Ultraviolet-B (UV-B) light (280–315 nm) is an important environmental signal that regulates plant development and photomorphogenesis, while also affecting the flavonoid pathway, including anthocyanin biosynthesis. Regarding the effects of UV-B radiation on fruits, the effects of a short-term or postharvest irradiation on fruit quality have been well-documented, but the effects of a long-term preharvest UV-B irradiation on fruit growth and coloration remain unclear. Thus, in this study, we investigated the effects of a long-term treatment involving an environmentally relevant UV-B dose on highbush blueberry (Vaccinium corymbosum) fruit. The preharvest UV-B treatment quickly promoted fruit growth and sugar accumulation, which is not commonly observed in other fruit tree species. The UV-B exposure also accelerated fruit ripening and coloration. The dual-luciferase assay proved that in blueberries, expression of VcUFGT encoding anthocyanin biosynthesis key enzyme, is positively and negatively regulated by VcMYBA1 and VcMYBC2, respectively. Throughout the fruit development stage, the UV-B treatment up-regulated VcMYBPA1 expression, which increased VcUFGT expression via VcMYBA1. In the green fruit stage, the UV-B treatment increased HY5 encoding UV receptor, which up-regulates VcMYBPA1 and down-regulates VcMYBC2, thereby promotes the accumulation of anthocyanins. On the other hand, excessive anthocyanin synthesis was inhibited by increased VcMYBC2 levels in mature fruits when exposed to UV-B light through HY5-independent pathway. In conclusion, anthocyanin-related MYB activators and repressor may coordinately balance the accumulation of anthocyanins in blueberry fruits, with UV-B treatments possibly influencing their effects in a stage-specific manner. The potential utility of preharvest UV-B treatments for improving blueberry fruit quality is discussed herein.

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Persimmon (Diospyros kaki Thunb.) is an economically important tree with a long history of cultivation in China. So far, a total of approximately 1000 varieties have been found in China. To systematically evaluate the diversity of persimmon fruit quality, 22 quality measures of appearance, intrinsic, and sensory quality were evaluated using 61 typical persimmon fruit. According to the findings, the coefficient of variation (CV) of 15 appearance and intrinsic quality index values ranged from 13.81% (fruit shape index) to 165.80% (firmness), and the CV values of 7 intrinsic quality attributes were all higher than 50%, with the CV of total polyphenols and ironic soluble pectin contents (ISP) being as high as 159.82% and 143.80%, respectively. These findings showed that several persimmon germplasm resources had a highly diverse range of fruit quality, wide variation, and distribution. Insoluble tannin and soluble sugar were shown to have a substantial positive correlation with the sensory flavor indexes (p < 0.05), indicating their significance in influencing the flavor quality of persimmon fruit. Cluster analysis was performed utilizing 15 indexes of appearance, intrinsic quality, and 7 indexes of sensory quality. The samples were divided into two groups: group I consisted of 52 pollination−constant and astringent (PCA) and 1 pollination−-variant astringent (PVA) persimmon resources, and group II consisted of 6 pollination−constant non−astringent (PCNA) and 2 pollination−variant non−astringent (PVNA) persimmon resources. The results were consistent with the classification based on the mode of astringency loss, indicating that there was a significant difference in the quality of astringent and non−astringent persimmon fruit. This study provides theoretical references for the development and application of persimmon germplasm resources.

Resonance Rayleigh scattering (RRS) spectra resulting from interaction between chondroitin sulfate A (CSA) and crystal violet (CV) have been investigated and applied to the determination of CSA. Though the intensity of RRS has proved very weak for CSA and CV, respectively, it can be greatly enhanced when both interact and form a supramolecular complex. A new RRS spectrum appears with a maximum scattering peak at 328 nm. In this paper, the optimum conditions of the interaction, influencing factors, and the relationship between the relative intensity of RRS (DeltaI) and the concentration of CSA have been thoroughly investigated. A new method of determination for the trace amount of CSA has been developed, which combines a simple procedure, high sensitivity, and a low detection limit of 4.8 ng/mL. It has been applied with satisfactory results to the determination of CSA in CSA injection samples and synthetic samples.