sd s were obtained from three biological replications. Petal vacuolar pH measurement. To measure the vacuolar pH, 2 g of fresh petals of the Pl and Pd flowers at the fully opened stage was ground in liquid nitrogen and centrifuged at 18,407 g n for
maintained at 30 °C using a thermostat column compartment. All separations were achieved using gradient mobile phase of 1) reverse osmosis water adjusted to pH 2.5 with trifluoroacetic acid and 2) acetonitrile. The gradient held the following percentages: 15
) and concentration of other nutrients, samples were acidified to pH ≈2 using H 2 SO 4 and filtered through a 0.45-µm syringe filter (09-719 F; Thermo Fisher Scientific Inc., Waltham, MA). Samples for determination of soluble PO 4 -P only were not
rack of 12 twigs per cultivar. Vials were filled with Floralife Crystal Clear (Floralife Inc., Walterboro, SC) at double strength (2× = 32 mL/L water; pH = 2.78; soluble solids = 1.4%). Crystal Clear contains no hormones and did not affect rate of
186001344; Milford, MA) with an isocratic elution using a phosphate buffer (200 m m ; pH 2.4) as the mobile phase. Ascorbic acid quantification was estimated at 244 nm using calibration curves made with an ascorbic acid standard (Sigma-Aldrich, St. Louis, MO
± 0.05 g of homogenized sample was added to a tared 15-mL centrifuge tube and the mass was recorded. Ten milliliters of 50% v/v aqueous ethanol acidified to pH 2 (≈1 mL 12.1 M HCL) was added to the 1-g sample and then mixed once every 5 min manually
, trachelium, and zinnia stems. Control solutions. Cut stems were held in DI water (pH 3.1–4.2; EC 0 dS·m −1 ), DI water supplemented with 200 mg·L −1 8-HQC (pH 2.8–3.1; EC 0.12–0.15 dS·m −1 ), tap water (pH 6.3–7.1; EC 0.18–0.23 dS·m −1 ), or tap water with 8
dihydrogen phosphate (H 2 PO 4 − ) and then to hydrogen phosphate (HPO 4 2− ) occurs at pH 2.1 and 7.2, respectively ( Schachtman et al., 1998 ). Plants can only absorb P as the free orthophosphate ions H 2 PO 4 − and HPO 4 2− ( Becquer et al., 2014
was also suspected that phytotoxicity was associated with the low pH of ABA solutions, which varied from pH = 2.8 for 3200 mg·L −1 to pH = 3.8 for 200 mg·L −1 . However, buffered ABA solutions to neutral pH led to more injury at equal concentration
mixture (4000 g n × 10 min), the aqueous phase was separated and adjusted to pH 2.8 with 1 m acetic acid and partitioned against 100% ethyl acetate. After being spun down at 16,000 g n for 2 min, the upper organic phase was recovered and completely