Toledo delta 320 ph meter

Reagents were purchased from Adamas (Basel, Switzerland), Acros (Pittsburgh, PA, USA), TCI (Tokyo, Japan), Sigma-Aldrich (St. Louis, MO, USA), and SCRC (Shanghai, China). All reagents were of analytical grade and obtained from commercial suppliers. Dichloromethane (CH₂Cl₂) was distilled over calcium hydride. Triethylamines were stored with molecular sieves (4A) before use. The water used in all experiments was purified using a Millipore Milli-Q water system (Billerica, MA, USA). ¹H NMR (400 MHz) spectra were recorded on a Bruker Ascend 400 (Fällanden, Switzerland) in CDCl₃ as a solvent with TMS as the internal standard. UV–vis absorption spectra were recorded on a Shimadzu UV-1800 spectrometer (Kyoto, Japan) in 1.0 cm path-length quartz. Fluorescence spectra were recorded on an Agilent Cary eclipse fluorometer (Santa Clara, CA, USA) with both excitation and emission slits set at 5 nm. The pH value measurements were carried out with a Mettler Toledo Delta 320 pH meter (Zurich, Switzerland). The fluorescence microscopy images of plant tissue were recorded with an Olympus CKX53 fluorescence microscope (Tokyo, Japan). Whole-plant real-time images were recorded with ImagingPhotonIMAGER (Paris, France). All experiments were performed in flame-dried glassware using dry solvents unless otherwise noted.