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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.

Selenium (Se) biofortification of plants has been recognized as a good strategy to improve the nutritive value of vegetables and increase Se daily intake in humans. Identifying the most appropriate method to enrich plants is a key issue in the biofortification process. We tested a biofortification technique that produces Se enriched seedlings for transplant, yet barely modifies conventional cultivation techniques. Lettuce (Lactuca sativa L.) and sweet basil (Ocimum basilicum L.) were exposed to selenium by adding 0, 1 and 3 mg L−1 (lettuce) and 0, 2 and 3 mg L−1 (basil) of Se, as sodium selenate, to the growing substrate immediately after sowing. When seedlings reached an appropriate size, they were transplanted into the open field, and plants were grown until maturity. Lettuce and basil seedlings accumulated selenium without any reduction in leaf biomass at maturity. The highest dose of Se induced a higher antioxidant capacity and flavonoid content in both species at both sampling times. At maturity, biofortified plants still showed a higher leaf Se content compared to the control, and would be able to provide from 10% to 17% (lettuce) and from 9% to 12% (basil) of the adequate intake (AI) of Se.

At appropriate concentrations, selenium (Se) is beneficial for humans. Tomato appears to be one of the best commodities for producing Se-biofortified fruit for dietary supplementation. To assess the efficacy of different enrichment protocols, a total of four on-plant and off-plant trials were conducted. Hydroponically grown tomato plants were sprayed with: (i) chemically synthesized Se nanoparticles (SeNPs) at 0, 1, and 1.5 mg Se L−1 at blooming; (ii) sodium selenate (Na2SeO4) or SeNPs solution at 0, 5, and 10 mg Se L−1 when the fruit entered the immature green stage. With regard to the off-plant trials, harvested mature green fruit were immersed in Na2SeO4 solution: (iii) at 0, 5, 10, and 20 mg Se L−1 for 15 s under a vacuum; (iv) at 0, 40, and 80 mg Se L−1 for 1 h. Spraying Na2SeO4 induced higher Se accumulation in plant tissue than SeNPs: both protocols were effective in enriching tomatoes. Postharvest Se enrichment via vacuum infiltration caused textural damage, whereas passive immersion in solution induced fruit Se accumulation without causing any damage. SeNPs appear to be quantitatively less effective than Na2SeO4, but might be environmentally safer. Elemental Se carried by NPs may be more easily incorporated into organic forms, which are more bioavailable for humans. Passive immersion may represent an alternative Se-enrichment strategy, allowing for the biofortification of harvested tomato fruit directly, with lower risks of environmental pollution.

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

Foliar spray with selenium salts can be used to fortify tomatoes, but the results vary in relation to the Se concentration and the plant developmental stage. The effects of foliar spraying with sodium selenate at concentrations of 0, 1, and 1.5 mg Se L−1 at flowering and fruit immature green stage on Se accumulation and quality traits of tomatoes at ripening were investigated. Selenium accumulated up to 0.95 µg 100 g FW−1, with no significant difference between the two concentrations used in fruit of the first truss. The treatment performed at the flowering stage resulted in a higher selenium concentration compared to the immature green treatment in the fruit of the second truss. Cu, Zn, K, and Ca content was slightly modified by Se application, with no decrease in fruit quality. When applied at the immature green stage, Se reduced the incidence of blossom-end rot. A group of volatile organic compounds (2-phenylethyl alcohol, guaiacol, (E)-2-heptenal, 1-penten-3-one and (E)-2-pentenal), positively correlated with consumer liking and flavor intensity, increased following Se treatment. These findings indicate that foliar spraying, particularly if performed at flowering stage, is an efficient method to enrich tomatoes with Se, also resulting in positive changes in fruit aroma profile.

The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf lettuce to investigate the effects on plant growth, leaf quality, and leaf I and Se accumulation of adding potassium iodide and sodium selenate, separately and simultaneously, to the nutrient solution in a floating system and aeroponics. The effect of I and Se biofortification on post-harvest quality of lettuce leaves was also evaluated. Our results evidenced that the Se and I treatments increased the content of the two microelements in lettuce leaves without any negative interactions in the plants, when applied either separately or simultaneously. Both hydroponic systems proved to be suitable for producing Se and/or I enriched lettuce. Biofortification with Se was more effective when performed in aeroponics, whereas I biofortification was more effective in the floating system. Quality of leaves during post-harvest storage was not affected by neither of the treatments. Lettuce leaves enriched with 13 µM Se and 5 µMI could be good dietary sources of Se and I without inducing toxic effects in humans.

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.

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.

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...

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.

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

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.

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.

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.

Soils characterized by low fertility, the absence of structure, low organic matter content, and a high content of alien materials can be valuable for the creation of species-rich vegetation communities. In fact such communities are often associated with low fertility soils, especially regarding nitrogen levels. Very few studies have been carried out in southern Europe on the cultivation techniques of native herbaceous species and on how to create and maintain semi-natural herbaceous communities in relation to soil properties. This study is aimed at determining the ecological characteristics and the cultivation needs of 26 herbaceous species native to Italy and southern Europe in order to identify their landscape potential in low-maintenance conditions. Mono-specific plots were set up in three different soils. The criteria for choosing the species were based on their capacity to thrive in poor dry soils and to tolerate stress and disturbance. In addition the criteria were also based on their ornamental value, including the ability to attract insects. Annuals, biennials and perennials were included in the study. Seedling emergence and plant biomass were determined. The percentage of field establishment and biomass appeared to be affected by the physical and chemical characteristics of the soil. Species were classified as having low or medium-high seedling emergence in the field assessment. Calamintha nepeta, Campanula rapunculus, Dianthus carthusianorum, Verbascum blattaria, Nigella damascena, Salvia verbenaca, and Scabiosa columbaria developed low biomass. Thus they were more suitable for long lasting plantings in unfertile soils (e.g. land restoration). Daucus carota, Matricaria chamomilla, Papaver rhoeas, Verbascum sinuatum, Coleostophus myconis and Senecio erraticus produced high biomass especially in the most fertile soil. They are more likely to survive competition in highly productive soils.

Two methods to control nutrient delivery to greenhouse melon plants grown with the nutrient film technique were compared: a conventional control system based on the adjustment of electrical conductivity (EC) of the recirculating nutrient solution, and a programmed nutrient addition, which was based simply on pre-established weekly supply of N, P and K without any attempt to maintain constant values of nutrient concentration and EC. The method to control nutrient supply did not influence significantly fruit yield or quality, but the nutrient addition reduced the crop consumption of water, N, P and K by 40–60% with respect to the EC method.

The influence of growing season on some physiological and biochemical variates related to fruit yield and quality was investigated in melon (Cucumis melo L.) plants cultivated in nutrient film tech...

Selenium is an essential element for animal nutrition [3], but the metabolic significance of Se in plants is not well known. In the genus Astragalus Se has been recognized as micronutrient and its effect on plant growth is different in accumulator and non accumulator species: in the former Se stimulates growth, whereas in the latter plant growth is strongly inhibited. Shrift [2] hypothesized that Se is an essential microelement in the accumulator species. Most of the cultivated plants are non accumulator and in maize it has been shown that Se can also affect plant development retarding leaf senescence [5]. Aim of this work was to assess the effect of selenium on tomato plant growth and yield, on leaf senescence and fruit ripening and the possible relationship with ethylene biosynthesis.

To invertigate the relationship between salt tolerance and plant mineral status in celery (Apium graveolens L.) growth and the concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), and chloride (Cl) in different tissues were determined in plants grown in hydroculture with nutrient solutions containing 5 (control), 50,100, and 300 mM sodium chloride (NaCl) for four weeks. At salinity levels of 50 and 100 mM NaCl, there was a moderate, albeit significantly, reduction of growth, while a drastic decrease in both fresh and dry weight was obtained at 300 mM NaCl. Regardless of the salinity level, growth resumed promptly and completely once the stress was ceased. Sodium chloride stress reduced the accumulation of nitrate (NO3)‐N in all plant tissues, but there were no relevant effects on the concentration of reduced N and P. The concentration of K in roots and leaf petioles was unaffected by NaCl treatment, but it gradually declined with increasing salinity in leaf bla...

Fully expanded leaves of tomato (Lycopersicon esculentum) growing with either complete or nitrogen-deficient nutrient solution were analysed for leaf water status, gas exchange and chlorophyll fluorescence during the vegetative and reproductive phases. N-deficiency did not affect leaf water relations but did decrease light saturated photosynthetic rate as well as stomatal conductance in the vegetative stage. A lower variable to maximum fluorescence ratio (Fv/Fm) was found in N-limited plants which also showed an increase in leaf starch content and in starch to sucrose ratio. The inhibition of photosynthesis and the alteration of photosynthates partitioning were responsible for the growth reduction in N-stressed plants. During the reproductive phase the limitation of photosynthesis may be due to a large accumulation of starch which determines both a decrease in the carbon demand from the sinks and a decrease in CO2 conductance in the mesophyll.

To investigate how the regulation of plant water status contributes to salt tolerance in celery (Apium graveolens L. cv. Istar) we determined growth, leaf gas exchange and water relations in hydroponically-grown plants supplied with nutrient solutions containing 5 (control), 50, 100 and 300 mM NaCI for 4 weeks, and supplied subsequently with the control solution to relieve salt stress. At salinity levels of 50 and 100 mM NaCl there was a moderate, albeit significant, reduction in biomass production. A drastic decrease in both dry weight and leaf area occurred at 300 mM NaCl, but the plants remained viable and showed appreciable photosynthesis and growth. Leaf water potential, turgor pressure, stomatal conductance and plant hydraulic conductance (L p ) decreased during salt exposure. After the first week of stress there was a progressive increase in leaf turgor and L p , which was associated with substantial recovery of stomatal conductance and photosynthesis in 50 and 100 mM NaCl-treated plants. The analysis of the pressure-volume isotherms showed that osmotic adjustment had occurred under all NaCl treatments. Leaf osmotic adjustment in salt-stressed plants was primarily accomplished by accumulation of Na 1 and Cl - . Upon relief of stress salinized plants rehydrated and regained turgor rapidly. and growth and photosynthesis resumed almost fully. These results indicate that maintenance of a favourable water status contributes substantially to the salt resistance of celery.

The effects of selenium (Se) addition on production and quality traits of Solanum lycopersicon ‘Red Bunch’ were investigated. Se was added as sodium selenate at the rate of 0, 0.5 and 1 mg Se L to the nutrient solution. Se was absorbed by roots and accumulated in leaves and fruits, and at the tested concentrations, it did not affect yield. Se concentration followed a gradient, decreasing from the basal to the apical part of the plant. At red ripe stage, the fruits on the lower trusses accumulated higher amount of Se than the fruits of the higher trusses. s-carotene and lutein significantly decreased only at 1.0 mg Se L. Lycopene increased either in 0.5 and, less markedly, 1.0 mg Se L-treated fruits where a pronounced increase in quercetin was also observed. INTRODUCTION Selenium (Se) is an essential trace element, a natural antioxidant and an effective anticarcinogenic agent both in humans and animals (Rotruck, 1973; Pallud et al., 1997; Ramauge et al., 1996). In plants, the essentiality of Se as a micronutrient has not been conclusively demonstrated, however it is believed that Se could delay plant senescence and decrease postharvest losses (Hartikainen et al., 2000; Xue et al., 2001). In tomato, Se is effective in reducing the plant growth and in delaying the onset of plant senescence and fruit ripening (Pezzarossa et al., 1999). Considering the effects of Se on secondary metabolism, Lee et al. (2007) found a variable effect on lycopene content in tomato fruit depending on the concentration of Se. In lettuce and chicory, Se has been shown to be effective in decreasing the production of ethylene and PAL activity, consequently improving the quality of leafy vegetables and the shelf life in both species (Malorgio et al., 2009). This paper reports the compositional parameters of ripe fruit of Solanum lycopersicon ‘Red Bunch’ (cherry tomato) due to Se-enrichment of the nutrient solution. MATERIALS AND METHODS The experiment was conducted in a temperature-controlled glasshouse located in Pisa, Italy (lat. 43°40’N). The plants (Solanum lycopersicon ‘Red Bunch’) were hydroponically grown during the spring-summer season, April 10-July 28, 2009. The minimum temperature and ventilation air temperature inside the glasshouse were 13 and 27°C, respectively; the maximum temperature was 30-32°C. The maximum photosynthetic photon flux density (PPFD) ranged from 600 to 800 μmol m s; the mean value of daily global radiation (R) was 8.4 MJ m. Seedlings were transplanted 50 days after sowing into 1-m long rockwool slabs. The plants were grown vertically with a single stem at a density of three plants m and pollination was favoured by mechanical vibration of the flower clusters. Drip irrigation was carried out using a nutrient solution with electrical conductivity (EC) 3.5 dS m and pH 6.5. Exhaust nutrient solution was discharged after three weeks or whenever the EC was higher than 6 dS m. The composition of the a beatrice.pezzarossa@ise.cnr.it Proc. 7 International Postharvest Symposium Eds.: H. Abdullah and M.N. Latifah Acta Hort. 1012, ISHS 2013 248 nutrient solution was as follows (concentration are expressed in mmol L): 12 N-NO3, 1.3 P-PO, 8 K, 4 Ca, 1.2 Mg, 9 Na, 1.5 S-SO4. Micronutrients were added at Hoagland’s concentration (in μmol L: B 40, 40 Fe, 1 Cu, 5 Zn, 10 Mn). Sodium selenate was added at the rate of 0, 0.5 and 1 mg Se L to the nutrient solution four weeks after transplanting. A second addition of sodium selenate at the same rate was performed after three weeks. When the solution containing selenium ran out, the tank was replenished with nutrient solution. Tomatoes were harvested at red ripe stage when the soluble solid content was on average 4.6°Brix and titratable acidity on average 0.65%. Ten tomato fruits were homogenized and dried at 75°C for 72 h to determine the dry weight. Carotenoid (lutein, lycopene, β-carotene) extraction was performed according to the method reported by Giuntini et al. (2005) partially modified. The extraction of flavonoids (quercetin, naringenin, rutin) was carried out according to Crozier et al. (1997). The measurements of carotenoids and flavonoids were carried out by HPLC (Jasco, Tokyo, Japan) consisting of a low pressure gradient pump with four solvent model PU-2089 UV-Vis detector and a multichannel UV-2077. The metabolites were identified based on retention times and quantified using calibration curves with pure standards of known concentration. Total selenium content was determined at harvest in oven-dried ground leaves and fruit samples after digestion with nitric and perchloric acids and reduction by hydrochloric acid, following Zasoski and Burau (1977). The digests were analyzed by hydride generation atomic absorption spectrophotometry (Varian VGA 77). The experimental design was completely randomized. Data were subjected to one way analysis of variance (ANOVA). The means were separated using the Least Significant Difference (LSD) test for p≤0.05 or p≤0.01. RESULTS AND DISCUSSION The selenium added to the nutrient solution was absorbed by roots and accumulated in fruits. The higher the amount of Se added, the higher the amount of Se accumulated in fruits (Fig. 1). Selenium concentration, expressed on a dry weight basis, was higher in leaves (data not shown) than in fruits, and followed a gradient, decreasing from the basal to the apical part of the plant. In fact, fruits of the lower trusses accumulated higher amount of Se than fruits of higher trusses (Fig. 1). Fruit yield was not statistically influenced by selenium addition, as well as the percentage of dry matter content. Selenium addition influenced the carotenoid concentration in fruits at harvest. Lycopene was higher in the treated samples, particularly at 0.5 mg Se L (Fig. 2), whereas s-carotene and lutein contents significantly decreased when Se was added at 1 but not at 0.5 mg L (Fig. 3). Lee et al. (2007) found an increase of selenium content in tomato fruit of ‘Super momotaro’ plants grown in nutrient solution added with 0.5, 1 and 2 mg Se L and only in correspondence of the highest Se concentration lycopene increased in ripe fruit tissues. The addition of selenium, either at 0.5 or 1 mg Se L, decreased the content of naringenin in fruits, whereas the highest dose of selenium induced a dramatic increase in the quercetin concentration (Fig. 4). The content of rutin was not influenced by the selenium addition (data not shown). Our data indicate that Se accumulating in tomato may affect fruit secondary metabolism and composition at ripening. The significant decrease of s-carotene and the slight increase in lycopene in the 1 mg Se L treatment would indicate that the carotenoid biosynthetic pathway is affected by Se. Sams et al. (2011) reported that, in Arabidopsis, a treatment with Se down regulates the expression of phytoene synthase, a key step in the carotenoid biosynthesis. However, in tomato fruit, other carotenoid genes and enzymes (e.g., lycopene cyclases, responsible for the formation of carotene and lutein from lycopene) may be affected by Se and, most likely, differently by the different concentrations of Se applied, as demonstrated by the effects of Se at 0.5 mg L (Figs. 2 and 3) and the results reported by Lee et al. (2007) on tomato fruit lycopene content.

Aim of this work was to investigate if the variation among tomato genotypes in selenium (Se) uptake and accumulation observed in short term experiments are maintained over longer growth periods and if there is a positive correlation in shoot between sulphur (S) accumulation and Se accumulation across different genotypes or if higher tissue S results in greater feedback inhibition of Se uptake. Two experiments were carried out under greenhouse conditions and different genotypes of Lycopersicon lycopersicum (UC82B and LA2711), Lycopersicon pennellii (LA716) and Lycopersicon peruvianum (LA2157) were grown until fruit ripening. The results obtained in the two experiments confirmed that sulphate in the growth solution reduced selenate uptake by plants and increased the S content of the leaves. Under low sulphate treatment there was a clear correlation (R2=0.82) between leaf S content and shoot Se content across genotypes in both experiments, indicating that the overall activity of the S transport syst...

Marine aerosol strongly affects the growth and development of urban, garden and landscape plants. The few studies available are focused on the sodium chloride effect on plant growth, usually applied in the irrigation water or substrate media. No information is available on responses of plants to marine aerosol. Therefore, the aim of this work was to evaluate the physiological responses of some species to sea water nebulisation treatment. Species were selected among those that are commonly used along the seaside and among those that might be potentially used. Plants were bought from local nursery and species used were: Acacia cultriformis, Callistemon citrinus, Carissa edulis microphylla, Gaura lindheimeri, Jasminum sambac, Westringia fruticosa. Plants were placed in randomised block in greenhouse and treated once a day for 5-10 seconds with sea water or irrigation water (control) using a nebulisation system. The effect of marine aerosol was studied by monitoring leaf chlorophyll a fluorescence, chlorophyll content, and leaf area damage by image analysis. Results were different among species. The effect of treatment was represented by leaf necrosis, reduction of chlorophyll and chlorophyll a fluorescence. The resistant species was Westringia fruticosa, while the intolerant species were A. cultriformis and G. lindheimeri. Intermediate behaviour was observed in the other species.

The paper reports a study on the influence of irrigation method on water relations and growth of pot geranium (Pelargonium peltatum L.) plants cultivated in a peat-perlite mixture. Two parallel experiments were conducted using difference sources of water for the preparation of nutrient solution: groundwater containing 10 mmol L NaCl or rainwater with less than 0.5 mmol L NaCl. In each experiment, six treatments, which derived from the factorial combination of three irrigation systems (openor closed-loop drip irrigation, trough technique with recycling drain water) and two scheduling methods (timer vs. tensiometer with a water tension threshold of 50 hPa), were compared. In closed systems, the mixing tank was completely emptied whenever the EC of recycling nutrient solution exceeded 3.50 dS m. In both experiments, the use of tensiometer reduced significantly the water runoff in free-drain drip irrigation compared to the timer-based scheduling. The use of rainwater did not affect plant water uptake, which averaged 81.2 L m. In all closed systems the recycling water was never flushed out and then total water use corresponded to plant water requirement. In open drip irrigation, a huge runoff was produced, although it was substantially reduced by the use of tensiometer When groundwater was used, in closed drip irrigation the nutrient solution had to be discharged in one (tensiometer) or two occasions (timer), since its EC had reached the pre-set ceiling value; total runoff was 12.5 or 25 L m , respectively. No important effects of irrigation system and scheduling method on plant growth characteristics was observed in the experiment carried out using rainwater. By contrast, the use of saline water resulted in a significant reduction of all growth parameters in closed-loop drip irrigation. Some reduction of plant fresh and dry weight, and leaf area and number of stems per plant was observed for subirrigation treatment with tensiometer-based control. The influence of irrigation technique and water quality on post-production plant performance was also investigated by simulating amateur cultivation in a patio with manual overhead irrigation. It was found that only the plants that had been subirrigated with saline water showed a rapid occurrence of leaf necrosis and abscission due to the solubilization of the salts accumulated during cultivation in the top layer of pot substrate. INTRODUCTION The water use efficiency of greenhouse crops depends principally on the adopted irrigation technique, on the method used to estimate crop water requirements and hence to define both watering frequency and dose, and on the quality (namely, salinity) of raw water. In fact, when saline water are available, growers have to over-irrigate the plant in order to avoid the salinization of the root zone or, in closed growing systems, to discharge, more or less frequently, the recirculating nutrient solution with obvious implications from the environmental point of view (Carmassi et al., 2007). The need for leaching requirement is imperative in the production of pot ornamentals, which generally a incrocci@agr.unipi.it Proc. IS on Prot. Cult. Mild Winter Climate Eds.: Y. Tuzel et al. Acta Hort. 807, ISHS 2009 284 are quite sensitive to salinity stress. The paper reports a study on the influence of irrigation method and the salinity of irrigation water on the water relations and the growth of potted geranium (Pelargonium peltatum L.) plants cultivated in a peat-perlite mixture. The influence of irrigation technique and water quality on post-production plant performance was also investigated. MATERIALS AND METHODS Rooted cuttings of geranium (Pelargonium peltatum L.) were transplanted in December 2005 in a heated glasshouse (minimum temperature 10°C) using pots (diameter of 15 cm and height of 14 cm) filled a peat-perlite mixture; plant density was 8 plant m. The cultivation was carried out for 109 days until early April 2006. Two parallel experiments were conducted using difference sources of water for the preparation of nutrient solution: groundwater containing 10 mmol L NaCl or rainwater with less than 0.5 mmol L NaCl. In each experiment, six treatments, which derived from the factorial combination of three irrigation systems (drip irrigation with or without the recirculation of drain water, and closed subirrigation, namely trough technique) and two methods to schedule water, that is with a predefined daily watering activated by a simple timer or under the control provided by a hydraulic tensiometer placed in a reference pot. Every day at fixed time (08.00 a.m.) or whenever the tensiometer reading reached the threshold value of 50 hPa., a pre-established water dose was applied to drip-irrigated pots by means of selfcompensating drippers (discharge rate of 2 L h) or the pots in trough system were subirrigated for 15 min with the thickness of water stream of nearly 1.5 cm. In drip irrigation system under timer control, the water dose ranged between 1.0 to 2.0 L m according to the growth stage and the climate inside the greenhouse, that is the dose tended to increase during the cultivation; diversely, for tensiometer-based drip irrigation, a fixed water volume of 1.7 L m was established in a preliminary experiment in order to restore the full water container capacity and produce a leaching fraction (LF, the percent ratio between supplied and drained water) not higher than 10-15%. The composition of the nutrient solution used for free-drain irrigation or to compensate for plant water uptake in closed systems was the following (mmol L): 7.8 N-NO3, 0.9 P, 4.0 K, 4.0 Ca, 0.8 Mg, Na 0.5 or 10, plus microelements. The electrical conductivity (EC) was approx. 1.5 and 2.5 dS m, for rainwater and groundwater treatment, respectively. Each treatment had three replicates, each consisting of 32 plants placed on a bench connected to a mixing tank containing free-drain irrigation or recycling water. Expressed on area basis, the water contained in the pot substrate and in the mixing tank was 8.0 (approx.) and 12.5 L m, respectively. In closed systems, the mixing tank was completely emptied whenever the EC of recycling nutrient solution exceeded 3.50 dS m. The volume and the nitrogen concentration (N-NO3, as determined using the sulphur-salicylic acid method) of the nutrient solutions supplied to the plants or drained out from the systems were measured in order to determine the water and nitrogen use efficiency. Plant growth was assessed destructively at the end of cultivation. EC and Na concentration (as determined by flame photometry) were also determined in the aqueous extracts of substrate, which was obtained by means of 1 substrate: 2 water suspension method (Sonneveld and van Ende, 1971) following the horizontal division of substrate in the pot in two equal layers. The influence of irrigation technique and water quality on post-production plant performance was also investigated by simulating plant cultivation in a patio with manual overhead irrigation for a period of four weeks. The values reported are means (+ s.e.) of three replicates (eventually, each consisting of two plants per treatment); after ANOVA, LSD test was used for mean separation in each experiment.