Effect of N on Fe, Mn, Zn & Cu concentration in lettuce and spinach
29
tions of Zn (r=0.37
***
) and Cu (r=0.18
*
).
Experiment C
The concentrations of Mn, Zn and
Cu in the foliage of spinach plants were
found significantly different among the
nitrogen treatments whereas the foliage
fresh weight and Fe concentration were
not significantly
affected. At Ν
1
level, the
foliage Mn, Zn and Cu concentrations
were found higher than those in the oth-
er treatments; at this nitrogen level the fo-
liage fresh weight was found reduced (Ta-
ble 3). The correlations between nitrogen
supply and the foliage Mn, Zn and Cu con-
centrations were found significantly neg-
ative; Mn (r=-0.77
***
), Zn (r=-0.60
**
) and Cu
(r=-0.74
***
) whereas the concentration of
Fe was found to be independent of nitro-
gen supply.
Besides, the concentration of
Fe, Mn, Zn and Cu was greater in the roots
than in the foliage (Table 3).
Discussion
At the low concentrations of nitrogen in
the nutrient solution, the growth of But-
terhead lettuce and spinach plants (exper-
iments A and C) was reduced due to nitro-
gen deficiency; characteristic symptoms
of nitrogen deficiency like senescence of
older leaves, as well as, decline in expan-
sion rate of both existing and newly devel-
oped leaves appeared on Butterhead let-
tuce plants grown with 0.1-0.5 mM N (13)
and on spinach plants grown with 1 mM
N; besides, the total nitrogen concentra-
Table 2.
Effect of six different nitrogen fertilization rates on foliage fresh and dry weights and Fe,
Mn, Zn and Cu concentration in Romaine (cv. Toledo) lettuce grown in the field (means, n=36).
The values followed by different letters within a column are significantly different at
P
<0.05.
N Fertilization
rate
Foliage
f. w.
Foliage
d. w.
Foliage
Fe
Foliage
Mn
Foliage
Zn
Foliage
Cu
(Κg N/ha)
(g)
(mg kg
-1
d.w.)
Ν
1
– (0.0)
124.8 d
7.72 d
183.9 ab 35.8 a
30.8 c
9.2 bc
Ν
2
– (45.0)
257.7 c
13.72 bc
171.5 b 34.5 a
30.8 c
8.9 c
Ν
3
– (90.0)
275.5 c
14.54 abc 177.4 ab 30.4 b
32.9 c
9.0 c
Ν
4
– (135.0)
314.8 b 15.51 ab 172.0 b 34.0 a
40.4 b
11.8 a
Ν
5
– (180.0)
363.0 a
15.73 a
189.2 a
34.9 a
47.6 a
11.6 a
Ν
6
– (225.0)
263.6 c
13.32 c
174.5 ab 30.3 b 42.1 b 10.6 ab
Table 3.
Effect of six different nitrogen concentrations in the nutrient solution on the growth and
concentration of Fe, Mn, Zn and Cu in spinach (cv. Viroflay) foliage and root (means, n=4). The val-
ues followed by different letters within a column are significantly different at
P
<0.05.
N conc. Foliage
f.w.
Root
f.w.
Foliage
Fe
Root
Fe
Foliage
Mn
Root
Mn
Foliage
Ζn
Root
Ζn
Foliage
Cu
Root
Cu
(mM)
(g)
(mg kg
-1
d.w.)
N
1
- (1)
10.8 a 1.14 a 114.8 a 182.3 ab 159.8 a 116.4 b 355.5 a 247.0 a 13.3 a 21.7 ab
N
2
- (3)
18.7 ab 1.90 ab 105.0 a 190.1 a 141.0 a 256.3 a 234.5 b 378.8 a 10.5 b 24.2 a
N
3
- (6)
20.7 ab 2.25 b 107.0 a 134.6 c 87.0 b 202.7 ab 165.0 b 250.1 a 10.3 bc 19.5 ab
N
4
-(10)
19.6 ab 1.93 ab 105.8 a 133.5 c 96.3 b 205.0 ab 174.5 b 336.8 a 9.8 bcd 19.0 ab
N
5
-(16)
23.2 b 2.31 b 114.5 a 155.7 bc 71.0 b 192.2 ab 159.5 b 307.8 a 7.8 cd 19.1 ab
N
6
-(22)
24.1 b 2.47 b 114.3 a 137.7 c 66.8 b 146.8 b 188.0 b 340.4 a 7.5 d 16.2 b
1...,21,22,23,24,25,26,27,28,29,30 32,33,34,35,36,37,38,39,40,41,...60