Results

The effect of isothiocyanates and phenolic acids on germination and early growth of the weed species Ambrosia artemisiifolia L. in vitro

Isothiocyanates - key findings

The results demonstrate that the inhibitory effects of isothiocyanates on A. artemisiifolia depend strongly on both compound type and applied concentration.

• Methyl isothiocyanate showed a markedly stronger inhibitory effect than phenyl isothiocyanate across most tested parameters.

• At higher concentrations (80 and 160 mg L⁻¹), methyl isothiocyanate caused:

  • Strong inhibition of germination (up to >90%)

  • Nearly complete suppression of hypocotyl growth

• Radicle length was highly sensitive to methyl isothiocyanate, showing substantial inhibition across nearly all tested concentrations, with minimal effects only at the lowest dose.

• Phenyl isothiocyanate exhibited a weaker and more variable inhibitory response, with pronounced effects only at higher concentrations.

Dose–response analysis indicated a higher biological potency of methyl isothiocyanate, with substantially lower concentrations required to achieve comparable inhibition levels.

Phenolic acids - key findings

Although the research is ongoing and publication is currently in preparation, several consistent trends have emerged:

• Radicle growth was identified as the most sensitive early indicator of phenolic-acid activity in A. artemisiifolia, responding more strongly than germination percentage or hypocotyl growth.

• Phenolic acids showed clear concentration-dependent effects, with stronger inhibition at higher concentrations.

• Mixtures of phenolic acids were generally more effective than individual compounds, suggesting additive or synergistic interactions.

• Germination dynamics were altered, with treated seeds germinating more slowly and less synchronously than untreated controls.

• Non-destructive physiological measurements (chlorophyll fluorescence and vegetation indices) indicated subtle but consistent stress responses following repeated foliar applications, even when visible damage was limited.

• Beneficial soil bacteria were less sensitive to individual phenolic acids than to their mixtures, and susceptibility varied among bacterial genera and strains, highlighting the importance of selectivity in future applications.

These results indicate that phenolic acids—particularly when applied in carefully designed mixtures—have potential as bio-based weed management tools, while also underlining the need for cautious dose optimization.

The research has reached an advanced stage, with experimental work completed and data fully analysed. Peer-reviewed manuscripts based on these results have been submitted to scientific journals and are currently under consideration.

This page will be updated once the publications become available.