Fig.2.
Effect of water stress on Rb
+
uptake(A),Rb
+
xylem transport(J
Rb
)(B)andK
+
xylemtransport(J
K
)(C)intheexcisedrootsofdifferentsun
fl
owercultivars.Theplantswere
grown in pots with perlite and watered with a standard nutrient solution for 14 days. Then, 50% of the plants were subjected to water stress byapplying d
e
fi
cit irrigation for
15 days. At the end of the water stress period, all plants were de-topped and immediately thereafter, the excised roots were watered with a standard nut
rient solution
containing 2.5mM RbCl. The exudates of the excised roots were collected for 24h (controlvs. water stress). Rb
+
uptake by the roots was calculated from the Rb
+
accumulated
in the roots plus the Rb
+
in the xylem sap during the exudation period. For all treatments, values are the mean of 4 replicates
standard error. The level of signi
fi
cance of
Tukey
’
s test for each cultivar is shown at the top of each bar; ** (
P
<
0.01) and *** (
P
<
0.001)