4. Discussion
It is known that water stress reduces the availability of
potassium in the soil (
Parra et al., 2003
), and K
+
starvation in
sun
fl
ower plants promotes hydraulic conductivity in excised roots
(
Quintero et al.,1998
) as well as water uptake in transpiring plants
(
Fournier et al., 2005
). According to these
fi
ndings, it seems that
water stress could cause K
+
starvation in the plant, which could
increase water transport in the root. However, it cannot be ruled
out that water stress itself could induce a speci
fi
c action on the
hydraulic behaviour of the root, which could lead to water stress
recovery in the plant after re-watering. The results obtained in this
study, based on excised roots in which the main route for radial
water transport is the cell-to-cellpath (
Steudle,1994
)