation of carbohydrates in plant extracts by anthrone. Biochem. J.
57: 508-514.
[24] Li, R., P. Guo, M. Baum, S. Grando, S. Ceccarelli, 2006. Evaluation of chlorophyll content and
fluorescence parameters as indicators of drought tolerance in barley. Agricul. Sci. China, 5: 751-757.
[25] Steel, R.G.D., J.H. Torrie, 1980. Principles and procedures of statistics. 2nd ed. McGraw-Hill Book Co.,
New York.
[26] Jiang, Q., D. Roche, T. A. Monaco, S. Durham, 2006. Gas exchange, chlorophyll fluorescence parameters
and carbon isotope discrimination of 14 barley genetic lines in response to salinity. Field Crops Research,
96: 269-278.
[27] Cropstat 7.2. 3, 2007. Free Software package for windows, International Rice Research Institute, IRRI,
Manila.
[28] Dash, S., N. Mohanty, 2001. Evaluation of assays for the analysis of thermo-tolerance and recovery
potentials of seedlings of wheat (Triticum aestivum L.) cultivars. J. Plant Physiol., 158: 1153-1165.
[29] Balouchi, H.R., 2010. Screening wheat parents of mapping population for heat and drought tolerance:
Detection of wheat genetic variation. International Journal of Biological and Life Sciences, 6: 56-66.
[30] Talebi, R., 2011. Evaluation of chlorophyll content and canopy temperature as indicators for drought
tolerance In durum wheat (Triticum durumDesf.). Australian Journal of Basic and Applied Sciences, 5:
1457-1462.
[31] Cseuz, L., 2009. Possibilities and limits of breeding wheat (Triticum aestivum L.) for drought tolerance.
PhD Thesis SzentIstvan Univ., pp: 18.
Téléchargement
Random flashcards
amour

4 Cartes mariam kasouh

Commune de paris

0 Cartes Edune

TEST

2 Cartes Enrico Valle

relation publique

2 Cartes djouad hanane

Créer des cartes mémoire