Potassium silicate and/or silicate-solubilizing bacteria stimulate Cuscuta campestris germination but mitigate oxidative stress induced by it on Guizotia abyssinica.

Environmental and economic considerations have heightened interest in silicate-solubilizing bacteria (SSB) as an alternative to silicon nanoparticles in agricultural crop production. However, related research has not considered the response of weeds to silicon. This study, conducted at three levels: laboratory, greenhouse, and field, examines whether KSiO and/or SSB affect the seed germination of dodder and niger, as well as their parasitic relationship. In the laboratory, a germination test was performed for each species with and without 1 mM KSiO or 0.1 % v/v SSB. In the greenhouse and field studies, niger was grown with and without dodder, KSiO, or SSB. Combined use of KSiO+SSB synergistically increased seed germination for niger and dodder by 12.3 and 142.6 %, while accelerating the process by 39.5 and 43.6 %, respectively. The invasion of dodder, when paired with KSiO and/or SSB, significantly increased the activity of superoxide dismutase and catalase in niger. Untreated niger contained 213.6 mg silicon kg dry weight. Dodder alone reduced it by 38.5 %, but when combined with KSiO+SSB, a 2.2-fold increase in the silicon content of niger occurred. Dodder-parasitized niger treated with KSiO+SSB exhibited over a 3-fold increase in lignin content and phenylalanine ammonia-lyase activity. The highest emergence of dodder was recorded when SSB was used alone or in combination with KSiO. Although dodder-parasitized niger treated with KSiO+SSB experienced more infestation due to the increased emergence of dodder, it yielded a higher seed than untreated niger, indicating a mitigated oxidative stress induced by dodder in niger through both physical and biochemical mechanisms.