Evaluation of water deficit on seed size and seedling growth of sunflower cultivars

Abstract

ABSTRACT
This experiment was conducted to evaluate the relationship between sunflower seed size and seedling growth from conditions of limited irrigation. The experiment was conducted as a factorial based on a completely randomized block design with three replications. Various irrigation treatments were applied to the cultivars; Lakomka, Master, Favorit, Soor and Armavirsky; and seeds from native plants. The irrigation treatments were 60 (Irrigation desirable), 120 (medium stress), 180 (severe stress) mm evaporation from pan of class Results showed that some characteristics such as seed length, seed width, seed diameter, seed weight, kernel weight, shell weight, dry weight of hypocotyls and cotyledon leaves were all affected significantly by water deficit The maximum seed length, seed width and seed weight were attained from cv. Lakomka from irrigation conditions of optimum and medium stress. Positive and significant correlation was observed between seed diameter to shell weight, kernel weight, dry weight of hypocotyls and cotyledon leaves. The highest dry weight of hypocotyls was attained from the cv. Master that showed a 25 and 44% decrement at medium and severe stress conditions respectively The higher cotyledon leaf dry weights were related to cv. Master and Soor at optimum irrigation that displayed 32 and 105% decrement at medium and severe stress conditions respectively.

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International Journal of AgriScience Vol. 2(3): 280-290, March 2012
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International Journal of AgriScience Vol. 2(3): 280-290, March 2012 280
Evaluation of water deficit on seed size and seedling growth of sunflower
cultivars
Hadi H.1*, Khazaei F.2, Babaei N.3, Daneshian J.4, Hamidi A.5
1Young Researchers Club, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran.*Author for
correspondence (email: hamedhadi9@yahoo.com)
2, 5 Seed and Plant Certification and Registration Institute (SPCRI), Karaj, Iran
3 Young Researchers Club, Rudehen Branch, Islamic Azad University, Rudehen, Iran
4 Seed and Plant Improvement Institute (SPII), oil seeds branch, Karaj, Iran
Received December 2011; accepted in revised form January 2012
ABSTRACT
This experiment was conducted to evaluate the relationship between sunflower seed size and
seedling growth from conditions of limited irrigation. The experiment was conducted as a
factorial based on a completely randomized block design with three replications. Various
irrigation treatments were applied to the cultivars; Lakomka, Master, Favorit, Soor and
Armavirsky; and seeds from native plants. The irrigation treatments were 60 (Irrigation
desirable), 120 (medium stress), 180 (severe stress) mm evaporation from pan of class Results
showed that some characteristics such as seed length, seed width, seed diameter, seed weight,
kernel weight, shell weight, dry weight of hypocotyls and cotyledon leaves were all affected
significantly by water deficit The maximum seed length, seed width and seed weight were
attained from cv. Lakomka from irrigation conditions of optimum and medium stress. Positive
and significant correlation was observed between seed diameter to shell weight, kernel weight,
dry weight of hypocotyls and cotyledon leaves. The highest dry weight of hypocotyls was
attained from the cv. Master that showed a 25 and 44% decrement at medium and severe stress
conditions respectively The higher cotyledon leaf dry weights were related to cv. Master and
Soor at optimum irrigation that displayed 32 and 105% decrement at medium and severe stress
conditions respectively.
Key words: seed length, seed width, seed diameter, cotyledon length
INTRODUCTION
The main objective in agricultural
production has so far been directed toward
increased yield and production (Ulusoy
2001). As Iran is classified as a dry and
semi-dry region and includes different
climate zones, it is necessary to identify
those traits that relate to growth, yield, and
that facilitate a capacity of the sunflower to
adapt, especially in relation to drought
stress. Seeds with these aforementioned
traits can remarkably affect the development
of a planting area and contribute to
increased yield.
Stress may be defined as any factor that
causes a reduction of yield when it is present
or absent (Tollenaar and Wu 1999).
Similarly, drought can be imposed when a
plant is unable to meet its evapo-tranpiration
demands. It may also be defined as “the
inadequacy of water availability (including
precipitation and soil moisture storage
capacity) in quantity and distribution during
the life cycle of a crop, thus restricting the

281 International Journal of AgriScience Vol. 2(3): 280-290, March 2012
expression of its full genetic yield potential”
(Sinha 1996).
Low water availability is considered the
main environmental factor limiting plant
growth and yield worldwide, especially in
semi-arid areas (Boyer 1982, Chaves et al.
2003). Global climate change will likely
make water a scarcity posing an even greater
limitation to plant productivity across an
ever increasing amount of the world’s land.
Water availability is decreased under
drought stress (Lawlor 1995) and salinity
stress (Munns 1993), primarily due to the
so-called osmotic or water deficit effect and
thus, reduces the ability of plants to take up
water.
Drought is a multidimensional stress
affecting plants at various levels of their
organization (Yordanov et al. 2000).
Drought affected environments are
characterized by wide fluctuations in
precipitation, quantity of precipitation, and
its distribution within and across seasons
(Swindale and Bidinger 1981). The effect of
stress is usually manifested as a decrease in
photosynthesis and growth (Yordanov et al.
2000). It is believed that drought is the
largest single factor to affect yield
reductions globally (Fischer and Turner
1978, Boyer 1982).
However, with some variation according to
plant species, certain stages such as
germination, seedling or flowering could be
the most critical stages vulnerable to water
stress. Seed germination is the first critical
stage and the most sensitive in the life cycle
of plants (Ashraf and Mehmood 1990) and
seeds exposed to unfavorable environmental
conditions, such as water stress at this stage
may have seedling establishment
compromised. (Albuquerque and Carvalho
2003).
Sunflower, with a world production of grain
and oil of over 28.5×106 and 10.5×106 Mg,
respectively, and is grown on around
22.6×106 ha of land producing a seed yield
of 1.3 Mg.ha-1 (2003 to 2007), means that it
is one of the most common grown oilseed
species (FAO-STAT Agriculture 2009).
Sunflower seeds contain a high amount of
oil (40 to 50%), which is an important
source of polyunsaturated fatty acid
(Linoleic acid) of potential health benefits
(Lopez et al. 2000, Leon et al. 2003, Monotti
2004). Sunflower grains are botanically
defined as fruit. They are composed of a thin
outer shell, the pericarp, also known as the
‘hull’, that surrounds and contains the seed,
(kernel). The seed contains the largest
proportion of oil in the fruit (Seiler 1997).
Sunflower fruits are hulled before the
industrial process of oil extraction begins.
Hulling consists of the separation of the
pericarp from the seed. The hulling
machinery frequently used in the oil industry
is based on a principle of impact. Large
propellers centrifugally throw the fruit
around at high speed (15-30 ms-1) against a
hard surface where the pericarps totally or
partially break off. The pericarp accounts for
20-26% (dry basis) of the total fruit weight
and is a brittle structure composed of
different tissues that have different physical
and biochemical properties. The two main
ones found in mature fruit are parenchyma
and sclerenchyma (Esau 1977). The later has
a high proportion of lignin (20–25% db;
Seiler 1997). This tissue is transversally and
longitudinally arranged forming compact
bundles defined as rays (Lindstrom et al.
2000, Seiler 1997).
One of the most important aspects for
sunflower seed production is rapid
emergence and good seedling establishment
in the field. However germination and
emergence are also important issues in plant
production and they have a significant effect
on the next stages of plant growth in the
field. Rapid and uniform field emergence is
essential to achieve high yield with good
quality in annual crops (Yari et al. 2010).
The effect of seed size on germination and

International Journal of AgriScience Vol. 2(3): 280-290, March 2012 282
seedling emergence of different crop species
has been the subject of numerous published
studies (Kawade et al., 1987; Roy et al.,
1996 and Guberac et al., 1998). However,
results from these studies revealed wide
variations among species. Large seeds of
pearl millet (Pennisetum glaucum L.)
increase germination and emergence
compared to small seeds (Kawade et al.
1987).
Willenborg et al., (2005) through studies of
germination specification of six oat cultivars
with three seed sizes (less than 1.95, 1.95-
2.35 and more than 2.35 mm) at water stress
condition (0, -0.4, -0.2 Mega Pascal)
established that genotypes with large seed
sizes under different degrees of osmotic
potential produced higher germination rates.
Germination and seedling growth declined
with many abiotic factors such as drought
and salt stress that are perhaps two of the
most important ground abiotic stresses that
limit numbers of seedling and seedling
growth (Ashraf et al. 1992, Almansouri et al.
2001, Kaya et al. 2006, Atak et al. 2006).
There are many studies on the selection of
plant species or seed treatments that are
helpful for alleviating the negative effects of
drought and salt on plants (Ashraf et al.
1992, Almansouri et al. 2001, Okçu et al.
2005, Kaya et al. 2006, Iqbal and Ashraf
2007). Nezami et al. (2008) reported that
plant height, plant dry matter, stem
diameter, head size, seed number head,
weight of 1000 grains and grain weight
head-1 under dry and semi-dried conditions
declined. It has been reported that plant
height and plant dry matter decreased with
increasing water stress under controlled
conditions (Ahmad et al. 2009). Sajjan et al.,
(1999) reported a decrease in percentage
germination and biomass accumulation in
sunflower with increasing osmotic stress in
germinating media whereas mean
germination time increased with increasing
water deficit (El-Midaoui et al. 2001). In an
experiment on 14 cultivars of sunflower,
Razi and Asad (1998) indicated that
irrigation led to an increase in days to
physiological maturity, head size, stem
diameter, number of leaves per plant, plant
height, 1000-seed weight, seed yield and
harvest index.
Drought stress at the flowering stage was
also observed to be a limiting factor for seed
filling, so a significant reduction of unfilled
seeds was observed as a result of irrigation.
D'Andria et al., (1995) concluded that yield
components of sunflower were affected by
irrigation treatments. Chimenti et al., (2002);
Erdem et al., (2006) noticed that grain yield
and weight of 1000 grains decreased with
increasing drought stress. Karam et al.,
(2007) showed that with increasing drought
stress leaf area index, grain yield and its
component decreased. Ali Meo (2000)
conducted an experiment showing that plant
height and number of grains per head-1
decreased significantly by lowering the
nitrogen level or increasing drought stress.
Jabari et al., (2007) showed that with
drought stress, grain yield decreased about
83 percent because of a decrease in the
weight of 1000 grains and number of grains
per head-1. Flenet et al., (1996) demonstrated
that decreasing the level of irrigation
resulted in a decline in the number of grains
per head-1.
Sunflower (Helianthus annuus L.) due to its
meaningful share in vegetable oil production
of Iran has become one of the country’s
most economically important crops. But
limited rainfall or shortage of water for
irrigation during the growing season restricts
its seed yield contributing to significant
reductions. Therefore, growing drought
tolerant cultivars will contribute to more
stable sunflower production and screening
the responses of various sunflower cultivars
or breeding lines to drought stress has a very
important role in breeding programs.
However, difficulties like uncontrolled

283 International Journal of AgriScience Vol. 2(3): 280-290, March 2012
climatic conditions, insufficient
homogeneity of the soil, large amounts of
plant material and time and labor
consumption all contribute to making the
drought screening of genotypes in field
conditions somewhat problematic.
According to the impact of water deficit
during plant growth on produced seeds, the
present study aimed to evaluate the
responses of sunflower cultivars to water
deficit in terms of seed size and seedling
growth.
MATERIAL AND METHODS
An experiment was conducted to evaluate
the relationship between sunflower seed size
and seedling growth produced at limited
irrigation conditions. The experiment was a
factorial based on a Completely
Randomized Block Design (CRBD) in three
replications at the Seed and Plant
Certification and Registration Institute
(SPCRI) Karaj, Alborz, Iran in 2007-08. The
treatments included various cultivars
(Lakomka, Master, Favorit, Soor and
Armavirsky) and seeds from native plants.
The irrigation treatments were [60
(Irrigation desirable), 120 (medium stress),
180 (severe stress) mm evaporation from
pan of class A.
Three separate field experiments were
performed. All the studied cultivars were
evaluated after 60, 120, 180 mm evaporation
from pan of class A. After the harvest of
each plot, some samples were selected and
the seed’s physical characteristics were
studied. Evaluations of seed length and seed
width were performed based on the
Lindstorm et al., (2006) method in that 02
grains from each head from each plot were
selected randomly and measured with 0.01
mm accuracy. For the weight of shells based
on the Lindstorm et al., (2006) method, 30
grains of each plot were selected randomly
and measured with 0.001 mm accuracy. To
evaluate seedling length, seeds were planted
between double layered rolled anchor
germination papers and kept at 20-30 ◦C for
7 days. 10 normal seedlings were selected
and hypocotyls were weighed and placed in
an oven (75 ◦C) for 24h and then hypocotyls
& cotyledons were weighed separately. The
analysis of laboratory tests performed in the
form of a factorial based on Completely
Randomized Design (CRD) in three
replications.
Seeds produced from the three different
irrigation conditions were sown in field such
that each plot consisted of 4 rows of 2.5
meters length and 60 cm apart, the rows
were spaced at 22 cm. Three seeds were
planted, one in each hole. Final seedling
emergence percentage (15 days after
planting) was measured by counting the
seedlings. Results of this investigation,
analyzed as a factorial based on Randomized
Complete Block Design (RCBD). The
MSTAT-C (Ver. 2.0) software was used and
also means comparison was obtained using a
Least Significant Difference Test (LSDT) at
the 0.05 probability level.
RESULTS AND DISCUSSION Results showed that the characteristics of
seed length, seed width, seed length/width
ratio, seed diameter, seed weight, kernel
weight, shell weight, kernel/shell ratio,
hypocotyl length, root dry weight, dry
weight of hypocotyl and cotyledon leaves
were affected significantly by water deficit.
There were also meaningful differences
among the studied cultivars for the
characteristics of seed length, seed width,
seed length/width ratio, seed diameter, seed
weight, kernel weight, shell weight,
kernel/shell ratio, hypocotyl length, root dry
weight, dry weight of hypocotyl and
cotyledon leaves (Table 1).
The maximum seed length, seed width and
seed weight were attained from cv.
Lakomka at optimum and medium stress
irrigation conditions. Positive and

International Journal of AgriScience Vol. 2(3): 280-290, March 2012 284
significant correlation was observed between seed diameter with shell weight,
kernel weight, dry weight of hypocotyl and
cotyledon leaves. The highest dry weight of
hypocotyl was attained from the cv. Master
that showed 25 and 44% decrement at
medium and severe stress conditions
respectively The higher cotyledon leaf dry
weights were related to cv. Master and Soor
at optimum irrigation that displayed 32 and
105% decrement at medium and severe
stress conditions respectively.
The longest seed length (12.39 and 12.32
mm) was related to cv. Lakomka at optimum
and medium stress irrigation conditions. It
was also observed that the seed length from
cv. Lakomka at severe stress decreased 8%
compared to optimum irrigation. There was
a decrement of seed length at medium and
severe stress compared to optimum
irrigation, except with cv. Master. The
maximum seed width (6.34 and 6.14 mm)
was obtained from cv. Lakomka at optimum
and medium stress irrigation conditions. It
was also found that the seed width of cv.
Lakomka at severe stress decreased 32%
compared to optimum irrigation. Other
cultivars also displayed ascending trends of
seed width during sever stress compared
with optimum condition. The higher seed
diameter (3.92 and 4.04 mm) was from cvs.
Lakomka and Soor at optimum irrigation
that had 36 and 33% decrement at severe
stress conditions respectively (Table 2).
Decreasing of seed diameter and seed width
at a deficit of soil humidity can cause less
photosynthesis and consequently wrinkling
of grain. It seems that seed length is
influenced significantly by genetics. Baldini
and Vannozzi (1996) reported the negative
effects of water stress on the physical traits
of seed such as length, width and diameter.
The maximum seed weight (0.0819 gr) was
obtained from cv. Lakomka at optimum
irrigation that showed a descending trend
(24 and 67%) at medium and severe stress
conditions respectively. Seed weight from
the other cultivars also declined under
medium and severe stress conditions. The
highest kernel weight was related to cv.
Lakomka at optimum irrigation (0.0213).
The greater shell weights were from
Lakomka, Master and Soor at optimum
irrigation (0.0606, 0.0573 and 0.0603). The
least shell weight (0.0267 gr) was observed
from cv. Armavirsky at severe stress (Table
2). Shell weight had a higher share of seed
weight compared to kernel weight. It seems
that a larger seed size had a higher weight
than a smaller seed size. Nel (2001 b)
presented that seed shell is influenced
meaningfully by genotype especially the
characteristics of seed width and diameter.
The greatest dry weight of hypocotyl
(0.0169 gr) was observed in cv. Master at
optimum irrigation while it decreased at
medium and severe irrigation conditions (25
and 44% respectively) (Table 2). The higher
dry weight of cotyledons (0.0235 and 0.0241
gr) was from cv. Master and Soor at
optimum irrigation while it declined at
severe irrigation conditions (32 and 105%
respectively) (Table 2). Seedlings produced
from larger seeds showed higher epicotyl
and hypocotyl lengths and also faster
seedling growth rates than those from
smaller seeds. The advantage of a larger
seed size is related to its ability to rapidly
produce the energy necessary for seedling
growth. The higher root dry weight (0.0136
gr) and dry weight of embryo (6.289) was
observed from cv. Lakomka at optimum
irrigation that displayed 40 and 79%
decrement at severe stress conditions
respectively (Table 2).
Results demonstrated that seed germination
of different cultivars was not affected
significantly from water stress (Table 2).
Albeit drought stress would have resulted in
early ripening, but it should not be expected
to affect seed germination (Meckel et al.,
1984). The greatest amount of seedling

285 International Journal of AgriScience Vol. 2(3): 280-290, March 2012
emergence (68%) was from cv. Armavirsky
at medium stress.
The impact of seed size on germination and
seedling emergence of different crop species
has been the subject of numerous published
studies that revealed wide variation among
species (Kawade et al. 1987, Roy et al.
1996, Guberac et al. 1998, Larsen and
Andreasen 2004). Large seeds of pearl
millet (Pennisetum glaucum L.)
demonstrated increased germination and
emergence compared to small seeds
(Kawade et al. 1987). Furthermore some
researchers observed increased germination
percentage and decreased median
germination time with increasing seed mass
in slender creeping red fescue (Festuca rubra
L. subsp. litoralis Vasey), perennial ryegrass
(Lolium perenne L.), and Kentucky
bluegrass (Poa pratensis L.) (Larsen and
Andreasen 2004).
Evaluation of simple correlation coefficients
displayed a positive and significant
correlation between seed dimension and
seed weight, dry weight of hypocotyls and
cotyledons. There was positive and
meaningful correlation between kernel
weight and hypocotyls length. Furthermore
there was not any significant correlation
between seed germination in the laboratory
and seedling emergence in the field for seed
length and seed weight (Table 3).
Table 1. Mean Squares of seed size and seedling growth
Testa
weight
Core
weight
Seed
weight
Seed
diameter
Length/ width
ratio
Seed
width
Seed
length
df
S.O.V
1.684**
13.088**
24.077**
1.955**
0.254**
4.281**
2.249**
2
Water deficit
stress
0.391**
2.492**
3.614**
0.219**
0.087**
0.458**
6.116**
4
Cultivar
0.108**
0.559**
0.989**
0.112**
0.036**
0.284**
0.749**
8
Water deficit
stress×
Cultivar
0.0059
0.0507
0.0771
0.0235
0.0037
0.0293
0.0324
14
Error
6.65
4.96
4.87
4.67
3.01
3.19
1.65
C.V (%)
Continuous of table 1
Cotyledone
leaf dry weight
Root dry
weight
Hypocoyle dry
weight
Root length
Epicotyle
length
Core/testa
ratio
df
S.O.V
1.758**
0.510**
0.743**
2.143
5.269*
1.398**
2
Water
deficit
stress
0.496**
0.123*
0.315**
4.196
2.750*
3.962**
4
Cultivar
0.294**
0.114*
0.087**
4.817
0.854
0.363**
8
Water
deficit
stress×
Cultivar
0.0645
0.0343
0.0221
2.220
0.7409
0.0564
14
Error
15.19
20.52
12.60
11.75
10.81
5.83
C.V
(%)

International Journal of AgriScience Vol. 2(3): 280-290, March 2012 286
Table 2. Mean of interaction effects of water deficit and cultivars on seed size and seedling growth
Water
deficit
stress (mm)
Cultivar
Seed
length
(mm)
Seed
width
(mm)
Seed
diameter
(mm)
Seed
weight (g)
Core
weight (g)
Testa
weight (g)
Length/
width ratio
60
Lakomka
12.39 a
6.343 a
3.92 a
0.0819 a
0.0213 a
0.0606 a
2.844 f
Master
11.46 b
5.648 cd
3.376 bc
0.0695 c
0.0122 d
0.0573 a
4.689 b
Favorit
11.01 d
5.563 de
3.467 b
0.0600 d
0.0131 cd
0.0486 c
3.578 e
Sour
10.87 d
6.034 b
4.041 a
0.0751 b
0.0148 b
0.0603 a
4.083 cd
Armavirski
10.43 e
5.888 bc
3.563 b
0.0609 d
0.0138 bc
0.0472 bc
3.424 e
120
Lakomka
12.32 a
6.14 ab
3.508 b
0.0658 c
0.0150 b
0.0508 b
3.392 e
Master
11.14 cd
5.317 ef
2.91 de
0.0582 e
0.0092 e
0.0480 bc
5.205 a
Favorit
9.947 f
5.174 fg
3.114 de
0.0499 fg
0.0096 e
0.0403 d
4.226 c
Sour
9.918 f
4.86 hi
3.174 cd
0.0541 ef
0.0896 e
0.0446 c
4.664 b
Armavirski
10.97 d
5.338 ef
3.444 b
0.0586 de
0.0128 cd
0.0459 c
3.596 e
180
Lakomka
11.46 b
4.797 hi
2.884
0.0490 g
0.0092 e
0.0398 d
4.362 bc
Master
11.44 bc
4.921 gh
2.918 de
0.0550 e
0.0086 ef
0.0465 c
5.436 a
Favorit
10.42 e
4.852 hi
2.986 de
0.0417 h
0.0088 ef
0.0330 e
3.766 de
Sour
9.747 f
4.966 gh
3.043 de
0.0407 h
0.0078 f
0.0329 e
3.236 c
Armavirski
9.227 g
4.598 i
2.958 de
0.0342 i
0.0076 f
0.0267 f
3.608 e
Continuous of table 2
Water
deficit
stress
(mm)
Cultivar
Epicotyle
dry weight
(g)
Cotyledone
dry weight
(g)
Embryo
dry weight
(mg)
Root
length (cm)
Root dry
weight
(cm)
Germination
percentage
(%)
Seedling
emergenc
e (%)
60
Lakomka
0.0140 bcd
0.0190 bc
6.289 a
12.29 c
0.0136 a
100 a
54 g
Master
0.0169 a
0.0235 a
4.598 bc
12.15 c
0.0097 bc
90 a
62.67 cd
Favorit
0.0121 cde
0.0157 cde
4.422 cde
12.87 abc
0.0101 bc
100 a
64.67 bc
Sour
0.0143 bc
0.0241 a
5.101 b
13.02 abc
0.0105 bc
94.67 bcd
62.67 cd
Armavirski
0.0102 ef
0.0161 cd
4.488 cde
15.21 a
0.0082 cd
98 ab
26 j
120
Lakomka
0.0147 ab
0.0209 ab
4.494 cd
12.56 bc
0.0106 abc
93.67 cd
59 ef
Master
0.0135 bcd
0.0173 bc
3.994 def
13.27 abc
0.0097 bc
99 a
59 ef
Favorit
0.0105 ef
0.0157 cde
3.416 fgh
11.06 c
0.0084 cd
98 ab
45.33 h
Sour
0.0108 ef
0.0152 cde
3.892 efg
10.94 c
0.0084 cd
98 ab
61.33 de
Armavirski
0.0136 bcd
0.0185 bc
4.017 c-f
14.91 ab
0.0118 ab
100 a
68 a
180
Lakomka
0.0117 de
0.0151 cde
3.383 gh
12.79 abc
0.0079 cd
97 abc
58.67 f
Master
0.0117 de
0.0179 bc
3.718 fg
12.7 bc
0.0097 bc
99 a
59.67 ef
Favorit
0.0083 f
0.0127 de
2.907 hi
12.33 c
0.0077 cd
100 a
66 ab
Sour
0.0091 f
0.0117 e
2.898 hi
12.75 abc
0.0058 de
99 a
51.67 g
Armavirski
0.0056 g
0.0075 f
2.678 i
11.35 c
0.0036 e
92 d
41 i
Table 3. Simple correlation coefficient between seed size and seedling growth
Seed length
2
3
4
5
6
7
8
9
10
11
12
13
2
Seed width
0.651**
3
Seed diameter
0.410
0.884**
4
epicotyle length
0.454
0.279
0.106
5
Root length
0.244
0.345
0.286
0.044
6
Cotyledone dry weight
0.701**
0.728**
0.641*
0.665**
0.243
7
Embryo dry weight
0.700**
0.900**
0.856**
0.313
0.228
0.741**
8
Epicotyle dry weight
0.784**
0.684**
0.531*
0.732**
0.231
0.939**
0.729**
9
Root dry weight
0.812**
0.735**
0.641*
0.601*
0.320
0.778**
0.837**
0.811**
10
Seed weight
0.743**
0.898**
0.837**
0.450
0.246
0.873**
0.975**
0.844**
0.868**
11
Testa weight
0.668**
0.917**
0.894**
0.139
0.262
0.601*
0.938**
0.590*
0.786**
0.883**
12
Core weight
0.736**
0.836**
0.765**
0.540*
0.226
0.923**
0.930**
0.889**
0.847**
0.984**
0.786**
13
Germination percentage
0.185
0.013
-0.050
0.348
0.260
0.108
0.161
0.223
0.421
0.153
0.091
0.167
14
Seedling emergence
0.388
-0.040
0.015
0.495
-0.119
0.384
0.096
0.471
0.434
0.198
0.022
0.252
0.306

287 International Journal of AgriScience Vol. 2(3): 280-290, March 2012
CONCLUSION Water is a factor that controls plant growth
and development. Plant response to water
stress is related to metabolical and
physiological activities, growth stages and
the potential yields of plants. Growth and
development of plant cells is very
susceptible to water stress. Water deficit
during plant growth results in leaf shrinkage,
a decreasing leaf area index, less light
absorption, less photosynthesis and
consequently lower yield. Seed size is a
function of the seed growth rate and the
period taken for seed growth is affected by
genetics and the environment. Furthermore
it is evident that final seed size is a function
of the number of cells present in the
cotyledons or endosperm (Egli 1998,
Lemontey et al. 2000). During the
development of seeds, an increase in cell
volume is limited, so the final seed size and
the capacity to accumulate dry matter in the
seminal tissue is determined by the number
of cells present in the cotyledons or
endosperm (Egli 1998). It has been
demonstrated that environmental factors
such as supra-optimal temperatures in corn
(Jones et al. 1985) and water or light stress
in wheat (Wardlaw 1970), which affected
the cell division process in the seed by
reducing the final number of embryos or
endosperm cells, producing seeds with a
lower weight. Water stress at the seed filling
period could decrease the seed filling period,
seed length and finally yield decrement (De
Souza et al. 1997). Water limitation
increases the speed of leaf senescence and
consequently a reduction of the seed filling
period. So seed dimension, seed weight,
germination rate and seedling emergence all
decreased from water deficit during plant
growth.
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