After the grape berries were picked, the excised samples wereimmediately pre-fixed in a 2% (w/v) aqueous solution of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC, Sigma) for 1 h, werepost-fixed overnight in a solution containing 4% paraformaldehydeand 2.5% glutaraldehyde at 4◦C, dehydrated with a graded ethanolseries, embedded in paraffin, and sectioned into slices.