Anthocyanin contents were determined according to the meth-ods described by Mita et al. (1997), with minor modifications.Frozen leaf tissue (300 mg) was homogenized in 3 mL of 1% (v/v) HCl:MeOH at 4◦C for 1 day. Following centrifugation at 3500 × g for gfor 15 min, the supernatant was measured spectrophotometricallyat 530 and 657 nm. One unit of anthocyanin was defined as beingequal to one absorbance unit (A530 − A657 × 1/4) per mL of extrac-tion solution.