Effects of NaCl and CaCl2 as Eustress Factors on Growth, Yield, and Mineral Composition of Hydroponically Grown Valerianella locusta.

Corn salad (Valerianella locusta) is a popular winter salad, cultivated as an ingredient for ready-to-eat salads. The application of mild salinity stress (eustress) can increase the flavor and reduce the nitrate content of certain crops but, at the same time, a wrong choice of the eustress type and dose can negatively affect the overall productivity. In this research, the effects of different isosmotic salt solutions, corresponding to two different electrical conductivity (EC) levels, were investigated on the yield and mineral composition of hydroponically grown Valerianella locusta "Elixir". Five nutrient solutions (NS) were compared, including a basic NS used as the control, and four saline NS were obtained by adding to the basic NS either NaCl or CaCl2 at two rates each, corresponding to two isosmotic salt levels at a low and high EC level. Corn salad proved moderately susceptible to long-term salinity stress, suffering growth losses at both low and high EC levels of saline solution, except from the low NaCl treatment. Hence, it appears that mild salinity stress induced by NaCl could be employed as an eustress solution and corn salad could be cultivated with low-quality irrigation water (20 mM NaCl) in hydroponic systems.

Seed Germination of Three Milk Thistle (Silybum marianum (L.) Gaertn.) Populations of Greek Origin: Temperature, Duration, and Storage Conditions Effects.

Milk thistle besides being a highly competitive weed is cultivated as a medicinal plant, and the seeds of which have been clinically utilized in several disorders caused in liver. The present study aims to evaluate the effect of duration and storage conditions, population, and temperature on seed germination. The experiment was conducted in Petri dishes with three replications and three factors: (a) wild populations of milk thistle (Palaionterveno, Mesopotamia, and Spata) originating from Greece, (b) duration and storage conditions (5 months at room temperature, 17 months at room temperature, and 29 months in the freezer at -18 °C), and (c) temperature (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C). All three factors significantly affected germination percentage (GP), mean germination time (MGT), germination index (GI), radicle length (RL), and hypocotyl length (HL) and significant interactions among the treatments were noted. In specific, no seed germination was recorded at 5 °C, while the populations showed higher GP and GI at 20 °C and 25 °C after 5 months of storage. Prolonged storage negatively affected seed germination although, cold storage mitigated this effect. Moreover, higher temperatures reduced MGT and increased RL and HL with the populations reacting differently in storage and temperature regimes. The results of this study should be taken into consideration when proposing the appropriate sowing date and storage conditions of the seeds used as propagation material for crop establishment. Moreover, the effects of low temperatures such as 5 °C or 10 °C on seed germination as well as the high decline rate in germination percentage over time could be utilized in the design of integrated weed management systems thereby indicating the importance of the sowing time and the suitable crop rotation system to weed control.

Bioactive properties of Sanguisorba minor L. cultivated in central Greece under different fertilization regimes.

In this study, the chemical characterization and bioactive properties of S. minor cultivated under different fertilization rates (control, half rate and full rate) were evaluated. Twenty-two phenolic compounds were identified, including five phenolic acids, seven flavonoids and ten tannins. Hydrolysable tannins were prevalent, namely Sanguiin H-10, especially in leaves without fertilization (control). Roots of full-rate fertilizer (660 Kg/ha) presented the highest flavonoid content, mainly catechin and its isomers, whereas half-rate fertilizer (330 Kg/ha), presented the highest content of total phenolic compounds, due to the higher amount of ellagitannins (lambertianin C: 84 ± 1 mg/g of dry extract). Antimicrobial activities were also promising, especially against Salmonella typhimurium (MBC = 0.44 mg/mL). Moreover, root samples revealed activity against all tested cell lines regardless of fertilization rate, whereas leaves were effective only against HeLa cell line. In conclusion, S. minor could be a source of natural bioactive compounds, while fertilization could increase phenolic compounds content.

Chemical composition and bioactive properties of Sanguisorba minor Scop. under Mediterranean growing conditions.

Sanguisorba minor Scop. is a perennial plant native to the Mediterranean region which exhibits several medicinal activities. In the present study, plant growth, chemical composition, and antitumor and antimicrobial properties of S. minor plants were evaluated under different growing conditions. In particular, plants were grown on different substrates, namely (A) peat, (B) peat : perlite (1 : 1) and (C) peat : perlite (2 : 1). The dry weight of the aerial parts and roots was higher for the peat treatment (A), whereas plant growth was severely affected in the peat : perlite (1 : 1) treatment (B). The major detected sugars were fructose and glucose, while the peat : perlite (2 : 1) treatment resulted in a significant increase of α-tocopherol, glucose and total sugars content, especially in the aerial parts. Oxalic acid and citric acid were the major organic acids detected, with a varied effect of growth substrate on organic acid profile. Growth substrate and plant part also had a significant effect on fatty acid composition, especially on linoleic acid and α-linolenic acid content which was higher in the peat : perlite (1 : 1) treatment in both aerial parts and roots. An impact on the composition of phenolic compounds was also observed, where the plants grown on peat : perlite (2 : 1) and peat : perlite (1 : 1) substrates had the highest content of individual and total phenolic compounds in their aerial parts and roots, respectively. Moreover, roots contained significantly higher amounts of phenolic compounds than the aerial parts. Moreover, plant extracts exhibited antiproliferative activity against four tumor cell lines (HeLa, HepG2, MCF-7 and NCI-H460) and a primary culture of porcine liver cells (PLP2), as well as significant antimicrobial properties. In conclusion, S. minor presented significant bioactive properties, while growth substrates affected the nutritional value, chemical composition, antitumor and antimicrobial properties of the species which could be probably attributed to the higher phenolic compound content and different compositions of phenolic compounds. Therefore, although the species is commonly found in the Mediterranean region, it is underexploited yet and its plant tissues could be a potential source of natural bioactive compounds with further use in pharmaceutical and medicinal applications.

Faba Bean Cultivation - Revealing Novel Managing Practices for More Sustainable and Competitive European Cropping Systems.

Faba beans are highly nutritious because of their high protein content: they are a good source of mineral nutrients, vitamins, and numerous bioactive compounds. Equally important is the contribution of faba bean in maintaining the sustainability of agricultural systems, as it is highly efficient in the symbiotic fixation of atmospheric nitrogen. This article provides an overview of factors influencing faba bean yield and quality, and addresses the main biotic and abiotic constraints. It also reviews the factors relating to the availability of genetic material and the agronomic features of faba bean production that contribute to high yield and the improvement of European cropping systems. Emphasis is to the importance of using new high-yielding cultivars that are characterized by a high protein content, low antinutritional compound content, and resistance to biotic and abiotic stresses. New cultivars should combine several of these characteristics if an increased and more stable production of faba bean in specific agroecological zones is to be achieved. Considering that climate change is also gradually affecting many European regions, it is imperative to breed elite cultivars that feature a higher abiotic-biotic stress resistance and nutritional value than currently used cultivars. Improved agronomical practices for faba bean crops, such as crop establishment and plant density, fertilization and irrigation regime, weed, pest and disease management, harvesting time, and harvesting practices are also addressed, since they play a crucial role in both the production and quality of faba bean.

Weed interference with peppermint (Mentha x piperita L.) and spearmint (Mentha spicata L.) crops under different herbicide treatments: effects on biomass and essential oil yield.

BACKGROUND: 'Minor crops' such as spearmint and peppermint are high added value crops, despite the fact that their production area is comparably small worldwide. The main limiting factor in mint commercial cultivation is weed competition. Thus, field experiments were carried out to evaluate the effects of weed interference on growth, biomass and essential oil yield in peppermint and spearmint under different herbicide treatments. RESULTS: The application of pendimethalin and oxyfluorfen provided better control of annual weeds resulting in higher crop yield. Additionally, when treated with herbicides both crops were more competitive against annual weeds in the second year than in the first year. All pre-emergence herbicides increased biomass yield, since pendimethalin, linuron and oxyfluorfen reduced the density of annual weeds by 71-92%, 63-74% and 86-95%, respectively. Weed interference and herbicide application had no effect on essential oil content; however, a relatively strong impact on essential oil production per cultivated area unit was observed, mainly due to the adverse effect of weed interference on plant growth. CONCLUSION: Considering that pendimethalin and oxyfluorfen were effective against annual weeds in both spearmint and peppermint crops, these herbicides should be included in integrated weed management systems for better weed management in mint crops. © 2017 Society of Chemical Industry.

Successive harvesting affects yield, chemical composition and antioxidant activity of Cichorium spinosum L.

In the present study, the effect of successive harvesting on yield, chemical composition and antioxidant activity of Cichorium spinosum plants was examined. C. spinosum plants were grown from seeds sown in seed trays containing peat and young seedlings were transplanted in 2L pots containing peat and perlite (1:1v/v). Plants were harvested two or three times during two consecutive growing periods. Total fresh weight and number of leaves were higher for successive harvests in both growing periods comparing to a single harvest. The application of more than two harvests resulted in quality loss during the 1st growing period, while in the 2nd growing period the overall chemical composition, antioxidant properties and phenolic compounds content was higher than the 1st period. In conclusion, cultivation practices such as sowing date and successive harvesting may be useful tools towards the production of high quality end-product with increased bioactive properties without compromising total yield.

Corrigendum to "Effects of Presowing Pulsed Electromagnetic Treatment of Tomato Seed on Growth, Yield, and Lycopene Content".

[This corrects the article DOI: 10.1155/2014/369745.].

Chemical Composition and Yield of Six Genotypes of Common Purslane (Portulaca oleracea L.): An Alternative Source of Omega-3 Fatty Acids.

Common purslane (Portulaca oleracea L.) is an annual weed rich in omega-3 fatty acids which is consumed for its edible leaves and stems. In the present study six different genotypes of common purslane (A-F) were evaluated for their nutritional value and chemical composition. Nutritional value and chemical composition depended on genotype. Oxalic acid content was the lowest for genotype D, whereas genotypes E and F are more promising for commercial cultivation, since they have low oxalic acid content. Genotype E had a very good antioxidant profile and a balanced composition of omega-3 and omega-6 fatty acids. Regarding yield, genotype A had the highest yield comparing to the other genotypes, whereas commercial varieties (E and F) did not differ from genotypes B and C. This study provides new information regarding common purslane bioactive compounds as affected by genotype and could be further implemented in food industry for products of high quality and increased added value.

Effects of presowing pulsed electromagnetic treatment of tomato seed on growth, yield, and lycopene content.

The use of magnetic field as a presowing treatment has been adopted by researchers as a new environmental friendly technique. The aim of this study was to determine the effect of magnetic field exposure on tomato seeds covering a range of parameters such as transplanting percentage, plant height, shoot diameter, number of leaves per plant, fresh weight, dry weight, number of flowers, yield, and lycopene content. Pulsed electromagnetic field was used for 0, 5, 10, and 15 minutes as a presowing treatment of tomato seeds in a field experiment for two years. Papimi device (amplitude on the order of 12.5 mT) has been used. The use of pulsed electromagnetic field as a presowing treatment was found to enhance plant growth in tomato plants at certain duration of exposure. Magnetic field treatments and especially the exposure of 10 and 15 minutes gave the best results in all measurements, except plant height and lycopene content. Yield per plant was higher in magnetic field treatments, compared to control. MF-15 treatment yield was 80.93% higher than control treatment. Lycopene content was higher in magnetic field treatments, although values showed no statistically significant differences.

Pulsed electromagnetic field: an organic compatible method to promote plant growth and yield in two corn types.

Pre-sowing treatment of pulsed electromagnetic fields was used in corn seeds, in both indoor and outdoor conditions, in order to investigate the effect on plant growth and yield. The results of this research showed that pulsed electromagnetic fields can enhance plant characteristics, both under controlled environmental conditions and uncontrolled field conditions. The two varieties responded differently in the duration of magnetic field. Seeds were treated for 0, 15, 30, and 45 min with pulsed electromagnetic field (MF-0, MF-15, MF-30, and MF-45). Common corn variety performed better results in MF-30 treatment, while sweet corn variety performed better in MF-45 treatment. Magnetic field improved germination percentage, vigor, chlorophyll content, leaf area, plant fresh and dry weight, and finally yields. In the very interesting measurement of yield, seeds that have been exposed to magnetic field for 30 and 45 min have been found to perform the best results with no statistical differences among them. Another interesting finding was in root dry weight measurements, where magnetic field has a negative impact in MF-30 treatment in both hybrids, however without affecting other measurements. Enhancements on plant characteristics with economic impact on producer's income could be the future of a modern, organic, and sustainable agriculture.

Investigation of pulsed electromagnetic field as a novel organic pre-sowing method on germination and initial growth stages of cotton.

Two different pre-sowing techniques have been investigated for their influence in an important industrial plant, namely cotton. Priming methods are very useful for agricultural practices because they improve crop seedling establishment, especially when environmental conditions are not optimum. Pulsed electromagnetic fields have been found to promote germination and improve early growth characteristics of cotton seedlings. Such priming techniques are especially valuable in organic cultivation, where chemical compounds are prohibited. PEG treatment showed an enhancement in some measurements, however in some cases the results were not statistically different compared to control plants. In addition, PEG treatment is a sophisticated method that is far from agricultural practices and farmers. In this research, two different ages of seeds were used (1- and 2-year-old) in order to investigate the promotory effects of priming techniques. Magnetic field treatment of 15 min was found to stimulate germination percentage and to promote seeds, resulting in 85% higher values than control seeds under real field conditions. Furthermore, seeds that were treated with magnetic field performed better in terms of early-stage measurements and root characteristics.