Influence of the phenological stage of Cistus ladanifer L. on the bioherbicidal potential of its essential oil

Abstract

The need to obtain new generation herbicides based on allelochemicals has prompted in recent years the use of more sustainable natural products, such as plant essential oils. This study evaluated the impact of plant phenological stage on the chemical composition and bioherbicidal potential of Cistus ladanifer L. essential oil. The essential oil was extracted by hydrodistillation and analysed by gas chromatography coupled to mass spectrometry (GC-MS). The oxygenated sesquiterpenes were the most representative group of the essential oil and the chemical composition varied according to the plant phenological stage. The bioherbicidal effect was tested in vitro on the weed Echinochloa crus-galli and two of its respective associated crops (rice and tomato). We tested three increasing doses of essential oil (0.022; 0.044 and 0.088 μl/mL of headspace in the Petri dish) and a control with distilled water. Five replicates per phenological stage, dose and species were prepared, with 10 seeds in each replicate. The Aligned Ranks Anova analysis showed a significant effect for the three factors analysed (phenological stage, dose and species). However, the dose-dependent phytotoxic effect was significantly higher on Echinochloa crus-galli compared to rice and tomato at medium and low doses (0.022 and 0.044 µl/ml). Furthermore, the essential oil extracted in October, with a higher percentage of hydrocarbon monoterpenes, showed a significantly higher phytotoxic effect than that obtained in August. Therefore, these results show the high potential of C. ladanifer essential oil for use as a bioherbicide in agriculture.