Accumulation, Source Identification, and Cancer Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Different Jordanian Vegetables

The accumulation of polyaromatic hydrocarbons in plants is considered one of the most serious threats faced by mankind because of their persistence in the environment and their carcinogenic and teratogenic effect on human health. The concentrations of sixteen priority polycyclic aromatic hydrocarbons (16 PAHs) were determined in four types of edible vegetables (tomatoes, zucchini, eggplants, and cucumbers), irrigation water, and agriculture soil, where samples were collected from the Jordan Valley, Jordan. The mean total concentration of 16 PAHs (∑16PAHs) ranged from 10.649 to 21.774 µg kg−1 in vegetables, 28.72 µg kg−1 in soil, and 0.218 µg L−1 in the water samples. The tomato samples posed the highest ∑16PAH concentration level in the vegetables, whereas the zucchini samples had the lowest. Generally, the PAHs with a high molecular weight and four or more benzene rings prevailed among the studied samples. The diagnostic ratios and the principal component analysis (PCA) revealed that the PAH contamination sources in soil and vegetables mainly originated from a pyrogenic origin, traffic emission sources, and biomass combustion. The bioconcentration factors (BCF) for ∑16PAHs have been observed in the order of tomatoes > cucumbers and eggplants > zucchini. A potential cancer risk related to lifetime consumption was revealed based on calculating the incremental lifetime cancer risk of PAHs (ILCR). Therefore, sustainable agricultural practices and avoiding biomass combusting would greatly help in minimizing the potential health risk from dietary exposure to PAHs

Genome-wide association mapping in a diverse spring barley collection reveals the presence of QTL hotspots and candidate genes for root and shoot architecture traits at seedling stage

Figure S1. Examples of scanned root images from individual plants. Figure S2. Concatenated split network tree for the collection of 233 accessions based on 6019 SNP markers. Figure S3. LD pattern along the individual chromosomes of barley. Figure S4. Schematic representation of the eight re-sequenced candidate genes models. (DOCX 3427 kb

Weed and Weeding Effects on Medicinal Herbs

Competition with weeds exerts significant depressive effects on yield and quality features of Medicinal Plants (MPs). According to the crop, the part of plant to be harvested, the environmental features (including cropping technique) and the severity of infestation, yield losses due to the presence of weeds may vary within wide intervals. Furthermore, unlike the majority of other crops, MPs are cultivated with the goal to obtain relevant quantities of specific secondary metabolites, whose final quantity determines the quality level (and, consequently, the market value) of the harvested drug. Almost all papers addressed to this topic agree on the statement that unrestricted weed growth may alter MP production also from the qualitative point of view, that is, determining an overall decrease in the yield of active substances for unit area. In part, this outcome can be attributed to the general decrease of harvestable biomass, but in some cases also modifications of crop metabolic pathways have been observed, resulting in a general unpredictability of the chemical characteristics of the product obtained in weedy fields. Competition with weeds may assume a different severity according to the time and duration of competition period. In the starting phases of cultivation, the outcome of an early weed infestation is expected to be severe, since very often weeds grow much faster than crops. The maximum tolerance period, i.e. the period when weeding operations must be started, varies according to the tolerated loss values, and in annual crops the time span when fields must be kept totally weed-free may cover more than 60% of the entire crop cycle. The tools that are used for weeds removal may affect MPs production in many ways. Chemical treatments have been studied with contrasting results, but an interference of herbicides with the metabolism of secondary products was found in some cases. Furthermore, the interest in growing MPs with organic or environmentally friendly methods is increasing. Hence, besides the traditional (and highly expensive) method of hand-weeding, other non-chemical methods are studied, including mechanical treatments, mulching, flaming, and even grazing by goats or lambs. There is scope for further research, embracing a larger number of MPs and different environments, also including the effects of weeds on MPs metabolic pathways