Journal of Bio-Environment Control ISSN:1229-4675(Print) 2765-3641(Online) 생물환경조절학회지

Tropical night phenomenon has been increasing due to global warming recently, it is expected that fruit quality of apples will decrease due to elevated night temperature condition. In the present study, fruit quality at maturity, periodic anthocyanin biosynthetic gene expression and sugar contents in leaves and fruit flesh were investigated to establish the physiological responses of ‘Fuji’ apples under high night temperature. The night temperature were treated with such as ambient (control), ambient -4°C, and ambient +4°C. After the treatment, high night temperature didn’t affect fruit diameter, weight, and soluble sugar contents. Coloration of ambient +4°C was poor than that of control, however there was no significant difference between these genes expression of control and that of ambient +4°C treatment in the late coloration season. Increase of sorbitol and glucose contents at ambient +4°C in leaves were smaller than those at control, and then sorbitol and sucrose contents in fruit flesh at ambient +4°C were smaller than those at control. The cross section of leaves showed that there were no differences with the structure of parenchyma and epidermis tissues between the treatments, but starch granules in the palisade parenchyma cells decreased in high night temperature treatments. Consequently, high night temperature didn’t affect the fruit quality, but changed sugar contents in leaves and fruit flesh, and suppressed coloration regardless of anthocyanin biosynthetic gene expression.