The effects of blue and red light irradiation at night on anthocyanin synthesis and abscisic
acid (ABA) metabolism were investigated in grape berries. Endogenous ABA were highest
in red light-emitting diode (LED)-treated skin. In contrast, anthocyanin concentrations
were highest in blue LED-treated skin, followed by red LED treatment. However, the
expressions of VlMYBA1-2 and UDP-glucose-flavonoid 3-O-glucosyltransferase(VvUFGT)
did not necessarily coincide with anthocyanin concentrations. The results suggest that blue
LED irradiation at night may be effective in increasing anthocyanin in grape berries. The
effect of UV-C irradiation on jasmonate, polyamines (putrescine) and antioxidant activities
was investigated in apple plants. The EC50 values of O2
- -scavenging activity in the UV-C
treated leaves were lower than those in the untreated control. The endogenous jasmonic
acid and putrescine concentrations in the UV-C treated plants were higher than those in the
untreated control. These facts suggest that the increase of jasmonates and polyamines may
be associated with UV-C stimulation, and UV-C irradiation may be effective for increasing
antioxidant activity in apple plants.