Seedlings prepared as
above were transplanted into plastic containers ¯lled
with 0.5 mmol L¡1 CaCl2 in the presence or absence
of 1.5 mmol L¡1 Si for 12 d. After washing roots with
distilled water for several minutes, plants were trans-
planted into 1-L bins ¯lled with Hoagland nutrition
solution having Ca2+ (as calcium nitrate) and Fe (as
Fe-EDTA) concentrations of 2 mmol L¡1 and 10 mg
L¡1 (both determined by direct measurement), respec-
tively, with or without addition of 0.1 mmol L¡1 2,4-
DNP or 1.0 mmol L¡1 NaCN. The stock solution for
2,4-DNP was prepared by dissolving substrate ethanol
so that the ¯nal concentration of ethanol in the up-
take solution was less than 0.4% (v/v) (Liang et al.,
2006a). The ERLT treatment was imposed by immer-
sion of transplanted bins into ice bath container to
keep root temperature around 4 ±C and the SSWV
treatment was achieved under the same condition by
sealing plant-bin system with moistened polyethylene
bags to prevent water loss. Ca2+ and Fe uptake were
measured in the four experiments by measuring the
depletion of these elements in the culture solution du-
ring 16 h under continuous light. The plant water loss
due to transpiration was also recorded gravimetrically
(Farshidi et al., 2012) as described earlier.