Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, Via G. Celoria 2, 20133, Milan, Italy.
Department of Molecular and Translational Medicine (DMMT), Università degli Studi di Brescia, Viale Europa, 11, 25123, Brescia, BS, Italy.
Environ Sci Pollut Res Int. 2020 Sep;27(26):33204-33214. doi: 10.1007/s11356-020-09573-8. Epub 2020 Jun 11.
Rice cultivation, particularly prone to weed issues, requires practices able to effectively control them, however reducing the use of herbicides, responsible for damage to human health and ecosystem sustainability. Alternative strategies for weed management can be based on plant-plant interaction phenomena. In this context, a group of organic farmers has developed a pragmatic approach for weed containment using Lolium multiflorum Lam. as a cover crop before rice. The present study aimed to confirm the farmer field observations reporting a preferential inhibitory effect of L. multiflorum on Echinochloa oryzoides (Ard.) Fritsch, one of the most yield-damaging rice weed, compared with Oryza sativa L. The study showed that L. multiflorum was able to significantly reduce the seed germination of E. oryzoides. It was found to be more susceptible than O. sativa both to the effect of the aqueous extract and powder of L. multiflorum leaves (23-79% vs. 3-57% and 26-100% vs. 23-31%, respectively). In addition, the leaf extract was able to affect E. oryzoides growth starting from 20% concentration both in relation to the root and shoot length while O. sativa exhibited differences compared with the control only under the influence of extract 50%. The L. multiflorum leaf characterization by NMR and UPLC-HR-MS analyses led to the identification of 35 compounds including several polyphenols, glycosyl flavonoids and glycosyl terpenoids, as well as different amino acids and organic acids. Some of them (e.g. protocatechuic and gallic acids) are already known as allelochemicals confirming that L. multiflorum is a source of plant growth inhibitors.
水稻种植，特别是容易出现杂草问题，需要采取能有效控制杂草的措施，然而减少除草剂的使用，因为除草剂会对人类健康和生态系统可持续性造成损害。杂草管理的替代策略可以基于植物-植物相互作用现象。在这种情况下，一群有机农民开发了一种实用的杂草控制方法，即在种植水稻前使用多花黑麦草作为覆盖作物。本研究旨在证实农民田间观察报告，即多花黑麦草对水稻最具破坏性的杂草之一稗草（Echinochloa oryzoides）具有优先抑制作用，而不是水稻。研究表明，多花黑麦草能够显著降低稗草的种子发芽率。与水稻相比，它对多花黑麦草叶的水提物和粉末都更敏感（分别为 23-79%比 3-57%和 26-100%比 23-31%）。此外，叶提取物在 20%浓度下就能影响稗草的生长，无论是根长还是茎长，而水稻仅在提取物浓度为 50%时才表现出与对照的差异。通过 NMR 和 UPLC-HR-MS 分析对多花黑麦草叶片进行表征，鉴定出 35 种化合物，包括几种多酚、糖苷黄酮和糖苷三萜，以及不同的氨基酸和有机酸。其中一些（如原儿茶酸和没食子酸）已被确认为化感物质，这证实了多花黑麦草是植物生长抑制剂的来源。
