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C. Cocozza C. Pulvento A. Lavini M. Riccardi R. d'Andria R. Tognetti 《Journal of Agronomy and Crop Science》2013,199(4):229-240
Quinoa is a native Andean crop for domestic consumption and market sale, widely investigated due to its nutritional composition and gluten‐free seeds. Leaf water potential (Ψleaf) and its components and stomatal conductance (gs) of quinoa, cultivar Titicaca, were investigated in Southern Italy, in field trials (2009 and 2010). This alternative crop was subjected to irrigation treatments, with the restitution of 100 %, 50 % and 25 % of the water necessary to replenish field capacity, with well water (100 W, 50 W, 25 W) and saline water (100 WS, 50 WS, 25 WS) with an electrical conductivity (ECw) of 22 dS m?1. As water and salt stress developed and Ψleaf decreased, the leaf osmotic potential (Ψπ) declined (below ?2.05 MPa) to maintain turgor. Stomatal conductance decreased with the reduction in Ψleaf (with a steep drop at Ψleaf between ?0.8 and 1.2 MPa) and Ψπ (with a steep drop at Ψπ between ?1.2 and ?1.4 MPa). Salt and drought stress, in both years, did not affect markedly the relationship between water potential components, RWC and gs. Leaf water potentials and gs were inversely related to water limitation and soil salinity experimentally imposed, showing exponential (Ψleaf and turgor pressure, Ψp, vs. gs) or linear (Ψleaf and Ψp vs. SWC) functions. At the end of the experiment, salt‐irrigated plants showed a severe drop in Ψleaf (below ?2 MPa), resulting in stomatal closure through interactive effects of soil water availability and salt excess to control the loss of turgor in leaves. The effects of salinity and drought resulted in strict dependencies between RWC and water potential components, showing that regulating cellular water deficit and volume is a powerful mechanism for conserving cellular hydration under stress, resulting in osmotic adjustment at turgor loss. The extent of osmotic adjustment associated with drought was not reflected in Ψπ at full turgor. As soil was drying, the association between Ψleaf and SWC reflected the ability of quinoa to explore soil volume to continue extracting available water from the soil. However, leaf ABA content did not vary under concomitant salinity and drought stress conditions in 2009, while differing between 100 W and 100 WS in 2010. Quinoa showed good resistance to water and salt stress through stomatal responses and osmotic adjustments that played a role in the maintenance of a leaf turgor favourable to plant growth and preserved crop yield in cropping systems similar to those of Southern Italy. 相似文献
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Ecotypic variations in leaf conductance, soil-to-leaf hydraulic conductance, components of tissue water potential, hydraulic architecture parameters and xylem embolism were examined in greenhouse-grown two-year-old Aleppo pine (Pinus halepensis Mill.) seedlings from six origins representing the geographic range of the species in Italy. Cortical resin composition of the seedlings was also determined. Measurements were made on well-watered seedlings and on seedlings subjected to recurring severe drought. Drought-stressed seedlings had lower mean leaf conductances, transpiration rates and soil-to-leaf hydraulic conductances than well-watered seedlings. They also exhibited more negative osmotic potentials, higher relative water deficit at incipient plasmolysis, but a similar maximum modulus of elasticity. Drought-stressed seedlings showed a higher degree of xylem embolism, a lower Huber value, lower leaf specific conductivity and lower specific conductivity than well-watered seedlings. Drought-stressed seedlings of provenances from more xeric habitats (Tremiti, Porto Pino and Mottola) had greater leaf conductances, transpiration rates and soil-to-leaf hydraulic conductances than drought-stressed seedlings of provenances from more mesic habitats (Imperia, Otricoli and Vico del Gargano). They also showed higher osmotic adjustment and a lower degree of xylem embolism. Among provenances, there were no significant differences in hydraulic architecture parameters in response to the drought treatment; however, Tremiti and Porto Pino seedlings displayed smaller drought-induced reductions in specific conductivity and leaf specific conductivity, respectively, than seedlings from other provenances. These differences suggest that seedlings from xeric provenances, especially Tremiti, have greater resistance to desiccation than seedlings from mesic provenances. No clear association was found between terpene variability and the other traits investigated, although terpene composition was related to the geographical distribution of the provenances. We conclude that the drought-tolerance responses of Tremiti make it a more suitable provenance than the others for establishment on sites prone to severe soil water deficits. 相似文献
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Water is the most important environmental constrain determining plant growth and fruit yield of olive tree plantations. Although olive trees are resilient to water-limited conditions of Mediterranean-type agroecosystems, crop yields may respond positively to any additional water up to a limit. A field experiment on olive trees was carried out with the aim to present guidelines for efficient management of irrigation scheduling, based on the relationship between plant water status and optimum fruit yield. These relationships were monitored during 2 years by analysing the influence of deficit irrigation strategies on vegetative development and yield parameters on mature modern-trained olive trees of cvs. Frantoio and Leccino. Treatments were: a non-irrigated control (rainfed) and three treatments that received seasonal water amount equivalent to 33, 66 and 100% of ETC in the period August–September, from the beginning of pit hardening to early fruit veraison. Atmospheric evaporative demand and soil moisture conditions were regularly monitored. Seasonal dynamics of plant water relations varied among treatments, and responded to variations in tree water status, soil moisture conditions and atmospheric evaporative demand. All measurements of tree water status were highly correlated with one another. Differences in yield between treatments indicated that water availability might have affected fruit weight before flowering or during the early stages of fruit growth rather than later in summer season. Results concerning crop yield revealed that irrigation of olive trees from the beginning of pit hardening could be recommended, at least in the experimental conditions of this study and in view of differences between genotypes. 相似文献
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Lanciotti R Belletti N Patrignani F Gianotti A Gardini F Guerzoni ME 《Journal of agricultural and food chemistry》2003,51(10):2958-2963
The aims of this work were to evaluate the effects of different concentrations of hexanal, (E)-2-hexenal, hexyl acetate, and their mixtures on the fate of pathogenic species such as Escherichia coli, Salmonella enteritidis, and Listeria monocytogenes inoculated in model systems as well as the antimicrobial activity against the target species of the chosen molecules when added to the packaging atmosphere of inoculated fresh-sliced apples. The result obtained in this work pointed out the potential use of compounds such as hexanal, (E)-2-hexenal, and hexyl acetate for both the extension of shelf life and an improvement of hygienic safety of "minimally processed foods". In fact, hexanal, (E)-2-hexenal, and hexyl acetate had a significant inhibitory effect against pathogen microorganisms frequently isolated from raw materials (E. coli, S. enteritidis, and L. monocytogenes) when inoculated in both model and real systems. In this last condition, these compounds, at the levels used (150, 150, and 20 ppm for hexanal, hexyl acetate, and (E)-2-hexenal, respectively), displayed a bactericide effect on L. monocytogenes and they exhibited significant extensions of lag phase of E. coli and S. enteritidis inoculated at levels of 10(4)-10(5) CFU/g. 相似文献
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Belletti N Ndagijimana M Sisto C Guerzoni ME Lanciotti R Gardini F 《Journal of agricultural and food chemistry》2004,52(23):6932-6938
The aim of this research was to assess the antimicrobial activity of nine different industrial essences used in a soft drink factory in relation to their composition, as well as to verify the role of vapor pressure on their bioactivity. The essences were tested against a Saccharomyces cerevisiae strain isolated from spoiled soft drinks. The tests were carried out by adding the essences directly to a liquid medium or into the headspace of closed systems inoculated with the yeast. The headspace composition was evaluated through a solid phase microextraction-gas chromatography technique. The use of a mass spectrometer allowed the identification of the peaks detected. The microbial growth was indirectly monitored by measuring the metabolic CO2 released by the yeast. The results obtained indicated that the most effective essences were characterized by the highest concentration of some terpenes, such as citral, beta-pinene, and p-cymene. Moreover, all of the essences were more bioactive when added directly to the liquid medium. 相似文献
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S Naik N Bouladoux C Wilhelm MJ Molloy R Salcedo W Kastenmuller C Deming M Quinones L Koo S Conlan S Spencer JA Hall A Dzutsev H Kong DJ Campbell G Trinchieri JA Segre Y Belkaid 《Science (New York, N.Y.)》2012,337(6098):1115-1119
Intestinal commensal bacteria induce protective and regulatory responses that maintain host-microbial mutualism. However, the contribution of tissue-resident commensals to immunity and inflammation at other barrier sites has not been addressed. We found that in mice, the skin microbiota have an autonomous role in controlling the local inflammatory milieu and tuning resident T lymphocyte function. Protective immunity to a cutaneous pathogen was found to be critically dependent on the skin microbiota but not the gut microbiota. Furthermore, skin commensals tuned the function of local T cells in a manner dependent on signaling downstream of the interleukin-1 receptor. These findings underscore the importance of the microbiota as a distinctive feature of tissue compartmentalization, and provide insight into mechanisms of immune system regulation by resident commensal niches in health and disease. 相似文献
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F. Lombardi P. Cherubini R. Tognetti C. Cocozza B. Lasserre M. Marchetti 《Annals of Forest Science》2013,70(1):101-111
Context
We investigated the relationships between decay classes, morphological characteristics and chemical compounds in Abies alba Mill. and Fagus sylvatica L. stumps in two forest stands in the central Apennines (Italy). The analysis of deadwood decomposition is important in estimating carbon sequestration potential and carbon residence time in forest ecosystems. In addition, deadwood decomposition affects nutrient cycling and microhabitat distribution.Aims
The overall aim of this study was to investigate the decomposition processes in a mountainous Mediterranean ecosystem, and specifically to assess changes in chemical variables (lignin, cellulose, carbon and nitrogen content) in deadwood during the decomposition process, in relation to decay classes and to the species.Methods
Cross-sections were collected from stumps. Samples were assigned to visually discernible decay classes, and cellulose, lignin and carbon (C) and nitrogen (N) content in relation to total dry mass were analysed during the decay process.Results
Results showed how C/N ratio decreased over decades due to an increase in nitrogen content. On the contrary, carbon concentration in stumps remained substantially stable. Lignin degraded slowly in comparison with cellulose and differences between species were observed.Conclusion
The hypothesis that the conifer species would decompose faster than deciduous species did not prove correct. The slower decay of lignin compared to cellulose suggested that lignin could be an important long-term source of soil organic carbon, and that this process could be greatly affected by forest species mixtures. Finally, decomposition processes in the investigated montane?CMediterranean forests were definitely faster than in the colder climates of northern Europe. 相似文献10.
The increasing demand for traditional and natural foods has renewed the interest in hulled wheat species. Among these, Triticum dicoccum Schübler has survived in Italy only in a few hilly and mountainous areas of central and southern Italy. As a rule, emmer is cultivated in marginal areas with organic farming procedures that use very low N inputs, since this wild species is characterised by low yield, long and weak culms that easily lodge under windy conditions. Unfortunately, there is a lack of information on crop productivity and N effect for this crop. Research was carried out to study the effect of cultivation year (2004 and 2005), plant origin (Garfagnana, Leonessa and Molise) and N dressing (N0, N30, N60 and N90 kg ha−1) on crop yield and grain quality of emmer grown in south-central Italy. Fertilizer was split at seeding, tillering and stem elongation. Tested parameters were highly influenced either by crop origin or N application (biomass, hulled and threshed grain yield, spikes m−2, spikelets per spike, kernel weight, plant height, lodging, kernel ash and proteins). Several parameters augmented as fertilization rate increased (hulled and unhulled grain yield, biomass accumulation, spikes m−2, kernels m−2, protein content); 1000-kernel weight showed an opposite trend and in some cases no differences were noticed among fertilized treatments (plant height and spikelets per spike). Molise was the most productive population, closely followed by Garfagnana. The present research rejected some common belief that emmer has to be grown without N dressing, and crop undergoes lodging in marginal mountainous areas. Besides, grain yield of N90 and N60 treated emmer was only 6 and 18% lower compared to the five most important durum wheat varieties cultivated in the same area, suggesting emmer as a possible alternative crop to durum wheat in marginal areas of Mediterranean-type agro-ecosystems. 相似文献