Peat-based substrates constitute the preferred media in conventional and organic nursery production. Nevertheless, in recent years, there has been a growing interest in environmental impacts associated with peat extraction that has increased with the demand of these non-renewable substrates. The re-use of organic wastes as substrate seems to be good solution to substitute commercial peat. This study evaluates date-palm peat (wastes of date-palm branches base locally known as “Kornef”) as an alternative nursery substrate.

This study is a contribution to the valorization of the Onopordum nervosum ssp. platylepis flowers in the agri-food sector. It aims to evaluate the effect of different drying methodologies (room, microwave, convective, oven and freeze-drying) on the chemical composition, the microbiological quality of aqueous extracts and their biological activities, namely clotting milk and antioxidant activities for both spontaneous and cultivated plants. The results showed that the drying methodology has significantly affected the phenolic composition. The extract obtained from freeze-dried flowers showed the best amounts of total phenols (6.19 ± 0.50 mg GAE/g), flavonoids (2.35 ± 0.07 mg QE/g) and condensed tannins (0.038 ± 0.002 mg CE/g) followed by the microwave-dried flowers. However, microwave-dried flowers presented the lowest protein content with only 3.58 ± 0.62 mg BSAE/g. Finally, the biological activities were significantly dependent on the used drying process. The extract of freeze-dried flowers was the most potent to inhibit free radicals (diammonium 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH)) and to reduce iron with the efficient concentrations EC_50s of 0.48 ± 0.02 mg/mL, 0.16 ± 0.04 mg/mL and 1.52 ± 0.19 mg/mL, respectively. It also showed the highest clotting milk activity followed by room-dried and forced convective-dried flowers. As a consequence, freeze drying was the best method for preserving most chemical and biological properties of Onopordum nervosum ssp. platylepis flowers. However, in consideration of production costs and drying duration, the convective dryer is recommended as a more practical choice. All the obtained results do not reveal a significant difference between cultivated and spontaneous plants, which can suggest that the domestication of Onopordum nervosum ssp. platylepis can be useful for industrial applications.

The expanding global population and rapid urbanization have dramatically increased municipal solid waste (MSW) generation worldwide. Given that population pressure demands greater nutritional needs...

This study aimed to compare the chemical composition of aqueous extracts from different aerial plant parts (leaves, stems, and flowers) of Onopordum nervosum ssp. platylepis growing in different regions (Sousse, Kairouan, and Nabeul) in Tunisia, as well as their antioxidant and milk-clotting properties for both spontaneously grown and cultivated plants. Results showed that phenolic composition varies significantly among ecotypes and plant organs (p < 0.05), with flowers containing the highest amounts of total phenols and flavonoids in both plant types. The flowers from Nabeul (NA) region showed the highest amounts of total phenols and higher phenolic contents compared to leaves and stems, with 44.75 mg GAE/g and 39.79 mg GAE/g in spontaneous and cultivated plants, respectively. However, flowers of spontaneously plants grown in Sousse (SO) showed the highest total flavonoid contents (11.42 mg QE/g). Additionally, the findings indicated that flowers contained higher concentrations of mono- and disaccharides than leaves and stems. The antioxidant activity showed that the radical scavenging activity of O. platylepis aqueous extracts is significantly affected by the organ and genotype (p < 0.05). NA genotype revealed the highest potency in inhibiting free radicals, with flowers having the lowest IC50s values in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) tests, registering 0.13 ± 0.02 and 0.14 ± 0.01 mg/mL, respectively. Milk-clotting activity was limited to flowers of this thistle. Moreover, SO and NA genotypes were identified as the most potent populations to coagulate milk in spontaneous and cultivated plants. The principal component analysis confirms the organ and genotype variability in this thistle, with the first two axes explaining 64.15% of the variance and highlighting a distinct flower group. The obtained results suggest that the domestication of this thistle could be useful for the conservation of biodiversity and the promotion of genotypes with potential technological properties.

Quality of vegetable seedlings is affected by nursery management practices, essentially growing media. For sustainable greenhouse horticulture, it is important to characterize biologically based approaches to improve plantlet quality. Here, we investigate the possibility of developing a biotized growth substrate for nursery production using date palm wastes (DPWs) peat as an alternative to commercial sphagnum peat and indigenous arbuscular mycorrhizal fungi (AMF). A greenhouse experiment was established using different rates of DPWs peat to substitute commercial peat in both conventional and organic nursery production systems. Lettuce seedlings were inoculated or not with native AMF isolated from plots with conventional or organic production system (CM and OM respectively). When lettuce plantlets attained commercial size, a microscopic observation revealed that the establishment of mycorrhizal association was successful in all mixtures of growing media. Significant increase in growth parameters (height shoot, number and area of leaves, shoot and root biomass) were observed on plantlets inoculated with indigenous AMF isolated from organic plot compared to those isolated from conventional plot and to control (without AMF). Commercial peat partial substitution with DPWs peat in proportion of 25–50% improves better lettuce performance than complete-peat use. Consequently, these mixtures seem to be an appropriate formulation for sustainable nursery production.

This study aims to evaluate the effect of different drying methodologies (room, microwave, convective, oven and freeze-drying) on the chemical composition, the microbiological quality of extracts and the biological activities namely clotting milk and antioxidant activities for both spontaneous and cultivated Onopordum nervosum ssp. platylepis. The results showed that the drying methodology has significantly affected the phenolic composition. Freeze dried flowers showed the best amounts of total phenols, flavonoids and condensed tannins followed by the microwave dried flowers. However, the latest presented the lowest protein content. Finally, the biological activities were significantly dependent on the used drying process. The effective concentration EC50 values let to classify the samples according to their decreasing power to inhibit DPPH free radicals: dryer<oven<room <microwave<freeze-drying. The drying process significantly affected the clotting milk activity, freeze dried flowers showed the highest activity. All the obtained results do not reveal a significant difference between cultivated and spontaneous plants.