Elicitation of the Allelopathic Potential of Rice by Methyl Salicylate Treatment

Abstract

Weed infestation is one of the most severe problems affecting rice production worldwide. Current weed control practices are either costly or pose a threat to the environment. The use of competitive rice genotypes seems to be a promising strategy. The aim of our study was to improve the allelopathic potential of three selected rice genotypes by foliar application of methyl salicylate (MeSA), a signaling molecule eliciting the plant defense response. Aqueous extracts of the shoots and roots of two competitive (UPR 2962-6-2-1 and Govind) and one non-competitive (UPR 2992-17-3-1) rice genotypes treated with MeSA solution at different concentrations (1 mM, 2 mM, and 3 mM) showed phytotoxic effects on the growth of the weed Echinochloa colona. Specifically, shoot and root extracts obtained from the competitive rice genotypes similarly decreased both the E. colona germination rate (9% to 44.5%) and the length of its roots and shoots (11% to 48%). Extracts of the non-competitive rice genotype showed a similar trend but lower effects, inhibiting the E. colona germination up to 32% and reducing the growth of the weed roots and shoots by 6–23.5% and 7–28%, respectively, according to the increasing MeSA concentrations. High-performance liquid chromatography (HPLC) analysis demonstrated an increase in different allelopathic phenolic acids in the three rice genotypes in response to MeSA treatments. Among the detected compounds, vanillic and protocatechuic acids showed the greatest differences compared to controls with values up to 2.1-fold higher in shoots of the two competitive UPR-2962-6-2-1 and Govind rice genotypes, while their roots were characterized by the greatest increases of 8-hydroxyquinoline (8.2-fold) and protocatechuic acid (1.7-fold). Differently, non-competitive genotype UPR 2992-17-3-1 showed the highest increase for gallic acid (2.2-fold) in shoots and for p-hydroxybenzoic acid (2.4-fold) in roots. Lastly, MeSA was found to improve the competitiveness of rice genotypes without any detrimental effect on the host plant.

Effect of phosphorus deficiency on allelopathic activity of lowland indica rice

“…In addition, P deficiency might increase the synthesis of phenolic allelochemicals through oxidative damage in plants [41]. It was reported that salicylic acid-induced stress is capable of activating the production of phenolic allelochemicals in shoots and roots of rice seedlings [45]. These and our findings suggest that the allelopathic potential of rice is induced by P deficiency and associated with the production of phenolic contents.…”

Viola calcarata L. and Viola dubyana Burnat ex Gremli hydrolates: DI-SPME-GC-MS analysis and biological activity evaluation

“…The herbicidal efficacy of the two hydrolates is most likely to be ascribed to methyl salicylate, whose role in plant allelopathy has been previously documented [Bi et al. 2007;Patni et al 2019;Asif et al 2021]. However, its interaction (additional or synergistic) with other components such as thymol [Azirak & Karaman, 2008;Nasrollahi et al 2018;Mohammedi, 2021], α-pinene [Luiza Ishii-Iwamoto et al 2012] and 2-propen-1-ol [Ye et al 2016], capable of inhibiting the germination of weed seeds even at low concentrations, is not to be underestimated and could partially explain the different activity between the two hydrolates.…”

Kandungan asam p-Hidroksibenzoat dan p-Kumarat akar padi varietas inpara dan pengaruhnya terhadap pertumbuhan Echinochloa crus-galli

“…Berdasarkan hasil penelitian Patni et al (2019), kandungan p-hidroksibenzoat pada 3 akar padi dengan varietas yang berbeda menunjukkan lebih rendah dibanding dengan hasil penelitian ini. Konsentrasi phidoksibenzoat dari ketiga varietas tidak mencapai 40 ppm.…”

“…Kemampuan perbedaan ekstrak akar padi menghambat pertumbuhan E. crus-galli kemungkinan disebabkan oleh jenis dan konsentrasi alelokimia. Salah satu alelokimia padi adalah senyawa kimia dari golongan asam fenolik (Patni et al, 2019;Ho et al, 2020). Asam fenolik dapat meningkatkan spesies oksigen reaktif (ROS) dengan mengurangi aktivitas enzim antioksidan dalam sel (Inderjit et al, 2002).…”