Changes in soluble solids, acidity, and abscisic acid contents in different portions of fruit during maturation of satsuma mandarin

摘要

Changes in soluble solids (SS), acidity and abscisic acid (ABA) contents in different portions of fruit during maturation of satsuma mandarin (Citrus unshiu Marc. cv. Okitsu) were examined. SS was highest in the stem end at 70 days after anthesis (DAA) and lowest in the stylar end at 100 DAA. However, it was consistently highest in the stylar end from 140 DAA. Acid content in the mid section was lower than in the stem end from 70 to 120 DAA, and was higher in the mid section than in the stem end from 140 to 160 DAA. However, the stylar end retained lowest acid levels during maturation. The acid ratio of mid section/stylar end was rapidly increased from 70 DAA, reached the maximum at 140 DAA, and then decreased to 190 DAA and leveled off. Fruit transverse diameter/longitudinal length (D/L) ratio increased with maturity. The maximum acid ratio of mid section/stylar end was in the midst of most rapidly increasing D/L ratio. Both the acid ratio and D/L ratio became consistent after 190 DAA, indicating the time when harvest be started to get fruit uniform in quality and shape. ABA content in the juice sharply increased from 100 to 160 DAA, and then decreased. The stylar end had consistently highest ABA levels from 120 DAA. However, ABA and acid content exhibited inward increasing gradients from the outer portion toward the central portion although SS showed the reverse gradient.