Fig. 6

Bright-field and autofluorescence images showing the new rhytidome at Stage 3 (a–c) in Tree B in August, 2016. a A light micrograph of a transverse section without staining. Lambda stack images of autofluorescence under fluorescence excitation at 405 nm (b) and 561 nm (c) obtained from the section in a. d Averaged emission spectra of autofluorescence under fluorescence excitation at 561 nm from ten randomly chosen pixels that distributed in the cell wall areas of new and previous periderms from the section in a–c. White arrows indicate phellem cells. NPr new periderm, NRh new rhytidome, Rh rhytidome. The right side of each micrograph corresponds to the outer side of the tree. Scale bars = 100 µm