Chemical Composition and Phytotoxicity of Cupressus sempervirens Leaves Against Crops

Abstract

The present study aims to evaluate the Cupressus sempervirens leaves phytotoxicity. Their leachate (100, 200, 300, 400 and 500 g/l), aqueous (10, 20, 30 and 40 g/l) and organic (petroleum ether, chloroform and acetone, at 2000, 4000 and 6000 ppm) extracts were tested on radish, lettuce, barley and tomato. Pot cultures were conducted by incorporation of leaves powder (50 and 100 g/kg) in soil and by irrigation with leaves leachate and aqueous extracts at IC50 and MIC, concentrations causing, respectively 50% and 100% inhibition. Over all, rate germination did not affected, however germination speed was significantly delayed. For growth, aqueous extracts had the most significant toxicity at 40 g/l and leachate at 500 g/l, inducing up to a total inhibition. The strongest toxicity of organic extracts, was recorded at 6000 ppm (30 mg) for the three ones. Radish seedling growth was more sensitive, especially to petroleum ether and acetone fractions whereas tomato showed a great sensitivity especially to petroleum ether fraction. Residues incorporation in soil (at 100 g/kg) significantly decreased root (86–99%) and shoot (65–100%) length of target species. Irrigation with aqueous extracts and leachate was harmful for especially, tomato and lettuce. Quantitative and qualitative analysis of the extracts were carried out by gas chromatography-mass spectrometry (GC-MS). Results showed that C. sempervirens had a significant allelopathic potential. This plant may be favorably used for incorporating in agricultural systems for sustainable weed management.