NUCIS number 10. December 2001. 48 pages (full ... - IAMZ - ciheam

Figure 2. Proline content of stocks at the beginning of stress
Figure 4. Proline content, the beginning of second stress week
after weekly irrigation
9
15
A
12
mg P./g f.w.
6
3
A
A
A
A
mg P./g f.w.
9
6
3
B B B
0
P. khinjuk
‘Sarakhs’ ‘Fandoghi’ ‘Qazvini’
0
P. khinjuk
‘Sarakhs’ ‘Fandoghi’ ‘Qazvini’
Figure 3. Proline content of stocks, end of first week of stress
Figure 5. Proline content, the end of second stress week
mg P./g f.w.
25
20
15
10
A
A
A
A
mg P./g f.w.
9
6
3
A
Proline 77/2/20
A
A
A
5
0
P. khinjuk
‘Sarakhs’ ‘Fandoghi’ ‘Qazvini’
0
P. khinjuk
‘Sarakhs’ ‘Fandoghi’ ‘Qazvini’
MATERIALS AND METHODS
The experiment was carried out on 10
month old seedlings of Pistacia vera cultivars
“Fandoghi”, “Sarakhs”, “Qazvini”,
and P. khinjuk in a greenhouse under
controlled temperature (25ºC day, 18-
20 o C night), light (7000-10000 lux) and
humidity (65-70%). Seeds were collected
from wild and cultivated areas and after
dehulling and washing with ethanol and
distilled water, disinfested by rinsing in
20% sodium hypochlorite solution. Then
they were planted in black polyethylene
bags filled with sandy loam soil.
The layout was factorial experiment in a
randomized complete design. Data were
statistically analyzed using analysis of variance
procedures by MiniTab and MSTA-
TC software.
Water stress was induced by water
withholding (Krizek, 1985). Treatments
were S1 as control (interval one-day irrigation),
S2 (weekly irrigation) and S3 (permanent
withholding i.e. death treatment).
Sampling and proline determination
Sampling was carried out at the end and
the beginning of every week. Fully expanded
leaves from middle part of shoots
were sampled. Samples analyzed for proline
using the method developed by Bates
et al (Bates et al, 1973) based on data
Figure 6. Significant difference in proline content of stocks at the end of stress
extracted from spectrophotometric absorption
determined at 520 nm. Proline
concentration was calculated applying a
standard curve (figure 1) on mg proline/g
fresh weight basis.
RESULTS
The first leaf dryness symptoms were reported
in “Fandoghi” during the fourth
week. By the end of fourth week all S3-
treated seedlings showed dryness.
According to results of this experiment
and other ones carried out simultaneously
studying other parameters e.g. growth
indices, leaf water potential and relative
water content (Gholipour and Zamani,
1999), P.khinjuk and “Fandoghi” has
been introduced as the most resistant
and sensitive rootstocks, respectively.
mg P./g f.w.
45
40
35
30
25
20
15
10
5
0
khi.
‘Sar.’
‘Qaz.’
‘Fan.’
S1
S2
S3
Rootstocks and proline content
No statistically significant difference
among rootstocks leaf proline content
was reported at the beginning and at the
end of the first week of stress period (fig.
2,3). After first irrigation of S2-treated and
S1-treated seedlings, proline content of
three rootstocks decreased, but proline
content of P.khinjuk remained high (fig.
4). At the end of the second week, proline
content of P.Khinjuk decreased (from
about 5.5 mM to 2.5 mM) but other rootstocks
showed an increased proline content
up to about 5-mM (fig. 5). By the end
of stress period proline content fluctuation
was almost similar to the first two
32 FAO-CIHEAM - Nucis-Newsletter, Number 10 December 2001