Postharvest Berry Abscission and Storage of Grape Fruit

Relationship between postharvest physiological characters and berry abscission of the fruit of grape (Vitis vinefera L vat. KyoHo) was investigated. It was found that the respiration and ethylene production rates of cluster stalk (including most of the pedicel) were markedly higher than those of berry and showed a climacteric-like course (Fig. 1,2). ABA content in the pedicel without berry (abscised) was much higher than the pedicel with berry attached and no GA could be detected (Fig. 4). It was interesting that when a berry was cut with only 2～3 mm of pedicel, there was no more abscission (Fig. 5). Lowering temperature .prevented effectively the abscission of berry (Fig. 5, Table 2 ). Postharvest berry drop was inhibited by exogenous treatments with GA, NAA, or AOA, inhibitor of ethylene biosynthesis ,either before or after harvest, but promoted by ABA or Ethrel (Table 2 ,Fig. 6). These resuls suggest that the stalks of cluster play an important role in the postharvesr abscission of berry in storage of grape fruit.