Partial recovery of grape energy metabolism upon aeration following anaerobic stress

The metabolic changes of mature grape berries during periods of anoxia and upon return to air were examined using two cultivars. Glutamate declined during anoxia, together with a corresponding accumulation of γ-aminobutyrate (GABA). The reverse occurred during a 24 h period of air. Total adenine nucleotide (AdN), ATP level, and adenylate energy charge (AEC) all declined during periods of anoxia but showed a reversible pattern upon subsequent aeration. However, aerobic recovery of metabolite levels was not observed when the duration of anoxia at 30 o C exceeded 6 d. Accumulated ethanol during anoxia (up to 0.22 M) triggered a further increase in the rate of ethanol synthesis when stressed berries were returned to air