Search

The increased need for consumption of raw vegetables has led to the production of minimally processed products like shredded carrots. There is a current trend towards the use of natural agents for the preservation of fresh produce quality, as alternatives to synthetic compounds such as chlorine. The purpose of this study was to evaluate the effects of different washing treatments with aqueous solutions of marjoram (Origanum majorana) essential oil (EO) (1:1500 v/v), marjoram hydrosol (Hyd) (1:15 v/v), ascorbic acid (AA) (1%) and their respective combinations on the quality of shredded carrot under storage at 4 °C for 9 d. The EO-treated carrots had acceptable aroma and AA-treated carrots obtained acceptable carrot-like aroma. The carrots’ orange color preserved with the AA application compared to the untreated control but marjoram Hyd application resulted to a final product with darker color and increased respiration after 6 and 9 d of storage at 4 °C and 90% RH. Furthermore, the application of AA increased total phenolic content and antioxidant activity of shredded carrots, while the combination of AA with EO and Hyd increased carotenoid content. Total soluble solids were increased following the application of marjoram Hyd. The application of AA increased total acidity and lowered pH values of shredded carrots at the 9th day of storage. Decay incidents, as observed by the total viable counts and yeast and filamentous fungi, were decreased by single or combined treatment during storage. Ascorbic acid alone or in combination with Hyd or EO maintained quality and preservation of processed carrots and in that way can be proposed as alternative sanitizers.

Medicinal and Aromatic Plants (MAPs) play an essential role in global health systems, since more than 80% of population use natural products in primary healthcare. Given that the global use of herbal medicines is exponentially increasing, as well as many MAPs products are introduced into the market, many cultivation practices are applied to produce high quality and standardized plant raw materials. Thus, the present study focuses on the chemical fingerprints of two cultivated Sideritis species. In Cyprus, Sideritis cypria Post and S. perfoliata L. subsp. perfoliata are widely used in traditional medicine. To date, there is no research work presenting the comparative chemical profiling between the aforesaid species using NMR methods. In this study, 1D and 2D NMR experiments were used to compare the chemical fingerprints of these species originated from conventional cultivation practices. Iridoids (ajugol, monomelittoside, and melittoside) and one flavone (4′-methyl-isoscutellarein 7-O-[6‴-O-acetyl]-β-D-allosyl(1→2)glucoside) were present in the infusion of S. perfoliata subsp. perfoliata. The phenylethanoid glycoside, acteoside, was detected in both samples. The phytochemical profiles of these cultivated species were similar to those of Sideritis species, indicating the positive impact of cultivation practices in MAPs.

The preservation of fresh produce quality is a major aim in the food industry since consumers demand safe and of high nutritional value products. In recent decades there has been a turn towards the use of eco-friendly, natural products (i.e., essential oils-EOs) in an attempt to reduce chemical-based sanitizing agents (i.e., chlorine and chlorine-based agents). The aim of this study was to evaluate the efficacy of an eco-friendly product (EP—based on rosemary and eucalyptus essential oils) and two different application methods (vapor and dipping) on the quality attributes of tomato fruits throughout storage at 11 °C and 90% relative humidity for 14 days. The results indicated that overall, the EP was able to maintain the quality of tomato fruits. Dipping application was found to affect less the quality attributes of tomato, such as titratable acidity, ripening index and antioxidant activity compared to the vapor application method. Vapor application of 0.4% EP increased fruit’s antioxidant activity, whereas tomatoes dipped in EP solution presented decreased damage index (hydrogen peroxide and lipid peroxidation levels), activating enzymes antioxidant capacity (catalases and peroxidases). Moreover, higher EP concentration (up to 0.8%) resulted in a less acceptable product compared to lower concentration (0.4%). Overall, the results from the present study suggest that the investigated EP can be used for the preservation of fresh produce instead of the current commercial sanitizing agent (chlorine), however, the method of application and conditions of application must be further assessed for every commodity tested.

Strawberry is considered as a fruit of high nutritional value, with appreciated benefits on human health. Arbuscular mycorrhizal fungi (AMF) are commonly used plant symbionts that affect plant growth and its effectiveness is plant species specific. Additionally, selenium (Se) projects a special interest to humans for its antioxidant specialties, and to plants, because of the potential to make them grow faster when added to the nutrient solution. Nonetheless, the performance of arbuscular mycorrhizal fungi (AMF) in Se biofortification in strawberry is unexplored. The purpose of the present study experiment was to determine whether mycorrhizal inoculation of AMF can have a positive impact on growth and quality of strawberries, and whether Se contributes in this effort or will adversely affect the plants. Four Se concentrations (0, 1, 5 and 10 mg L−1) in the nutrient solution, with or without mycorrhizal inoculation of AMF to the root system, were evaluated. Results demonstrated that Se of 10 mg L−1 negatively affected plant growth, photosynthetic rates, decreased fruit firmness and total soluble solids, induced oxidative stress in fruits and affected nutrient accumulation in different plant organs. Mycorrhizal inoculation of AMF mainly stimulated antioxidative mechanisms of the fruits and increased nutrient accumulation for plants grown at high Se levels. Based on our observations, mycorrhizal inoculation can enhance the nutritional value of strawberry fruits and strawberry plants seem to be a strong candidate for Se biofortification, allowing the rise of Se of the consumers’ intake.

Plant-associated bacterial communities are important contributors towards plant health and productivity, and are increasingly acknowledged for having the potential to alter plants' response to climate extremes, such as drought. Viticulture is generally conducted in areas that are prone to seasonal water deficit, and irrigation is the common way to counter this. In addition, soil conservation measures, such as cover cropping and no-tillage, are increasingly used. However, the effect of these management practices, in particular in viticulture, on soil bacterial communities remains unclear. Therefore, the objective was to examine the effect of irrigation and tillage on shaping soil bacterial communities associated with different grapevine cultivars, at different plant phenological stages.We conducted an experiment whereby we examined the soil bacterial community of three Vitis vinifera L. (grapevine) cultivars (two indigenous and one international, grown at different locations in the same vineyard) under different management practices (irrigated and non-irrigated, tillage and no-tillage). Since there is evidence that plant phenology can also affect soil microbial communities, we sampled soil at three different plant developmental stages (flowering, veraison and harvest).Soil bacterial communities primarily correlated with cultivar and location. At harvest we observed a link between bacterial communities and grape quality and yield measures and at all stages with soil physicochemical properties. A number of taxa were enriched in one or two cultivars, but these were generally in low abundance in our dataset. We also found an effect of plant phenology and management practices within each cultivar. For the two indigenous cultivars, soil bacterial communities at the flowering stage were most distinct, while for the international cultivar it was at the veraison stage. However, for all three cultivars, this effect differed by tillage treatment: bacterial communities in the tillage treatment varied by plant phenology, but in the no-tillage treatment less difference was observed, suggesting a buffering effect. While irrigation did lead to changes in bacterial communities, the effect was not as strong as that of the other factors.Our results show that soil bacterial communities in grapevines are shaped by both plant-associated effects (i.e. cultivar and plant phenological stage) and environmental variables (i.e. soil management and soil physicochemical properties), and importantly, that these factors have an interactive effect. Future research on soil bacterial communities in grapevines should take this variability into account, as well as focusing on its functional implications.

Climate change will increase the occurrence of plants being simultaneously subjected to drought and pathogen stress. Drought can alter the way in which plants respond to pathogens. This research addresses how grapevine responds to the concurrent challenge of drought stress and Plasmopara viticola, the causal agent of downy mildew, and how one stress affects the other. Self-rooted cuttings of the drought-tolerant grapevine cultivar Xynisteri and the drought-sensitive cultivar Chardonnay were exposed to full or deficit irrigation (40% of full irrigation) and artificially inoculated with P. viticola in vitro or in planta. Leaves were sampled at an early infection stage to determine the influence of the single and combined stresses on oxidative parameters, chlorophyll, and phytohormones. Under full irrigation, Xynisteri was more susceptible to P. viticola than the drought-sensitive cultivar Chardonnay. Drought stress increased the susceptibility of grapevine leaves inoculated in vitro, but both cultivars showed resistance against P. viticola when inoculated in planta. Abscisic acid, rather than jasmonic acid and salicylic acid, seemed to play a prominent role in this resistance. The irrigation-dependent susceptibility observed in this study indicates that the practices used to mitigate the effects of climate change may have a profound impact on plant pathogens.

Sideritis cypria Post is an endemic and endangered species of Northern Cyprus. The overall aim of the present study was to evaluate the total phenolic content, the antioxidant, the cytotoxic and the antimicrobial activity of the methanol extract obtained from the aerial parts of cultivated S. cypria. A bio-guided approach led to the isolation of 27 chemical compounds by using various analytical techniques. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopy. The crude extract exerted strong antioxidant activity (DPPH and FRAP assays) which was attributed to its high total phenolic content. Furthermore, groups rich in phenolic content showed highest antioxidant property, whereas groups with phytosterols, diterpenoids and apigenin derivatives exerted cytotoxic effects in MDA-MB231 cancer cell line by the MTT method. Moreover, the cytotoxic activity of four isolated apigenin derivatives was evaluated in the same cancer cells. The antimicrobial activity of the extract and groups were measured, demonstrating lack of activity. To the best of our knowledge, this survey is the first report on the biological activities of the methanol extract of S. cypria.

The environmental burden from crop production byproducts is gradually increasing and necessitates the sustainable management of waste towards a circular economy approach. In the present study, three byproducts (cotton ginning waste (CGW), ground hazelnut husks (GHH) and ground peanut husks (GPH)) were evaluated in lettuce cultivation. For this purpose, the tested materials were incorporated in soil at two different rates (25% and 50% of total substrate volume) while a control treatment (no addition of byproducts) was also considered. Fresh weight per plant and total yield was the highest for the GHH50% treatment. The highest fat, protein, carbohydrates and energy content were observed for the CGW25% treatment. Chemical composition also differed among the tested byproducts where CGW25% treatment had the highest total tocopherols, sugars (sucrose, fructose, trehalose and total sugars) and organic acids content. The most abundant fatty acids were &alpha, linolenic, linoleic and palmitic acid in all the tested treatments, while the highest antioxidant activity was observed for the GHH50% treatment. Regarding polyphenols, phenolic acids content was the highest in the GHH treatments, whereas flavonoids were the highest for the CGW25% treatment. No cytotoxicity against the PLP2 non-tumor cell line was observed, whereas only the GPH50% treatment showed moderate efficacy against HeLa, HepG2 and MCF-7 cell lines. The tested extracts also showed moderate antibacterial activities and only the extracts from the CGW50% treatment were more effective than the positive control against Trichoderma viride. In conclusion, the present results showed the great potential of using the tested byproducts as soil amendments for vegetable crops production, since they may improve the nutritional parameters, the chemical profile and the bioactivities of the final product. The suggested alternative use of the tested byproducts not only will increase the added value of crops but will also alleviate the environmental burden from bulky agroindustry byproducts.

Significant quantities of paper waste (PW) have been accumulated in recent years and the reuse/recycling of PW is required due to environmental concerns. In the present study, printed PW was used as a peat (P) substitute in growing medium for the Brassica seedlings production, considering recycling, sustainable agriculture, and partly peat replacement. Seeds of cauliflower, broccoli, and cabbage were seeded in growing media made of 0&ndash, 10&ndash, 30&ndash, 50% PW. The addition of PW improved the growing media pH and mineral content, reduced the media aeration, and affected seed emergence. The PW decreased plant growth and the effects were more pronounced at 50% PW. The PW &ge, 30% decreased stomatal conductance, while chlorophyll fluorescence and content of chlorophylls decreased with high PW ratio, negatively affecting the plant physiology. The PW decreased plant sodium and iron and increased potassium, calcium, magnesium, and copper content. The PW increased antioxidant activity to a certain degree for cauliflower and cabbage and resulted in no change for broccoli, while polyphenols increased in cabbage seedlings. The addition of PW did not cause cellular damage as both lipid peroxidation and hydrogen peroxide production remained at low levels, maintaining low levels on the antioxidant enzymes (catalase, superoxide dismutase, peroxidase) metabolism. The present study shows that low PW content can partially replace peat for Brassica seedling production under a sustainable agriculture and environmentally friendly scheme.

Low-fertility soil and the use of brackish water for irrigation act as obstacles and limit crop production. The utilization of municipal solid waste (MSW), compost (C), and treated wastewater (TWW) is receiving attention nowadays not only to overcome the above limitations but also as an efficient way for waste management and reuse of raw materials. In the present study, MSW compost in different ratios (5%, 10%, 20%, and 40%), fertigation and/or irrigation with TWW were studied in tomato plants (Solanum lycopersicum L.). The addition of compost increased organic content, pH, electrical conductivity (EC), and mineral content of the growing media, while fertigation and TWW supported the mineral status of the growing media, and this was reflected in the increase of N, K, and Na in tomato leaves. Plants grown in compost-based media with fertigation produced more leaves, compared to the control, while irrigation with TWW did not increase the number of leaves. Plant biomass increased with the application of &ge, 20% C, fertigation, and/or TWW applications. Plant yield increased in 40% C, while fertigation increased yield in case of lower (5%-10% C) compost ratios, but TWW application did not change the yield. The combination of high C ratios and fertigation and/or TWW decreased tomato fresh weight. Different levels of C did not affect leaf photosynthesis, stomatal conductance, internal CO2 concentration, and chlorophyll fluorescence, but, in general, the combination of compost with fertigation and/or TWW affected them negatively. Fruit total soluble solids, acidity, ascorbic acid, firmness, and total phenolics were increased with the high ratios of compost and/or fertigation and TWW applications, but marketability did not. Bacteria (total coliform and Escherichia coli) units increased in growing media subjected to TWW, but lower levels were counted on the fruit, mainly due to splashing or fruit contact with the soil. The results indicate that up to 40% C can be added into the substrate, as increased plant growth and maintained plant yield for greenhouse tomato cultivation is observed, while fertigation and TWW could be used in a controlled manner as alternative means for nutrient and irrigation in vegetables following safety aspects.

A process for the valorization of citrus peel waste (CPW) has been developed aiming to produce succinic acid and a series of added-value products through the biorefinery platform. CPW was subject to physicochemical and biological treatment to isolate essential oils (0.43%) and pectin (30.53%) as extractable products, pretreating the material for subsequent production of succinic acid that enabled application of remaining biorefinery residues (BR) as fertilizer substitute. Cellulose, hemicellulose and lignin contents of CPW accounted for 22.45%, 8.05% and 0.66% respectively, while acid hydrolysis reduced hemicellulose by 3.42% in BR. Moreover, essential oils extracted from CPW included 17 compounds, among which D-limonene reached 96.7%. The hydrolyzate generated was fermented for succinic acid production using Actinobacillus succinogenes. Different batch experiments demonstrated that the combined use of corn steep liquor (CSL) and vitamins in a lab-scale bioreactor resulted in product concentration and yield that reached 18.5 g L−1 and 0.62 g g−1 respectively. Although simultaneous saccharification and fermentation (SSF) could not enhance succinic acid production, a fed-batch fermentation strategy increased succinic acid concentration and yield generating 22.4 g L−1 and 0.73 g g−1 respectively, while the mass of the platform chemical formed was enhanced by 27% as compared to the batch process. BR was explored as fertilizer substitute aiming to close the loop in the management of CPW towards development of a zero-waste process demonstrating that although the material imposed stress on plant growth, the content of potassium, phosphorus and nitrogen in the mixture increased.

The paper industry generates significant quantities of waste. The recycling of paper waste (PW) for peat replacement in growing media for ornamental plants cultivation was studied. Five ratios of PW–peat (0%, 10%, 30%, 50% or 100% v/v) were evaluated for marigold (Calendula officinalis L.), petunia (Petunia × hybrita L.) and matthiola (Matthiola incana L.) plants. Addition of PW increased the substrate pH and mineral content but decreased the air-filled porosity. In marigold, the use of 100% PW reduced plant height, plant diameter, fresh weight for both leaves and flowers and the total number of flowers produced compared to the control (100% peat). In matthiola, 100% PW reduced plant height, whereas the addition of PW even at 10% decreased plant diameter and fresh weight (biomass) but increased dry matter content. Petunia plants grown in 100% PW exhibited lower growth (plant height and diameter), whereas adding ≥ 50% of PW decreased plant fresh weight. The total number of flower buds and open flowers increased (more than twofold) on plants grown in 30% PW compared to the control substrate, indicating flower earliness. Plant leaf chlorophyll content (Chl a, Chl b, total Chl) decreased as the PW ratio increased. Total phenolics and antioxidant capacity as well as plant damage index and enzymes scavenging activities varied among species. Mineral content fluctuated among species with decreases of N and P in plants grown in PW mixtures while matthiola showed phytotoxicity symptoms. The present study suggests that peat can be substituted by up to 30% of PW for marigold and petunia for potting culture, but not for matthiola, as the physicochemical properties of the substrate need further improvement.

The Middle East, the cradle of viticulture and wine production, is gradually but steadily becoming hotter and drier because of climate change (CC). In the current study, we evaluated the effect of tillage and irrigation on yield and quality characteristics of the heat-resistant, indigenous red-grape variety Maratheftiko for one year. Yield increased (two-fold) in vines with irrigation and tillage compared to tillage with no irrigation. The absence of tillage buffered the negative effect of the lack of irrigation on yield. At the veraison stage, leaf stomatal conductance decreased in non-irrigated vines, independently of the application of tillage or not. At veraison, tillage increased (up to 27.5%) phenolics when compared to no tillage in non-irrigated vines. Vines accumulated more N, P, and K and less Mg during the flowering stage compared to veraison. At veraison, irrigation decreased K content in vines subjected to tillage and decreased Mg content in vines subjected to no tillage. Total soluble solids and anthocyanins of berries increased with the absence of irrigation and tillage. Total phenolics increased with tillage in both irrigated and non-irrigated plants. Our results indicate that no tillage systems may be viable as an adaptation strategy in the context of CC.

The effect of climate change (CC) on viticulture in Europe is of great concern and several international and indigenous grapevine cultivars have been examined for their adaptation to CC. In this study we focused on the short-term effects of light and moderate drought stress (DS) as well as heat stress (HS) on physiological and biochemical stress markers in Maratheftiko cultivar. We showed that leaf photosynthetic rate was decreased with DS and HS after 8 and 20 days. The leaf stomatal conductance was decreased in the case of DS after 8 days, while no differences could be found due to HS. Total phenols and flavonoids content and antioxidant capacity (FRAP and ABTS) were increased and seemed to be dependent on the relevant DS, HS and the period of stress exposure. Chlorophyll fluorescence was decreased in 50% volumetric water content (VWC) after 8 days of DS compared with the 100% VWC (control treatment). Leaf K and P content increased in moderate (50% VWC) irrigation stress and HS. Leaf hydrogen peroxide and lipid peroxidation increased after 8 days of DS, and this resulted in the increase of antioxidant enzymes activity. Overall, Maratheftiko performance against environmental stresses is related more to short-term DS than HS.

Potassium (K) deficiency in leafy vegetables such as lettuce is a major concern regarding quality. Seaweed (SW) extracts, as biostimulants, are biodegradable materials and have become increasingly popular as they are reported to enhance crop growth and yield.; Results: In order to overcome K deficiencies (i.e. 375 vs 125 mg L-1 ), alternative foliar applications with extracts of Ascophyllum nodosum SW or K were examined using lettuce plants which were grown hydroponically. Potassium deficiency (at 125 mg L-1 ) reduced plant biomass, photosynthetic rate, leaf stomatal conductance, lettuce potassium content and tissue antioxidant capacity as compared with the higher K level (375 mg L-1 ). Application of SW increased the relative growth of lettuce in the low-K treatment. The K level and/or SW application altered the plant's enzyme protective activity (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD) against oxidative stress and hydrogen peroxide (H2 O2 ) production. Spray applications of SW mitigated the effects of K deficiency on indicators of enzyme activity and plant damage, back to levels of high K content (375 mg L-1 ). The high K level, but also SW application, increased the antioxidant activity of the processed lettuce before storage. Foliar application of the SW extract increased the quality of cut lettuce grown in 125 mg L-1 K conditions by reducing the rate of respiration and increasing consumer preference.; Conclusion: The SW application could alter the detrimental effects of K deficiency during lettuce growth and storage of processed products. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

The major problem of olive fruit protection in the Mediterranean basin is the control of the olive fruit fly Bactrocera oleae. The aim of this study was to investigate the status of resistance against insecticides which are registered and used against this major olive pest in Greece. During a 9-year survey, 55 B. oleae populations were collected. Insecticide application records showed extensive use of pyrethroids (alpha-cypermethrin) and to a lesser extent macrocyclic lactones (spinosad) and organophosphates (dimethoate). Low-to-moderate resistance levels were identified in the majority of populations for alpha-cypermethrin until 2012. After 2013, however, a dramatic increase of alpha-cypermethrin resistance was observed, especially in populations from Crete, Greece. The phenotype has an obvious impact on control efficacy. In real-field-cage trials, the mortality of the pyrethroid resistant field population from Crete was dramatically lower compared to the mortality of a respective field population from Samos with low-resistance level. Low-resistance levels were observed for spinosad in most of the populations tested. The frequency of the organophosphate resistance mutations G488S and I214V remained very high across most populations in Greece, despite the reduction in the application of these insecticides in the last decade. In contrast, the frequency of the mutation Δ3Q was very low. In conclusion, field evolved and practical resistance against alpha-cypermethrin seems to be emerging in B. oleae populations from Greece. It needs to be monitored and further characterised for the application of evidence-based control strategies.

Pepper (Capsicum annuum L.) seed germination and seedling growth using municipal solid waste compost (MSWC) in various proportions was examined. MSWC extracts (10− 0 up to 10− 6 dilutions) were evaluated for seed priming/germination in Petri dishes. The MSWC extracts at 10− 1–10− 6 showed similar seedling germination, whereas extracts at 10− 1–10− 3 accelerated root radical length compared to the control treatment. However, pure extracts (at 10− 0) almost failed seed germination. Under nursery conditions, six substrates were prepared from commercial peat and MSWC and were further assessed in conjunction with the nutrient application as basic fertilizer (BF) or hydro fertilizer (HF). The addition of MSWC into peat inhibited seed emergence and increased the mean germination time, while fertigation accelerated seed emergence at 15% addition of MSWC. Addition of > 30% MSWC reduced seedling height, leaf number and fresh weight. BF and HF increased fresh weight in seedlings grown in 15% MSWC. Leaf chlorophyll and total carotenoids content decreased in > 60% MSWC into the peat. The greatest leaf photosynthetic rate was found with the application of HF, while higher leaf stomatal conductance and leaf internal CO2 concentration were found in plants grown without fertilizers for both 15 and 45% of MSWC addition. The K content decreased, Na content increased, while P content did not differ with MSWC addition. Fertigation improved seedlings’ nutritive status. No visual phytotoxicity was observed macroscopically. Low content (15–30%) of MSWC may act as alternative substitute to peat with more positive effects observed, if nutrients are provided through HF rather than BF.

Mint family is considered of great importance all over the world with increasing needs for cultivation under controlled environment, but only narrow information is available about their response in relation to potassium supplementation. The present study determines the effects of different potassium levels (K: 275–300–325–350–375 mg/L) on the morphological and biochemical characteristics of spearmint (Mentha spicata L.). The results indicated that the middle K levels of 325 mg/L increased biomass dry matter content without differences on fresh weight. Mineral content was affected, mainly for the micronutrients. High K application increased spearmint polyphenols content and antioxidant activity (DPPH, FRAP), while K > 325 mg/L revealed oxidative stress (increased H2O2), followed by the activation of antioxidant enzymes (SOD, APX, CAT) providing protective action to the plant. The main essential oil components were carvone, limonene, 1,8-cineole, germacrene D, β-pinene and β-caryophyllene. Considering greater carvone content, the 325 mg/L K treatment could be appropriate for spearmint cultivation and production for essential oil uses, improving their antioxidant and antibacterial activity against foodborne pathogens.

Mints are regarded as one of the most important spices throughout the world with increased demands on cultivation under controlled environment. We conducted a study to evaluate the effects of different nitrogen levels (N: 150–175–200–225–250 mg/L) on the morphological and biochemical characteristics of spearmint (Mentha spicata L.) in hydroponics. The results indicated that N levels affected plant growth and chlorophyll content, while no differences were found in chlorophyll fluorescence and stomatal conductance. Essential oil yield increased at the 225 mg/L of N application. The main constituents of the essential oil were carvone, limonene, 1,8-cineole, germacrene D and β-pinene. High N application reduced leaf micronutrients content (i.e. Mn) and therefore reduced the carvone content. Nitrogen levels did not alter total phenols and antioxidant activity (DPPH, FRAP), while flavonoids were higher in 175 and 250 mg/L comparing to the 225 mg/L of N application. The increase in ascorbate peroxidase (APX) activity in spearmint under 200 mg/L of N application was towards the oxidative stress (increased hydrogen peroxide −H2O2), providing protective action to the plant. No differences were observed in antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) and malondialdeyde (MDA) content. Thus, the recommendation for increase upper plant biomass and essential oil quality in spearmint is to employ 200 mg/L N.

The increasing scarcity of water demands proper water management practices to ensure crop sustainability. In this study, the effect of drought stress and biostimulants application on the yield and chemical composition of green pods and seeds of common bean (Phaseolus vulgaris L.) was evaluated. For this purpose, four commercially available biostimulant products, namely Nomoren (G), EKOprop (EK), Veramin Ca (V), and Twin-Antistress (TW), were tested under two irrigation regimes: normal irrigation (W+) and water-holding (W-) conditions. The highest increase (20.8%) of pods total yield was observed in EKW+ treatment due to the formation of more pods of bigger size compared to control treatment (CW+). In addition, the highest yield under drought stress conditions was recorded for the GW- treatment (5691&plusmn, 139 kg/ha). Regarding the effects of biostimulants on the protein and ash content of pods, the application of VW+ treatment (first harvest of pods, 201&plusmn, 1 and 79&plusmn, 1 g/kg dw for proteins and ash content, respectively) and GW+ (second harvest of pods, 207.1&plusmn, 0.1 and 68.4&plusmn, 0.5 g/kg dw for proteins and ash content, respectively) showed the best results. For seeds, the application of GW+ treatment resulted in the highest content for fat, protein, and ash content (52.7&plusmn, 0.1, 337&plusmn, 1, 56&plusmn, 1 g/kg dw) and energetic value (5474&plusmn, 3 kcal/kg dw). &gamma, tocopherol was the main detected tocopherol in pods and seeds, and it was significantly increased by the application of TWW- (first harvest of pods, 6410&plusmn, 40 &mu, g/kg dw), VW- (second harvest of pods, 3500&plusmn, 20 &mu, g/kg dw), and VW+ (seeds, 39.8&plusmn, 0.1 g/kg dw) treatments. EKW- treatment resulted in the lowest oxalic acid content for both pod harvests (26.3&plusmn, 0.1 g/kg dw and 22.7&plusmn, 0.2 g/kg dw for the first and second harvest of pods, respectively) when compared with the rest of the treatments where biostimulants were applied, although in all the cases, the oxalic acid content was considerably low. Fructose and sucrose were the main sugars detected in pods and seeds, respectively, while the highest content was recorded for the TWW- (first harvest of pods) and GW- (second harvest of pods and seeds) treatments. The main detected fatty acids in pods and seeds were &alpha, linolenic, linoleic, and palmitic acid, with a variable effect of the tested treatments being observed. In conclusion, the application of biostimulants could be considered as an eco-friendly and sustainable means to increase the pod yield and the quality of common bean green pods and seeds under normal irrigation conditions. Promising results were also recorded regarding the alleviation of negative effects of drought stress, especially for the application of arbuscular mycorrhizal fungi (AMF, G treatment), which increased the total yield of green pods. Moreover, the nutritional value and chemical composition of pods and seeds was positively affected by biostimulants application, although a product specific effect was recorded depending on the irrigation regime and harvesting time (pods and seeds).

esearch and practice during the last 20 years has shown that urban agriculture can contribute to minimising the effects of climate change by, at the same time, improving quality of life in urban areas. In order to do so most effectively, land use and spatial planning are crucial so as to obtain and maintain a supportive green infrastructure and to secure citizens' healthy living conditions. As people today trend more towards living in green and sustainable city centres that can offer fresh and locally produced food, cities become again places for growing food. The scope of urban agriculture thereby is to establish food production sites within the city's sphere; for example, through building-integrated agriculture including concepts such as aquaponics, indoor agriculture, vertical farming, rooftop production, edible walls, as well as through urban farms, edible landscapes, school gardens and community gardens. Embedded in changing urban food systems, the contribution of urban agriculture to creating sustainable and climate-friendly cities is pivotal as it has the capacity to integrate other resource streams such as water, waste and energy. This article describes some of the current aspects of the circular city debate where urban agriculture is pushing forward the development of material and resource cycling in cities. European Cooperation in Science and Technology (COST): CA17133; EU Horizon 2020 Programme info:eu-repo/semantics/publishedVersion

Due to the remarkable medicinal properties of Sideritis spp, the commercial demand for the plant is continuously on the rise both in the European and in the global market. Cultivation of Sideritis species have been occurred to successfully meet the need for mass production of high-quality plant material. The present study was undertaken in order to investigate the impact of different cultivation practices (conventional versus organic cultivation; full versus deficit irrigation) in the yield and phytochemical profile of S. perfoliata L. subsp. perfoliata from Cyprus, under two harvestings for biomass production. Deficit irrigation decreased plant growth, but increased dry matter content. The content of chlorophylls and the nitrogen and potassium content decreased in organically grown plants. Both organic cultivation and/or deficit irrigation increased total phenolics, flavonoids, vitamin C and antioxidants. Essential oil yield increased under deficit irrigation at the 2nd harvest, while essential oil composition fluctuated among the treatments. Infusions of each plant material were prepared according to the European Medicines Agency (EMA) monograph. Based on their NMR spectra, the deficit-irrigated plants from conventional cultivation were the most rich in secondary metabolites and chosen for further chemical analysis. Six iridoids such as three flavonoids, two phenylethanoid glucosides and one phenolic acid have been isolated indicating new knowledge on the effects of cultivation practices on plant secondary metabolisms with putative industrial applications and interest.

Large quantities of spent coffee grounds (SCG) are generated the last decades, and their recycling is of research interest challenge. In the present study, SCG was tested to substitute peat (P) in substrate mixtures for the production of Brassica seedlings. Seeds of cauliflower, broccoli, and cabbage were placed in substrate mixtures containing 0-2.5-5-10% SCG. The mixture of SCG with peat affected several physicochemical characteristics of the growing media, providing also considerable amount of mineral elements for the seedling growth needs. Seed emergence was stimulated in 2.5–5% of SCG for cauliflower and at 2.5% of SCG for cabbage, while 10% of SCG decreased the percentage and increased the mean emergence time of the examined species. Plant biomass and leaf number were increased at 2.5% SCG for broccoli and cabbage but maintained at cauliflower when compared with control. The SCG at 10% decreased stomatal conductance of broccoli and cabbage (including 2.5–5% SCG in cauliflower) while chlorophyll content was increased at 10% of SCG media. The incorporation of SCG impacted the mineral content accumulated in plants with increases in nitrogen, potassium, and phosphorus and decreases in magnesium and iron content. Total phenolics and antioxidant activity (DPPH, FRAP) decreased at ≥ 5% SCG at cauliflower and cabbage or unchanged for broccoli when compared with the control. The cabbage seedlings grown in 10% SCG media subjected to stress with increases in the production of hydrogen peroxides and lipid peroxidation, and reflected changes in the antioxidant enzymatic metabolism (catalase, superoxide dismutase). The present study demonstrates that SCG (up to 5%) can be used for seed germination biostimulants and/or partially substitute the peat for Brassica seedling production.

We investigated the effect of water stress on the growth and essential oil quality of lavender (Lavandula angustifolia) and Greek sage (Salvia fruticosa) plants. In addition, we assessed the toxicity of essential oils to females of the two-spotted spider mite (Tetranychus urticae). Lavender and sage plants were grown in a greenhouse under adequate irrigation (AI), moderate (MWD) and severe water deficit (SWD). Plant growth related parameters, total phenols and total chlorophylls content as well as the yield and composition of essential oils hydrodistilled from the plants were assessed. In general, plants under water stress exhibited reduced growth and altered chemical composition than plants under regular irrigation. In addition, water stressed plants benefited in essential oil yield and quality, with higher concentrations of antioxidants (phenolic) level. The LC50 of lavender essential oil vapors from control plants was estimated at 4.93 μl/l, while that of Greek sage at 3.77 μl/l. Essential oil vapors from lavender plants under MWD caused significantly higher mortality to T. urticae females, than essential oils from plants under AI. In contrast, essential oils from sage plants under water stress caused similar mortality to T. urticae irrespectively of water stress levels.

Vegetables and fruits have been recognized as a healthy and nutritive value food, with both a noticeable rise in consumption nowadays and greater frequency of foodborne illnesses associated with fresh produce. Current sanitation disinfectants fail to adequately control common spoilage microorganisms as well as potential harmful human pathogens. Alternative and effective disinfectants are being sought, with ozone being a viable alternative to traditional disinfectants. Despite the considerable commercial interest that ozone has attracted, several contradictions regarding the ozone efficiency are often found in the literature and further research is still needed to explore its potential application in the food industry as sanitizer.

In the present study, the yield, the chemical composition, and the antioxidant activities of the essential oils (EOs) of eight medicinal and aromatic plants (MAPs) cultivated under two environmental conditions characterized by a different altitude (namely mountainous and plain) were evaluated. Cultivation at different environmental conditions resulted in significant differences in the chemical composition and antioxidant activity for most of the studied species. In particular, high altitudes resulted in increased phenolic compounds&rsquo, content and antioxidant activity for artemisia plants, while specific parameters increased in the case of spearmint (total phenols) and rosemary (flavonoids). In contrast, in pelargonium, all the tested parameters were positively affected in the plain area, whereas, for laurel and sage, only flavanols remained unaffected. EO yield in mountainous pelargonium and spearmint decreased while, in mountainous laurel, pelargonium and spearmint increased when compared to plain areas. In addition, the major EO constituents&rsquo, content for most of the species were affected by environmental conditions. The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and ferric reducing antioxidant power (FRAP) were variably correlated with total phenols, flavonoids, and flavanols, depending on the species and the altitude. Lastly, in limited cases, antioxidant activity (DPPH or FRAP values) was positively correlated with some EO components (e.g., borneol and &beta, pinene in artemisia and laurel plants grown in the plain, respectively, or 1,8-cineole in mountainous grown verbena plants). In conclusion, environmental conditions (altitude) affected antioxidants&rsquo, content and EO yield and composition of the studied MAPs. These findings can be used to introduce cultivation of MAPs in specific ecosystems for the production of high added value products.

The impact of climate change on viticulture is of major importance. Several international and indigenous grapevine cultivars have been examined for their adaptive performance to drought and heat stresses. However, the underlying physiological mechanisms are not well known. In the present study we examined the short-term effects of light and moderate drought stress (DS) as well as heat stress (HS) on physiological and biochemical attributes in two grapevine cultivars: Chardonnay (international) and Xynisteri, an indigenous adapted to the specific Cypriot microclimate. Xynisteri plants exhibited decreasing leaf stomatal conductance and photosynthetic rate as well as increasing total phenols and antioxidant capacity under DS conditions. These reactions were concomitant to a rapid accumulation of hydrogen peroxide and lipid peroxidation in leaves, associated to an increase of the antioxidant superoxide dismutase activity. However, Chardonnay plants did not exhibit the same responses as Xynisteri against DS (i.e., stomatal closure, total phenolics and antioxidants) over the first four days. Additionally, Chardonnay showed leaf damage with increased lipid peroxidation levels and activation of catalase and peroxidase. Interestingly, HS increased leaf stomatal conductance and decreased total phenolic content, flavonoids and antioxidant capacity in Chardonnay after 20 d of stress. In both cultivars, HS had milder effects compared to DS, and again Xynisteri showed better performance than Chardonnay in terms of damage index and antioxidative activities. Overall, Xynisteri adaptation to DS and HS was higher than that of Chardonnay, and both cultivars reacted more to the short-term DS than to HS. Although the Xynisteri performances under stress conditions provide an important resource for adaptation to stressful conditions, the impacts on earliness, yield and grape quality remain to be explored.

Irrigation with saline water causes significant crop yield loss. However, short-term saline application might cause less negative effects on yield yet at the same time improve quality aspects of edible products. Tagetes (Tagetes patula L.) plants were subjected to salinity (0, 50, and 100 mM NaCl) and harvested flowers were stored up to 14 days in passive modified atmosphere packaging (with or without ethanol application). Salinity of 100 mM NaCl decreased plant biomass and plant size (i.e., height) and had a negative effect on physiological processes such as stomatal closure and chlorophylls content decrease. Salinity increased flower polyphenols, antioxidant activities, and total carotenoids but decreased anthocyanins, and greater impacts were found at salinity of 100 mM NaCl, providing higher antioxidant value of the edible flowers. Short-term saline exposure of tagetes plants activated metabolic processes and as a result there was an accumulation of minerals such as N, P, Na, and Zn on edible flowers. During storage, salinity maintained but ethanol application increased the flower CO2 production. Ethanol application decreased the decay of flowers subjected to 100 mM NaCl. Flower weight losses and marketability accelerated at salinity of 100 mM NaCl after 14 days of storage. Tagetes flowers demonstrated induction in both non-enzymatic (i.e., proline content) and enzymatic mechanisms (catalase) to overcome stress caused by salinity during harvest stage and/or ethanol at storage. Our results have shown that short-term exposure to salinity and/or ethanol is able to achieve higher carotenoids and anthocyanins levels and these compounds can be considered as a new source of nutraceuticals.

Copper is essential for plant growth, but in excess may cause adverse effects on plant physiology. Harmful effects are also caused by plant exposure to salinity (NaCl) due to the excessive use of fertilizers, soil degradation and/or the quality of the water used for irrigation. The impact of single and combined salinity (Sal) and copper (Cu) stress on spearmint metabolism were studied in hydroponics. Spearmint plants (Mentha spicata L.) were subjected to salinity stress (150 mM NaCl) and/or excessive Cu concentration (60 μM Cu) via the nutrient solution. Not only Sal and Cu, but also their combination suppressed plant growth by decreasing plant biomass, root fresh weight and plant height. Chlorophyll content decreased mainly for the combined stress treatment (Sal + Cu). Polyphenols and antioxidants (FRAP, DPPH, ABTS) increased in single stress treatments (Sal or Cu), but decreased in the combined stress (Sal + Cu). The application of Sal or Cu stress decreased Zn, N and K (leaves), K, Ca, P and Mg (roots) content. Copper application increased Ca and Mg in leaves. In conclusion, salinity stress and Cu exposure may change the primary metabolic pathways in favor of major volatile oil components biosynthesis, resulting in significant changes of essential oil yield and composition.

Marginal water, including saline water, has been proposed as an alternative source of irrigation water for partially covering plant water requirements due to scarcity of adequate water supply in hot arid and semi-arid areas, such as those usually found in the Mediterranean basin. In the present study, spearmint plants (Mentha spicata L.) were grown in a deep flow hydroponic system under saline conditions, namely 0, 25, 50, and 100 mM NaCl. Moreover, foliar application of specific cations (K, Zn, Si) was tested as a means for alleviation of salinity stress under a plant physiological and biochemical approach. The results indicated that the highest salinity level of 100 mM NaCl severely affected plant growth, photosynthetic rates, leaf stomatal conductance, content of total phenolics and antioxidant status, while low to moderate salinity levels (25–50 mM NaCl) did not significantly affect plant growth and biochemical functions. In addition, leaf potassium and calcium accumulation decreased in saline-treated plants. Cations foliar application had small to no effect on plant growth, although it increased antioxidant activity and detoxified oxidative stress products/effects, through the increased enzymatic activities and proline accumulation. The present results have demonstrated that spearmint could be considered as a salinity tolerant species which is able to grow successfully under moderate salinity levels, while cation enrichment through foliar sprays was proved as a useful means to alleviate the stress effects caused by high salinity.

Peat-based growing media are not ecologically sustainable and peat extraction threatens sensitive peatland ecosystem. In this study, olive-stone waste (OSW) and paper waste (PW) were used in different ratios—as growing media—for ornamental crop production, as peat (P) substitutes. Marigold (Calendula officinalis L.), petunia (Petunia x hybrita L.) and matthiola (Matthiola incana L.) plants were grown in (1) P (100%), (2) P:OSW (90%:10%), (3) P:OSW (70%:30%), and (4) P:OSW:PW (60%:20%:20%). The physicochemical properties of these substrates and the effects on plant growth were determined. The addition of 10–30% OSW into the substrate increased marigold height compared to plants grown in 100% peat. No differences in plant size, plant biomass (leaves and flowers), and dry matter content were found. Adding PW, in combination with OSW, maintained marigold height and total number of flowers produced to similar levels as in plants grown in 100% peat. In matthiola, adding 30% OSW into the substrate reduced plant size and fresh weight, but not plant height. No differences were observed when plants grew in lower OSW (i.e., 10%) content. Petunia’s height, its total number of flowers and flower earliness (flower opening) were increased in the presence of OSW compared to the plants grown in 100% peat. The addition of OSW did not affect petunia’s size and fresh weight among treatments. The addition of PW suppressed several plant growth-related parameters for both matthiola and petunia. The insertion of OSW did not change leaf chlorophyll content whereas the presence of PW decreased chlorophylls for marigold, petunia, and matthiola. Both OSW and PW altered the content of total phenolics and antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) in leaves and flowers for marigold and petunia. Both 30% OSW and PW increased antioxidative enzyme metabolism due to the increased damage index and lipid peroxidation observed in plants. Leaf N and P content decreased in PW-based media, while matthiola displayed visual phytotoxicity symptoms when PW was added into the substrate. The present work indicates that up to 30% of OSW can replace peat for marigold and petunia growing and only up to 10% of OSW for matthiola, while the addition of PW on top of OSW is not recommended, so further research is needed.

Saline water has been proposed as a solution to partially cover plant water demands due to scarcity of irrigation water in hot arid areas. Lavender (Lavandula angustifolia Mill.) plants were grown hydroponically under salinity (0–25–50–100 mM NaCl). The overcome of salinity stress was examined by K, Zn, and Si foliar application for the plant physiological and biochemical characteristics. The present study indicated that high (100 mM NaCl) salinity decreased plant growth, content of phenolics and antioxidant status and essential oil (EO) yield, while low-moderate salinity levels maintained the volatile oil profile in lavender. The integrated foliar application of K and Zn lighten the presumable detrimental effects of salinity in terms of fresh biomass, antioxidant capacity, and EO yield. Moderate salinity stress along with balanced concentration of K though foliar application changed the primary metabolites pathways in favor of major volatile oil constituents biosynthesis and therefore lavender plant has the potential for cultivation under prevalent semi-saline conditions. Zn and Si application, had lesser effects on the content of EO constituents, even though altered salinity induced changings. Our results have demonstrated that lavender growth/development and EO production may be affected by saline levels, whereas mechanisms for alteration of induced stress are of great significance considering the importance of the oil composition, as well.

The aim of this report was to study the effect of salinity (control: 2dS/m, S1: 4 dS/m and S2: 6 dS/m) and harvest time (first harvest on 9 May 2018 and second harvest on 19 April 2018) on the growth and the chemical composition of Centaurea raphanina subsp. mixta plants. The plants of the first harvest were used for the plant growth measurements (fresh weight and moisture content of leaves, rosette diameter, number and thickness of leaves), whereas those of the second harvest were not used for these measurements due to the flowering initiation, which made the leaves unmarketable due to their hard texture. The results of our study showed that C. raphanina subsp. mixta plants can be cultivated under mild salinity (S1 treatment) conditions without severe effects on plant growth and yield, since a more severe loss (27.5%) was observed for the S2 treatment. In addition, harvest time proved to be a cost-effective cultivation practice that allows to regulate the quality of the final product, either in edible form (first harvest) or for nutraceutical and pharmaceutical purposes as well as antimicrobial agents in food products. Therefore, the combination of these two agronomic factors showed interesting results in terms of the quality of the final product. In particular, high salinity (S2 treatment) improved the nutritional value by increasing the fat, proteins and carbohydrates contents in the first harvest, as well as the tocopherols and sugars contents (S1 and S2 treatments, respectively) in the second harvest. In addition, salinity and harvest time affected the oxalic acid content which was the lowest for the S2 treatment at the second harvest. Similarly, the richest fatty acid (&alpha, linolenic acid) increased with increasing salinity at the first harvest. Salinity and harvest time also affected the antimicrobial properties, especially against Staphylococcus aureus, Bacillus cereus and Trichoderma viride, where the extracts from the S1 and S2 treatments showed high effectiveness. In contrast, the highest amounts of flavanones (pinocembrin derivatives) were detected in the control treatment (second harvest), which was also reflected to the highest antioxidant activity (TBARS) for the same treatment. In conclusion, C. raphanina subsp. mixta plants seem to be tolerant to medium salinity stress (S1 treatment) since plant growth was not severely impaired, while salinity and harvesting time affected the nutritional value (fat, proteins, and carbohydrates) and the chemical composition (tocopherols, sugars, oxalic acid, fatty acids), as well as the bioactive properties (cytotoxicity and antimicrobial properties) of the final product.

Sideritis perfoliata L. subsp. perfoliata is an endemic species of the Eastern Mediterranean region with several uses in traditional medicine. The present study aims to explore the unknown properties of S. perfoliata investigating the nutritional content as well as the antioxidant, anticancer, antituberculosis, antiwrinkle, anti-acne, hyper/hypo-pigmentation and antibacterial activities. Mineral content, nutritional value, the composition and antioxidant properties of the essential oil, the antityrosinase, the antibacterial activity and anti-elastase potential of the extract, were evaluated. The antiproliferative activity of S. perfoliata against cervical cancer (HeLa), human melanoma (UCT-Mel-1), human hepatocellular carcinoma (HepG2) and human epidermoid carcinoma (A431) was investigated. Cytotoxic effects on normal human keratinocyte (HaCat) and kidney epithelial (Vero) cell lines were also determined. Sideritis perfoliata exhibited high nutritional value of proteins and minerals (K, P, Mg, Fe, Zn, Cu). The most abundant components of the essential oil were found to be &alpha, pinene, &beta, phelladrene, valeranone, &beta, pinene and sabinene. The ethanolic extract of S. perfoliata displayed moderate antioxidant potential and antibacterial activity against Prevotella intermedia. Noteworthy elastase and moderate anticancer potential against the human liver cancer cell line (HepG2) was observed with IC50 values of 57.18 &plusmn, 3.22 &mu, g/mL and 64.27 &plusmn, 2.04 &mu, g/mL respectively. The noteworthy in vitro activity of S. perfoliata could be due to the presence of flavonoids and phenols in the leaves, having high nutritional value. Sideritis perfoliata could potentially be useful to reduce the appearance of wrinkles and for the treatment of liver cancer. The moderate antibacterial, antioxidant and elastase activity of the plant can be linked to the traditional use of S. perfoliata for the treatment of wounds and inflammation.

Intensified cropping systems and irrational use of fertilizers and agrochemicals has reduced quality and availability of water for agricultural uses due to high salinity. In the present study, the effect of salinity (0 mM, 25 mM, 50 mM and 100 mM NaCl) and foliar application of distilled water (dH2O), K, Zn, and Si (1250 mg/L, 144 mg/L, and 725 mg/L of K, Zn, and Si, respectively) on essential oil yield and composition of hydroponically grown spearmint plants was investigated. The results showed that saline conditions and foliar application of cations did not affect essential oil yield, except for the case of Zn application and the highest salinity level (100 mM NaCl) where a significant increase of oil yield by 44% and 47% was observed comparing to control treatments (sprayed plants +0 mM NaCl, and non-sprayed plants +100 mM NaCl, respectively). The major volatile constituents were carvone and limonene, which ranged between 59.74%–72.87% and 9.76%–18.76%, respectively. Other compounds detected in significant amounts 1,8-cineole, germacrene D, β-caroyphyllene, β-pinene, bicyclogermacrene, and α-pinene. Moreover, carvone’s content decreased with increasing salinity by up to 15.8% for the highest salinity level (100 mM NaCl), whereas contrasting effects were observed for limonene which increased by up to 75.6% for the highest salinity level. Foliar application of K, Zn and Si alleviated negative salinity effects on carvone’s content at the highest salinity level (reduction by 7.4%, 7.7%, and 8.0% for K, Zn, and Si respectively), while limonene content showed similar increasing trends to the unsprayed plants, especially at salinity levels higher than 50 mM NaCl. In conclusion, irrigation with saline water is possible when foliar application of K and Zn is also considered, allowing us to stabilize major compounds content and increase essential oil yield, respectively.

Lavandula angustifolia (Mill.) is a medicinal plant of great importance with a variety of applications in perfume and pharmaceutical industries or landscaping, but only limited information is available about its response to potassium supplementation. This experiment was conducted in order to determine the effects of potassium (K: 275-300-325-350-375 mg L-1) levels on the morphological and biochemical characteristics of lavender grown hydroponically. Results showed that K levels affected plant growth, mainly the root development while no differences were found for leaf chlorophyll content and stomatal conductance. Essential oil yield increased in the 300 mg L-1 in comparison to 275 or 325-375 mg L-1 of K application. The middle ranged K levels (300-325-350 mg L-1) enhanced leaf content in total phenols, flavonoids and antioxidant activity (DPPH, FRAP). Lipid peroxidation content (MDA) employed as damage index, was lower in the 325 mg L-1 of K treatment. No differences were observed in antioxidant enzymes (SOD, CAT, APX) activity and H2O2 content among K applications. The main constituents of leaves essential oil (1,8-cineole, borneol, camphor, α-terpineol, myrtenal) and mineral accumulation were affected by K treatments. Lavender grown in 300 mg L-1 of K was appropriate for the essential oil uses/production while the 325 mg L-1 of K were more appropriate for lavender cultivation for fresh and dry matter uses.

Lavandula angustifolia (Mill.) is a multidisciplinary medicinal and aromatic plant of great importance in fragrance and pharmaceutical industries and/or landscaping. Minerals rate affect yield and quality of medicinal plants therefore, this experiment was conducted in order to determine the effects of nitrogen (N: 150–175–200–225–250 mg/L) and phosphorus (P: 30–40–50–60–70 mg/L) levels on the morphological and biochemical characteristics of lavender under hydroponic condition. The results indicated that P levels mainly affected plant growth, while lower N levels (150 mg/L) reduced chlorophylls content. Essential oil yield was remained unaffected under N and P levels. The N levels greater than 200 mg/L as well as 60 mg/L of P, benefited antioxidant status (total phenols, DPPH, FRAP, flavonoids). The main constituents of leaves essential oil (1.8-cineole, borneol, camphor, α-terpineol, myrtenal) and mineral accumulation were affected by N and P treatments.

Although widely adopted by growers worldwide, hydroponic cultivation of lettuce is relatively new in Cyprus. Currently, ∼32 ha of lettuce are cultivated in the region, with only a few commercial trials using hydroponics. During March and April 2016, ∼23% of lettuce plants cv. Verde Degli Ortolani grown hydroponically (deep flow technique) in Polemidia, Limassol, showed severe stunting and poor growth. Older leaves wilted during the warmer period of the day and over the next 2 weeks the outer leaves became chlorotic and yellow. Small feeder roots had brown lesions, and subsequently the entire root system became necrotic. Diseased roots of 10 plants were excised, surface-disinfested, and plated on PARP-V8 medium selective for oomycetes (Jeffers and Martin 1986). Root isolations consistently yielded pure cultures of Pythium species. After 48 h incubation at 25°C, isolates produced white, circular, flat colonies with little aerial mycelia. Sections from the margin of colonies were transferred to 9 cm dia. plates containing 15 ml sterile water, which was incubated for at least 24 h at 25°C. Microscopic examination revealed filamentous and slightly inflated sporangia forming dendroid structures. Zoospores formed in vesicles and were up to 8 μm in diameter. The isolates failed to produce sexual structures during 30 days of incubation. Based on these morphological characteristics, the isolates could not be identified to the species level. Therefore, genomic DNA was extracted from six isolates, and the internal transcribed spacer (ITS) region of rDNA was partially amplified and sequenced using universal primers ITS4 and ITS5. A representative sequence was deposited in GenBank (accession no. KX518318). BLAST analysis revealed a 99% similarity to a P. dissotocum strain CBS 166.68 sequence (AY598634). This species belongs to the Pythium cluster B2a species complex including P. coloratum, P. diclinum, P. dissotocum, and P. lutarium (Robideau et al. 2011), which are indistinguishable based on ITS and cytochrome c oxidase subunit I (COI) sequences. To confirm pathogenicity under hydroponic conditions, six different Pythium isolates, of which the sequences were similar than accession AY598634, were used in pathogenicity experiments. Two-week-old lettuce plants cv. Nogal, started in a nursery in peat pellets, were placed in 14-liter plastic containers containing a full-based nutrient solution (Christoulaki et al. 2014) in growth chambers at 25 ± 1°C and 16-h photoperiod. Three containers were used per isolate, each containing four plants. Five days after transplanting, one intact 48-h old Pythium culture growing on a V-8 agar plate (9 cm dia.) was added to each container and removed 48 h later. Control plants were inoculated with sterile V-8 agar plates. After 3 weeks, older leaves of inoculated plants exhibited chlorosis, and feeder roots and taproots showed discrete brownish lesions. Control plants did not show any symptoms. Pythium was consistently reisolated from symptomatic roots but not from the control plants, fulfilling Koch’s postulates. The pathogenicity experiments were repeated once. P. dissotocum, which belongs to Pythium cluster B2a, has long been reported to infect lettuce plants in hydroponic culture (Stanghellini and Kronland 1986). To our knowledge, this is the first report of root rot of lettuce caused by a Pythium spp. belonging to Pythium cluster B2a species complex in Cyprus.

Strawberry (Fragaria × ananassa Duch.) plants were grown hydroponically in different ratio of sawdust (Saw-100), coco soil (Coc-100) and/or pumice (Pum-100) mixtures. Leaf number doubled in plants grown in Saw-100 while runners (stolons) number increased up to 70% in plants grown in Coc-100 compared with the control treatment (Pum-100). Fruit number increased (up to 50%) in plants grown in Pum-100. Leaf stomatal conductance, photo-synthetic rate and internal concentration of CO2 differentiated according to the plant vegetative or reproductive stage and/or substrate medium. Leaf and stem fresh weight as well as leaf area was increased (up to 32, 24 and 44%, respectively) in case of Coc-100 compared with the Saw-100 or Pum-100. Plant yield was doubled when Pum-Saw (50-50) was used compared with the Saw-100, which is due to the reduced fruit number produced rather than the difference in fruit fresh weight. Substrate affected fruit quality parameters. The present findings highlight the puta-tive use of organic medium i.e. Sawdust on top of the widely used coco soil as substrate medium in strawberry cul-ture.