Li Shuang, Yang Lei, Wang Min, Chen Yang, Yu Jianjun, Chen Hao, Yang Haijian, Wang Wu, Cai Zhiyong, Hong Lin
Research Institute of Pomology, Chongqing Academy of Agricultural Sciences, Chongqing, China.
Front Plant Sci. 2024 Aug 27;15:1382768. doi: 10.3389/fpls.2024.1382768. eCollection 2024.
Citrus fruit is rich in important functional constituents such as flavonoids, phenolic acids terpenes and other functional substances that play an important role for treating clinical diseases or controlling major agricultural diseases and pests. Plant secondary metabolites have become one of the most important resources of novel lead compounds, especially young citrus fruits contain multiple functional substances. 'Orah', a type of citrus reticulata, is known for its fine appearance, productivity, delicious sweetness, late-maturing characteristics, and is widely cultivated in China. Fruit thinning and rootstock selection are commonly used agronomic measures in its production to ensure its quality and tree vigor. However, few studies have demonstrated the effects of these agronomic measures on the functional substances of 'Orah'.
In this study, we used HPLC coupled with UV to detect the dynamic changes of fruit quality, 13 main flavonoids, 7 phenolic acids, 2 terpenes, synephrine and antioxidant capacity in both peel and pulp of citrus fruits grafted on four rootstocks (Red orange Blanco cv. red tangerine, Ziyang xiangcheng Sieb. ex Tanaka, Trifoliate orange L. Raf, and Carrizo citrange Osb.× Raf) at six different developmental stages (from 90 DAF to 240 DAF).
The results indicated that rootstock can significantly affect the contents of functional constituents and antioxidant capacity in 'Orah'. Additionally, it was found that pruning at either 90 DAF (days after flowering) or 150 DAF produced the most favorable outcomes for extracting functional substances. We also identified rootstock 'Trifoliate orange' has the highest total soluble solids (TSS) and 'Ziyang xiangcheng' to be the optimal in terms of comprehensive sensory of fruit quality, while 'Red orange' and 'Ziyang xiangcheng' are optimal in terms of functional substance quality, and 'Red orange' excels in antioxidant capacity.
Overall, the findings demonstrate the important role of rootstocks and developmental stage in shaping fruit sensory quality and functional substance synthesis, providing valuable insights for guiding rootstock selection, determining thinning time, and utilizing pruned fruits in a more informed manner.
柑橘类水果富含黄酮类化合物、酚酸、萜类化合物等重要功能成分以及其他对治疗临床疾病或控制主要农业病虫害起重要作用的功能物质。植物次生代谢产物已成为新型先导化合物的最重要来源之一，尤其是幼嫩的柑橘类水果含有多种功能物质。“沃柑”是一种宽皮柑橘，以其优良的外观、产量、甜美口感、晚熟特性而闻名，在中国广泛种植。疏果和砧木选择是其生产中常用的农艺措施，以确保其品质和树势。然而，很少有研究证明这些农艺措施对“沃柑”功能物质的影响。
在本研究中，我们使用高效液相色谱仪结合紫外检测器，检测了嫁接在四种砧木（红橘、 Blanco 红橘、资阳香橙、枳橙）上的柑橘类水果在六个不同发育阶段（从盛花后90天到240天）果皮和果肉中的果实品质、13种主要黄酮类化合物、7种酚酸、2种萜类化合物、辛弗林和抗氧化能力的动态变化。
结果表明，砧木能显著影响“沃柑”中功能成分的含量和抗氧化能力。此外，还发现盛花后90天或150天进行疏果对提取功能物质最为有利。我们还确定砧木“枳橙”的总可溶性固形物含量最高，“资阳香橙”在果实品质综合感官方面最佳，而“红橘”和“资阳香橙”在功能物质品质方面最佳，“红橘”的抗氧化能力最强。
总体而言，研究结果证明了砧木和发育阶段在塑造果实感官品质和功能物质合成方面的重要作用，为指导砧木选择、确定疏果时间以及更明智地利用疏果后的果实提供了有价值的见解。
