BACKGROUND Newhall navel orange (Citrus sinensis Osbeck cv. Newhall) is the major navel orange cultivar planted in China. Almost all Newhall navel orange peels produced in that country are currently discarded, which is not only harmful to the environment but also a waste of resources. It is therefore necessary to carry out research to explore the utilization potential of this resource. RESULTS A 95% ethanol extract (EE) of Newhall orange peel was prepared and fractionated into three subextracts: petroleum ether extract (PEE), ethyl acetate extract (EtOAcE), and water extract (WE) by simple liquid / liquid extractions. These four extracts were then subjected to antioxidant, antibacterial, and tyrosinase inhibition assays. Interestingly, EtOAcE was significantly superior to all other three extracts, exhibiting the best biological effects. The total polyphenol content (TPC), total flavonoid content (TFC), and primary individual flavonoids of these four extracts were analyzed and compared. This was followed by principal component analysis (PCA) and the Pearson's correlation test. The result indicates that the primary bioactive compounds responsible for the biological effects of the EtOAcE are sinensetin, 4′,5,6,7‐tetramethoxyflavone, nobiletin, 3,3′,4′,5,6,7‐hexamethoxyflavone, and narirutin. In view of its easy preparation and potent biological effects, EtOAcE might demonstrate excellent application potential in various industrial areas. CONCLUSIONS This study successfully identified EtOAcE as a potent naturally occurring antioxidant, antibacterial, and tyrosinase inhibitory agent, which might add value to the utilization of Newhall navel orange peel in the food, cosmetic, and pharmaceutical industries. © 2020 Society of Chemical Industry

Water stress is the main abiotic factor that limits soybean grain yield. We investigated eight soybean cultivars under well-watered (WW) and terminal drought stress (TDS) conditions to determine the traits associated with water saving and the relationship between water use, root morphology, canopy architecture, flower and tagged-pod number, and yield performance. Under WW conditions, the average grain yield across the new soybean cultivars was significantly higher (18.7 g plant−1 vs. 15.1 g plant−1), but significantly less water was used (36 L plant−1 vs. 47 L plant−1) than in the old soybean cultivars. Under TDS, the four old soybean cultivars failed to produce a measurable grain yield, while the new soybean cultivars Zhonghuang 30 (ZH) and Jindou 19 (J19) produced a measurable grain yield. Water stress significantly reduced the flower numbers and tagged-pod numbers; the four new soybean cultivars on average had low flower and tagged-pod numbers under WW treatment, while they had low flower but high tagged-pod numbers under TDS conditions. ZH and JD exhibited a lower branch number and leaf area under both WW and TDS conditions. Water use during the flowering and podding periods was significantly positively correlated with the flower number and the tagged-pod number under both WW and TDS conditions. Thus, the small canopy size and low root length and root surface area contributed to a water-saving mechanism in the new soybean cultivars and improved the yield under drought conditions.

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