Seakem agarose

The Arabidopsis thaliana (L.) Heynh. accession wild type Col-0 was used. Seeds were surface-sterilised with 70% (v/v) ethanol and 0.05% (v/v) Triton X-100 and sown on media containing optimal (1.75 mM) or suboptimal (0.5 mM) KCl, 2 mM Ca(NO₃)₂, 0.5 mM phosphoric acid, 0.75 mM MgSO₄, 50 μM H₃BO₃, 10 μM MnCl₂, 2 μM ZnSO₄, 1.5 μM CuSO₄, 0.075 μM NH₄Mo₇O₂₄ and 74 μM Fe-EDTA, pH 5.8, with Ca(OH)₂, 1% (w/v) sucrose and 0.6% (w/v) when the screening was performed and 1% (w/v) for the rest of the experiments of SeaKem agarose (Cambrex) supplemented with designated concentrations of CsCl and other chemicals. After stratification for 3 to 4 days at 4°C, plants were placed in a growth cabinet at 22°C in a 16 h light/8 h dark photocycle with a light intensity of 70–90 μmol m⁻² sec⁻¹. Liquid media were prepared without agarose in Erlenmeyer flasks placed on a shaker in a growth chamber set as 22°C, a 16 h light/8 h dark photocycle.

All Arabidopsis thaliana wild-type and transgenic lines were Columbia-0 ecotype. Seeds were sterilized in 70% (v/v) ethanol and 0.05% (v/v) Triton X-100 and then planted on 10 cm-diameter sterile plates containing complete nutrient medium [1.75 mM KCl, 2 mM Ca(NO₃)₂, 0.5 mM phosphoric acid, 0.75 mM MgSO₄, 50 μM H₃BO₃, 10 μM MnCl, 2 μM ZnSO₄, 1.5 μM CuSO₄, 0.075 μM NH₄Mo₇O₂₄, 74 μM Fe-EDTA, pH 5.6 with Ca(OH)₂], 2% sucrose, and 0.8% SeaKem agarose (Cambrex). This complete nutrient medium was used throughout the study unless otherwise stated. After stratification of the seeds at 4 °C for 2~ 3 days, the plates were transferred to the growth chamber at 22 °C with a 16 h daylength at 200 μmol·m^− 2 s^− 1. Seedlings were grown on vertically oriented plates. Four- to 10-day-old seedlings were used throughout the study. For nitrate-deficient (-N) medium, 2 mM Ca(NO₃)₂ was replaced with 2 mM CaCl₂.