Pre-harvest Application of Chitosan with Carvacrol on Biochemical, Qualitative and Shelf Life Characteristics of Strawberry (Fragaria × ananassa Duch)

IntroductionThe increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds. Strawberry (Fragaria   ananassa cv. qingxiang) is one of the most popular and widely consumed berries due to its taste, sweetness and healthy function. The taste of strawberry is related to its hardness, viscosity, sugars, protein, total soluble solid, titratable acidity content and minerals like P, K, Ca and Fe. It is a good source of polyphenolic compounds such as flavanols and has antioxidant activity. This, together with higher vitamin C content in strawberries, contributes beneficial effects on the maintenance of consumer health. Strawberry has higher antioxidant activities than orange, grape, banana, apple, etc. Strawberries are among the fruits sensitive to mechanical and physiological damage and have a fast metabolism and deterioration during the storage period. For this reason, it is necessary to use safe methods to control spoilage and maintain the quality of strawberry fruit during storage. Materials and Methods The experiment was conducted in a completely randomized design, in a 5 x 4 factorial scheme (5 treatments x 4 periods evaluated), with four replications The first variable was the type of material with different concentrations in five levels including 0, 0.3%, 0.6% carvacrol, the combination of chitosan with 0.3% and 0.6% carvacrol, and the second variable was storage time in four periods including 0, 10, 20, 30 days of storage. The harvested fruits were kept at  4°C and with a relative humidity of 90±5% and parameters such as weight loss, pH, firmness of the fruit tissue, acidity (TA), soluble solids (TSS) and taste index, vitamin C, phenol and flavonoid, fruit shelf life (number of days) during the storage period were investigated and studied. Results and Discussion The ANOVA results showed that the effect of the type of treatment and storage time on all investigated traits except for the firmness of the fruit texture was significant at the probability level of 1%. The fruits treated with the combination of chitosan and carvacrol 0.6% had more texture firmness, vitamin C, total phenol content and the amount of soluble solids and better shelf life than the control. In all four storage times, the highest content of total phenol (2.49 mg of gallic acid per 100 gr FW), total flavonoid (0.435 mg of Quercetin per 100 gr FW) and firmness (3.80 N) was related to the combined treatment of chitosan with carvacrol 0.6% and the lowest amount was related to the control. The firmness of the fruit tissue gradually decreased during storage, but this process was observed at a significantly slower rate in the treated fruits. ConclusionConsidering the increase of 10 and 12 days of shelf life post- harvest of the combined treatment of chitosan + 0.6% carvacrol compared to other treatments and the control, hence the application of chitosan pre harvest and the use of 0.6% carvacrol edible coatings can be recommended as a safe and low-cost strategy to increase the shelf life post harvesting of 'Parus ' strawberry cultivar

Investigation of Growth Indices and Gas Exchanges in Two Cultivars of Sweet William (Dianthus barbatus) under Salinity Stress

Introduction  Salinity stress impairs the absorption of elements such as potassium, leads to decrease in water and minerals, or due to an increase in Na+ effects the absorption of other elements. Salinity of water and soil is one of the obstacles to the expansion of agriculture in most part of the world. Salinity causes several physiological and morphological changes in plants and affects growth and photosynthesis. Salinity stress also affects the absorption of nutrients, and finally the plants sensitivity to stress increases. High concentrations of Nacl in rhizosphere reduce the water potential and cause physiological drought stress. In addition, salinity stress can cause ion toxicity and imbalance, which can damage the plant. Salinity stress has been shown to reduce plant biomass by decreasing photosynthetic capacity and chlorophyll content. As stress increases, stomatal conductance and CO2 assimilation decrease, which both negatively impact photosynthesis and lead to a decrease in plant growth. Dianthus is an annual or perennial plant that produces velvety flowers in various colors. Due to its resistance to cold and wide range of colors, it is commonly used in landscaping. However, limited research has been conducted on the response of Dianthus to environmental stress, making it important to investigate its behavior under such conditions. Material and Method  This research was conducted at greenhouse of municipality of Khomein, Iran. The statistical design was used in the factorial experiment based on CRD. Experimental factors included salinity stress (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 mM) and cultivars (Barbarin and Diana). After preparing the seeds, it is first disinfected using sodium hypochlorite and then planted in plastic pots containing soil, sand and manure. At the end of the experiment, morphological traits, stomatal conductance, photosynthesis rate, Na+, K+ and Na+/K+ was also examined. Gas exchanges were measured using an exchange measuring device (LCA4, ADC Bioscientific,Ltd., Hoddesdon, England). At the time of measuring gas exchanges, the temperature under chamber was 26-29 C and relative humidity was 58-62%. (stomatal conductivity is based on mmol/m2/s and photosynthesis in µmol/m2/s). To measure the concentration of Na+ and K+, the leaf first turned to ash (at 550 C). Then 5 ml of hydrochlorid was added to dissolve the sample and the volume of the filtered solution was reduced to 50 ml with distilled water and the concentration of Na+ and K+ was measured with flame meter. In order to measure the fresh weight of leaves and roots, plant components were separated. Fresh weight was recorded with a scale and then samples were placed in the oven (for 48 h) and weighted again to measure dry weight. Leaf area was measured with a leaf guuge device (A30325) and plant height and root length using a ruler. Statistical analysis of data was performed using Mini Tab and Excel software. Results and Discussion  Results showed that salinity stress generally affected the growth of both carnation cultivars and reduced vegetative and reproductive growth. According to the results obtained from the study, fresh and dry weight of shoot, root and leaves, root length, plant height, stem diameter, diameter and number of flower, lateral shoot number, stomatal conductance, photosynthesis rate, K+ concentration in Diana and Barbarin cultivars decreased with increasing salinity level. Na+ concentration and Na+/K+ increased with increasing salinity and these two traits were higher in Diana than Barbarin cultivar, which indicates lower resistance of Diana cultivar. The plant's first response to stress is to reduce its leaf area, which reduces the supply of photosynthetic material to the growing parts and consequently hinders growth and flowering. Salinity stress and high osmotic potential in the rhizosphere greatly affect photosynthesis as they decrease pore conductivity. Moreover, excessive absorption of Na+ can interfere with the absorption of other elements, thereby restricting plant growth. Potassium (K+) is an essential inorganic molecule that plays a crucial role in increasing plant resistance to stress. It helps in maintaining turbidity, promoting cell development, and regulating stomatal function. In this study, salinity stress affected the growth and yield of both carnation cultivars, and with increasing stress, all morphological traits decreased. This stress also reduce photosynthesis by reducing stomatal conductance and subsequently reduce other growth characteristics. Growth reduction was observed at high salinity stress concentrations in both cultivars. However, barbarin cultivar showed higher resistance than Dian

Chemical Composition and Antioxidant Activity of Essential Oils in Origanum vulgare subsp. gracile at different Phenological Stages and Plant Parts

Origanum vulgare, a popular flavoring herb, is valued for several biological properties. The present study focused on the chemical composition and antioxidant activity of the essential oils of Origanum vulgare subsp. gracile in different plant parts and at different phenological stages. Qualitative and quantitative analyses of the essential oil identified 41 constituents that varied with plant age and organ. The phenolic monoterpenoid carvacrol (18.1–79.2%) was predominant in all the essential oil samples. Other major constituents were p-cymene (3.9–18.0%), γ-terpinene (0.9–15.8%), carvacrol methyl ether (0.8–9.9%), and (Z)-α-bisabolene (0.5–8.7%). Among the different plant parts and phenological growth stages, the highest levels of carvacrol were identified in the essential oils from flowers (79.2%), roots (70%), and the early vegetative growth (67.34%). All the essential oils exhibited high radical-scavenging properties as shown in the DPPH* assay. The essential oils from flowers, however, exhibited the highest antioxidant activity and could be used as a preservative agent on an industrial scale

Biochar amendment improves growth and the essential oil quality and quantity of peppermint (Mentha × piperita L.) grown under waste water and reduce environmental contamination of waste water disposal

The reuse of waste water (WW) in agriculture is challenging as a potential strategy for sustainable agriculture development. However, its high content of heavy metals may cause damage to ecosystems. The property of biochar (BC) to minimize heavy metals accumulation into the soil was studied taking as a case study peppermint (Mentha x piperita L., Lamiaceae) irrigated with WW. Application of BC and WW, separately, promoted height, shoot number, crown diameter, internode length, leaf number, leaf length, leaf width, fresh (FW) and dry aerial parts weights (DW), root FW and root DW of peppermint. Also an increment in canopy diameter was observed. BC application considerably increased N, Mg, Mn, Fe and Zn, while WW increased N, P, K and Fe levels. Irrigation of peppermint with WW led to an increase of chlorophyll (Chl) a, Chl b, Chl a+b, carotenoids, anthocyanins, photosynthetic rate, transpiration, stomatal conductance, relative water content (RWC), and crop yield. On the other hand, BC application led to a decrease of Cd and Pb accumulation in plants. BC and WW application, separately, increased the essential oil content, the total phenol content, and the antioxidant capacity. Regardless of BC levels, irrigation of plants with WW decreased the percentage of menthone, menthofuran, isomenthone and pulegone in the essential oil, and increased the percentage of menthol and carvone. Similarly, BC application raised the percentage of menthol, and decreased that of pulegone. Overall, the application of BC in the culture medium is able to decrease the heavy metal concentration and improves the essential oil quality and quantity of peppermint under WW irrigation

Effects of Micronutrients on the Growth and Phytochemical Composition of Basil (Ocimum basilicum L.) in the Field and Greenhouse (Hydroponics and Soil Culture)

The current research was conducted to compare the growth, yield, and phytochemical composition of basil (Ocimum basilicum) in the open field and the soil and hydroponic cultivation in a greenhouse. Furthermore, the effect of foliar spraying of micronutrients on this crop was also evaluated. In each of the cultivation systems, foliar spraying of one micronutrient, either iron sulfate (Fe), zinc sulfate (Zn), copper sulfate (Cu), manganese sulfate (Mn), or boric acid (B), at a concentration of 0.1% was applied in a randomized complete block design. Plants grown in the hydroponic system had higher yield and biomass. The concentration of the elements K, Ca, Mg, N, P, Mn, Fe, B, and Zn in the leaves of hydroponic plants was higher. Contrarily, plants cultivated in the field showed higher stem dry weight, essential oil content, phenolic and flavonoid content, and antioxidant activity. The level of methyl chavicol was higher in the hydroponic culture, but the level of 1,8-cineole was much lower in this cropping system. Foliar spraying of Cu, Mn, Zn, Fe, or B significantly increased leaf dry weight and anthocyanin content. In field conditions, the highest levels of phenolics, flavonoids, and antioxidant capacity were observed with Zn or Mn application. In the hydroponic system, foliar spraying of Zn or B led to the highest antioxidant capacity, and total phenolic and flavonoid contents. Overall, the basil plants cultivated in the field showed higher bioactive ingredients. However, the essential oil of plants cultivated in the hydroponic system had a higher economic value due to its higher percentage of methyl chavicol

Natural diversity in phenolic components and antioxidant properties of oregano (Origanum vulgare L.) accessions, grown under the same conditions

Oregano (Origanum vulgare L.) is a rich source of biologically active components such as phenolic compounds. Here, seven pot grown O. vulgare accessions belonging to three subspecies (subsp. virens, subsp. vulgare and subsp. gracile) were investigated for their content in sixteen bioactive phenolic compounds as well as their antioxidant capacities (DPPH• and FRAP tests), total phenolic content (TPC) and total flavonoid content (TFC) in order to identify the most suitable ones on an industrial level. HPLC analyses showed that rosmarinic acid (659.6–1646.9 mg/100 g DW) was by far the most abundant constituent, followed by luteolin (46.5–345.4 mg/100 g DW), chicoric acid (36.3–212.5 mg/100 g DW), coumarin (65.7–193.9 mg/100 g DW) and quercetin (10.6–106.1 mg/100 g DW), with variability in concentration depending on the accession and subspecies. The highest level of rosmarinic acid and TPC was obtained from Ardabil accession (subsp. virens). There was a significant and positive correlation between rosmarinic acid and antioxidant activity (r = 0.46). TFC significantly correlated to TPC (r = 0.57) as well as to chicoric acid (r = 0.73). Cluster (CA) and principal component (PCA) analyses classified the investigated accessions in three different groups. Such natural variabilities in phenolics provide the possibility of using elite plants for nutraceutical and pharmaceutical industries and domestication of highly antioxidative accessions of oregano

Comparison of drying methods for the extraction of essential oil from dragonhead (Dracocephalum moldavica L., Lamiaceae)

In the present study, the effect of six different drying methods on the essential oil content and compositions of aerial parts of Iranian dragonhead was assessed. The highest and lowest essential oil contents (1.85 and 0.45%, respectively), were achieved in freeze-drying method and oven drying at 60°C, respectively. Essential oil analyses showed that the main constituents were geranyl acetate (56.5–33.2%), geranial (10.8–27.9%), neral (7.3–20.3%), and geraniol (6.7–13.5%). The high- est percentages of geranyl acetate (56.5%) and geraniol (13.5%) were obtained with oven drying at 60°C. Cluster analysis of the essential oil constituents demonstrated three main groups based on drying methods. Freeze drying of aerial parts of dragonhead was the most suitable method allowing high-essential oil yields and short drying time. On the other hand, the highest level of marker compounds such as geranyl acetate and geraniol was obtained with oven drying at 60°C

Phenolic monoterpene-rich essential oils from Apiaceae and Lamiaceae species: insecticidal activity and safety evaluation on non-target earthworms

The genera Oliveria (Apiaceae), Thymus and Satureja (Lamiaceae) encompass important medicinal and aro- matic plants of Iran, which contains noteworthy amounts of essential oils (EOs) that are worthy of exploitation on an industrial level, including pesticide formulation development. In this study, the efficacy of five EOs obtained from O. decumbens, T. daenensis, S. sahendica, S. khuzistanica and S. rechingeri, was evaluated against three insects of economic relevance, the mosquito Culex quiquefasciatus, the housefly Musca domestica, and the moth Spodoptera littoralis. Potential non-target effects of these EOs were assessed on earthworms, Eisenia fetida. The chemical composition of the five EOs was determined by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). EOs from O. decum- bens, T. daenensis, S. khuzistanica and S. rechingeri were characterized by oxygenated monoterpenes (70.3, 91.6, 89.7 and 89.4%, respectively), whereas the EO from S. sahendica was dominated by monoterpene hydrocarbons (63.3%) followed by oxygenated monoterpenes (35.3%). In all cases, the biogenetically related thymol (0.3–36.7%), carvacrol (1.3–89.6%), p-cymene (2.1–13.7%) and γ-terpinene (1.5–41.3%) were found as the characteristic volatile compounds of the five EOs, with high quantitative variation according to the species considered. The five EOs exhibited high toxicity on the three target insects, with LC50/LD50 values in the range of 16.2–29.3 μg mL-1, 18.1–48.1 μg adult-1 and 7.4–23.1 μg larva-1 on C. quin- quefasciatus, M. domestica and S. littoralis, respectively. Toxicity of the five EOs on non-target soil invertebrates was mini- mal, leading to no or very low (5.0–7.5%) mortality on E. fetida when tested at the concentration of 200 mg kg-1, at variance with the positive control α-cypermetrin, which caused 100% mortality at 0.1 mg kg-1 of soil. Overall, our study discloses new opportunities to farmers growing these Iranian endemic plants, shedding light on the potential of these EOs to formu- late effective and eco-friendly insecticides