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Two field experiments were carried out in 2005 and 2006 in central Italy in order to evaluate the effects of different nitrogen (N) application rates (0, 50 100 and 150 kg ha-1) on flowering date, plant height, biomass production and partitioning (leaves, panicles and stems) and biomass quality of a sorghum hybrid (H133). Sorghum showed a high potential in terms of biomass production without N fertilization (18.5 t ha-1 of d.m. in 2005 and 26.6 t ha-1 of d.m. in 2006). The rate that maximized the biomass production was 100 kg ha-1 of N, increasing the biomass dry weight by 23.8% in 2005 and 18.8% in 2006, with respect to unfertilized sorghum; higher N rates are not advisable in order to avoid increasing fertilization costs and environmental impact without benefit of greater biomass production. The two highest N rates when combined with low water availability appeared to increase the rate of plant development, causing earlier flowering and increasing the percentage of panicles in total biomass. Higher heating value (HHV), lower heating value (LHV) and ash concentration of biomass varied among N rates, with values of HHV and LHV lower for unfertilized sorghum (17.6 and 16.7 MJ kg-1 d.m., respectively) than when N was applied (from 19.0 to 19.7 and from 18.1 to 18.8 MJ kg-1 d.m., respectively); on the contrary, ash concentration was greater for unfertilized sorghum (7.5% d.m.) than for fertilized sorghum (from 5.8 to 6.7% d.m.). This research showed the high potential of sorghum in terms of biomass production also when cultivated with limited irrigation and fertilization inputs. The biomass dry yield obtained by one hectare of sorghum crop without N nitrogen fertilization (i.e. 22.6 t ha-1 of d.m., average of 2005 and 2006 values) produces the same energy, by thermal utilisation, of 9.3 toe, that is equivalent to energy produced by 10,385 L of diesel fuel or 11,097 m3 of methane fuel. This aspect increases the certainty of the energetic and environmental sustainability of sorghum crop. [ABSTRACT FROM AUTHOR]

In 2017, in a new Chenopodium quinoa cultivation area (Central Italy), emergence failures of the Titicaca, Rio Bamba, and Real varieties, whose seeds were obtained the previous year (2016) in the same location, were observed. Moreover, leaf disease symptoms on the Regalona variety, whose seeds came from Chile, were detected. Visual and microscopic analyses showed the presence of browning/necrotic symptoms on the seeds of the three varieties whose emergence in the field had failed. In addition, their in vitro germination rates were strongly compromised. Fusarium spp. was isolated with high incidence from Titicaca, Rio Bamba, and Real seeds. Among the detected Fusarium species, in the phylogenetic analysis, the dominant one clustered in the sub-clade Equiseti of the Fusarium incarnatum-equiseti (FIESC) species complex. Instead, the pathogen associated with Regalona leaf symptoms was identified, by morphological and molecular features, as Peronospora variabilis , the causal agents of downy mildew. This is the first report of both P. variabilis and F. equiseti on C. quinoa in Italy. Species-specific primers also detected P. variabilis in Regalona seeds. These results underline the importance of pathogen monitoring in new quinoa distribution areas, as well as of healthy seed production and import for successful cultivation.

Wild sunflower ( Helianthus annuus L.) is an invasive species widely distributed in several regions of the world, where it shares a large area with domesticated sunflower. The imidazolinone-tolerant sunflower enables the control of problematic weeds (such as Xanthium spp., Brassica spp., wild sunflower) with imidazolinone herbicides (Clearfield ® production system) in cultivated sunflower crops, but could facilitate the gene transfer of herbicide resistance, from cultivated sunflower to wild sunflower, generating hard-to-control weed biotypes or herbicide-resistant populations. The development of new practices that involve the selective inhibition of reproduction structures, such as pollen granules, could be an innovative strategy to minimize outcrossing and the origin of weed-crop hybrids in Clearfield ® production systems. In this study, the effects of mugwort ( Artemisia vulgaris L.) aqueous extract on cytosolic Ca 2+ and the germination of pollen grains collected from conventional, wild and IMI-tolerant sunflower were tested. The results showed that mugwort deregulated Ca 2+ homeostasis and markedly reduced the germination of conventional and wild sunflower pollen, but not IMI-tolerant pollen. The HPLC analysis revealed the presence of phenolic acids belonging to the hydroxycinnamic and benzoic classes in the mugwort extract. Hydroxycinnamic acids (caffeic and ferulic) deregulated the cytosolic Ca 2+ of conventional and wild sunflower pollen, but not those which were IMI-tolerant, similar to mugwort extract. Selective inhibition of wild sunflower pollen in the Clearfield ® sunflower crop contributes to a possible new weed management strategy, reducing the wild sunflower reproduction by seed, minimizing the potential risks of outcrossing with the formation of weed-crop hybrids. The Ca 2+ selective chelating activity of caffeic or ferulic acids provides elements to be investigated for their possible use as an alternative to mugwort extract.

Water pollution by excessive amounts of nitrate (NO 3 - ) has become a global issue. Technologies to clean up nitrate-contaminated water bodies include phytoremediation. In this context, this research aimed to evaluate four tree species ( Salix alba L., Populus alba L., Corylus avellana L. and Sambucus nigra L.) to remediate nitrate-contaminated waters (100 and 300 mg L -1 ). Some physiological parameters showed that S. alba L. and P. alba L. increased particularly photosynthetic activity, chlorophyll content, dry weight, and transpired water, following the treatments with the above NO 3 - concentrations. Furthermore, these species were more efficient than the others studied in the phytodepuration of water contaminated by the two NO 3 - levels. In particular, within 15 days of treatment, S. alba L. and P. alba L. removed nitrate quantities ranging from 39 to 78%. Differently, C. avellana L. and S. nigra L. did not show particular responses regarding the physiological traits studied. Nonetheless, these species removed up to 30% of nitrate from water. In conclusion, these data provide exciting indications on the chance of using S. alba L. and P. alba L. to populate buffer strips to avoid NO 3 - environmental dispersion in agricultural areas.

From the organic extract of Lavandula stoechas , a Mediterranean native plant species, two new phytotoxic copaane sesquiterpenoids were isolated and named stoechanones A and B ( 1 and 2 ). They were obtained together with the methyl esters of caffeic and p -coumaric acids and the flavonoid apigenin ( 3 - 5 , respectively). The structures of stoechanones A and B were determined by spectroscopic (essentially 1D and 2D 1 H and 13 C NMR and HRESIMS) and chemical methods, and they were characterized as 9,10-dihydroxy-8-isopropyl-1,5-dimethyltricyclo[4.4.0.0 2.7 ]dec-4-en-3-one and its 9- O -acetyl derivative. Their relative configurations were assigned by NOESY experiments, and the absolute configurations by comparison of the experimental and DFT-computed ECD spectra. When assayed through Petri dish bioassays, both stoechanones A and B showed phytotoxic effects against seed germination and seedling growth of Amaranthus retroflexus , strongly inhibiting seed germination percentage and radicle and hypocotyl lengths of seedlings. Owing to the herbicidal activity toward A. retroflexus , these two new tricyclic sesquiterpenoids could be proposed and developed as natural bioherbicides in order to increase the control of this problematic weed in the future.

The capacity of two grasses, tall fescue (Festuca arundinacea) and orchardgrass (Dactylis glomerata), to remove terbuthylazine (TBA) from polluted solutions has been assessed in hydroponic cultures. Different TBA concentrations (0.06, 0.31, 0.62, and 1.24 mg/L) were chosen to test the capacity of the two grasses to resist the chemical. Aerial biomass, effective concentrations (to cause reductions of 10, 50, and 90% of plant aerial biomass) and chlorophylls contents of orchardgrass were found to be more affected. Tall fescue was found to be more capable of removing the TBA from the growth media. Furthermore, enzymes involved both in the herbicide detoxification and in the response to herbicide-induced oxidative stress were investigated. Glutathione S-transferase (GST, EC. 2.5.1.18) and ascorbate peroxidase (APX, EC. 1.11.1.11) of tall fescue were found to be unaffected by the chemical. GST and APX levels of orchardgrass were decreased by the treatment. These negative modulations exerted by the TBA on the enzyme of orchardgrass explained its lower capacity to cope with the negative effects of the TBA.

Bioassays and chemical analyses were performed to study the effect of hydrophobic dissolved organic matter (HoDOM) extracted from a municipal waste compost (MWC) on the behavior of triflusulfuron methyl in soil and water. Bioassays with oilseed rape showed that HoDOM in culture solution lowered the effective dose 50 of triflusulfuron methyl by up to 4.8 times. Equilibrium dialysis experiments showed that in aqueous solution triflusulfuron methyl was adsorbed to HoDOM (K(OC) of 446.5 mL g(-1)). The half-life in water (pH 7.0) was increased from 52 to 76 days in the presence of HoDOM, but this cannot completely explain its phytotoxicity, as bioassays lasted for 21 days only. On the other hand, the addition of HoDOM to soils did not change the degradative behavior of triflusulfuron methyl. Fluorescein diacetate hydrolysis showed that HoDOM in soil did not significantly influence soil microbial activity, which may explain the above result on degradation in soil. Furthermore, in batch equilibrium experiments on soil, triflusulfuron methyl was only weakly adsorbed and the presence of HoDOM significantly modified the isotherm form. Results suggest that although the addition of exogenous HoDOM from MWC to soil did not influence the herbicide's persistence, its enhanced mobility could be of environmental concern and may deserve further research.