Department of Horticultural Science, Chungnam National University, Daejeon, South Korea.
Department of Agronomy, Tay Bac University, Son La, Vietnam.
PLoS One. 2024 Jul 25;19(7):e0306340. doi: 10.1371/journal.pone.0306340. eCollection 2024.
Salicylic acid (SA) plays a crucial role as a hormone in plants and belongs to the group of phenolic compounds. Our objective was to determine the optimal concentration of SA for enhancing the production of bioactive compounds in Agastache rugosa plants while maintaining optimal plant growth. The plants underwent SA soaking treatments at different concentrations (i.e., 0, 100, 200, 400, 800, and 1600 μmol mol-1) for 10 min at 7 days after they were transplanted. We observed that elevated levels of SA at 800 and 1600 μmol mol-1 induced oxidative stress, leading to a significant reduction across many plant growth variables, including leaf length, width, number, area, shoot fresh weight (FW), stem FW and length, and whole plant dry weights (DW) compared with that in the control plants. Additionally, the treatment with 1600 μmol mol-1 SA resulted in the lowest values of flower branch number, FW and DW of flowers, and DW of leaf, stem, and root. Conversely, applying 400 μmol mol-1 SA resulted in the greatest increase of chlorophyll (Chl) a and b, total Chl, total flavonoid, total carotenoid, and SPAD values. The photosynthetic rate and stomatal conductance decreased with increased SA concentrations (i.e., 800 and 1600 μmol mol-1). Furthermore, the higher SA treatments (i.e., 400, 800, and 1600 μmol mol-1) enhanced the phenolic contents, and almost all SA treatments increased the antioxidant capacity. The rosmarinic acid content peaked under 200 μmol mol-1 SA treatment. However, under 400 μmol mol-1 SA, tilianin and acacetin contents reached their highest levels. These findings demonstrate that immersing the roots in 200 and 400 μmol mol-1 SA enhances the production of bioactive compounds in hydroponically cultivated A. rugosa without compromising plant growth. Overall, these findings provide valuable insights into the impact of SA on A. rugosa and its potential implications for medicinal plant cultivation and phytochemical production.
水杨酸（SA）作为植物中的一种激素，起着至关重要的作用，属于酚类化合物。我们的目的是确定 SA 的最佳浓度，以在保持植物最佳生长的同时提高 Agastache rugosa 植物中生物活性化合物的产量。将植物在移栽后 7 天进行不同浓度（0、100、200、400、800 和 1600μmol mol-1）的 SA 浸泡处理 10 分钟。我们观察到，800 和 1600μmol mol-1 的 SA 水平升高会引起氧化应激，导致许多植物生长变量显著降低，包括叶长、叶宽、叶数、叶面积、地上部鲜重（FW）、茎 FW 和长度，以及整个植株干重（DW）与对照植物相比。此外，用 1600μmol mol-1 SA 处理的花分支数、花的 FW 和 DW 以及叶、茎和根的 DW 达到最低值。相反，施加 400μmol mol-1 SA 会导致叶绿素（Chl）a 和 b、总 Chl、总类黄酮、总类胡萝卜素和 SPAD 值最大增加。光合速率和气孔导度随 SA 浓度（800 和 1600μmol mol-1）的增加而降低。此外，较高的 SA 处理（400、800 和 1600μmol mol-1）会增加酚类物质含量，几乎所有的 SA 处理都会提高抗氧化能力。在 200μmol mol-1 SA 处理下迷迭香酸含量最高。然而，在 400μmol mol-1 SA 下，tilianin 和 acacetin 含量达到最高水平。这些结果表明，将根系浸泡在 200 和 400μmol mol-1 SA 中可以在水培条件下提高 A. rugosa 中生物活性化合物的产量，而不会影响植物生长。总的来说，这些发现为 SA 对 A. rugosa 的影响及其对药用植物栽培和植物化学物质生产的潜在影响提供了有价值的见解。
