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The aim was the evaluation of the biochemical and physiological responses of green- (GP) and red-leafed (RP) Prunus cerasifera mature leaves to 20 d of polyethylene glycol (PEG 6000)-induced water stress in order to elucidate a possible ameliorative role exerted by anthocyanins. At 10 d, the anthocyanin content remained unchanged in RP water-stressed leaves. Photosynthetic rate was lower in GP than that of RP (83.4 vs. 76.5%, respectively), paralleled by a higher degree of photoinhibition (Fv/Fm) in GP leaves. Leaves of GP accounted for higher content of soluble sugars at 10 d, when RP only showed a slight sucrose increase. At 20 d of stress, both morphs recovered their Fv/Fm values, suggesting the ability of both genotypes to adjust their photosynthetic metabolism under conditions of water stress. In conclusion, besides the sunscreen role served by anthocyanins, the carbon sink by these flavonoids might have further prevented sugar accumulation and the consequent sugar-promoted feedback regulation of photosynthesis in drought-stressed red leaves.

Microgreens of wild herbs are a source of healthy compounds. Selenium (Se) biofortification of microgreens could help increase the Se content and thus contribute to Se requirements in humans. We evaluated whether three wild herbs, Rumex acetosa L., Plantago coronopus L., and Portulaca oleracea L., were suitable for biofortification in order to obtain products with high nutraceutical value. In the first experiment, the three species were enriched with Na2SeO4 at 0 and 1.5 mg Se L−1, and the effects of Se on the nutraceutical characteristics of microgreens were evaluated. In the second experiment, using P. oleracea enriched with 0, 1.5, 5, and 10 mg Se L−1, we investigated whether there was a relation between the increasing Se concentrations in the nutrient solution and the Se content in microgreens. The Se added was taken up by roots and accumulated in the aerial part. P. coronopus exhibited the highest ability to accumulate selenium, and the Se-enriched microgreens showed the highest chlorophyll and flavonoid content. The strong correlation between the Se concentration in the growth solution and the Se accumulated in P. oleracea may enable the cultivation of microgreens with the targeted Se content. The resulting Se-biofortified microgreens of wild species could represent a new vegetable product with high nutraceutical value also ensuring a sufficient dietary intake of Se.

Sweet basil (Ocimum basilicum L.) is an aromatic annual plant belonging to the Lamiaceae family, cultivated and utilized throughout the world. Basil has a culinary value, and pharmaceutical properties. The aromatic oil extracted from its leaves has antioxidant and antimicrobial activity. Selenium (Se) is an essential element for humans, and acts as antioxidant and anticarcinogenic agent. Since healthy nutrient plant compounds are more bioavailable than compounds contained in food supplements, biofortification of fruiting and leafy vegetables with Se is a good way to increase consumption and supplementation of Se by humans. Further, Se appears to be effective in delaying fruit ripening and plant senescence, thus decreasing postharvest losses due to enhanced antioxidation. We investigated the effect of Se addition on production and quality traits of Ocimum basilicum L. 'Tigullio'. Two experiments were conducted on sweet basil seedlings hydroponically grown under greenhouse conditions at rate of 0 (control), 0.5, 1, 2, 4 mg Se L‑1. Selenium was added to the nutrient solution as sodium selenate. In order to evaluate the growth, physiology, and nutritional value of basil plants the following parameters were determined at harvest time: plant biomass, antioxidant capacity, total phenols, rosmarinic acid, nitrate, macro- and micronutrients, total chlorophyll and total carotenoid. Our results showed that the addition of selenium significantly and linearly increased the Se content in basil. In general, selenium did not affect the plant biomass and the quality of product. The amount of Se accumulated in plants could provide the rational Se intake for human nutrition in accordance with the recommended dietary allowance (RDA) guidelines.

Selenium (Se) enrichment of plants seems effective in enhancing the health-related properties of produce and in delaying plant senescence and fruit ripening. The current study investigated the effects of Se on tomato fruit ripening. Tomato (Solanum lycopersicum L.) plants were grown in hydroponics with different Se-enriched nutrient solutions. Se, as sodium selenate, was added at a rate of 0?mg?L?1 (control), 1, and 1.5?mg?L?1. Results Selenium was absorbed by roots and translocated to leaves and fruit. Enrichment with Se did not significantly affect the qualitative parameters of fruit at commercial harvest; instead it delayed ripening by affecting specific ripening-related processes (respiration, ethylene production, color evolution) during postharvest. In the current experiment 100?g of tomato hydroponically grown with a 1.5?mg Se L?1 enriched solution provided a total of 23.7?µg Se. Selenium recommended daily intake is 60?µg for women and 70?µg for men; thus the daily consumption of 100?g of enriched tomato would not lead to Se toxicity but would provide a good Se diet supplementation. Conclusions The cultivation of tomato plants in a Se-enriched solution appeared effective in producing tomato fruit with improved performance during storage and postharvest shelf life, and also with greater potential health-promoting properties. ? 2018 Society of Chemical Industry

Selected light wavebands promote plant development and/or the biosynthesis of targeted metabolites. This work offers new insights on the effects of red (R), green (G), blue (B), and white (W - R:G:B; 1:1:1) LED light supplementation on physiochemical traits of strawberry leaves. Gas exchange and chlorophyll fluorescence parameters, photosynthetic pigments, and superoxide anion (*O2-) content were analysed in plants grown for 1 (T1) and 17 (T17) d with light supplementations. At T1, light supplementations resulted in the enhancement of the de-epoxidation state of xanthophylls and nonphotochemical quenching, but no changes were observed in maximal photosynthetic rate (PNmax), irrespective of light spectra. At T17, xanthophyll contents remained higher only in R-supplemented plants. Overall, W light resulted in higher photosynthesis, whilst R and B light depressed PNmax values and promoted *O2- formation at T17. G light did not induce variations in photosynthetic traits nor induced oxidative stress at both T1 and T17.

The biofortification of leafy vegetables with selenium (Se) is a good way to increase human dietary Se intake. In addition, selenium delays plant senescence by enhancing the antioxidant capacity of plant tissues, decreasing postharvest losses. We investigated the effects of selenium addition on the production and quality of sweet basil (Ocimum basilicum) leaves of two harvesting phases, hereafter referred to as cuts, during the crop cycle. Plants were hydroponically grown and treated with 0 (control), 4, 8 and 12 mg Se L&minus, 1 as selenate. To evaluate the growth, nutritional value and quality of the basil leaves, selected qualitative parameters were determined at harvest and after five days of storage. Application of Se at varying rates (4, 8 and 12 mg L&minus, 1) was associated with an increased leaf selenium concentration in the first, but not the second cut. The application of Se significantly affected the antioxidant capacity as well as the total phenol and rosmarinic acid contents at harvest. The reduction in ethylene production observed in the plants at 4 mg Se L&minus, 1 after five days of storage suggests that this Se treatment could be used to prolong and enhance the shelf-life of basil. The daily consumption of 10 g of Se-enriched basil leaves, which, as an example, are contained in a single portion of Italian pesto sauce, would also satisfy the recommended selenium supplementation in humans.

The final stage of leaf ontogenesis is represented by senescence, a highly regulated process driven by a sequential cellular breakdown involving, as the first step, chloroplast dismantling with consequent reduction of photosynthetic efficiency. Different processes, such as pigment accumulation, could protect the vulnerable photosynthetic apparatus of senescent leaves. Although several studies have produced transcriptomic data on foliar senescence, just few works have attempted to explain differences in red and green leaves throughout ontogenesis. In this work, a transcriptomic approach was used on green and red leaves of Prunus cerasifera to unveil molecular differences from leaf maturity to senescence. Our analysis revealed a higher gene regulation in red leaves compared to green ones, during leaf transition. Most of the observed DEGs were shared and involved in transcription factor activities, senescing processes and cell wall remodelling. Significant differences were detected in cellular functions: genes related to photosystem I and II were highly down-regulated in the green genotype, whereas transcripts involved in flavonoid biosynthesis, such as UDP glucose-flavonoid-3-O-glucosyltransferase (UFGT) were exclusively up-regulated in red leaves. In addition, cellular functions involved in stress response (glutathione-S-transferase, Pathogen-Related) and sugar metabolism, such as three threalose-6-phosphate synthases, were activated in senescent red leaves. In conclusion, data suggests that P. cerasifera red genotypes can regulate a set of genes and molecular mechanisms that cope with senescence, promoting more advantages during leaf ontogenesis than compared to the green ones.

Background Microgreens (i.e. tender immature greens) are a popular alternative to sprouts (i.e. germinating seeds) because of their higher content of vitamins, carotenoids and phenols, as well as their lower content of nitrates. Their nutritional value can be improved by biofortification, which increases micronutrient levels during plant growth. Because selenium (Se) plays a significant role in antioxidant defense, biofortification with Se is a good way of improving the nutritional quality of sprouts and microgreens. The present study investigated the production of Se-fortified microgreens from Se-enriched seeds of sweet basil (Ocimum basilicum L.). These microgreens could be used as new beneficial dietary supplements. Results Basil plants were grown in a nutrient solution, containing 0 (control), 4 or 8 mg Se L-1 as sodium selenate, to full maturity. Seeds accumulated a high amount of Se and were then used to produce microgreens. The germination index was higher in the seeds from Se-treated plants and the microgreens were enriched in Se. The antioxidant capacity of Se-fortified microgreens was higher compared to the control. Conclusion The production of microgreens from Se-enriched seeds could comprise a good system for obtaining microgreens with a high nutritional value. Basil plants treated with Se could be used to produce both Se-fortified leaves and microgreens. © 2019 Society of Chemical Industry.

Selenium (Se) enrichment of plants seems effective in enhancing the health-related properties of produce and in delaying plant senescence and fruit ripening. The current study investigated the effects of Se on tomato fruit ripening. Tomato (Solanum lycopersicum L.) plants were grown in hydroponics with different Se-enriched nutrient solutions. Se, as sodium selenate, was added at a rate of 0 mg LSelenium was absorbed by roots and translocated to leaves and fruit. Enrichment with Se did not significantly affect the qualitative parameters of fruit at commercial harvest; instead it delayed ripening by affecting specific ripening-related processes (respiration, ethylene production, color evolution) during postharvest. In the current experiment 100 g of tomato hydroponically grown with a 1.5 mg Se LThe cultivation of tomato plants in a Se-enriched solution appeared effective in producing tomato fruit with improved performance during storage and postharvest shelf life, and also with greater potential health-promoting properties. © 2018 Society of Chemical Industry.

Anthocyanic morphs are generally less efficient in terms of carbon gain, but, in turn, are more photoprotected than anthocyanin-less ones. To date, mature leaves of different morphs or leaves at different developmental stages within the same species have generally been compared, whereas there is a lack of knowledge regarding different stages of development of red vs. green leaves. Leaves (1-, 7-, and 13-week-old) of red- (RLP) and green-leafed (GLP) Prunus in terms of photosynthetic rate, carbon metabolism and photoprotective mechanisms were compared to test whether anthocyanin-equipped leaves perform better than anthocyanin-less leaves and whether photoprotection is the primary role of epidermally-located anthocyanins, using for the first time a recently-developed parameter of chlorophyll fluorescence (qPd). GLP leaves had a higher photosynthetic rate in 1- and 7-week-old leaves, but RLP leaves performed better at an early stage of senescence and had a longer leaf lifespan. Anthocyanins contributed to leaf photoprotection throughout the leaf development, but were tightly coordinated with carotenoids. Besides photoprotecting, we propose that epidermal anthocyanins may be principally synthetized to maintain an efficient carbon-sink strength in young and senescent leaves, thus extending the RLP leaf lifespan.

Peat is the most representative component in the preparation of growing media used in horticulture. However, environmental issues and increased production costs, related to peat extraction and commercialization, are stimulating the use of new materials and technologies as alternatives to peat-based growing media. Among other locally-produced materials, green compost is one of the most promising alternatives for peat substitution although its variability in terms of physico-chemical characteristics represents the main constraint. In the present work, two composts, differing in terms of the initial composting raw materials, were evaluated for peat substitution and their influence on plant growth and quality, nutrient and water uptake, and gaseous exchange activity. A bedding plant (geranium), cultivated in an intensive growing system, was chosen as the test plant and 100% peat as the control. During the greenhouse experiment, plants were grown in five different growing media, i.e. only peat, 30% and 50% peat volume replaced by the two composts. Growing medium characteristics, plant growth and biometric parameters, water and nutrient uptake, and gaseous exchange activity were evaluated as crop performance indicators. The green compost derived from mixed raw material negatively influenced plant nutrition and photosynthesis, thus significantly reducing plant biomass accumulation and quality. The green compost derived from selected material was found to be a valuable growing medium for peat substitution. This thus supports the widespread opinion that high-quality compost can be produced through the selection of composting material.

Iris spp. rhizomes are used in cosmetics and perfumery thanks to the presence of irones, violet-scented ketonic compounds. Between the several Iris species, Iris pallida Lam. is rich in irones and is the most valuable. In Tuscany, the cultivation of I. pallid is an integral part of the rural tradition. The aim of the research is to study the possibility of producing I. pallid plants by micropropagation and to overcome some critical factors of traditional cultivation. This study was based on the induction of somatic embryogenesis from flower buds and from leaf tissues of in vitro plantlets. Results demonstrated that the most suitable factors to begin the induction of embryogenic callus were the medium, a modified MS medium named i1B containing 0.1 mg L-1 Kinetin (Kin) and 1 mg L-1 2,4-dichlorophenoxy acetic acid (2,4-D), and the explant, the petal hafts (the base of the petals) of the flower buds. Another medium, named i1A, containing 1 mg L-1 Kin and 1 mg L-1 2,4-D was the most appropriate for the successive subcultures of the embryogenic callus among the tested ones. To induce and maintain embryo formation, an expression medium, named i2, containing a modified Knudson C macro elements, 1 mg L-1 Kin and 0.1 mg L-1 indole-3-butyric acid (IBA) was efficient. The protocol was subsequently improved with the use of in vitro microplant leaf tissues for the production of embryogenic callus. Transferring the embryos onto a modified MS medium named i3 with 0.1 mg L-1 of 6-benzyladenine (BA) and ?-naphthaleneacetic acid (NAA), allowed us to obtain microplants to acclimatize ex vitro. As regards the presence of irones precursors, the HPLC chromatographic profile of the rhizomes from micropropagated I. pallida plants after acclimatization in open field, was comparable to that of rhizomes from mother plants cultivated in the place of origin.

Biofortification of edible crops with selenium (Se) may represent an alternative system for providing selenium in the human diet. The aim of the present study was to provide insights into the ability of basil plants grown in hydroponics to take up Se from the growth substrate, and to study the effects of Se concentration on plant growth and Se accumulation. The addition of sodium selenate at the rates of 4, 8 and 12 mg Se L −1 to the nutrient solution induced a dose-dependent increase in the Se uptake rate. Se was absorbed by the roots and translocated to the above-ground organs and accumulated particularly in the leaves, without affecting the biomass production of the plants. Se concentration increased during seedling growth, was highest in the younger leaves, and then declined before or upon flowering. The results clearly highlight the potential of selenizing basil shoots through the addition of selenate to the nutrient solution. This study provides crucial information for assessing the appropriate Se dosage in order to obtain the desired Se content in leaves, and the best harvest time to obtain the highest leaf Se concentration in basil. The addition of selenate to the nutrient solution could be an efficient system for providing enriched basil plants.

The ability of some crops to accumulate selenium (Se) is crucial for human nutrition and health. Selenium has been identified as a cofactor of the enzyme glutathione peroxidase, which is a catalyzer in the reduction of peroxides that can damage cells and tissues, and can act as an antioxidant. Plants are the first link in the food chain, which ends with humans. Increasing the Se quantity in plant products, including leafy and fruity vegetables, and fruit crops, without exceeding the toxic threshold, is thus a good way to increase animal and human Se intake, with positive effects on long-term health. In many Se-enriched plants, most Se is in its major organic form. Given that this form is more available to humans and more efficient in increasing the selenium content than inorganic forms, the consumption of Se-enriched plants appears to be beneficial. An antioxidant effect of Se has been detected in Se-enriched vegetables and fruit crops due to an improved antioxidative status and to a reduced biosynthesis of ethylene, which is the hormone with a primary role in plant senescence and fruit ripening. This thus highlights the possible positive effect of Se in preserving a longer shelf-life and longer-lasting quality.

Lettuce (Lactuca sativa L.) var. ‘Lollo rossa’ was grown in a floating hydroponic system. Six saline treatments were used, adding different concentrations of calcium chloride (CaCl2) to the nutrient solution (mol m−3): 0, 2.5, 5, 10, 15, 20, which, respectively, corresponds to an electrical conductivity of 2.5, 3, 3.5, 4.4, 5.4, 6.3 dS m−1. In plants subjected to moderate salinity stress the growth was not affected and yields were not statistically significant; however, the data shows a slight decline in 20 mol m−3 CaCl2 treatments. Nitrate contents in the leaf decreased when the concentration of CaCl2 in nutrient solutions increased. Other quality parameters were positively affected by treatment with CaCl2, especially at moderate concentrations such as 5 and 10 mol m−3. In fact, both the content of phenols and antioxidant power increased at moderate salt concentrations and reduced in the treatment with 20 mol m−3 CaCl2. The content of chlorophyll and carotenoids were not affected by treatment even at hig...

Species-rich herbaceous communities, such as prairies, steppes, meadows and pastures, have a high biodiversity value. There is considerable interest in the loss of these complex ecosystems and the associated biodiversity, due to intensive agriculture, pasture abandonment, pollution, and climate change. These habitats can constitute models, in terms of landscape management and plant community composition, that can be successfully duplicated in anthropized areas in order to mitigate the adverse effects of human activities in the city and enhance the biotic component. The idea is to revegetate urban degraded soil with aesthetically pleasing wildflower meadows, while increasing biodiversity, creating a habitat and conserving the local flora, with low management cost. In urban sites seed mixtures containing a high percentage of native and exotic herbaceous flowering plants have been successfully used. We review the factors affecting the ecological aspects of species-rich herbaceous communities in disturbed environments and urban landscape design. The review addresses the use of these communities in urban green areas for recreation, socialization and environmental education.

Solanum lycopersicum L. (tomato) is a very important fruit vegetable with high economic importance and nutritional impact on the consumers worldwide. Moreover, tomato fruits are an important source of nutraceutical compounds. This work describes the physiological diversity affecting the ripening process that yields variation in fruit pigmentation with regard to anthocyanins compounds for one non-anthocyanin-accumulating (Ailsa Craig) and two anthocyanin-accumulating tomato genotypes (anthocyanin fruit type, low pigment accumulation, and Sun Black, high pigment accumulation). Using tomato fruits obtained by traditional breeding the present study reported modified hormone equilibrium at different ripening stages. This phenomenon can be considered as a consequence of the different pattern in the anthocyanins accumulation in fruits. Moreover, the fruit genotype showing the highest pigment accumulation appear more firm at the commercial stage. Overall, these results showed the considerable potential of exploiting natural genetic diversity to obtain tomatoes with higher levels of anthocyanins, and different quality traits such as colour and firmness.

Growing traditional ornamental plants in urban soil often fails, due to the low quality of the soil modified by anthropic activities. The aim of this research was to study the behavior of herbaceous plants suitable for sowing in mixes in order to revegetate soils in different urban environments. Three different mixes of herbaceous plants were studied: N (native) was composed of autochthonous species, US (urban short) and UT (urban tall) were composed of both autochthonous and allochthonous species. Plant height was lower than 60 cm in N and US, and above 60 cm in UT. Each mix was sown in three randomized plots and each plot was mown at three different times: 110, 140 and 170 days after sowing (early, mid and late season respectively). Number of plants per square meter, plant height and biomass were recorded at each mowing time. In order to assess how well the plants would establish themselves we calculated the Shannon diversity index, the evenness of species and Simpson's index of dominance. The N mix composed of autochthonous species resulted to be well-balanced with an equal number of annual and perennial species grown. The presence of annuals and perennials made the community richer and the individual plants more evenly distributed. The best mowing time to improve diversity in all the mixes was late-season. Our study suggests that native species from southern Europe are suitable for creating diverse herbaceous communities for ornamental purposes, thus enhancing the role of Mediterranean urban areas in the conservation of biodiversity.

A composite model was developed for water and mineral relations of greenhouse tomato (Solanum lycopersicum L.) cultivated in semi-closed or open soilless (rockwool) culture. The model simulated on a daily basis: (i) the evolution of crop leaf area index and water uptake using empirical equations; and (ii) the variations of ion concentrations and electrical conductivity (EC) in the recirculating or drainage nutrient solution using a mass balance equation based on the concept of ion uptake concentration. The model was calibrated using measured data collected in previous works and validated in two independent experiments carried out in 2005 and 2007. In these experiments, different fertigation strategies were tested using nutrient solutions prepared with saline (9.5molm^-^3 NaCl) water. In semi-closed systems, the recirculating nutrient solution was discharged whenever EC exceeded a pre-defined threshold (4.5, 6.5 or 7.5dSm^-^1, depending on the experiment) and/or nitrate (NO"3^-) concentration was lower than 1.0molm^-^3. This value was selected because 20mgL^-^1 (1.43molm^-^3) is the limit imposed to NO"3^- concentration of wastewater discharged into surface water by the current Italian legislation. In open system, the crop was irrigated with full-strength nutrient solution without recirculation of drainage water. In both years, fertigation strategy did not affect significantly crop growth, fruit yield and water uptake. In most cases, simulations of seasonal crop water uptake were within the confidence interval of the measurements with a maximum deviation of -6%. The model predicted acceptably the time course of EC and ion concentration in recirculating (semi-closed systems) or drainage (open system) nutrient solution. A moderate discrepancy between observations and simulations was found for NO"3^- concentration, especially during the first weeks after planting. In general, there was a good agreement between simulated and measured values of total water and nitrogen (N) use. In 2005, simulated values of N uptake in semi-closed systems were -11% to +5% of measured values. Prediction of N uptake was less accurate in 2007, when simulated values were +17% of measured values. In open system, the model underestimated N uptake (-17%) mainly due to overestimation of N leaching (+6%). Applications of the composite model for operative management of soilless culture and for scenario analysis are discussed.

BACKGROUND:Inrecentyearstheconsumptionofminimallyprocessedleafyvegetableshasbeenincreasing.Atthesametime food quality and its effects on human health have become crucial issues. Since selenium (Se) is an important microelement due to its ability to defend human organisms against free radicals, we investigated the effects of Se on chicory and lettuce production, and assessed the feasibility of a floating system as a method of producing Se-enriched vegetables. RESULTS: The addition of 0.5 and 1.0 mg Se L −1 to the nutrient solution resulted in an increase in the selenium concentration in the leaves, which had a positive effect on the plant yield. Selenium was generally effective in decreasing the production of ethylene and phenylalanine ammonia lyase (PAL) activity, even though a seasonal effect seemed to be present, consequently improving the quality of leafy vegetables and the shelf life in both species. The amount of Se accumulated in plants grown in thenutrientsolutioncontaining0.5 mgSekg −1 couldprovidetherationalSeintakeforhumannutritioninaccordancewiththe recommended dietary allowance (RDA) guidelines. CONCLUSIONS: The addition of Se in an utrient solution can be au seful system for providing enriched leafy vegetables. The floating system can be used to modulate the availability of Se in nutrient solutions and to grow vegetables with the optimal Se content for humanhealth. c � 2009 Society of Chemical Industry

Public green areas represent a heavy burden for local Councils and they are often neglected due to a lack of resources. In fact traditional horticulture requires a large amount of agronomical and economical input to succeed. Since the 1970s in northern Europe and USA it has been common practice to manage roadsides, roundabouts and derelict urban areas with mixed plantings of annual and perennial wildflowers with a consequent large reduction in input (water and chemicals). In the Mediterranean regions very few studies have been carried out on this subject, in spite of the more serious water shortage. The Agency for the Development and Innovation in Agriculture and Forestry (ARSIA) of Tuscany, Italy, has financed the project "Production and strategic employment of wildflowers for the beautification and environmental regeneration of derelict, urban and peri-urban areas". Its aim was to study the ecology of some wildflowers and their suitability for naturalistic plantings and to promote a more sustainable urban horticulture. Twelve plantings were set up in different areas of Tuscany in cooperation with town councils, schools and motorway companies. Soils were sampled to determine their physical and chemical characteristics. The plantings were monitored up until the flowering period and sustainable management was employed. Most of the species thrived, while the soils turned out to be unsuitable for traditional ornamental plantings. Most of the species flowered in the first and second year. The use of local wildflowers in naturalistic plantings proved to be a low-cost technique for managing green areas, contributing to biodiversity, and a useful tool for the conservation of species

The paper reports an aggregated model for the water requirements (W) of greenhouse tomato grown in spring or summer�autumn season in closed (recycling nutrient solution) rockwool culture. A series of experiments were conducted between 2000 and 2003. In each experiment, two different nutrient solution treatments were established in a randomized block design, with three replicates. The nutrient solutions differed only for the concentration of NaCl and the electrical conductivity (EC), which were, respectively, 10 mol m-3 and 3.0 dS m-1 in T10 treatment, and 20 mol m-3 and 3.9 dS m-1 in T20 treatment. Fruit yield was 10.1 ± 0.3 and 9.6 ± 0.2 kg m-2 in T10 and T20 treatments, respectively, and the difference was not significant. Two diverse sub-models were developed, for the daily crop water uptake (WU) and for the leaching requirement (LR) in dependence of a maximum tolerable sodium (Na+) concentration in the recycling nutrient solution. WU was simulated using a simple regression model, which considered the radiation actually intercepted by the crop. The determination coefficient for the linear regression between predictions (P) and measurements (M) of daily WU was 0.853 (n = 581), with the slope (0.963) and the intercept (-0.053) of the linear regression not significantly different, respectively, from 1 and 0. There was a good agreement between P and M values of WU, with a mean deviation between P and M of 2 ± 10%. The modelling of LR was less satisfactory, especially in spring crops; the average value for P and M values of LR was 0.30 and 0.28, respectively. The P�M residual averaged 11 ± 25% for LR and 13 ± 26% for the volume of drainage water or runoff (WR). Nevertheless, the aggregated model accounted well for W with an average deviation of 4 ± 11% between P and M. The sensitivity analysis showed the great influence of radiation on W and suggested that the quality of irrigation water (namely, NaCl concentration) is more relevant for crop water use efficiency than any other factor considered by the LR model, including the affinity of the plant for the salts contained in the nutrient solution.

Disturbance and soil fertility are some of the main drivers influencing the dynamics of herbaceous communities. Such communities are among the most biodiverse and represent a model for introducing species-rich and low-input green systems into anthropized environments, at the same time creating opportunities for conservation and restoration. Trials were set up to evaluate the effects of compost and mowing on the dynamics of purpose-sown herbaceous vegetation, inspired by the phytocenosis spontaneously growing in the nearby rural areas. Both soil properties (organic carbon, total nitrogen content, bulk density and pH) and plant species characteristics (density, biomass, height, functional traits) were determined. Our results showed that the addition of compost countered the soil compaction process with a positive effect on soil bulk density. Irrespective of compost and mowing, the amount of carbon and nitrogen in the soil was greatly influenced by the vegetation. Early season mowing increased the Shannon index and decreased the Simpson index, while over the years, with the increase in productivity, biodiversity decreased. Compost and mowing had a species-specific effect on seed mass and plant height.

In closed-loop soilless culture, one of the most relevant problems may be the accumulation in the recirculating nutrient solution of ions contained in irrigation water that are not or scarcely absorbed by the plants (e.g. Na, Cl) In order to verify the possibility to reduce the rate of recirculating water salinisation by means of subirrigation, an experiment was carried out in the spring of 2002 and 2004, with tomato plants (cv. Jama) grown in glasshouse and watered by conventional drip irrigation (D) or by subirrigation (trough bench system; S). The plants were cultivated in pots filled with a peat-perlite substrate for approximately 3 months and fed with complete nutrient solution, which was prepared with fresh water containing 10 mol m−3 NaCl; the nutrient solution in the collecting tank was replaced when the value of electrical conductivity (EC) exceeded 6.0 dS m−1. Water and nutrient crop use, salt accumulation in the substrate, and fruit yield were monitored. In S culture, the composition and EC of the recirculating nutrient solution changed slightly, while in D treatment there was a fast water salinisation that made it necessary to flushed out the nutrient solution in six different occasions, with consequent loss of water and fertilisers. In S culture, the upward water movement in the substrate, coupled with selective mineral uptake by the roots, caused salinity build-up in the upper region of the substrate, which was associated with Na+ accumulation. No significant influence of irrigation methods on fruit yield and quality was observed. These findings suggest that subirrigation can be a tool to reduce the water consumption and nutrient runoff in closed-loop substrate culture of tomato conducted with saline water.

This paper presents a simple model for the changes in ion concentration and electrical conductivity (EC) of the recirculating nutrient solution in a closed-loop soilless culture of tomato (Lycopersicon esculentum Mill.). The model was designed on the basis of a balanced equation for plant nutrient uptake: for macrocations (K+, Mg2+ and Ca2+), a linear dependence of concentration on crop water uptake was assumed, while for non-essential ions, such as sodium (Na+), a non-linear function was used. The model was developed for closed-loop hydroponic systems in which crop water uptake (namely, transpiration) is compensated by refilling the mixing tank with complete nutrient solution. In these systems, EC gradually increases as a result of the accumulation of macro-elements and, principally, of non-essential ions, like Na+, for which the apparent uptake concentration (i.e., the ratio between nutrient and water uptake) is lower than their concentration in the irrigation water. For model calibration, data...

The article presents a number of empirical models for predicting the macronutrient uptake of melon plants grown in nutrient film technique under environmental conditions of plastic greenhouse in the Mediterranean region. Models were developed according to two statistical procedures: stepwise multiple regression (MR) and canonical correlation (CC). Independent variables considered by the modeling were global radiation and air temperature in the greenhouse, crop age (expressed as number of weeks from planting, growing degree days and photo-thermal units), and the uptake of water as well as of a guide-ion that could be routinely measured manually by means of easy-to-use test-kits or automatically with chemo-sensors. The best models, as selected on the basis of determination coefficient and the correlation coefficient for the relationship between residuals and observations, explained only 36-72% of the variance in the mineral uptake, depending on the considered nutrient. Moreover, the models were conservative, as predicted values tended to be less extreme with respect to the observed values and the residuals were positively correlated to the observations. The results of MR and CC were similar, although the validation of the models derived from CC produced better results compared to MR. The models provided evidence for the close relationship between ion and water uptake and indicated the possibility to predict the crop mineral requirements on the basis of the consumption of a guide-ion (i.e., nitrogen).

One approach to reduce the waste of water and chemicals in hydroponics and the resultant environmental pollution is the development of a drain nutrient solution reuse system, which is based on the cultivation of plants with successively higher salt tolerance. In a cascade cropping systems salt-tolerant crops would be cultivated with salt-enriched nutrient solutions flushed out of growing systems with less tolerant species. The drainage nutrient solution becomes progressively more saline as each successive species is grown and it is finally discarded when the salinity is too high for cropping, but the nutrient content (in particular that of nitrate and phosphate) is low and, therefore, environmentally-safe. An experiment was carried out to evaluate the feasibility to use a cascade cropping system (based on recirculating nutrient solution culture) with a round-fruit tomato as a drainage (exhausted) water-donor crop and a cherry tomato as a drainage water-user crop, in order to limit the fertiliser losses in the environment with a contemporaneous economic production. In this study, it was also included a treatment involving a tomato culture irrigated with a synthetic drainage water (prepared with fresh water and salts) with the aim to distinguish the genuine effects of high salinity of exhausted solution from those that may be related to the presence of potentially toxic root exudates. The results demonstrated that cherry tomato may be grown with exhausted nutrient solutions that are flushed out from a culture of more salt-sensitive tomato cultivar, thus reducing the environmental impact that is provoked by semi-closed soilless systems.

Selenium appears to be effective in promoting plant development and delaying the onset of senescence. Besides the effects on the metabolism and physiology of different crops, controlled increases in Se concentrations enhance the health-related properties of the produce. To study the effects of selenium on fruit composition and ripening physiology, an experiment was carried out on tomato ( Solanum lycopersicum ) plants grown in hydroponics. Sodium selenate was added to the nutrient solution at a rate of 0 (control) and 1 mg Se L −1 . The selenium added to the nutrient solution was absorbed by the roots, and the Se concentration was higher in leaves than in fruits. The addition of Se did not significantly influence the cumulative yield of tomato plants, but a delay in the onset of fruit ripening was detected, and the harvesting of control plants began earlier than in Se-treated plants. The addition of Se did not significantly affect the qualitative parameters with the exception of β-carotene content, which was lower in red ripe fruit treated with selenium. Since β-carotene accumulation is a ripening-related event in tomato, the lower amount of this compound may be associated with a general delay of ripening. This is confirmed by the reduced biosynthetic rate of ethylene, observed in Se-treated tomatoes, which also showed a reduced rate in colour change. This thus confirmed that ripening-related processes, such as the degradation of chlorophyll and the synthesis of carotenoids, are affected by selenium - with potential benefits in terms of storage and shelf-life. Our results showed that 100 g of tomato hydroponically grown with a nutrient solution supplemented with Se provided a total of 58 μg Se. Thus, the daily consumption of 100 g of enriched tomato does not lead to Se toxicity, but can even provide a rational Se supplementation. This suggests that the addition of Se in a nutrient solution is useful for producing tomatoes with greater beneficial properties for human health.

The effects of NaCl salinity and foliar application of calcium nitrate on the biomass production, water relations and mineral uptake were investigated in celery ( Apium graveolens L., cv. Istar) plants grown by the nutrient film technique (NFT) under greenhouse conditions during winter. Plants were supplied with nutrient solutions containing different concentrations of NaCl for a final electrical conductivity (EC) of 2.0, 6.0 and 10.0 mS cm −1 . Increasing salinity had little or no influence on plant growth, water relations, and the tissue concentration of macronutrients, but it enhanced the uptake of Na and Cl, which accumulated markedly in the mature leaves and to a much lesser extent in the actively growing leaves. Salinization also improved the yield quality by reducing the accumulation of nitrate–nitrogen and the incidence of `blackheart' in young leaves. `Blackheart' was completely prevented by foliar application of calcium nitrate. To conclude, celery grown in NFT exhibited substantial tolerance to NaCl salinity and, therefore, it could be used to exploit saline water in soilless culture. These findings also suggest that a proper management of the salt concentration of the nutrient solution can provide an effective tool to improve the quality of celery with little effect on yield.

Irrigation is now recognized as an important component in the agriculture economy of Mediterranean regions. As practiced by many growers, it is often based on traditional application methods that fail to measure the supply of water needed to satisfy the variable requirements of different crops. In order to achieve more profitable and sustainable cropping systems, it is essential to modernize existing irrigation systems and improve irrigation water use efficiency (WUE). Up-to-date methods of irrigation should likewise be based on sound principles and techniques for attaining greater control over the soil-cropwater regime and for optimizing irrigation in relation to all other essential agricultural inputs and operations. Accurate predictions of crop water requirements are necessary for an efficient use of irrigation water in container crops cultivated both outdoors and in greenhouse. Irrigation scheduling (IS) has conventionally aimed to achieve an optimum water supply for productivity, with soil or container water content being maintained close to field capacity. Different approaches to IS have been developed, each having both advantages and disadvantages but despite the number of available systems and apparatus, not entirely satisfactory solutions have been found to rationalize IS, assuring optimal plant growth with minimal water use (Jones, 2004). Many growers, especially in the Mediterranean regions, use simple timers for automated irrigation control of containerized crops and scheduling is based on their own experience. According to Baille (2001), the available advanced methods for controlling irrigation at the short-term decision level are based either on climate or on soil moisture status. In the climate-based method, crop water use is computed by means of algorithms that estimate ET using meteorological data. The Penman-Monteith (PM) equation (Monteith, 1973; Stanghellini, 1987) and its simplified versions (e.g. Baille et al., 1994) have been used for predicting ET in many container-grown crops, where substrate evaporation losses are generally negligible and ET is determined almost exclusively by crop transpiration. The soil-based method uses the measurement of soil water potential or content. A combination of climate and soil-based methods would be recommended, because this allows a check of the coherence and concordance between data regarding soil moisture and crop water demand thus making IS more reliable and accurate. In this chapter, different approaches for ET modelling in container crops grown both in greenhouse and outdoor will be described and its application to IS is briefly discussed.

One nonanthocyanin-accumulating (Ailsa Craig) and three anthocyanin-accumulating tomato genotypes (Anthocyanin fruit type, Atroviolaceum, and Sun Black) were analyzed to assess differences in their carotenoid and anthocyanin levels and color and to evaluate the effects of nutrient solutions with different salt concentrations on these parameters. The carotenoid content of control Atroviolaceum tomatoes was ca. 2-2.5-fold higher relative to the other two types, and the color of its puree could be visually distinguished from those of other genotypes. Salinity stress led in some cases to a 2-3-fold increase in the lycopene content. Saline treatment increased the accumulation of total anthocyanins in fruits of Sun Black (2-fold increase), while it reduced it in fruits of Anthocyanin (10-fold decrease). In general, the treatment increased the differences in color of different purees. These results indicate that salinity stress can lead to similar or higher increases in tomato carotenoids than those achieved by genetic engineering. In addition, these changes were accompanied by visually discernible color differences in tomato products. Our findings show the considerable potential of exploiting saline soils to obtain tomatoes with higher levels of secondary metabolites like carotenoids and anthocyanins.

The Iris genus includes about 300 species. Iris spp. rhizomes are used in cosmetics and perfumery thanks to the presence of irones, violet-sciented ketonic compounds. The rhizomes of the Italian Iris are much appreciated and requested by the perfume and cosmetics industries and are often preferred to those of other origins (Morocco, India, China). Among the different species of Iris, Iris pallida Lam. is the species most valuable and rich in irones. In Tuscany, the typical areas of cultivation of I. pallida are located on the hills of Chianti (Firenze) and Pratomagno (Arezzo). The technique of micropropagation, increasing the plant production for the Iris cultivation in the region of origin, might allow to obtain a greater amount of rhizomes to the extraction of aromatic essences. This study is based on the induction of somatic embryogenesis from tissues of I. pallida adult plants harvested in the endemic area of Pratomagno (Arezzo). In this work we have developed different types of sterilization procedures for I. pallida explants (rhizomes or immature flower buds). These explants were tested for different types of media to induce embryogenetic callus and the development of somatic embryos.

Aerosol marine strongly affects the growth and development of urban, garden and landscape plants. Few studies have focused on the effects of sodium chloride on plant growth, which is usually applied through irrigation water or substrate media. Even less information is available on the eco-physiological responses of plants to marine aerosol. The aim of this work was to evaluate the physiological responses of different plant species to seawater nebulisation treatments. Plant species that are commonly used along sea fronts were selected as being potentially useful for the study. Plants were bought from a local nursery and included: Acacia cultriformis, Callistemon citrinus, Carissa edulis microphylla, Gaura lindheimeri, Jasminum sambac, Westringia fruticosa. Plants were placed in a randomised block design in a greenhouse and treated for 5 s with seawater or irrigation water (control) using a nebulisation system once every day for 77 days. In the seawater aerosol-treated plants, the following parameters were monitored: leaf area damage using an image analysis tool, chlorophyll a fluorescence, hormonal changes and cation concentrations. We found that seawater aerosol treatment leads to: (i) leaf necrosis; (ii) chlorophyll loss; and (iii) a decrease in chlorophyll a fluorescence. The ion exclusion mechanism might have played a key role in the tolerance mechanism. Ethylene production increased in all species as a good biomarker and the strong increase in ABA content in the sensitive species may play a role in the plant's adaptation to stress. The chlorophyll a fluorescence parameters such as Fv/Fm and the performance index were the most affected by treatment and led to a screening sensitive (A. cultriformis and G. lindheimeri) and tolerant (W. fruticosa) species.

In order to study the effects of repeated phosphate fertilization under protected cultivation, tomato (Lycopersicon esculentum Mill.), radish (Raphanus sativus L.), celery (Apium graveolens L.), and lettuce (Lactuca sativa L.) plants were grown in subsequent cycles on the same substrate and fertilized with increasing amounts of superphosphate containing varying amounts of heavy metals. The accumulation of metals in the soil and the consequent increased uptake of metals by plants did not result in any reduction in the marketable production. The reduced plant yield observed in lettuce and in radish with the increase in the addition of superphosphate was most likely due to the increased salinity of the growth substrate, which affected the metabolic processes of the plants. The high concentration of salts as a result of the addition of high amounts of phosphorus fertilizer made it unadvisable to reuse the substrate under the experimental conditions adopted.