UV-C IRRADIATION AFFECTS ACCUMULATION OF SCOPARONE IN CITRUS
Ultraviolet (UV) irradiation induces the accumulation of a phytoalexin, which has strong anti-fungal properties, scoparone (6, 7-dimethoxycoumarin), in the leaves and flavedo of Citrus. We examined the effects of UV-C (250 nm, 0.29 W cm-2) irradiation on the scoparone accumulation in leaves and flavedo of Hyuga-natsu and Calamondin harvested in August by high-performance liquid chromatography (HPLC). The duration of irradiation was 10, 20, 30, 40, 50, and 60 minutes. In leaves, the amount of scoparone increased in Hyuga-natsu but not in Calamondin with increasing the duration of irradiation. In flavedo, the amount of scoparone increased with increasing the periods of irradiation. In Hyuga-natsu, leaves produced markedly more scoparone than the flavedo did (0-200 and 2-35 μg g FW-1, respectively). In contrast, Calamondin produced almost the same amount of scoparone in leaves (1-4 μg g FW-1) and flavedo (2-10 μg g FW-1). Thus, the effects of UV-C irradiation differed among Citrus species and organs.
Kuniga, T. and Nesumi, H. (2011). UV-C IRRADIATION AFFECTS ACCUMULATION OF SCOPARONE IN CITRUS. Acta Hortic. 907, 81-85
Botrytis cinerea, 'Calamondin', Colletotrichum gloeosporioides, 'Hyuga-natsu', phytoalexin