Abdalla Muna Ali, Lentz Christine, Mühling Karl H
Institute of Plant Nutrition and Soil Science, Faculty of Agricultural and Nutritional Sciences, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
Plants (Basel). 2022 Mar 30;11(7):927. doi: 10.3390/plants11070927.
This study investigated the beneficial effects of selenium (Se) and sulfur (S) enrichment on the primary metabolism in butterhead lettuce. The plants were treated with three levels of Se via foliar application in the presence of two S levels in the nutrient solution under greenhouse conditions. The lettuce plants that were exposed to the lower selenate level (1.3 μM) in combination with the adequate and high S supplies (1 and 2 mM, respectively) accumulated 38.25 ± 0.38 µg Se g DM and 47.98 ± 0.68 µg Se g DM, respectively. However, a dramatic increase in the Se concentration (122.38 ± 5.07 µg Se g DM, and 146.71 ± 5.43 µg Se g DM, respectively) was observed in the lettuce heads that were exposed to the higher selenate foliar application (3.8 μM) in response to the varied sulfate concentrations (S1 and S2, respectively). Under higher Se and S supplies in the lettuce plants, the levels of organic acids, including malic acid and citric acid, decreased therein to 25.7 ± 0.5 and 3.9 ± 0.3 mg g DM, respectively, whereas, in the plants that were subjected to adequate S and lower Se fertilization, the malic acid, and citric acid levels significantly increased to 47.3 ± 0.4 and 11.8 ± 0.4 mg g DM, respectively. The two Se levels (1.3 and 3.8 μM) under the S1 conditions also showed higher concentrations of water-soluble sugars, including glucose and fructose (70.8.4 ± 1.1 and 115.0 ± 2.1 mg g DM; and 109.4 ± 2.1 and 161.1 ± 1.0 mg g DM, respectively), compared to the control. As with the glucose and fructose, the amino acids (Asn, Glu, and Gln) exhibited strikingly higher levels (48.7 ± 1.1 μmol g DM) under higher S and Se conditions. The results presented in this report reveal that the "crosstalk" between Se and S exhibited a unique synergistic effect on the responses to the amino acids and the soluble sugar biosynthesis under Se and S enrichment. Additionally, the Se-and-S crosstalk could have an important implication on the final nutritional value and quality of lettuce plants.
本研究调查了富硒（Se）和富硫（S）对奶油生菜初级代谢的有益影响。在温室条件下，通过叶面喷施三种硒水平，并在营养液中设置两种硫水平来处理植株。在分别供应充足和高硫（分别为1 mM和2 mM）的情况下，暴露于较低硒酸盐水平（1.3 μM）的生菜植株分别积累了38.25±0.38 μg硒/g干物质和47.98±0.68 μg硒/g干物质。然而，在响应不同硫酸盐浓度（分别为S1和S2）时，暴露于较高叶面喷施硒酸盐水平（3.8 μM）的生菜头中观察到硒浓度显著增加（分别为122.38±5.07 μg硒/g干物质和146.71±5.43 μg硒/g干物质）。在生菜植株中供应较高的硒和硫时，包括苹果酸和柠檬酸在内的有机酸水平分别降至25.7±0.5和3.9±0.3 mg/g干物质，而在供应充足硫和较低硒肥的植株中，苹果酸和柠檬酸水平分别显著增加至47.3±0.4和11.8±0.4 mg/g干物质。与对照相比，在S1条件下的两种硒水平（1.3和3.8 μM）也显示出较高浓度的水溶性糖，包括葡萄糖和果糖（分别为70.84±1.1和115.0±2.1 mg/g干物质；以及109.4±2.1和161.1±1.0 mg/g干物质）。与葡萄糖和果糖一样，在较高的硫和硒条件下，氨基酸（天冬酰胺、谷氨酸和谷氨酰胺）表现出显著更高的水平（48.7±1.1 μmol/g干物质）。本报告中的结果表明，硒和硫之间的“串扰”对富硒和富硫条件下氨基酸和可溶性糖生物合成的响应表现出独特的协同效应。此外，硒-硫串扰可能对生菜植株的最终营养价值和品质具有重要影响。
