Table1_Foliar application of sodium selenite affects the growth, antioxidant system, and fruit quality of strawberry.xlsx

IntroductionSelenium (Se) plays a vital role in various physiological processes in plants and is regarded as an essential micronutrient for human health as well.
MethodsIn this study, sodium selenite solution at 10, 40, 70, and 100 mg·L-1 concentrations was foliar sprayed, and the strawberry plant growth, antioxidant system, and fruit quality with an emphasis on sugar and acid content were assessed.
ResultsThe results showed that 10 mg·L-1 of sodium selenite treatment promoted plant growth, while all the treated concentrations could enhance photosynthesis, the antioxidant system in leaves, the content of Se, and ascorbic acid in fruits. More importantly, 40 mg·L-1 sodium selenite treatment significantly increased fruit weight, total soluble solid, total phenolic content, and anthocyanins, as well as improved the shape index. Furthermore, it decreased the total flavonoid and proanthocyanidin content. Particularly, sodium selenite treatment at 40 and 70 mg·L-1 largely increased the ratio of soluble sugars to titratable acid. The changes of predominant sugars and organic acids during fruit development were further investigated. The sucrose, fructose, and glucose content was upregulated by sodium selenite treatment through upregulating the activities of sucrose phosphate synthase (SPS) and acid invertase, as well as the FaSPS expression. In addition, sodium selenite treatment inhibited the activity of citrate synthase and phosphoenolpyruvate carboxylase, rather than modulating their transcript levels to reduce the citric acid content.
ConclusionsThis work presented a potentially efficient approach to enhance plant growth and fruit quality and supplement Se in strawberry, providing insights into the mechanism of regulating sugar and acid metabolism by Se.

引言 硒（Selenium）在植物的多种生理过程中发挥至关重要的作用，同时也是维持人体健康所必需的微量营养素。
材料与方法 本研究设置10、40、70及100 mg·L⁻¹四个浓度梯度的亚硒酸钠溶液进行叶面喷施，随后对草莓植株生长状况、叶片抗氧化系统，以及以糖酸含量为重点的果实品质开展评估。
结果 研究结果表明，10 mg·L⁻¹亚硒酸钠处理可促进草莓植株生长，而所有处理浓度均能提升植株光合能力、叶片抗氧化系统活性，以及果实中硒与抗坏血酸的含量。更为关键的是，40 mg·L⁻¹亚硒酸钠处理可显著提高单果重、可溶性固形物含量、总酚含量与花青素含量，同时改善果形指数；此外该处理还降低了果实总黄酮与原花青素的积累量。值得注意的是，40与70 mg·L⁻¹的亚硒酸钠处理大幅提升了可溶性糖与可滴定酸的比值。本研究进一步探究了果实发育过程中主要糖类与有机酸的变化规律：亚硒酸钠处理通过上调蔗糖磷酸合酶（SPS）与酸性转化酶的活性，以及FaSPS基因的表达量，促进了蔗糖、果糖与葡萄糖的积累。此外，亚硒酸钠处理可抑制柠檬酸合酶与磷酸烯醇式丙酮酸羧化酶的活性，而非通过调控其转录水平来降低柠檬酸含量。
结论 本研究提出了一种可有效促进草莓植株生长、改善果实品质并补充硒元素的潜在实用方法，同时为解析硒调控糖酸代谢的分子机制提供了理论依据。