Agronomic, nutraceutical, and organoleptic performances of wild herbs of ethnobotanical tradition

There is a lack of information on how to grow wild herbs as nutraceutical foods. Ten wild herbs were collected in natural and/or anthropized environments and assessed for their agronomic performance as fresh-cut (or ready-to-eat) leafy vegetables and their nutraceutical and organoleptic attributes. Seed dormancy prevented acceptable germination in many species. However, a physiological seed treatment (soaking with sodium hypochlorite followed by incubation for 3 mo at 4°C in sand moistened with potassium nitrate solution) allowed satisfactory germination, usually above 80%. Cultivation in alveolar containers produced highly diversified fresh-cut productivity (250-550 g·m-2), lower than that of lettuce (Lactuca sativa L.; 16 >900 g·m-2) grown as a reference fresh cut green vegetable. Antioxidant power was often much 17 greater in wild herbs (20.0 to 62.0 mmol Fe2+·kg-1 FW) than in lettuce (21.0 mmol Fe2+·kg-1 18 FW). Evaluation of the sensory profile indicated that softness and sweet taste of lettuce were 19 generally preferred to the more robust flavors of wild herbs. Hardness and bitter taste produced a poor appreciation of most wild herbs. However, exceptions were evidenced due to characteristics of spiciness [Alliaria petiolata (M.Bieb) Cavara & Grande] and/or crunchiness (Silene vulgaris [Moench] Garcke). Frequent distrust for most herbs was expressed as an example of food neofobia that generally occurs for unknown bitter flavors. Most of the wild herbs were not suitable as fresh-cut leafy vegetables, but some species could be ingredients for mixed products with better flavor and health properties

Wild edible plant species grown hydroponically with crop drainage water in a Mediterranean climate: Crop yield, leaf quality, and use of water and nutrients

There is an increasing interest in the cultivation of wild edible plants (WEP) in consideration of their quality attributes and salt tolerance, which makes these species good candidates for cascade cropping systems (CCS). In these systems, saline effluents from a salt-sensitive donor crop are used to irrigate a receiving crop with greater salt tolerance. The objective of this study was to evaluate two WEP species, Picris hieracioides (PH) and Plantago coronopus (PC) as candidate crops for CCS. Both species were grown hydroponically with saline effluent from a semi-closed substrate culture of tomato (the donor crop). Both PH and PC were grown in floating system for 36 days during spring using one of the following nutrient solutions: i) standard nutrient solution (CNS, control); ii) NaCl-enriched (50 mmol L-1) standard nutrient solution (SNS); iii) effluent from tomato substrate culture (TE); iv) artificial effluent (ATE), i.e. a nutrient with ion concentrations and salinity level (approximately 50 mmol L-1 NaCl) very close to those of TE. Compared with CNS, leaf production was significantly reduced in both TE (-33.6%) and ATE (-33.6%) plants of PH, and only in TE (-23.3%) plants of PC. In both species, leaf Na content increased in SNS (+858.1% in PH; +279.4% in PC), TE (+704.7% in PH; +226.3 in PC) and ATE (+697.7% in PH; +229.4% in PC) plants compared with the controls. Leaf antioxidant capacity was positively correlated with total phenol content and, in PC, increased in SNS (+74.3%), TE (+53.9%) and ATE plants (+37.7%) compared with the controls. In conclusion, both PH and PC could be grown in CCS with saline greenhouse hydroponic effluents since the moderate reduction of leaf production could be partially compensated by reduced production costs because of zero costs for fertilisers. The growth inhibition observed in both WEPs species cultivated with the hydroponic effluent was primarily due to its high salinity with minor or no effects due to the suboptimal nutrient levels and/or the presence of phytotoxic root exudates or microbial metabolites

Multidisciplinary integrated characterization of a native Chlorella-like microalgal strain isolated from a municipal landfill leachate

To date, more than one-hundred taxa of green unicellular coccoid organisms have been wrongly included under the genus Chlorella. This is mainly due to the incomplete characterization resulting from studies that have not adopted and integrated the description of cell morphology, metabolic characteristics and genomic features. In this work, a new native Chlorella-like microalgal strain named “SEC_LI_ChL_1”, is described through a multimethod study. This strain was isolated from a pond where municipal landfil leachate flwed before wastewater treatment. The molecular characterization and the phylogenetic reconstructions based on two different DNA marker regions (i.e. the concatenated SSU and ITS rRNA gene and the complete 18S rRNA gene) were combined with light and transmission electron microscope observations, in addition to the analysis of metabolic traits under four different growing conditions (i.e. autotrophy, heterotrophy, mixotrophy and reduced autotrophy). The two separate phylogenetic analyses highlighted that the strain falls within the Chlorella-Micractinium clade, but with two different placements. According to the morphological-ultrastructural and metabolic analyses, “SEC_LI_ChL_1” shares some features with different Chlorella-like microalgae. Interestingly, two peculiar traits rarely or never previously described in Chlorella-like microalgal strains were observed: the association of the cells with endocellular bacteria, and the presence of doublets (i.e. two-celled microalgae aggregates not due to cell division)

Root Zone Sensors for Irrigation Management in Intensive Agriculture

Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy

Hydraulic Relations and Water Use of Mediterranean Ornamental Shrubs in Containers

A detailed, species-specific comprehension of plant water behavior can be a central tool to improve water management in nursery production and irrigated landscapes. Potted plants of Nerium oleander, Pittosporum tobira, and Ligustrum japonicum 'Texanum' were exposed to controlled increasing drought conditions in greenhouse. Water use, gas exchange, and foliar thermoregulation were monitored along the trial. N. oleander showed the most efficient response to increasing water stress, maintaining high levels of gas exchange and evapotranspiration rate during the whole trial, whereas L. japonicum emerged as the most sensitive species, with a significant drop in physiological performances already from the second day. The more aggressive water behavior of N. oleander can be compared to the one of anisohydric plants, whereas L. japonicum displays an isohydric strategy. P. tobira showed intermediate characteristics between the two other species. This work comes to provide useful tools for the management of irrigation in plant nursery and for decision making in the use of ornamental shrubs for landscape applications

Weeds for weed control: Asteraceae essential oils as natural herbicides.

The aim of this study was to test the botanical family of Asteraceae as a source of natural herbicides. Twenty Asteraceae species were collected during flowering time and evaluated in terms of the yield and quality of essential oils (germination inhibition and growth of weeds). Half the species showed a sufficient yield of essential oil (from about 0.1% to 1.43%) when testing these phytochemicals in vitro as germination inhibitors of two typical weeds, Amaranthus retroflexus and Setaria viridis. Despite the higher tolerance of S. viridis, the concentration of 100 lg L 1 of essential oils of the two Artemisia species and Xanthium strumarium could totally inhibit germination. In addition, at 10 lg L 1, the same essential oils showed full inhibition of A. retroflexus seeds. A comparison of their effectiveness at suboptimal doses led to a further selection of the most promising sources of essential oils. After their chemical characterisation, the essential oils were tested as post-emergence herbicides on seedlings of the above-cited weeds. After spraying the weeds at different concentrations (10, 100 and 1000 mg L 1) during two different phenological stages of weed seedlings (cotyledons and the third true leaf), the essential oils of Artemisia annua and X. strumarium showed the best performance. The essential oils of X. strumarium were then tested again on both weeds to monitor the dynamics of plant injury. A reduction in plant fresh weight (about 20%–30% after 10 days) and chlorophyll content (destroyed, after the same amount of time) was found, thus confirming the total and rapid effectiveness of these essential oils. In summary, A. annua and X. strumarium have elicited considerable agronomic interest and appear to be suitable as a source of essential oils to act as natural herbicides