Agriculture Reference
In-Depth Information
Table 3. Effect of the different Al, Cd and Cu
treatments on photosynthesis of barley leaves
Genotypes
Treatments
Gebeina
Shang 70-119
Gebeina
Shang 70-
119
Gebeina
Shang
70-119
g s (mol m -2 s -1 )
Pn
(CO 2 µmol m -2 s -1 )
Ci
(µl L -1 )
pH 6.5
18.9 a
18.7 a
0.43 a
0.44 a
259 c
256 e
pH 4.5
17.8 b
17.3 b
0.41 a
0.40 b
268 c
284 d*
Al
16.5 c
15.6 c*
0.38 b
0.37 c
292 b
306 c*
Al + Cu
15.9 d
14.8 d*
0.35 b
0.33 d *
316 a
339 b **
Al + Cd
15.6 d
14.9 d*
0.35 b
0.33 d *
323 a
341 b *
Al + Cu +
Cd
16.3 c
14.0 e**
0.37 b
0.30 d **
301 b
362 a **
abc, different letters within columns indicate significant differences (P < 0.05) between treatments.
* and **, represent significant differences at the 0.05 and 0.01 probability levels, respectively, between
cultivars.
3.4. Chlorophyll Fluorescence
Pn in stress treated plants was inhibited mainly as a result of low chlorophyll content and
disturbing in chloroplast structure, on the other hand, inhibition in PS ￿activity showed in
Fv/Fm ratio, an indicator of structural damage and affecting the photosynthetic transport of
electrons, could also play an important role. In this study, a significant decline in Fv/Fm ratio
evaluated for chlorophyll fluorescence was detected in barely seedlings in the presence of Al,
Cd and Cu individual, binary and ternary combinations (Figure1).
Gebeina
Shang 70-119
0.9
0.9
0.8
0.8
0.7
0.7
0.6
0.6
0.5
0.5
0.4
0.4
0.3
0.3
0.2
0.2
0.1
0.1
0
0
pH 6.5
pH 4.5
Al
Al + Cu
Al + Cd Al + Cu + Cd
pH 6.5
pH 4.5
Al
Al + Cu
Al + Cd Al + Cu + Cd
Treatments
Treatments
Figure 1. Effect of the different Al, Cd and Cu treatments on chlorophyll fluorescence (Fv/Fm) of
barley leaves.
This decrease was more marked in Shang 70-119 than in Gebeina, especially for the metal
combinations treatments. The parameter significantly decreased to 0.576 (66.9% of the
control) at the ternary metals combination in Shang 70-119, where for Gebeina, a marked
decrease was observed at binary metals combinations, 84.7% of the control. Zhou et al.
(2006) found that a significant decrease of F v / F m value in cyanobacterium Microcystis
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