CHARACTERIZATION AND PHYSIOLOGICAL SIGNIFICANCE OF VOLATILE TERPENE COMPOUNDS (VTCs) IN POSTHARVEST NEEDLE ABSCISSION OF BALSAM FIR (ABIES BALSAMEA (L.) MILL.)

Abstract

In the quest to understand the physiological basis of postharvest needle loss in balsam fir, we hypothesized that, volatile terpene compounds (VTCs) have a role in needle abscission. This study focused on understanding the role of VTC’s in postharvest needle abscission. We demonstrated that balsam fir contains twelve VTCs with varying concentrations depending on whether it is a seedling or a clonal tree branch. Total VTC concentration consistently increased prior to needle loss. Five specific VTCs (?-Pinene, ?-Terpinene, Fenchyl acetate, Camphene and 3-Carene) have been identified as possible key signal molecules in needle abscission. VTCs were synthesized independently of ethylene, thus VTCs can be a possible signal molecule to needle abscission. Exposure of branches to ethylene showed an increase in both ethylene and VTC however, total VTC concentration was below the threshold required to cause needle abscission.