The relationship between sugar accumulation and development of watercore in apple fruit.
Murayama H., Sugawara M., Sakurai N.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 8
2004
บทคัดย่อ
The relationship between sugar accumulation and development of watercore in apple fruit.
It has been reported that the accumulation of sorbitol might be related to the development of watercore in apple fruit.To confirm it, we measured the sugar concentration of apoplastic and symplastic solution of mesocarp tissues during ripening of apples.Fruit of 3 cultivars, ‘Yoko’, ‘Orin’ and ‘Fuji’, were used in this study.Fruit were harvested in 2002 in a commercial orchard near Yamagata (Japan) at 10-day intervals over a 1-month period during ripening.Mesocarp tissues were sampled and centrifuge (1000 g for 20 min).This effluent was regarded as apoplastic solution.After collecting apoplastic solution, tissues were frozen with liquid nitrogen, allowed to thaw at room temperature and centrifuged (1000 g for 20 min) again.This effluent was regarded as symplastic solution.Sugar composition of both solutions was analyzed using HPLC.
Watercore occurred during ripening in ‘Fuji’ 30 days before the optimum harvest time, and developed during ripening.It was not observed in ‘Yoko’ and ‘Orin’ throughout experimental period.Concentrations of glucose and fructose in both apoplastic and symplastic solutions did not change significantly during ripening in all cultivars.Concentration of sucrose in both solutions in creased in ‘Yoko’.‘Orin’ and ‘Fuji’ did not show a significant change in sucrose concentration throughout ripening.Sorbitol concentration increased during ripening in both solution of all cultivars.This increase was remarkable particularly in apoplastic solution of ‘Fuji’ where the concentration at optimum harvest time was 4 to 5 times higher than those of ‘Yoko’ and ‘Orin’.In addition, sorbitol concentration in apoplastic was significantly higher than that of symplastic solution in ‘Fuji’ throughout experimental period.These results indicate that sorbitol might be related to the development of watercore in apple fruit.