The results obtained, along with ot

The results obtained, along with others from a previous paper
(Pontin et al., 2010) suggest that UV-B modulates the metabolism
of terpenes leading to specific responses according to fluence rate
of UV-B. Relatively low UV-B irradiation induces acclimation responses
consisting in de novo synthesis of terpenes (sterols) related
with membrane stability, and sesquiterpenes involved in defense
against abiotic (like UV-B) and biotic stresses. While relatively high
irradiance induces mechanisms of defense against the oxidative
damage, diterpenes with antioxidant properties and ABA (11).
Therefore, it can be accepted the hypothesis that high UV-B irradiation
promoted in grapevine leaves production of plastidic terpenes
via the methylerytritol phosphate (MEP; Lichtenthaler et al., 1997)
pathway as a way to cope with ROS, while low UV-B induce synthesis
of enzymes of terpene cytosolic MAV pathway leading to production
of sterols and triterpenes involved in adaptation to stress.