Relative Water Content, Proline, and Antioxidant Enzymes in Leaves of Long Shelf-Life Tomatoes under Drought Stress and Rewatering.

Some physiological, oxidative, and antioxidant enzymatic patterns were assessed in plants of three local Sicilian landraces of long shelf-life tomatoes ('Custonaci', 'Salina', and 'Vulcano'), as compared to the commercial tomato hybrid 'Faino' (control). Three water treatments were considered in open-field: DRY (no irrigation); IRR (long-season full irrigation); REW (drought/rewatering cycles). During the growing season, soil water deficit (SWD) was estimated, and relative water content (RWC), specific leaf area (SLA), proline and malondialdehyde (MDA) content, and glutathione peroxidase (GPX), catalase (CAT), and superoxide dismutase (SOD) activities were measured in leaves. Differently from control, RWC in local landraces exhibited a similar pattern in REW and DRY, indicating a low capacity to re-hydrate after rewatering. Positive correlation of proline content vs. SWD in all local landraces highlights an osmotic adjustment occurring in these tomatoes in response to limited soil water content. Long shelf-life tomatoes suffered minor oxidative stress due to severe soil water deficit, as revealed by the lower levels of MDA with respect to the control. Significant correlation of CAT vs. SWD for all tomatoes indicates that this antioxidant enzyme, among those analyzed, may be considered as a biomarker for a water stress condition more than for oxidative stress due to water deficit.

Effects of Different Light Spectra on Final Biomass Production and Nutritional Quality of Two Microgreens.

To improve microgreen yield and nutritional quality, suitable light spectra can be used. Two species-amaranth (Amaranthus tricolor L.) and turnip greens (Brassica rapa L. subsp. oleifera (DC.) Metzg)-were studied. The experiment was performed in a controlled LED environment growth chamber (day/night temperatures of 24 ± 2 °C, 16 h photoperiod, and 50/60% relative humidity). Three emission wavelengths of a light-emitting diode (LED) were adopted for microgreen lighting: (1) white LED (W); (2) blue LED (B), and (3) red LED (R); the photosynthetic photon flux densities were 200 ± 5 µmol for all light spectra. The response to light spectra was often species-specific, and the interaction effects were significant. Morphobiometric parameters were influenced by species, light, and their interaction; at harvest, in both species, the fresh weight was significantly greater under B. In amaranth, Chl a was maximized in B, whereas it did not change with light in turnip greens. Sugar content varied with the species but not with the light spectra. Nitrate content of shoots greatly varied with the species; in amaranth, more nitrates were measured in R, while no difference in turnip greens was registered for the light spectrum effect. Polyphenols were maximized under B in both species, while R depressed the polyphenol content in amaranth.

Strategies to Modulate Specialized Metabolism in Mediterranean Crops: From Molecular Aspects to Field.

Plant specialized metabolites (SMs) play an important role in the interaction with the environment and are part of the plant defense response. These natural products are volatile, semi-volatile and non-volatile compounds produced from common building blocks deriving from primary metabolic pathways and rapidly evolved to allow a better adaptation of plants to environmental cues. Specialized metabolites include terpenes, flavonoids, alkaloids, glucosinolates, tannins, resins, etc. that can be used as phytochemicals, food additives, flavoring agents and pharmaceutical compounds. This review will be focused on Mediterranean crop plants as a source of SMs, with a special attention on the strategies that can be used to modulate their production, including abiotic stresses, interaction with beneficial soil microorganisms and novel genetic approaches.

Compostable Polylactide and Cellulose Based Packaging for Fresh-Cut Cherry Tomatoes: Performance Evaluation and Influence of Sterilization Treatment.

For food packaging, plastic materials display large appeal, mostly due to their versatility, mechanical, optical and barrier properties. However, they play an important role in environmental concerns and waste management issue. Compostable bioplastics represent alternative materials designed for a lower environmental impact. In this work, a biobased compostable packaging, constituted by polylactide (PLA) trays and NatureFlex™ film, was evaluated for fresh-cut cherry tomato. A comparative analysis was accomplished using traditional packaging materials, that is, polyethylene terephtalate (PET) trays and polypropylene (PP Coex) film. Structural stability under food contact conditions, mechanical and physical-chemical properties were investigated. Tensile mechanical properties, puncture resistance, contact angle (CA) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), before and after UV or radiofrequency (RF) sterilization treatment, were evaluated. UV irradiation method resulted the less invasive one. Therefore, oxygen and water vapor transmission rate (OTR and WVTR), overall chemical migration test, biodegradation assessment by biochemical oxygen demand (BOD) according to ISO 14851 and disintegration test by ISO 20200 were carried out to establish the further influence of UV sterilization on the packaging. Overall, data showed that the biobased compostable packaging for a prolonged shelf-life of fresh-cut cherry tomato has better properties that were surprisingly enhanced by the UV treatment.

Targeted secondary metabolic and physico-chemical traits analysis to assess genetic variability within a germplasm collection of "long storage" tomatoes.

"Long storage" tomato is a crop traditionally cultivated in the Mediterranean area under no water supply, that recently has attracted the interest of breeders for its high tolerance to drought and as potential genetic source in breeding programs for water stress resistance. A collection of 28 genotypes of "long storage" tomato (Solanum lycopersicum L.) was studied for carotenoid and polyphenol profile and content, vitamin C, and other physico-chemical traits of fruits. Tomato carotenoids and polyphenols were identified and quantified using high-performance liquid chromatography coupled with diode array detection and electrospray-mass spectrometry (HPLC/DAD/ESI-MS); nineteen different phenolic compounds and six different carotenoids, for a total of 25 markers, have been detected, quantified and used to discriminate among the different landraces to find out which could be the best candidate for a medium-to-large scale cultivation. Different statistical approaches (ANOVA, Principal Components Analysis, Cluster Analysis) have been used for data analysis.

Physiological screening for drought tolerance in Mediterranean long-storage tomato.

Long-storage tomato is a drought-tolerant plant traditionally cultivated under no water supply in semi-arid areas of Italy. In 2009, physiological traits of ten "long-storage" tomato lines cultivated under no irrigation were screened for low soil water tolerance. Leaf relative water content (RWC), proline content and leaf transpiration (E) were measured throughout the growing season. Instantaneous leaf water use efficiency was also calculated on a single date, as the ratio between net photosynthesis (A) and E. Close relationships were observed among the physiological parameters, positive for E vs. RWC and inverse for RWC and E vs. proline. Results indicate that the increase in proline concentration involves a water stress tolerance, and genotypes more sensitive to soil water deficit respond to drought stress through less proline in leaves. Close significant linear relationships (positive with RWC and E, negative with proline) were also found between fruit yield and all the physiological parameters examined. Among them, the most reliable indicator for yield prediction under water restriction was leaf transpiration rate as measured at the flowering stage. The study made it possible to understand the complex relationships between physiological processes, drought tolerance, and plant productivity in long-storage tomato, and to identify those traits that regulate plant physiology under low water availability.

Benefits for agriculture and the environment from urban waste.

Soluble bio-based substances (SBO) that have been isolated from urban biowaste have recently been reported to enhance plant leaf chlorophyll content and growth. The same SBO have also been shown to enhance the photochemical degradation of organic pollutants in industrial effluent. These findings suggest that SBO may promote either C fixation or mineralization, according to operating conditions. The present work aims to investigate SBO performance, as a function of source material. Thus, three materials have been sampled from a municipal waste treatment plant: (i) the digestate of the anaerobic fermentation of a humid organic fraction, (ii) a whole vegetable compost made from gardening residues and (iii) compost made from a mixture of digestate, gardening residues and sewage sludge. These materials were hydrolyzed at pH13 and 60°C to yield SBO that display different chemical compositions. These products were applied to soil at 30, 145 and 500 kg ha(-1) doses for tomato cultivation. Soil and plant leaf chemical composition, plant growth, leaf chlorophyll content and CO2 exchange rate as well as fruit quality and production rate were measured. Although it did not affect the soil's chemical composition, SBO were found to significantly increase plant photosynthetic activity, growth and productivity up to the maximum value achieved at 145 kg ha(-1). The effects were analyzed as a function of SBO chemical composition and applied dose. The results of this work, compared with those of previous works, indicate that urban biowaste, if properly exploited, may furnish conjugate economic and environmental benefits, within a friendly sustainable ecosystem.

Re-evaluation of traditional Mediterranean foods. The local landraces of 'Cipolla di Giarratana' (Allium cepa L.) and long-storage tomato(Lycopersicon esculentum L.): quality traits and polyphenol content.

BACKGROUND: The heightened consumer awareness for food safety is reflected in the demand for products with well-defined individual characteristics due to specific production methods, composition and origin. In this context, of pivotal importance is the re-evaluation of folk/traditional foods by properly characterizing them in terms of peculiarity and nutritional value. The subjects of this study are two typical Mediterranean edible products. The main morphological, biometrical and productive traits and polyphenol contents of three onion genotypes ('Cipolla di Giarratana', 'Iblea' and 'Tonda Musona') and three long-storage tomato landraces ('Montallegro', 'Filicudi' and 'Principe Borghese') were investigated. RESULTS: Sicilian onion landraces were characterized by large bulbs, with 'Cipolla di Giarratana' showing the highest bulb weight (605 g), yield (151 t ha(-1)) and total polyphenol content (123.5 mg kg(-1)). Landraces of long-storage tomato were characterized by low productivity (up to 20 t ha(-1)), but more than 70% of the total production was obtained with the first harvest, allowing harvest costs to be reduced. High contents of polyphenols were found, probably related to the typical small fruit size and thick skin characterizing these landraces. CONCLUSION: The present study overviews some of the most important traits that could support traditional landrace characterization and their nutritional value assessment.

Yield, physicochemical traits, antioxidant pattern, polyphenol oxidase activity and total visual quality of field-grown processing tomato cv. Brigade as affected by water stress in Mediterranean climate.

BACKGROUND: The 'processing tomato' is an important source of natural antioxidants whose concentration depends, along with other parameters, on water availability. In order to better understand the mechanisms that regulate the response to water stress, a study was carried out in a typically semi-arid Mediterranean environment to investigate the yield, chemical composition and visual quality of tomato cv. 'Brigade' field grown under no irrigation (V0) in comparison with those of the conventional fully irrigated crop (V100). RESULTS: The stressful conditions of V0 affected the total yield. Nevertheless, fruits exhibited an increase in firmness (+27%), total solids (+23%) and total soluble solids (+5%). The dynamic balance between the antioxidant pattern and polyphenol oxidase activity under water stress conditions resulted in fruits with increased antioxidant activity (+12%), due to a decline in enzyme activity (-48%) and a rise in vitamin C (+20%) and total phenolic (+13%) contents. CONCLUSION: It is possible to manage water stress by applying water-saving irrigation strategies in order to promote the quality and nutritional properties of tomatoes while also contributing to saving water. This is a relevant aspect in processing tomato cultivation in semi-arid environments, where both the cost and availability of irrigation water represent a rising problem in agricultural activities.

Polyphenols as chemotaxonomic markers in Italian "long-storage" tomato genotypes.

"Long-storage" tomato ( Solanum lycopersicum L.) is a niche product typical of the Mediterranean area, traditionally cultivated under no water supply, the fruits of which combine a good taste with excellent nutritional properties. High-performance liquid chromatography coupled with diode array detection and electron spray-mass spectrometry (HPLC/DAD/ESI-MS) was used to identify the phenolic profile in 10 landraces of long-storage tomato, grown under a typical semiarid climate, as compared to a processing tomato hybrid cultivated in the same environment, under both well-irrigated and unirrigated conditions. Sixteen different secondary metabolites, belonging to the classes of cinnamoylquinic acids and flavonoids, were identified. Quantitative analyses were also performed to monitor the changes in the phenolic content along the batch. The results highlighted that landraces originating from the same area exhibit different fruit morphologies but own a similar biochemical profile. Moreover, the two controls (well irrigated and unirrigated) are placed into the same cluster, suggesting that these secondary metabolites in tomato fruits may be more genetics-dependent than environment-dependent. Given the analysis of phenols nowadays represents a useful tool to assess the genetic variability in tomato, these compounds could be adopted as chemotaxonomic markers in the traceability of this niche product.

Gas exchange and photosynthetic water use efficiency in response to light, CO2 concentration and temperature in Vicia faba.

Light and temperature-response curves and their resulting coefficients, obtained within ecophysiological characterization of gas exchanges at the leaf level, may represent useful criteria for breeding and cultivar selection and required tools for simulation models aimed at the prediction of potential plant behaviour in response to environmental conditions. Leaf-scale gas exchanges, by means of an IRGA open-flow system, were measured in response to light intensity (8 levels from 0 up to 2000 micromol m(-2) s(-1)), CO(2) concentrations (ambient-350 micromol mol(-1) and short-term enriched-700 micromol mol(-1)) and air temperature (from 7 up to 35 degrees C) on three Vicia faba L. genotypes, each representing one of the three cultivated groups: major, equina and minor. The net assimilation rate response to light intensity was well described by an exponential rise to max function. The short-term CO(2) enrichment markedly increased the values of light response curve parameters such as maximum photosynthetic rate (+80%), light saturation point (+40%) and quantum yield (+30%), while less homogenous behaviour was reported for dark respiration and light compensation point. For each light intensity level, the major and minor genotypes studied showed assimilation rates at least a 30% higher than equina. The positive effects of short-term CO(2) enrichment on photosynthetic water use efficiency (WUE) indicate a relevant advantage in doubling CO(2) concentration. In the major and minor genotypes studied, similar assimilation rates, but different WUE were observed. The optimum leaf temperature for assimilation process, calculated through a polynomial function, was 26-27 degrees C and no relevant limitations were observed in the range between 21 and 32 degrees C. Analysis at the single leaf level provided both rapid information on the variations in gas exchange in response to environmental factors and selection criteria for the screening of genotypes.

Physico-chemical characteristics, water absorption, soaking and cooking properties of some Sicilian populations of chickpea (Cicer arietinum L.).

The physical and physico-chemical properties of several Kabuli chickpeas originating from Sicily (South Italy) were determined. Twelve genotypes in all, including two controls (ILC484, of the ICARDA genebank, and 'Calia', a traditional Italian cultivar), were analysed. A large variability among genotypes was ascertained for swelling capacity (coefficient of variation [CV] = 27.9%), swelling index (CV = 30.5%) and calcium content (CV = 39.3%). The lowest variability was observed for seed coat (CV = 8.6%) and seed weight (CV = 9.6%). Genotype statistically affected all traits, whose mean values were: seed weight, 0.340 +/- 0.03 g; seed coat, 4.47 +/- 0.38%; seed volume, 0.292 +/- 0.04 ml; seed density, 1.18 +/- 0.15 g/ml; hydration capacity, 0.361 +/- 0.09 g/seed; hydration index, 1.05 +/- 0.21; swelling capacity, 0.346 +/- 0.10 ml/seed; swelling index, 1.21 +/- 0.37; cooking texture, 2.61 +/- 0.38 kg/cm(2); and calcium, 109.6 +/- 43.11 mg/100 g dry weight. Correlation coefficients among characteristics were also estimated. The genotype '44M33' was found to be interesting having good seed weight and low seed coat incidence and calcium content, all important attributes affecting cooking quality.