darkness during 48 h to facilitate

darkness during 48 h to facilitate extraction. Total phenolics were
determined using the Folin–Ciocalteau method as described by
Swain and Hillis (1959). Briefly, phenolic extract was mixed with
the Folin–Ciocalteau reagent and kept for 2min at room temperature
before sodium carbonate (7.5%, w/v) addition. After 5min
at room temperature the absorbance was measured at 760nm in
a UV–Vis spectrophotometer (Hitachi U-2800A, Japan). The total
phenolic content was expressed asmol phenol equivalent g−1 FW.
UV-B absorbing compounds were extracted from 0.1 g FWof powdered
tissue with 2ml of acidified methanol (methanol/water/HCl,
79:20:1) in darkness (Mirecki and Teramura, 1984). The UV-B
absorbing compound content was expressed as A305 per 0.1 g
FW.