Impact of Ecklonia maxima Seaweed Extract and Mo foliar treatments on biofortification, spinach yield, quality and NUE

Seaweed extract (SE) application is a contemporary and sustainable agricultural practice used to improve yield and quality of vegetable crops. Plant biofortification with trace element is recognized as a major tool to prevent mineral malnourishment in humans. Mo deficiency causes numerous dysfunctions, mostly connected to central nervous system and esophageal cancer. The current research was accomplished to appraise the combined effect of Ecklonia maxima brown seaweed extract (SE) and Mo dose (0, 0.5, 2, 4 or 8 \u3bcmol L 121) on yield, biometric traits, minerals, nutritional and functional parameters, as well as nitrogen indices of spinach plants grown in a protected environment (tunnel). Head fresh weight (FW), ascorbic acid, polyphenols, N, P, K, Mg and nitrogen use efficiency (NUE) were positively associated with SE treatment. Moreover, head FW, head height (H), stem diameter (SD), ascorbic acid, polyphenols, carotenoids as well as NUE indices were enhanced by Mo\u2010biofortification. A noticeable improvement in number of leaves (N. leaves), head dry matter (DM) and Mo concentration in leaf tissues was observed when SE application was combined with a Mo dosage of 4 or 8 \u3bcmol L 121. Overall, our study highlighted that E. maxima SE treatment and Mo supply can improve both spinach production and quality via the key enzyme activity involved in the phytochemical homeostasis of SE and the plant nutritional status modification resulting in an enhanced spinach Mo tolerance

Stand-Alone or Combinatorial Effects of Grafting and Microbial and Non-Microbial Derived Compounds on Vigour, Yield and Nutritive and Functional Quality of Greenhouse Eggplant

The current research investigated the effects of endophytic fungi such as Trichoderma atroviride (Ta) or Ascophyllum nodosum seaweed extract (An) and their combination on growth, yield, nutritive and functional features, and mineral profile of ‘Birgah’ F1 eggplant either ungrafted, selfgrafted or grafted onto the Solanum torvum rootstock. Eggplant exposed to An or An+Ta had a significant increase in root collar diameter 50 days after transplanting (RCD50), total yield (TY), marketable yield (MY), ascorbic acid (AA) content, Mg, Cu, and Zn concentration, and a reduction in glycoalkaloids (GLY) compared with the control. Furthermore, grafted plants had a higher TY, MY, number of marketable fruits (NMF), RCD50, AA, Cu, and Zn and a lower SSC, GLY, and Mg than the ungrafted plants. The combination of grafting and An+Ta significantly improved mean weight of marketable fruits (MF), plant height 50 days after transplanting (PH50), number of leaves 50 days after transplanting (NL50), fruit dry matter (FDM), chlorogenic acid (ClA), proteins, and K and Fe concentration. This combination also produced fruits of high premium quality as evidenced by the higher AA and ClA concentration, the lower GLY concentration, and an overall improved mineral profile

Exploring the Simultaneous Effect of Total Ion Concentration and K:Ca:Mg Ratio of the Nutrient Solution on the Growth and Nutritional Value of Hydroponically Grown Cichorium spinosum L.

Nutrient-efficient plants and agricultural systems could tackle issues resulting from conventional agriculture. Spiny chicory (Cichorium spinosum L.), a very adaptive, wild edible vegetable, is gaining commercial interest as a functional food. Floating-raft hydroponics is a method commonly used for the commercial cultivation of leafy vegetables due to numerous advantages compared to soil cultivation. In this paper, the simultaneous effects of different potassium, calcium and magnesium ratios and different electrical conductivity (EC) levels on the growth and mineral composition of hydroponically grown C. spinosum were investigated. Four nutrient solutions (NS) were compared, two NS with low EC (L, 2.4 dS/m) and two with high EC (H, 3.6 dS/m) with K:Ca:Mg ratios of either 50:40:10 or 40:50:10. The results showed no interactions between the two factors. No significant effects were observed on the fresh and dry weight, leaf number and leaf area. High EC levels increased the K content and decreased the Mn and Zn content in the leaf tissues. The 40:50:10 ratio led to increased Ca content in plant tissues. The Nitrate-N was only affected by the EC level and was increased under H conditions, whereas the total-N was not affected

Celery (Apium graveolens L.) Performances as Subjected to Different Sources of Protein Hydrolysates

The vegetable production sector is currently fronting several issues mainly connected to the increasing demand of high quality food produced in accordance with sustainable horticultural technologies. The application of biostimulants, particularly protein hydrolysates (PHs), might be favorable to optimize water and mineral uptake and plant utilization and to increase both production performance and quality feature of vegetable crops. The present study was carried out on celery plants grown in a tunnel to appraise the influence of two PHs, a plant-derived PH (P-PH), obtained from soy extract and an animal PH (A-PH), derived from hydrolyzed animal epithelium (waste from bovine tanneries) on yield, yield components (head height, root collar diameter, and number of stalks), mineral composition, nutritional and functional features, as well as the economic profitability of PHs applications. Fresh weight in A-PH and P-PH treated plants was 8.3% and 38.2% higher, respectively than in untreated control plants. However, no significant difference was found between A-PH treated plants and control plants in terms of fresh weight. Head height significantly increased by 5.5% and 16.3% in A-PH and P-PH treated plants, respectively compared with untreated control (p ≤ 0.05). N content was inferior in PHs treated plants than in untreated control. Conversely, K and Mg content was higher in A-PH and P-PH treated plants as compared to the untreated ones. Furthermore, A-PH and P-PH improved ascorbic acid content by 8.2% and 8.7%, respectively compared with the non-treated control (p ≤ 0.001). Our results confirmed, also, that PHs application is an eco-friendly technique to improve total phenolic content in celery plants. In support of this, our findings revealed that animal or plants PH applications increased total phenolics by 36.9% and 20.8%, respectively compared with untreated plants (p ≤ 0.001)

Interaction of Temperature and Light in the Development of Freezing Tolerance in Plants

Abstract Freezing tolerance is the result of a wide range of physical and biochemical processes, such as the induction of antifreeze proteins, changes in membrane composition, the accumulation of osmoprotectants, and changes in the redox status, which allow plants to function at low temperatures. Even in frost-tolerant species, a certain period of growth at low but nonfreezing temperatures, known as frost or cold hardening, is required for the development of a high level of frost hardiness. It has long been known that frost hardening at low temperature under low light intensity is much less effective than under normal light conditions; it has also been shown that elevated light intensity at normal temperatures may partly replace the cold-hardening period. Earlier results indicated that cold acclimation reflects a response to a chloroplastic redox signal while the effects of excitation pressure extend beyond photosynthetic acclimation, influencing plant morphology and the expression of certain nuclear genes involved in cold acclimation. Recent results have shown that not only are parameters closely linked to the photosynthetic electron transport processes affected by light during hardening at low temperature, but light may also have an influence on the expression level of several other cold-related genes; several cold-acclimation processes can function efficiently only in the presence of light. The present review provides an overview of mechanisms that may explain how light improves the freezing tolerance of plants during the cold-hardening period

Long-term storage of onion and the factors that affect its quality: A critical review

Storage of onions is a multifaceted issue, which involves many preharvest and postharvest factors. One of the major factors that affect onion storage is the selection of the proper cultivar, since there are significant differences in storability between the cultivars and not all of them are suitable for storage. Proper preharvest and postharvest conditions are essential for storability of onion bulbs, whereas they also affect marketability (weight losses, texture and color depth of bulbs) and quality (chemical composition, nutritional value, antioxidant activity). Irrigation and fertilization are essential preharvest factors that substantially affect storability, whereas curing methods and storage conditions (temperature, relative humidity, controlled atmospheres) and processing treatments are postharvest factors. This review article examines the effect of long-term storage on the main quality features of onions, such as the incidence of sprouting and root growth, water losses, and changes in chemical composition (mineral composition, sugar content, nutritional value) and antioxidant activity (phenolic and flavonoid contents, DPPH [2,2-diphenyl-1-picrylhydrazyl] scavenging activity). © 2017 Taylor & Francis

Impact of chelated or inorganic manganese and zinc applications in closed hydroponic bean crops on growth, yield, photosynthesis, and nutrient uptake

In this study, we investigated the effect of individual and combined applications of manganese (Mn) and zinc (Zn) chelates on common bean grown in hydroponics (nutrient film technique-NFT) on physiological and agronomical responses. Inorganic sulphate forms of Mn and Zn were compared to their synthetic chelate forms, in the replenishment nutrient solution (RNS). Nutrient (N, P, K, Ca, Mg, Fe, Mn, Zn and Cu) to water uptake ratios (termed uptake concentrations; UCs), growth, pods yield and quality, photosynthetic parameters and tissue nutrient status were evaluated in different cropping seasons (spring-summer and autumn-winter crops). Mean UCs of nutrients ranged as follows: 10.1-12.4 (N), 0.8-1.0 (P), 5.2-5.6 (K), 1.8-2.2 (Ca), 0.9-1.0 (Mg) mmol L−1; 12.2-13.4 (Fe), 5.2-5.6 (Mn), 4.4-4.9 (Zn), 0.9-1.0 (Cu) µmol L−1. Tissue macronutrient status remained unaffected in both seasons, however, Mn chelates in the RNS affected Fe within plants. Pod yield and quality, growth, photosynthesis and water uptake did not differ among treatments; however, seasonal variations are presented. Results suggest that the chelate forms of Mn and/or Zn in the refill solution for NFT-grown beans do not lead to any changes, adding superiority in the yield, photosynthesis, and nutritional status of the crops compared to their mineral forms. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Vegetable organosulfur compounds and their health promoting effects

Background: Trends in modern pharmaceutical science show an increase in demand for new drugs and diet supplements derived from natural products, while during the last decades, great research is conducted regarding the natural compounds and their medicinal and bioactive properties. Organosulfur compounds are present in many plants and their bioactive properties have been used in folk and traditional medicine throughout the centuries. Not until recently, modern science confirmed and revealed the chemical compounds that are responsible for these properties, the chemistry involved in their biosynthesis and the main mechanisms of action. Objective: In the present review, the organosulfur compounds of vegetable origin and their health effects are presented, focusing on the chemical composition of their main compounds, their biosynthesis and the mechanisms involved in their health effects. Sulfur compound sources presented include mainly vegetable species belonging to Allium genus and Brassicaceae family. Conclusion: Organosulfur compounds of vegetable sources are very important in human diet, and their regular consumption has a beneficial contribution to health and well-being. Moreover, their medicinal properties and therapeutic effects have been described thousands of years ago, while they constitute an important ingredient in traditional medicines and preparations. However, not until recently, the mechanisms of action of organosulfur compounds have started to unravel, with promising results for further exploitation of these significant bioactive compounds in drug development and novel nutraceutical products. This review reveals the numerous biological activities of organosulfur compounds of vegetable origin, while it also presents the results of recent clinical studies and trials. © 2017 Bentham Science Publishers

Current situation of greenhouse vegetable production in Greece

The total greenhouse area in Greece amounts to about 5,600 ha, which corresponds to approximately 0.12% of the total cultivated area of the country. Of this area, 92% (5,200 ha) is used for vegetable production and only 8% (400 ha) is occupied by ornamental crops. Nearly 93% of the total greenhouse area of Greece is plastic-covered but nearly 96% of the greenhouses used for vegetables in Greece are plastic-covered. Glasshouses are used mainly in floriculture. The main vegetable crops in the Greek greenhouses are tomato and cucumber followed by pepper. Crete is the leading region of Greece in greenhouse production, followed by Peloponnese, Macedonia, Thessaly, Central Greece, Epirus and Aegean Islands. A significant proportion of the greenhouse area used for vegetables is occupied by high tunnels. Low tunnels are used to a large extent too, particularly for early melon, watermelon and strawberry production. Only a minor percentage (about 17%) of the greenhouse area used for vegetable production is heated in Greece. The level of automation in the greenhouses used for vegetable production in Greece is unsatisfactory. Computer controlled automation systems are only exceptionally used in greenhouse vegetable production. The fuel cost for greenhouse heating is relatively high in Greece and, therefore, most vegetable greenhouses are not heated. However, heating in the winter is necessary to attain proper temperature levels for high yield and good quality products. Currently, soilless culture in Greece occupies approximately 180 ha, which is nearly 3.3% of the total greenhouse area. Soil solarization and soilless culture in combination with grafting seem currently the safest and most effective practices to overcome the problem of soil-borne pathogens in intensively cultivated greenhouses in Greece