Phytotoxicity of phenolic compounds of Pistacia vera leaves and its potential use as bioherbicide

Abstract

[EN] In recent years, the intensive and uncontrolled use of synthetic herbicides has resulted in severe soil and water contamination, inducing herbicide resistance and damage to living organisms. The aim of this work was to study the potential bioherbicidal effect of extracts obtained from pistachio leaves. Aqueous extracts (3, 6, 12, and 25%) were prepared and their inhibitory effect on three weed species (Lolium rigidum, Solanum nigrum, and Lactuca serriola) and four crops (maize cv. Celestquatro, barley cv. Yurico, wheat cv. Rimbaud, and lentil cv. Castellana) was studied. Germination bioassays in Petri dishes and in vivo tests on organic and inert substrates were carried out with the extracts. In addition, the phenolic compounds present in the extracts were analysed and germination bioassays of the pure and individual compounds identified were performed. The results showed that the extracts caused a significant suppression of germination in weeds, being more remarkable for broadleaf species. For crops, no adverse effects on germination rates were observed. Inert substrate experiments showed a stronger inhibitory influence on weed germination, whereas organic substrate did not. Autumn leaf extracts showed a higher content of total phenols. Component analysis and bioassay showed that gallic acid, catechin, myricetin, and rutin were identified as individual phenolic compounds in the extracts and demonstrated some allelopathic activity. It may be concluded that pistachio leaf extracts had season-varied allelopathic activity, which is attributed to the combined bioactivity with those individual phenolic compounds