Microelement Research Center/Hubei Provincial Engineering Laboratory for New Fertilizers, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China; Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China.
Microelement Research Center/Hubei Provincial Engineering Laboratory for New Fertilizers, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei Province 430070, PR China.
Food Chem. 2018 Sep 1;259:278-285. doi: 10.1016/j.foodchem.2018.03.102. Epub 2018 Mar 24.
The fruit quality of 6 citrus cultivars growing in the same orchard was determined at ripening stage in both 2014 and 2015. We further measured the components of sugar (sucrose, fructose and glucose), organic acid (citric, malate and quinic acid), enzymes related to Glycolysis and Krebs cycle and mineral elements at 5 stages of fruit development in the second year. The results showed that at ripening stage of both years, 'Newhall' cultivar had higher TSS concentration and the TSS/TA ratio but lower TA concentration, while 'Flame' cultivar was exactly opposite. Sucrose and citric acid were the most accumulated compounds in fruit during the fruit development of 6 citrus cultivars. Fruit sucrose concentration increased from 9.26 mg·kg at 60 DAFB to 50.92 mg·kg at 180 DAFB, and the citric acid concentration increased from 1.41 mg·kg at 60 DAFB to 29.87 mg·kg at 90 DAFB or 29.02 mg·kg at 120 DAFB then decreased till ripening (5.47 mg·kg). We found ACO was the key enzyme resulting in the difference of citric acid accumulation, but not quite clear in sucrose metabolism. The fruit mineral nutrient concentrations of 6 cultivars during the fruit development were 0.94-1.92% of N, 0.11-0.23% of P, 1.03-1.37% of K, 0.31-1.15% of Ca, 0.11-0.29% of Mg, 3.97-72.34 mg·Fe kg, 1.93-10.64 mg·Mn kg, 1.56-10.73 mg·Cu kg, and 0.90-16.80 mg·Zn kg. We also analyzed the relationship among each sugar, organic acid component and mineral nutrient in this study by curve estimation and PCA analysis. The results indicated that only Mg was significantly correlated with both sugar and organic acid component, negative and positive respectively. It suggested that the accumulation of sugar and organic acid might be related to the dynamic changes of fruit Mg concentrations of 6 citrus cultivars.
2014 年和 2015 年，在同一果园中对 6 个柑橘品种的果实成熟阶段的果实品质进行了测定。第二年，我们又在果实发育的 5 个阶段测量了与糖酵解和三羧酸循环相关的酶和矿物质元素的组成，以及糖（蔗糖、果糖和葡萄糖）和有机酸（柠檬酸、苹果酸和奎宁酸）的成分。结果表明，在两年的成熟阶段，“纽荷尔”品种的 TSS 浓度和 TSS/TA 比值较高，但 TA 浓度较低，而“火焰”品种则正好相反。蔗糖和柠檬酸是 6 个柑橘品种果实发育过程中积累最多的化合物。果实蔗糖浓度从 60 DAFB 的 9.26 mg·kg 增加到 180 DAFB 的 50.92 mg·kg，柠檬酸浓度从 60 DAFB 的 1.41 mg·kg 增加到 90 DAFB 的 29.87 mg·kg 或 120 DAFB 的 29.02 mg·kg，然后在成熟时（5.47 mg·kg）下降。我们发现 ACO 是导致柠檬酸积累差异的关键酶，但在蔗糖代谢中并不明显。在果实发育过程中，6 个品种的果实矿质营养浓度分别为 N 的 0.94-1.92%、P 的 0.11-0.23%、K 的 1.03-1.37%、Ca 的 0.31-1.15%、Mg 的 0.11-0.29%、Fe 的 3.97-72.34 mg·kg、Mn 的 1.93-10.64 mg·kg、Cu 的 1.56-10.73 mg·kg 和 Zn 的 0.90-16.80 mg·kg。我们还通过曲线估计和 PCA 分析研究了各糖、有机酸成分和矿质养分之间的关系。结果表明，只有 Mg 与糖和有机酸成分呈显著负相关和正相关。这表明，糖和有机酸的积累可能与 6 个柑橘品种果实中 Mg 浓度的动态变化有关。
