Effect of variety choice, resistant rootstocks and chitin soil amendments on soil-borne diseases in soil-based, protected tomato production systems

Soil-borne diseases are the most significant crop protection problem in soil-based, low-input and especially organic glasshouse production systems in Europe. While chemical soil disinfestation has been the control method of choice in conventional farming systems, soil steaming has been the main strategy for the control of soil-borne diseases in organic production. Both methods are extremely expensive and have been increasingly restricted for environmental reasons by governments, and integrated and organic farming standard-setting bodies. The use of disease-tolerant varieties, grafting onto resistant rootstocks and chitin soil amendments were evaluated as potential replacements for soil steaming in organic and other low-input tomato production systems. When only Pyrenochaeta lycopersici and/or Meloidogyne spp. were present in soil, grafting and/or chitin soil amendment were found to be as effective in reducing root disease and/or increasing yield as soil steaming, but the efficacy of both treatments was reduced when Verticillum albo-atrum was also present in soil. No additive effects of combining grafting and chitin soil amendments could be detected. A more widespread use of grafting and/or chitin soil amendments may therefore allow significant reductions in the use of steam and chemical soil disinfestation in glasshouse crops. It will also allow integrated and organic farming standard-setting bodies to impose further restrictions on the use of soil disinfestation treatments.     

Residual heavy metal (Cu and Cd) removal byIris Pseudacorus

The uptake of Cu and Cd by the roots ofIris pseudacorus and its transport to rhizome and leaves were examined using solutions containing 0.5 and 5.0 mg L^?1 of Cu and Cd. Heavy metal accumulation was measured while replacing the metal absorbed by the plants with daily introduction to restore the initial concentrations. The heavy metal accumulation by Iris p. was 1.01 g Cu and 0.69 g Cd kg^?1 of fresh plant at the end of the tests for the solutions of 5.0 mg L^?1 metal concentration, respectively.     

Isolation of phytotoxic compounds from tree-of-heaven (Ailanthus altissima swingle)

The aqueous root extract of Ailanthus altissima showed allelopathic activity against radish (Raphanus sativus L. cv. "Saxa"), garden cress (Lepidium sativum L.), and purslane (Portulaca oleracea L.) seeds. A bioassay-oriented purification of active extracts, chromatographic fractions, and compounds demonstrated dose-dependent activity on germination and radicle growth of test seeds; radish seed was the most sensitive to allelochemicals. Active compounds have been isolated: ailanthone, ailanthinone, chaparrine, and ailanthinol B (quassinoid derivatives); the alkaloid 1-methoxycanthin-6-one is not active. The compound with greatest inhibitory activity is ailanthone. The data obtained suggest a possible use of tree-of-heaven root extracts or of its active constituents as natural herbicides.     

Furosine: a suitable marker for assessing the freshness of royal jelly

Fifteen commercial samples of royal jelly, consisting of 10 imported samples, and 5 samples of known origin obtained freshly harvested from beekeepers, were analyzed for protein, lysine, and furosine content. In addition, a commercial sample of royal jelly, at the beginning of its commercial shelf life, was stored for 10 months both at 4 degrees C and at room temperature in order to assess the development of the Maillard reaction (furosine) and relative nutritional damage (blocked lysine). The commercial royal jelly products contained different amounts of furosine, ranging from 37.1 to 113.3 mg/100 g protein, evidence of different storage times and conditions. The average furosine content of the royal jelly samples of known origin and harvesting was significantly lower than that of the imported samples (41.7 versus 73.6 mg/100 g protein, respectively). With regard to shelf life, furosine content increased significantly from 72.0 mg/100 g protein to 500.8 mg/100 g protein after 10 months of storage at room temperature, while it increased to a much lower level (100.5 mg/100 g protein) when the royal jelly was stored at 4 degrees C. However, nutritional damage, expressed as blocked lysine (calculated indirectly from the furosine content), was minor or negligible, 11.9 and 2.3% of total lysine, in samples stored at room temperature and at 4 degrees C, respectively. Lysine was determined by an innovative procedure based on high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The results showed that furosine is a suitable index for assessing the quality and freshness of royal jelly.     

Rotenone residues on olives and in olive oil

The disappearance of rotenone on olives under field conditions was studied. The field data showed that rotenone residues on olives decreased with a half-life (t(1/2)) of 4.0 days. After pre-harvest time (10 days) the residues were higher than the maximum residue level fixed in Italy (0.04 mg/kg). Experiments with model systems showed that the mechanism of disappearance of rotenone is not related to evaporation, thermodegradation, or co-distillation, but only to photodegradation. When the olives were processed for oil, the residues in the oil were higher than the residues on the olives by a factor of 2.4-4.8.     

Elemental leaching from quercus ilex L. in response to simulated acidic fog

Quercus ilex L. seedlings were intermittently exposed to simulated acidic and non-acidic fogs in 6-hr events for 16 times. After a 1-mo break, treatments were carried out again for a 5 day period. Strong acidity neutralization, weak acidity release and cation leaching from foliage and stem were determined. Leaching of Al, Cu, Mn, Fe, Cd, Pb, Ca, Mg, and K increased in response to acid treatment. This effect was less marked for Na. A positive correlation between H^? uptake and cation leaching was found. Cationic release and neutralization of strong acidity increased after breaks in acid treatment, but this faculty and the amount of leached cations and neutralized acidity decreased with time. The stem showed a higher cation loss and higher buffer capacity than the leaves.     

Characterization of Pectobacterium species from Iran using biochemical and molecular methods

Characteristics of forty strains from macerated potato tubers and water-soaked lesions of some ornamental plants were studied in north parts of Iran. The causal organisms isolated from infected tissues were identified as Pectobacterium spp. based on their physiological and biochemical assays and confirmed by species and subspecies specific PCR and RFLP analysis of 16S–23S intergenic transcribed spacer region. Artificial inoculation of isolates to their related hosts generated the same symptoms on potato and ornamental plants, from which the same bacteria were isolated and identified. We detected two groups of atypical isolates in this study. The first group from potato classified as Pectobacterium carotovorum subsp. carotovorum by phenotypic tests but was unable to elicit HR on tobacco leaves, to grow at 37°C and to amplify the pel gene relevant to this subspecies. The second one from ornamental plants which was again characterized as Pectobacterium carotovorum subsp. carotovorum in biochemical assays, produced a unique ITS-RFLP profile different from all of known Pectobacterium species and subspecies. Our findings based on phylogenetic analysis using concatenated partial sequences of housekeeping genes mdh and gapA, indicated the occurrence of P. wasabiae as a novel species in potato storage in Iran. Furthermore we detected a distinct clade of Pectobacterium spp. from some ornamental plants including Schlumbergera bridgesii, Syngonium podophyllum and Iris spp.     

Host-pathogen interaction of root-knot nematode <Emphasis Type="Italic">Meloidogyne incognita</Emphasis> on pepper in the southeast of Spain

The feeder roots of pepper plants (cv. California Wonder) in Campo de Cartagena (southeast Spain) were found to be severely infected by Meloidogyne incognita. Morphometric traits, differential host test and DNA analysis based on PCR were used to characterize the nematode. Naturally and artificially infected pepper plants showed severe yellowing and stunting, with heavily deformed and damaged root systems. Root galls were spherical and commonly contained more than one female and egg masses with eggs. Typical giant cells with a granular cytoplasm and many hypertrophied nuclei were observed in histological preparations. The relationship between initial nematode population density (Pi) and pepper plant growth was tested in greenhouse experiments with inoculum levels that varied from 0 to 64 eggs and second-stage juveniles (J₂) ml⁻¹ soil. A Seinhorst model was fitted to plant height and top fresh weight data of inoculated and non-inoculated plants. The tolerance limit with respect to plant height and fresh top weight of pepper to M. incognita was estimated as 0.85 eggs and J₂ ml⁻¹ soil. The minimum relative values (m) for plant height and top fresh weight were 0.15 and 0.16, respectively, at Pi ≥ 64 eggs and J₂ ml⁻¹ soil. The maximum nematode reproduction rate (Pf/Pi) was 315.4 at an initial population density (Pi) of 4 eggs and J₂ ml⁻¹ soil. The obtained results could be used as a base to establish field experiments that allow strategies to prevent surpassing the threshold of nematodes in fields that are infested.     

Development of functional spaghetti enriched in bioactive compounds using barley coarse fraction obtained by air classification

Barley byproducts obtained by air classification have been used to produce a different barley functional spaghetti, which were compared to different commercial whole semolina samples. Total, insoluble, and soluble fiber and β-glucan contents of the barley spaghetti were found to be greater than those of commercial samples. Furthermore, it was proved that barley spaghetti reached the FDA requirements, which could allow these pastas to deserve the health claims "good source of dietary fiber" and "may reduce the risk of heart disease". When the barley coarse fraction was used, a flavan-3-ols enrichment and an increase of antioxidant activity were reported, while commercial samples showed the absence of flavan-3-ols and a higher presence of phenolic acids and tannins. Whole semolina commercial spaghetti had a significantly higher content of phenolic acids than semolina spaghetti samples. Besides, it was observed that when vital gluten was added to the spaghetti formulation, phenolic compounds were blocked in the gluten network and were partially released during the cooking process.