The whole plants fixed in 2.5% glutaraldehyde in 5 mM phosphate
buffer for 3 h were rinsed with the buffer before fixing
in 1% osmium tetroxide for 2 h. The samples were rinsed again,
dehydrated in graded ethanol series and transferred into amyl
acetate. The critical point drying was done using carbon dioxide.
These samples were then gold coated and viewed under Hitachi
2460N scanning electron microscope (Hitachi Ltd., Tokyo, Japan)
with 20 kV accelerating voltage using backscattered electrons or
secondary electrons depending on the features of interest to be
observed in the given samples.