S 2400 scanning electron microscope

Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) analyses were performed on polymeric membranes, while SEM with element mapping was performed on the surface of ceramic membranes. The morphology of the support and active layers of the membranes was studied by a Hitachi S-2400 scanning electron microscope. The microscope was equipped with a silicon drift detector (SDD) to characterize the elemental composition of the surface based on the EDS spectroscopy and a digital acquisition system with Esprit 7.1 software to detect Bruker light elements. Prior to SEM-EDS and SEM mapping characterizations, membranes were coated with gold to make them electrically conductive.
Cross-sections of each membrane were processed using the software ImageJ (University of Wisconsin, Madison, WI, USA) [39 ,40 (link)] for the ×300 SEM image amplification obtained. The images were spatially scaled, and their total membrane surface area was calculated and then binarized after setting a certain threshold level (149 for pristine polymeric membrane and 255 for aged polymeric membranes). Pore density (number of pores divided by area of membrane), porosity (area of pores divided by membrane area), total pore area and the average Feret’s diameter (the longest distance between any two points along the selection boundary) were further automatically determined by the software.

To measure the ABA induced stomata closure, rosette leaves of the 3-week-old WT and OX seedlings were detached and floated (abaxial side down) on the solution containing 30 mM KCl, 0.1 mM EGTA, and 10 mM MES-KOH (pH 6.15) under light for 2.5 h, to induce stomatal opening. Then, leaves were transferred to solution containing 30 mM KCl, 0.1 mM CaCl₂, 10 mM MES-KOH (pH 6.15), and 10 μM ABA for 2 hours. After that, leaves were fixed in the 0.1 M phosphate buffer (pH 7.4) containing 2.5% glutaraldehyde and 4% para-formaldehyde at 4°C for 3 days, mounted onto standard aluminum stubs for the Hitachi scanning electron microscope, and then sputter-coated with approximately 30 nm gold using a sputter coater (K550, Emitech). The images were then viewed using an S2400 scanning electron microscope (Hitachi) with an accelerating voltage of 1.5 kV. For statistical analysis, 30 stomata were used for each line, and the ratio of length over width was used to represent stomata aperture.

The surface of A47 was visualized using scanning electron microscopy (SEM). A working protein fixing solution (2% formaldehyde, 2% glutaraldehyde, and 0.1 M phosphate buffer) was used to fix A47 cells. A section of A47 was extracted and transferred into a sterile glass vial. Lipids and fatty acids were fixed with 2% osmium tetroxide. The sample was dehydrated with ethanol and mounted to a degreased stub using double stick tape. The stub was coated in gold/platinum and imaged with the Hitachi S-2400 scanning electron microscope.