2.7 Observations of leaf stomata, chloroplasts, and
autophagosome
The fully expanded leaves were immediately cut into small pieces and
fixed in a 4% glutaraldehyde solution, then kept at 4°C for 24 h. After
three washing with 0.2 M phosphate buffered solution, the samples
underwent dehydration with different ethanol concentrations (70%, 80%,
and 90%). The samples were then coated with gold using isoamyl acetate
and imaged using a JSM-6360LV scanning electron microscope (SEM, JEOL
Ltd., Tokyo, Japan) for observation and photography. The width/length
ratio was calculated using the ImageJ software. The chloroplast and
autophagosome were observed using a JEOL-1230 transmission electron
microscope (TEM, Hitachi, Japan).