4 Combination of Elevated CO 2 Levels and Soil Contaminants’ Stress ... 83
concentration inCu)-1 wheat shoots (mg kgCuadded to soil (mg kg-1)FACE
Ambient12 10 8 6 4 2 0050400fconcentration inCu)-1 wheat shoots (mg kgFACE
Ambient10 8 6 4 2 0dconcentration inCu(^24) )-1 (^201612) wheats shoots (mg kg
8 4 0
FA
CE
Ambient
e
concentration inCu
)-1 wheat shoots (mg kg
FA
CE
Ambien
t
24 20 16 12 8 4 0
c
concentration inCu
(^18) ) (^15) -1 (^12) wheat shoots (mg kg
9 6 3 0
FA
CE
Ambient
a
concentration inCu
)-1 wheat shoots (mg kg
FA
CE
Ambient
18 15 12 9 6 3 0
b
Fig. 4.6
Copper concentrations in tissues of wheat plants grown in soil with 0, 50, or 400
mg
kg
−1
Cu added, under either ambient CO
levels or elevated CO 2
(^2)
levels
(
FACE
).
a Wheat shoots at the mid-tillering
growth stage of the first season,
b wheat shoots at the panicle-initiation growth stage of the first season,
c^
wheat shoots at grain maturity of the first season,
d wheat seeds at grain maturity of the first season,
e wheat shoots at grain maturity of the second season, and
f wheat seeds at grain maturity of the second season. Values represent means
±
SD. An
asterisk
indicates a significant difference between
FACE and ambient
conditions
( p
<^
0.05).
FACE
free-air CO
enrichment 2