Thallium is a non-essential, toxic element that concerns mining areas and their acid drainage effluents. Minerals containing thallium can be eroded, and Tl can be leached into soil, thus being spread into the environment and adsorbed by plants and living organisms, entering the food chain, and inducing serious toxicity problems. In this study, the Tl cycle was observed and analyzed on basil, mint, and strawberry cultivated in a greenhouse and irrigated with Tl-contaminated water. The Tl content in both bulk and rhizosphere soils as well as thallium present in different plant organs were analyzed during the experiment, with the aim of revealing both physiological symptoms and metabolic disorders linked to the Tl toxicity. The mechanism of plants to exclude, uptake, translocate, and tolerate Tl varied among the different species, and both the bioconcentration factor (BCF) and the translocation index (TI) were calculated to highlight a different response to Tl toxicity of strawberry, mint, and basil. Basil is the less tolerant species, while mint and strawberry showed different self-defense mechanism against Tl adsorption and translocation.

Twelve Mediterranean hydrophyte species collected inLebanon were evaluated for their potential asbioindicator species for heavy metal pollution innutrient cultures enriched with 1 ppm Cr, Ni and Cd.These were: Nasturtium officinale R.Br, Apium nodiflorum L., Veronica beccabunga L., Veronica anagallis aquatica L., Veronicalysimachioides L., Veronica anagalloides L., Mentha longifolia L., Mentha aquatica L., Mentha pulegium L., Potentilla reptansL., Mentha sylvestris L., and Cardamine uliginosa L.. Large variability in responseto exposure to the heavy metals was observed. Growthrates remained high during the experimental period,indicating that the plants were little affected by thepresence of the metal at the experimentalconcentration. Metal accumulation and bioconcentrationvaried within at least one order of magnitude, andranged from less than 10 to over 200. Cr waspreferentially accumulated in the roots. All speciesbut M. pulegium, P. reptans and V. anagallisaquatica accumulated and bioconcentrated sufficientCr to qualify as bioindicator species. Five of thespecies that accumulated Cr also accumulated Ni, withthe same partitioning into the root. These were: N. officinale, C. uliginosa sp., M. longifolia, M. aquatica and M. sylvestris, all of which mayalso be used as bioindicators of Ni pollution. Onlyone species, M. aquatica, accumulated Cdsignificantly, and may, therefore, be used as abioindicator for all three metals.

Chemical composition and antifungal activity of essential oils of Algerian Mentha species were studied. Chemical compositions of different Mentha species oils (Mentha rotundifolia, M. spicata, M. pulegium, and M. piperita) were investigated by capillary GC and GC/MS, and their antifungal activities were evaluated by means of paper disc diffusion method and minimum inhibitory concentration (MIC) assays. In total, 98 components from all Mentha species were identified. All oils were rich in monoterpene-oxygenated components. In addition, we reported fumigant antifungal activity of Algerian Mentha essential oils against four fungi: Botrytis cinerea, Penicillium expansum, Monilinia laxa, and M. fructigena. All oils demonstrated very good inhibition especially against B. cinerea, M. laxa, and M. fructigena. Both Monilinia fungi were extremely sensitive to all Algerian Mentha oils, which suggests that Mentha essential oils have the potential to be used as bio-pesticides to protect fruit trees, such as apple and pear trees, and provides an alternative to chemical pesticides.

The western flower thrips (Frankliniella occidentalis Perg.) is one of the most economically important insect pests of greenhouse plants. Plant protection against this pest is based predominantly on synthetic insecticides; however, this form of protection poses problems in terms of thrip resistance to the active substances, along with health risks associated with insecticide residues on the treated plants. Therefore, new active substances need to be sought. Essential oils could be a new, appropriate, and safe alternative for greenhouse culture protection. As greenhouses are enclosed areas, fumigation application of EOs is possible. This paper presents acute toxicity results for 15 commercial EOs applied by fumigation, as well as the effect of sublethal concentrations on fertility of F. occidentalis females. The most efficient EOs were obtained from Mentha pulegium and Thymus mastichina, with LC₅₀₍₉₀₎ estimated as 3.1(3.8) and 3.6 (4.6) mg L⁻¹ air, respectively. As found for the very first time, sublethal concentrations of EOs could result in a significant reduction in the fertility of surviving T. occidentalis females. Among the tested EOs, the EO from Nepeta cataria provided the highest inhibition of fertility, with EC₅₀₍₉₀₎ estimated as 0.18 (0.36) mg L⁻¹ air. Chemical composition of the most efficient EOs and possible applications of the results in practice are discussed. In conclusion, in light of the newly determined facts, EOs can be recommended as active substances for botanical insecticides to be applied against Thysanopteran pests by fumigation.