Espinosa-Colín María, Hernandez-Caballero Irene, Infante Celia, Gago Irene, García-Muñoz Javier, Sosa Teresa
Department of Plant Biology, Ecology and Earth Sciences, Faculty of Science, University of Extremadura, 06006 Badajoz, Spain.
Department of Anatomy, Cellular Biology and Zoology, Faculty of Science, University of Extremadura, 06006 Badajoz, Spain.
Plants (Basel). 2023 Mar 6;12(5):1187. doi: 10.3390/plants12051187.
This is the first study to evaluate the phytotoxic activity of three phenolic compounds present in the essential oil of the labdanum of , an allelopathic species of the Mediterranean ecosystem. Propiophenone, 4'-methylacetophenone, and 2',4'-dimethylacetophenone slightly inhibit total germination and radicle growth of , and they strongly delay germination and reduce hypocotyl size. On the other hand, the inhibition effect of these compounds on was stronger on total germination than on germination rate, and radicle length compared to hypocotyl size. The position and number of methyl groups will affect the efficacy of the derivative. 2',4'-dimethylacetophenone was the most phytotoxic compound. The activity of the compounds depended on their concentration and presented hormetic effects. In , on paper, propiophenone presented greater inhibition of hypocotyl size at greater concentrations, with IC = 0.1 mM, whereas 4'-methylacetophenone obtained IC = 0.4 mM for germination rate. When the mixture of the three compounds was applied, in , on paper, the inhibition effect on total germination and the germination rate was significantly greater compared to the effect of the compounds when they were applied separately; moreover, the mixture inhibited radicle growth, whereas propiophenone and 4'-methylacetophenone did not exert such effect when applied separately. The activity of the pure compounds and that of the mixture also changed based on the substrate used. When the trial was conducted in soil, the separate compounds delayed the germination of the to a greater extent compared to the trial on paper, although they stimulated seedling growth. In soil, against 4'-methylacetophenone also showed the opposite effect at low concentrations (0.1 mM), with stimulation of germination rate, whereas propiophenone and 4'-methylacetophenone presented a slightly increased effect.
这是第一项评估岩蔷薇精油中存在的三种酚类化合物植物毒性活性的研究，岩蔷薇是地中海生态系统中的一种化感物种。苯丙酮、4'-甲基苯乙酮和2',4'-二甲基苯乙酮对[具体植物名称未给出]的总发芽率和胚根生长有轻微抑制作用，且它们会显著延迟发芽并减小下胚轴大小。另一方面，这些化合物对[具体植物名称未给出]的抑制作用在总发芽率上比发芽速率更强，对胚根长度的抑制比对下胚轴大小的抑制更强。甲基的位置和数量会影响衍生物的功效。2',4'-二甲基苯乙酮是植物毒性最强的化合物。这些化合物的活性取决于其浓度，并呈现出 hormetic 效应。在[具体植物名称未给出]的纸上试验中，苯丙酮在较高浓度下对下胚轴大小的抑制作用更大，IC50 = 0.1 mM，而4'-甲基苯乙酮对发芽速率的IC50 = 0.4 mM。当将这三种化合物混合使用时，在[具体植物名称未给出]的纸上试验中，与单独使用这些化合物相比，对总发芽率和发芽速率的抑制作用显著更强；此外，混合物抑制胚根生长，而苯丙酮和4'-甲基苯乙酮单独使用时未产生这种效果。纯化合物和混合物的活性也会根据所用底物而变化。当试验在土壤中进行时，与纸上试验相比，单独的化合物对[具体植物名称未给出]发芽的延迟程度更大，尽管它们刺激了幼苗生长。在土壤中，[具体植物名称未给出]对4'-甲基苯乙酮在低浓度（0.1 mM）时也表现出相反的效果，即刺激发芽速率，而苯丙酮和4'-甲基苯乙酮则呈现出略有增强的效果。
