Terpene yield of native spearmint (Mentha spicata) increases proportionally to photosynthetic photon flux density

Pythium sp. is a soil fungus that can cause serious seed and root rot in several crops. Pseudomonas aeruginosa strain 7NSK2, a plant-growth promoting rhizobacterum showed an iron-regulated antagonism against Pythium splendens strain 706 in vitro. Pythium splendens strain 706 is a heterothallic strain that produces big chlamydospores or hyphal swellings but is not able to produce zoospores. As Pythium spp. are important pathogens in nutrient film technique (NFT) systems, the possibilities for biological control of this fungus by P. aeruginosa 7NSK2 in NFT were evaluated. By using a marked P. aeruginosa strain (beta-galactosidase positive and kanamycin resistant) it was shown that these bacteria could survive and spread in a NFT system when added to the recirculating nutrient solution or applied to the seed. They were also able to colonize the plant roots. We were unable to obtain an infection with Pythium splendens in NFT by adding the fungus to the nutrient solution or by placing a Pythium infested pot in the gully. A good Pythium infection could only be obtained by mixing the chlamydospores into the substrate. It was shown that the chlamydospores did not spread into the gullies. Also in NFT, seed treatment with P. aeruginosa significantly reduced damping-off. Moreover, additional protection was obtained when the nutrient solution was also inoculated. We are currently working with a zoospore-producing Pythium aphanidermatum strain to further study the epidemiology of Pythium in NFT systems.

Natural antioxidants have drawn growing interest for use in animal feed and the food industry. In the current study, essential oils (EOs) obtained from hydrodistillation of three mentha species, including Menthapiperita (peppermint), Mentha spicata (native spearmint) and Menthagracilis (Scotch spearmint), harvested in the Midwest region in the United States, were analyzed for their chemical composition using gas chromatography-mass spectrometry, and their antioxidant properties were assessed through chemical assays, in vitro cell culture modeling and in Caenorhabditis elegans (C. elegans). The activity of ferric iron reduction and free-radical scavenging capacity were assessed through chemical-based assays, including the reducing power assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, and Trolox equivalent antioxidant capacity assay (TEAC). Subsequently, the capacity of EOs to mitigate lipid peroxidation was analyzed at various doses using fresh liver homogenates from pigs. A porcine jejunum epithelial cell line (IPEC-J2) was employed as in vitro model to study the cellular antioxidant activity of the mint EOs. Finally, the effectiveness of mint EOs to alleviate acute systemic oxidative damage were evaluated in vivo using C. elegans. Data were analyzed by the MIXED procedure of SAS. Contrast statement was performed to assess linear or quadratic effects of mint EOs given at various doses. All three EOs are mostly composed of monoterpenes and their derivatives (76–90%), but differed in the major compounds, which are menthol and menthone (50%) in peppermint EO and carvone (70%) in spearmint EOs. Three mint EOs demonstrated prominent radical scavenging and Fe3+ reducing activity in chemical-based assays. In comparison with native and Scotch spearmint EOs, peppermint EO had the lowest (p < 0.05) half maximal effective concentration (EC50) in DPPH and TEAC assays and higher efficacy in the reducing power assay. All three EOs exhibited equivalent activity in mitigation of chemical-induced lipid peroxidation in liver tissues in a dose-dependent manner (linear, p < 0.001). The maximal cellular antioxidant activity (CAA) was observed at 5 µg/mL for peppermint, and 100 µg/mL for native and Scotch spearmint EOs. The addition of 25 µg/mL of both spearmint EOs increased (p < 0.05) cellular concentrations of glutathione in H2O2-treated IPEC-J2 cells, suggesting enhanced endogenous antioxidant defense. Supplementation of 100 µg/mL of peppermint or Scotch spearmint EO significantly increased (p < 0.05) the survival rate of C. elegans in response to H2O2-induced oxidative stress. The protective effect is comparable to that of supplementation of 10 µg/mL of ascorbic acid. However native spearmint EO failed to reduce the death rate within the same supplementation dose (10–200 μg/mL).

• Evergreen oaks from the Mediterranean basin exhibit a conservative resource-use strategy based on a reduced expression of phenotypic variation (i.e. canalization). We hypothesized that genetic variation across closely related species is more canalized than the response to environmental variation. • Seedlings of Quercus ilex and Q. coccifera, two important oak species from the Mediterranean basin that belong to the same subgenus and section, were grown in contrasted light and nutrient environments following a factorial design. Phenotypic variation was explored in a total of 75 variables including photosynthetic capacity, nutrient allocation, allometric relationships and crown architecture. • Path analysis showed that phenotypic variation was not significantly affected by differences between species but by those between and within environments, which are argued to be primarily linked to phenotypic plasticity and developmental instability, respectively. This finding is interpreted as evidence of genetic canalization across species. • The similar importance of plasticity and instability as sources of phenotypic variation and the high degree of genetic canalization are consistent with the expected role of the environmental unpredictability of Mediterranean ecosystems in shaping the developmental patterns of these two species.

‘Scotch’ (Mentha × gracilis Sole) and ‘Native’ (Mentha spicata L.) spearmints are grown in the northern United States, but have not been evaluated in the Southeast. Two‐year field studies were conducted in Mississippi at two locations (Verona and Stoneville) to evaluate the effects of N application rate and cut (harvest time) on yields, essential oil contents, compositions, and the yield of individual oil constituents [(–)‐carvone, (R)‐(+)‐limonene, and eucalyptol] in Scotch and Native spearmints. Application of N at 80 and 160 kg/ha increased herbage and oil yields in Scotch, suggesting that commercial Scotch plantations should be provided with 160 kg N/ha. Native spearmint provided similar herbage yields when fertilized with 80 or 160 kg N/ha, but the higher N rate increased oil yields. The essential oil yields in this study were higher than the average oil yields for spearmint grown in the United States during 2008. The essential oil composition of Scotch and Native spearmints grown in Mississippi were similar to the oil produced in other states and other regions in the world. At the Verona site, the average (–)‐carvone concentration in the essential oil of Scotch was 68 to 75%, whereas the concentration of (–)‐carvone in Native oil ranged from 59 to 62%. At Stoneville, the average (–)‐carvone concentration in Scotch oil was 74%, whereas (–)‐carvone in Native oil was 68 to 74%. Both Scotch and Native spearmints could be grown as essential oil crops in Mississippi and possibly in other areas of the southeastern United States.

Water spinach (Ipomoea reptans Poir) is one of the horticultural crops known for its very easy cultivation and fast harvest cycle and high nutritional value. This plant can be produced or cultivated hydroponically using NFT (Nutrient Film Technique) and DFT (Deep Flow Technique) systems. Cultivation of plants in the NFT system uses a sloping circuit with shallow nutritious water that circulates for 24 hours at a fast flow. The DFT system uses a closed-circuit insulated with stagnant water that circulates for 24 hours at a slow flow. Thus, this research was conducted to determine the differences in the production of water spinach in two hydroponic systems, namely NFT and DFT. The research was conducted using a Randomized Block Design (RAK) and observation method by observing plant height, number of leaves, wet weight, and root length. Data were analyzed using independent samples T-test with a prerequisite test in the form of the Shapiro-Wilk normality test. The results of this research showed that the cultivation of water spinach using NFT and DFT hydroponic systems had significant differences in plant height, number of leaves, root length, and wet weight. Water spinach production can be increased by using DFT compared to NFT.

The objective of this study was to find the influence of different humic acid concentration and foliar application times on aboveground biomass and essential oil production of hyssop (Hyssopus ofi¬cinalis L.) in 2008 and 2009 at experimental field of Ferdowsi University of Mashhad in Iran. The field experiment was a factorial based on randomized complete block design with three replications. Two times of foliar applications of humic acid (one time in first cut, two times in both cuts) were applied along with four humic acid concentrations (0, 100, 200 and 300 mg/l) in this experiment. Aboveground and leaf biomass and essential oil production, harvested at flowering were measured as annual production of hyssop (H. ofi¬cinalis L.). Essential oil percentage did not response to different treatments in both years of experiment. Different application times did not change harvested aboveground biomass and essential oil production. Humic acid concentration showed great influence on aboveground and leaf biomass and essential oil production. Highest concentration of humic acid (300 ml/L) resulted in highest amounts of aboveground (+88%) and leaf (+77%) biomass and essential oil production (+71%) compared to control treatment. Hyssop produced higher biomass (+4%) and oil (+3%) in highest concentration of humic acid (300 ml/L) in the second year of the experiment compared to the first year. Key words: Biomass, essential oil, foliar application, humic acid, Hyssopus ofi¬cinalis.

Nutrient film technique (NFT) is characterized by the reduction of the dissolved oxygen concentration (DOC) in the recirculating nutrient solution along the gully; this is most intense in warm climates like the Mediterranean region. In this case, plant’s roots at the end of gully suffer from oxygen deficiency. The aim of this study was to develop a new soilless system without substrate which eliminates this NFT drawback and the cost of the substrate. Therefore, a new soilless system was designed. This new system associated the continuous drip irrigation along the gully with the recirculation of the nutrient solution and it was defined as Nutrient Drip Technique (NDT). In addition, the root gully was modified and shaped as W to provide better drainage of the nutrient solution in NDT system compared to NFT system. This system was tested for a tomato crop and compared with an NFT system and for a cucumber crop and compared with a media-based perlite and an NFT system. DOC measurements were taken along the gullies of the different systems. The results indicated that DOC of the nutrient solution along the gullies of NDT was higher and more uniform compared to NFT. Both tomato and cucumber plants grown in NDT system had higher Leaf Area Index (LAI) and were more productive compared to the conventional NFT system. Cucumber crop in NDT system had similar growth and productivity as in the perlite system. Water Use Efficiency (WUE) was higher in NDT compared to NFT system. Consequently, NDT system provides a better control of the root environment and the independence of porous substrates.

Mentha Spicata (spearmint), an herbaceous perennial aromatic plant, is the most common herb in tropical and subtropical countries. The essential oil (EO) of Mentha spicata is a valuable source of antioxidants in nutraceuticals and cosmetic industries. In-vitro culturing of Mentha Spicata was done via the micro-propagation technique, and exogenous Mel was used as a plant growth regulator. The field trials involved the plant’s foliar spray of different concentrations of Mel at various time points. The EO of leaves of control and Mel-treated plants (S1-S6) was steam-distilled using a Clavenger-type apparatus. The UV, FTIR, and GC analyses of the EO of control and S1-S6 were recorded. The antioxidant capacity of the EO of control and S1-S6 was measured using a DPPH (1, 1-diphenyl-2-picrylhydrazyl) assay. The nodal explants of Mentha Spicata showed different responses to the shoot proliferation process in the presence of exogenous Mel. The EO yield percentage of control and S1-S6 were in the range of 0.92±0.05% and 0.74±0.03%-0.39±0.04%%, respectively. The UV, FTIR, and GC spectra of the EO of control and S1-S6 presented different numbers of peaks and compounds in the selected range. The EO of control and Mel-treated plants could reduce the free radical DPPH to DPPHH with varying values of IC50. Melatonin could regulate the plant’s growth and development, change the EO yield, improve the EO’s phytochemical profile qualitatively, and enhance the free-radical scavenging capacity of the plant’s EO in a concentration and time-dependent mode. So, it may act as a promising molecule to increase aromatic crop yield with the desired quality.

HYDROPONIC FORCING OF TULIP USING A NUTRIENT FILM TECHNIQUE

The development of aquaculture with a hydroponic system is now more and more chosen by the community because of the increasingly limited land, but also comparable to the increasing demand for water. Hydroponics with the Nutrient Film Technique (NFT) system can be used as a solution to the water needs needed in the cultivation of hydroponics plants. This study aims to design the hydroponic installation of the NFT system and grow plants in the NFT system. The study was conducted with the stages of making the hut, making the installation, seeding, making nutritional solutions and transferring seed to the installation. The research will be conducted for five months. Descriptive research with qualitative data obtained is the way of making the NFT system, plant growth speed and the amount of water needed. Making the installation begin with the construction of the hut and shade then arranges the installation. For lettuce, the harvest time is 38 days dan tomatoes 50 days after the plants are moved to the plant. The need for water in the NFT hydroponic system is 190 liters.

Current vector control strategies based on synthetic chemicals are not eco-friendly against non-target organisms; hence, alternative approaches are highly required. Commercially purchased oil of Mentha spicata (Spearmint) and Eucalyptus citriodora (Citriodora) were examined against the medical pest Cx. quinquefasciatus (Say) and their non-toxicity on the aquatic species was evaluated. Chemical screening with gas chromatography coupled with mass spectrometry (GC-MS) analysis revealed a total of 14 and 11 compounds in Citriodora and Spearmint oils, respectively, with the highest peak (%) at carvone (70.44%) and isopulegol (30.4%). The larvicidal activity on the fourth instar larvae of Cx. quinquefasciatus showed dose-dependent mortality and significance at a 100ppm concentration 48h post-treatment with Citriodora (76.4%, P ≤ 0.001) and Spearmint (100%, P ≤ 0.001). Additionally, the photomicrograph of the fourth instar larvae revealed significant physical abnormalities in the head and midgut tissues post-exposure to Spearmint and Citriodora oils. Moreover, the histological assay revealed severe damage in the epithelial cells and gut lumen 2 to 24h post-treatment. The repellency percentage of adult Culex mosquitoes was prominent across both oils at 150ppm 210min post-exposure. Non-target toxicity on the aquatic predator showed both essential oils (Spearmint oil (17.2%) and Citriodora oil (15.2%)) are safer at the maximum treatment (200ppm) compared to temephos (75.4% at 1ppm). The in silico screening of phyto-compounds derived by both essential oils with BeeTox (online server) showed no contact toxicity to the honey bee Apis mellifera. Overall, the present research revealed that Spearmint and Citriodora essential oils and their active phyto-compounds were toxic to Cx. quinquefasciatus and harmless to the aquatic predator and honey bee.

The present study was carried out to evaluate aerial yield, agronomic traits, essential oil production, and their relationships in 21 populations of Ziziphora tenuior in Karaj, Iran over two years (2016–2017). The experimental layout was a randomized complete block design with three replications. Data were collected for GDD (Growth Degree Days), plant height, canopy area, stem number, flower number, aerial fresh yield, aerial dry matter (DM) yield, seed yield, essential oil percentage and oil production. The essential oil compositions were detected in accession 2929 (Tassoj) using GC/MS. Result of combined analysis of variance across two years showed significant differences between years, populations and population x year interaction for all traits (P &lt; 0.01). In comparisons among populations, the population of Avaj and Ijroud with average values of 13.5 and 14.33 g/p had higher aerial dry yield and other agronomic traits followed by Meshkin2 and 3. For seed yield, Ormieh with average values of 3.11 g/p had higher production. For oil content, the populations of Tassoj, Salmas and Sharkord with average values of 1.25 to 1.56% had higher oil content and essential oil production. Result of correlation analysis showed that DM yield was positively correlated with GDD, plant height, canopy area, stem number, flower number. Oil content was negatively correlated with aerial DM yield. The results of PCA analysis showed that the first four components accounted for 50, 20, 12 and 10% of the total variation, respectively. Plant height, canopy area, stem number, flower number and aerial yield in the PCA1, essential oil content and oil production in the PCA2, seed yield in the PCA3 and GDD in PCA4 components were identified as important traits. Using Ward cluster method, the 21 populations were grouped into 3 clusters. In total, 23 compounds were identified in the essential oil from the aerial parts Z. tenuior. The major components in the essential oil were pulegone ranged (47.54 to 65.26%) followed by neo-iso-dihydro carveol, carvacrol, piperitenone, limonene, 1.8-cineole, p-mentha-3,8-dien, alpha-terpinene and terpinen-u-ol. It was concluded that there were wide range of variations for agronomic trait and essential oil in domestic germplasm of Z. tenuior to improved breeding new varieties in Iran.

Mentha viridis (Lamiaceae) has a great potential for economic exploration due to its essential oil production, which is widely used in chemical and pharmaceutical industries. The aim of this work was to study the effect of light spectra, in the presence and absence of growth regulators (BAP), and light intensity on M. viridis growth and production of volatile compounds under in vitro conditions. Nodal segments from prior established in vitro cultured plants were placed on solidified MS medium in the presence and absence of BAP under different light-emitting diodes (LED): blue; red; blue:red at proportions of (2.5:1) and (1:2.5); and fluorescent light. The explants were also exposed to a photosynthetic photon flux density (PFD) of 28, 51, 64, 76 and 113 μmol m(-2) s(-1) using a cool fluorescent light. After 30/40 days of culture, growth and production of volatiles of the plants was verified by Head-Space - GC/MS. Blue and red LED combinations promoted the growth of plantlets significantly. The presence of BAP negatively affected plantlet growth. PFD affected plantlet growth and morphological characteristics of M. viridis. The rise in light intensity promoted a higher accumulation of dry matter of leaves and total plant. The production of volatile compounds was affected both in quality and quantity by light conditions applied in this experiment. Therefore, the manipulation of spectrum and light intensity in in vitro culture environment, might be a strategy for the production of compounds of interest to industries.

Aims: The cultivation of medicinal plants in intercropping with other species of agricultural use has been an alternative to make production sustainable in family farming. The objective of this work was to evaluate the growth, biomass production, and chemical composition of the essential oil of mint (Mentha x gracilis Sole) in intercropping with fruit species in an agroforestry system.&#x0D; Study Design: The experimental design was randomized blocks with four treatments, mint interplanted with citrus (Citrus sinensis L. Osbeck), bananas (Musa spp.), blackberries (Morus nigra), or Barbados cherries (Malpighia glabra).&#x0D; Place and Duration of Study: The experiment was conducted in the agroforestry located in the sector of Olericultura of the Federal University of Technology – Paraná (UTFPR), Brazil, in the period between November 2015 to February 2017.&#x0D; Methodology: We analyzed light intensity, relative chlorophyll index, height, leaf area, biomass accumulation, essential oil content, oil production and chemical composition of mint grown in agroforestry.&#x0D; Results: The highest production of biomass and essential oil were obtained in the intercropping of mint with citrus and Barbados cherries, possibly due to the edaphic climatic conditions, such as greater light intensity, that favored the growth, production, and chemical composition of the mint essential oil. Bananas and blackberries intercropped with mint were not beneficial for the growth and production of essential oils.&#x0D; Conclusion: The intercropping of mint with citrus and Barbados cherries resulted in higher growth, biomass accumulation, and essential oil content and production. The major components of the essential oils were linalool and carvone, with higher percentages in the intercropping of mint with citrus and Barbados cherries. The cultivation of mint by intercropping with fruit species such as citrus and Barbados cherries is an option to diversify the production of medicinal plants, making it sustainable.

Hydroponic Nutrient Film Technique (NFT) system is a method of cultivating plants with plant roots growing in shallow and circulating hydroponic nutrient layers so that plants can get enough water, nutrients, and oxygen. Plants grow in layers of polyethylene with plant roots submerged in water containing nutrient solutions that are circulated continuously with a pump. Arduino is used as a microcontroller that regulates the composition of solutions containing nutrients to be circulated with a pump by the NFT system Hydroponics. A tool that can regulate the circulation of nutrients for the NFT system automatically.