The insights into the activity of the extracts from Polygonum aviculare L. and Pseudomonas fluorescens for enhancing and modeling seed germination and seedling growth of Melilotus officinalis L. Lam

The empirical evidence indicated that chemicals in plants and selected microorganisms can promote the germination process and determine the growth, viability, survival and yield potential of industrial crop plants. The main objective of this study was exploring the phytochemical and microbiological synergistic activity between plant extracts from Polygonum aviculare L. and beneficial bacteria Pseudomonas fluorescens to enhance germination of Melilotus officinalis seeds and improve morphological characteristics of seedlings. The derived plant preparations were analyzed qualitatively, which showed that the aqueous extracts of P. aviculare were characterized by a higher content of phenolic compounds, micro- and macroelements and carbohydrates compared to the macerates, and that no phytohormones were detected in both the infusions and macerates. Pure macerates (MAC), infusions (IF), bacterial cultures (PF) and their mixtures (MAC+PF; INF+PF) were used for seed treatment of test plants. In the control group, lower values of M. officinalis seed germination and seedling growth rates were observed in relation to the applied treatments. The most effective germination rates were obtained after the application of pure infusions (IF) and their mixture with P. fluorescens (IF+PF), while the highest growth rates (including an almost twofold increase in the length of the nostril shoots compared to the control) were obtained after the application of P. fluorescens inoculum (PF) and the mixture of the infusion and these bacteria (IF+PF).

The use of modeling, as a tool for predicting germination efficiency, has been shown to provide screening opportunities for identifying the effectiveness of biostimulant treatments. Thereby, this indicates the need to develop such an approach under field conditions.