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
rate of 0.5 mL·min −1 with absorbance measured at 254 nm. Sample injection volume was 5 µL, each with duplicate HPLC injections. Mobile phase was buffered potassium phosphate monobasic (KH 2 PO 4 , 0.5%, w/v) at pH 2.5 with metaphosphoric acid (HPO 3
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
aqueous solution were used as the mobile phase, the flow rate was 0.4 mL⋅min −1 , the detection wavelength was 255 nm, and the injection volume was 10 μL. A 1-g sample was ground with 10 mL of isopropanol hydrochloric acid buffer (pH = 2.2; isopropanol
phase of acids was KH 2 PO 4 (18 m m , pH 2.1) and flowed at a rate of 0.8 mL⋅min −1 . Sugar and acid amounts were determined using peak areas with external standards (fructose, glucose, sucrose, tartaric acid, malic acid, and citric acid) and expressed
, 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
described by Nour et al. (2010) . Chromatographic separation was performed with an HPLC system (1260 Series; Agilent Technologies, Santa Clara, CA), using 50 m m potassium dihydrogen orthophosphate buffer, pH 2.8, as a mobile phase (flow rate of 0.7 mL
ruthenium red for 20 min and observed for red color ( Jensen, 1962 ). A 1% Alcian blue 8GX solution in 3% acetic acid (pH 2.5) was applied to tissue sections for 20 min, rinsed with water, and the sections were examined for blue color under visible radiation
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
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