Uota (1952) claimed that at higher temperature, a greater amount of energy is required
to synthesize the pigment; the lower efficiency of light at higher temperature must be
substituted by more light for comparable results. The experiments described here indicated
that, during red color formation in 1997, the cool, higher irradiant habitat of Maoxian with
monthly mean irradiation of 151.8 h increased the efficiency of anthocyanin synthesis over
the habitat of Ya’an, with a warm temperature and a lower monthly mean irradiation of
141.4 h (Table 1 and Fig. 1a).