H3bo3

These were similar to those of (Papadimitriou et al., 2010 (link)). Glassy carbon from Alfa Aesar (1 mm thick) was cut into 5 mm diameter discs and sealed into glass tubes with epoxy resin glue. Electrodes to be used for SEM/EDS and XPS experiments were prepared by connecting the carbon disc (Alfa Aesar 1 mm, cut into 3 mm diameter specimens) to a glass tube via a bridge made of a shrinkable thermoplastic tube. The latter was filled with mercury to ensure electrical contact between the disc and a commercial wire inserted from the open end of the glass tube.
Ni sulfamate (p.a. 99%) from Fluka, NiCl₂ (puriss> 97%) from Merck and H₃BO₃ (puriss 98%)from Aldrich were used in the preparation of Ni deposition solutions. H₂PtCl₆ hexahydrate from Sigma-Aldrich (ACS reagent, ≥37.50% as Pt) was employed for the Pt exchange solution. RuCl₃ hydrate was from Merck. HClO4 from Riedel, (puriss p.a., ACS reagent, ≥70%) was used in the working solutions and MeOH was also from Riedel (Chromasolv®, for HPLC, gradient grade, ≥99.9%).

All solutions were prepared with analytical grade chemicals and MilliQ water (resistivity > 18 MΩcm, Millipore, Burlington, MA, USA).
A stock solution of 50.0 mg L⁻¹ of copper(II) and zinc(II) were prepared by dilution of the respective 1000 mg L⁻¹ atomic absorption standard solutions (Spectrosol, Poole, England). An intermediate solution of 500 µg L⁻¹ of each metal solution was prepared by dilution of a 50.0 mg L⁻¹ stock solution. Working standards, in the range 10–40 µg L⁻¹ in 0.01 mol L⁻¹ of nitric acid, were prepared weekly by dilution of a 500 µg L⁻¹ intermediate solution with a 0.01 mol L⁻¹ nitric acid solution.
A 0.01 mol L⁻¹ nitric acid solution was prepared by dilution of the commercial concentrated nitric acid solution (d = 1.39; 65%, Merck; Darmstadt, Germany).
A buffer solution of 0.50 mol L⁻¹ boric acid was prepared by dissolution of the solid (H₃BO₃, Aldrich, Germany) in a solution of 0.2 mol L⁻¹ NaOH (Panreac, Chicago, IL, USA), with the final pH adjusted to 11.0 with a sodium hydroxide solution.
A 2 mmol L⁻¹ stock solution of PAR (C₁₁H₈N₃NaO₂·H₂O, Sigma-Aldrich, St Louis, MO, USA) was prepared by dissolving the corresponding quantity of the monosodium salt hydrate in water. A PAR reagent solution of 25 µmol L⁻¹ was prepared weekly by dilution of the stock solution with MilliQ water.

MC of high purity was purchased from Alfa Aesar. GO (>99%) was bought from ACS Material. H₃BO₃ (>99.5%), (NH₄)₂TiF₆ (>99.9%) and ethanol (>99.8%) were acquired from Sigma. TiO₂ was acquired from Evonik (so-called P25), which contains 77.1% anatase, 15.9% rutile and 7% of amorphous TiO₂. Milli-Q water was attained from an Advantage A10 system (Millipore).

The 0.01% boric acid solution (0.099 g H₃BO₃ in 1 L of distilled water, Sigma-Aldrich) was sprayed to 1 branch per tree of 36 trees on 3 May 2022 at full bloom (with 3 trees per plot, 12 plots randomized in 6 rows, 2 plots per row). Flower counts at white tip–full bloom and fruitlet counts after shuck fall were recorded on treated branches and adjacent control branches of the same trees; percent fruit set was estimated as described in Section 4.1 and analyzed for statistical significance of boric acid spray effect by ANOVA (n = 36, Tukey’s test, p ≤ 0.05).

The bulk chemical composition of the major elements in the individual slag samples (L1-L11) and the composite landfill sample PTO were determined by XRF (MAGI’X FAST, PANalytical), and those of the minor elements by ICP-MS (Agilent 7500ce, Agilent Technologies Inc., Santa Clara, CA, USA) following acid digestion (first step: 3 mL H₃PO₄ s. p. (Fluka) + 5 mL HNO₃ s. p. (Fluka) + 1 mL HF s. p. (Fluka); second step: 6 mL H₃BO₃ (Sigma-Aldrich) + 2 mL HNO₃ s. p. (Fluka)). The C and S contents were measured by carbon/sulfur analyser (CS 233, LECO). All the analyses were performed in duplicate.

The following reagents were used: hexane, chloroform, methanol, and acetone from RBM (Puebla, Mexico); dimethyl sulfoxide (DMSO), formamide (FA), HPLC-grade methanol, H₃PO₄, HCl, AlCl₃, Na acetate, H₃BO₃ were purchased from Sigma-Aldrich.

The composition of the aqueous phase in all experiments was either luria broth or as described by Wubbolts et al30 (link). KH₂PO₄, 4 g/L; K₂HPO₄ (3H₂O), 15.9 g/L; Na₂HPO₄ (12H₂O), 7 g/L; (NH₄)₂SO₄, 1.2 g/L; NH₄Cl, 0.2 g/L (all from Sigma Aldrich); yeast extract (Oxoid), 5 g/L; L-leucine, 0.6 g/L; L-proline, 0.6 g/L; thiamine, 5 mg/L (All from Alfa Aesar). After autoclaving, MgSO₄ (7H₂O) (BDH), 1 g/L (BDH); 1 mL of trace minerals (composition below); 1 mL of 4% (w/v) CaCl₂(2H₂O) (Alfa Aesar) and 10 g/L D-glucose (Sigma Aldrich) were added having all been heat sterilized separately. 1 ml of 10 mg/ml filter sterilised tetracycline (Sigma Aldrich) was also added.
The solution of trace minerals contained per liter of 5 M HCL: FeSO₄ (7H₂O) (Sigma Aldrich), 40 g; MnSO₄ (H₂O) (Sigma Aldrich), 10 g; CoCl₂ (6H₂O) (Fluka), 4.75 g; ZnSO₄ (7H₂O) (VWR), 2 g; MoO₄Na₂ (2H₂O) (Sigma Aldrich), 2 g; CuCl₂, (2H₂O) (Riedel-de Haen), 1 g; H₃BO₃ (Sigma Aldrich), 0.50 g.