Effects of organic and chemical nitrogen fertilization and postharvest treatments on the visual and nutritional quality of fresh-cut celery (Apium graveolens L.) during storage.

The shelf life of horticultural commodities depends on pre- and postharvest factors, such as soil fertilization and postharvest handling. The current study aimed to evaluate fresh-cut celery's postharvest quality as affected by the rate and type (organic and chemical) of nitrogen (N) fertilizer and postharvest treatments. Celery ('Tall Utah') crop was grown in a field in Karaj, Iran. The experimental design was a randomized complete block with three replications and seven preharvest (fertilizer), and five postharvest treatments. Organic fertilizers were vermicompost (VER) and bio-organic fertilizer [farmyard and livestock manure plus Trichoderma harzianum (COM)]. Chemical fertilizers were urea (46% N) at high rate [322 kg·ha1 N (UREA_HIGH)], optimal rate [196 kg·ha-1 N (UREA_OPT)], and low rate [138 kg·ha-1 N (UREA_LOW)]; ammonium nitrate [35% N (AN)] at 196 kg·ha-1 N; and treatment without fertilization was used as a control. Postharvest treatments included plastic packaging (PP), hydrocooling (HC), blanching (B), and edible coating of psyllium seed mucilage (EC). After postharvest treatments, celery petioles were stored (0-2°C, 85%-90% RH) for 4 weeks and evaluated weekly for quality attributes. Organic fertilizers and UREA_LOW were the most effective treatments in reducing the changes in color, weight loss, titratable acidity (TA), pH, and total soluble solids (TSS) of fresh-cut celery. Organic fertilizers enhanced the vitamin C content, total phenols, and antioxidant activity in celeries. As postharvest treatments, hydrocooling, plastic packaging, and blanching maintained chroma and hue values. Blanching had the greatest effect on the L* value. Hydrocooling increased celery's TA, TSS, and vitamin C content and reduced weight loss and pH during storage. Thus, celery quality was improved when grown under low or adequate N fertilization. Hydrocooling was an effective postharvest treatment for preserving fresh-cut celery quality during storage.

Essential oil constituents and variations in antioxidant compounds of dried summer savory (Satureja hortensis cv. Saturn) affected by storage conditions and ammonium sulfate.

Considering the importance of spice plants and their shelf life, as affected by various factors, the current study considered Summer savory plants (Satureja hortensis cv. Saturn) for evaluation under the application of different concentrations of ammonium sulfate (0, 40, 60, 80, and 100 kg/ha) as primary treatments. Based on the plant response, the control group and 100 kg/ha ammonium sulfate were selected as suitable treatments for storage experiments (i.e., storage at ambient, refrigerator, and freezer temperatures for 8 months). Based on the results, the highest percentage and yield of S. hortensis essential oil and biomass occurred in response to 100 kg ammonium sulfate, whereas the lowest amounts were observed in the control group (i.e., in the absence of ammonium sulfate). During the storage period, the essential oil content decreased, but the carvacrol content of the essential oil increased. During the different durations and conditions of storage, the stability of secondary metabolites varied. Essential oil, rosmarinic acid, and carvacrol contents maintained greater stability in plants treated with ammonium sulfate (100 kg/ha), compared with the control group during the storage period. It can be concluded that the preharvest application of ammonium sulfate on S. hortensis improved plant growth and quality indices at preharvest time, while also maintaining the stability of its active ingredients at the postharvest stage and storage time. It also led results to recommend storing Summer savory in the freezer to better preserve its secondary metabolites.

Selenium Fortification Alters the Growth, Antioxidant Characteristics and Secondary Metabolite Profiles of Cauliflower (Brassica oleracea var. botrytis) Cultivars in Hydroponic Culture.

Nowadays the importance of selenium for human health is widely known, but most of the plants are poor in terms of selenium storage and accumulation because of the low selenium mineralization potential of the soil. For this purpose, foliar application of different sodium selenate concentrations (0, 5, 10, 15, 20 mg/L) was used to treat the cauliflower cultivars "Clapton" and "Graffiti". Higher yields and other related vegetative attributes were improved at 10 and 15 mg/L sodium selenate application. At a concentration of 10 mg/L sodium selenate, photosynthetic pigments, total phenolic compounds and antioxidant capacity were enhanced in both cultivars, but the "Graffiti" cultivar responded stronger than the "Clapton" cultivar. The glucosinolates were accumulated in response to selenium fortification and the highest amounts were found in the "Graffiti" cultivar at 10 mg/L. Selenium accumulated concentration-dependently and rose with higher fertilization levels. In general, foliar application of selenium at 10 mg/L led to an accumulation of secondary metabolites and also positively affected the growth and yield of florets.

Effects of exogenous application of citrulline on prolonged water stress damages in hyssop (Hyssopus officinalis L.): Antioxidant activity, biochemical indices, and essential oils profile.

This study examined the effects of exogenous citrulline (control, 1 and 2 mM) and water availability (100%, 50% and 25% WA) on antioxidant attributes and essential oil constituents of Hyssopus officinalis L. in two successive harvests. Hyssop tolerantly responded to water deficiency by well-promoted antioxidant enzymes (i.e., superoxide dismutase, and catalase), strong DPPH-scavenging activity, and increasing polyphenols; however, the essential oil content was negatively reduced by water stress. External citrulline further increased the activity of antioxidant enzymes. Citrulline application at 2 mM under severe water stress could also improve essential oil (EO) content in the first and second harvests by about 15 and 30%, respectively. Furthermore, under severe drought, citrulline at 2 mM could obtain the highest yield of isopinocamphone (47%) as the main component of EO. The results showed the high potential of this novel applied metabolite agent to be used in a well-fulfilled production of this medicinal plant.

Morphological, physiochemical and antioxidant responses of Maclura pomifera to drought stress.

Drought is one of the most important environmental factor limiting the growth of woody and non woody plants. In the present paper, we aimed to explore the performance of Maclura pomifera under a prolonged drought period followed by re-watering. M. pomifera plants were exposed to four different watering regimes (100%, 75%, 50% and 30% of the field capacity (FC)) for three weeks and then rewatered. The exposure to drought affected physiological, morphological and biochemical traits of M. pomifera. Leaf area, relative water content and water potential of leaf decreased in parallel with increased water deficit. Malondialdehyde content increased along with the drought stress experiment. Soluble carbohydrates (sucrose, glucose and fructose) accumulated during drought stress, but decreased after 22 days of water deficit in severe stressed plants (30% FC). Proline and mannitol, two compatible osmolytes, were higher in drought stresses plants than in control plants. Additionally the activity of antioxidant enzymes (SOD, APX, DHAR and GR) resulted affected by drought stress. In the recovery period, the physiological parameters as well as the proline content recovered at control levels, whereas soluble sugars, mannitol and total activity of antioxidant enzymes remained slight higher than in control plants, presumably to allow plants a complete recovery after stress. Our results suggest that M. pomifera has a good adaptive response to drought stress, probably corresponded to decreasing oxidative injury by induction of the antioxidant system and accumulation of stable and protective osmolytes such as proline and mannitol at higher rates.

Effect of foliar application with sodium selenate on selenium biofortification and fruit quality maintenance of 'Starking Delicious' apple during storage.

BACKGROUND: Selenium (Se) is an essential micronutrient due to its anticarsinogenic properties and positive influence on human immune system. Fortification of some fruits based on their rates of consumption and availability all year round appears to be an effective way to supplement Se in the human diet. In this study the possibility of augmenting Se content in 'Starking Delicious' apple fruit during two growing seasons was investigated. In 2016, the impact of 0, 0.5, 1 and 1.5 mg Se L-1 by foliar application on Se accumulation and fruit ripening as well as quality attributes was investigated. In 2017, the effects of 1.5 mg Se L-1 foliar application on fruit Se content and changes in the antioxidant system and storability were studied with a 30-day interval during 6 months storage at 0 ± 1 °C. RESULTS: Foliar application of Se significantly increased both leaf and fruit Se concentration. The increase in Se content enhanced the flesh firmness, titrable acidity, and soluble solid content of the fruit. The activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were markedly amplified by Se treatments as compared to the control, resulting in lower superoxide anion radical (O2 -• ) and hydrogen peroxide (H2 O2 ) contents, correspondingly higher membrane integrity as revealed by lower ion leakage and malondialdehyde accumulation and the fruit with lower water core. CONCLUSION: Application of Se was efficient in increasing fruit Se content and nutraceutical properties, retarding the flesh firmness reduction, and postponing fruit ripening resulting from lower ethylene biosynthesis rate, thereby positively affecting apple fruit quality and storability. © 2019 Society of Chemical Industry.

Comparison the effect of putrescine application on postharvest quality of Pyrus communis cv. "Shah-Miveh" and "Spadona".

Role of putrescine for extending storage life of pear cv. "Shah-Miveh" and "Spadona" was evaluated. The trees were sprayed by various concentrations of putrescine (0.5, 1, and 2 mM) and distilled water "control." After harvest, all samples were stored at 0 ± 1°C, 80%-85% RH for 21 weeks. Thereafter, some physico-chemical attributes were measured initially and after each storage period 7, 14, and 21 weeks. Putrescine at 1 and 2 mM reduced fruit softening, weight loss, color changes (L*, hue angle), fungal infection as well as retarded the degradation of total soluble solids, titratable acidity, ascorbic acid, total phenol (TP), and total antioxidant activity (TAA). However, fruit softening, weight loss, and hue angle rates were slower in "Shah-Miveh" to "Spadona." Moreover, at the end of storage, "Shah-Miveh" demonstrated more TP and TAA in compare to "Spadona." Thus, putrescine application at higher values may be an effective tool to prolong pear postharvest life during storage.

Preferentially enhancing anti-cancer isothiocyanates over glucosinolates in broccoli sprouts: How NaCl and salicylic acid affect their formation.

Broccoli (Brassica oleracea L. var. italica) sprouts contain glucosinolates (GLs) that when hydrolysed yield health promoting isothiocyanates such as sulforaphane (SF). SF content can be increased by salt (NaCl) stress, although high salt concentrations negatively impact plant growth. Salicylic acid (SA) treatments can attenuate the negative effects of salt on growth. To test whether sprout isothiocyanate content could be elevated without sprout growth being compromised, broccoli seed were germinated and grown for seven days in salt (0, 80 and 160 mM) alone and in combination with 100 µM SA. Increasing concentrations of salt lowered transcript accumulation of GL biosynthetic genes which was reflected in lowered content of Gluconapin, 4-methoxyglucobrassicin and neoglucobrassicin glucosinolates. Other glucosinolates such as glucoraphanin did not alter significantly. Salt (160 mM) increased transcript abundance of the GL hydrolytic gene MYROSINASE (BoMYO) and its cofactor EPITHIOSPECIFIER MODIFIER1 (BoESM1) whose encoded product directs MYROSINASE to produce isothiocyanate rather than nitrile forms. SF content was increased 6-fold by the 160 mM salt treatment, but the salt treatment reduced percentage seed germination, slowed seed germination, and reduced sprout hypocotyl elongation. This growth inhibition was prevented if 100 µM SA was included with the salt treatment. These findings suggest that the increase in SF production by salt occurs in part because of increased transcript abundance of genes in the hydrolytic pathway, which occurs independently of the negative impact of salt on sprout growth.

Impact of exogenous GABA treatments on endogenous GABA metabolism in anthurium cut flowers in response to postharvest chilling temperature.

Anthurium flowers are susceptible to chilling injury, and the optimum storage temperature is 12.5-20 °C. The γ-aminobutyric acid (GABA) shunt pathway may alleviate chilling stress in horticultural commodities by providing energy (ATP), reducing molecules (NADH), and minimizing accumulation of reactive oxygen species (ROS). In this experiment, the impact of a preharvest spray treatment with 1 mM GABA and postharvest treatment of 5 mM GABA stem-end dipping on GABA shunt pathway activity of anthurium cut flowers (cv. Sirion) in response to cold storage (4 °C for 21 days) was investigated. GABA treatments resulted in lower glutamate decarboxylase (GAD) and higher GABA transaminase (GABA-T) activities in flowers during cold storage, which was associated with lower GABA content and coincided with higher ATP content. GABA treatments also enhanced accumulation of endogenous glycine betaine (GB) in flowers during cold storage, as well as higher spathe relative water content (RWC). These findings suggest that GABA treatments may alleviate chilling injury of anthurium cut flowers by enhancing GABA shunt pathway activity leading to provide sufficient ATP and promoting endogenous GB accumulation.

Establishment and characterization of a Satureja khuzistanica Jamzad (Lamiaceae) cell suspension culture: a new in vitro source of rosmarinic acid.

An in vitro approach to the production of rosmarinic acid (RA), a medicinally important caffeic acid ester, in a cell suspension culture (CSC) of Satureja khuzistanica Jamzad (Lamiaceae) has been investigated for the first time. The CSC was established from friable calli derived from shoot tip explants in Gamborg's B5 liquid medium supplemented with 30 g/L sucrose, 20 mg/L L-glutamine, 200 mg/L casein hydrolysate, 5 mg/L benzyladenine (BA) and 1 mg/L indole-3-butyric acid (IBA). The effect of nitrogen source (KNO3 and (NH4)2SO4) and their different concentrations on the fresh and dry weight (g/L), as well as RA content (mg/g dry weight) were measured. CSC growth measurements indicated a maximum specific cell growth rate of 1.5/day, a doubling time of 7.6 days and a high percentage of cell viability (96.4 %) throughout the growth cycle. Maximum cell fresh weight (353.5 g/L), dry weight (19.7 g/L) and RA production (180.0 mg/g) were attained at day 21 of culture. Cell growth and RA content were affected by nitrogen deficiency. Media containing 8.3 mM of total nitrogen (» of B5 standard medium) led to a minimum cell fresh weight (243.0 g/L), dry weight (17.4 g/L) and RA content (38.0 mg/g) after 21 days. The established CSC provided useful material for further optimization experiments aimed at a large-scale production of RA.

In-vitro Callus Induction and Rosmarinic Acid Quantification in Callus Culture of Satureja khuzistanica Jamzad (Lamiaceae).

In the present study, an efficient protocol has been developed for callus induction and production of RA in callus culture of Satureja khuzistanica for the first time. In-vitro callus induction was achieved from young shoot tip explants cultured on MS and B5 media supplemented with different concentrations of IBA (0.1, 1.0, 2.0 and 5.0 mgL(-1)) solely or in combination with cytokinins BAP and KIN (1.0, 2.0 and 5.0 mgL(-1)). B5 medium supplemented with 1.0 mgL(-1) IBA plus 5.0 mgL(-1) BAP and MS medium fortified with 2.0 mgL(-1) IBA and 2.0 mgL(-1) BAP were the most favorable media for callus formation with the highest induction rate (96%). Maximum growth index (2.89 and 2.63) and maximum callus biomass (2.34 and 2.33 g fresh weight) were obtained from the callus cultured on B5 medium supplemented with 1.0 mgL(-1) IBA plus 5.0 mgL(-1) BAP and MS medium fortified with 1.0 mgL(-1) IBA plus 1.0 mgL(-1) KIN, respectively. Determination and quantification of RA in cultured calli were performed by HPLC UV/MS analysis. Calli induced from the plant and maintained on supplements of IBA and BAP in the absence of light produced RA 7.5% based on dry weight (DW). No differentiation was observed in any callus during the course of this study.

Prestorage oxalic acid treatment maintained visual quality, bioactive compounds, and antioxidant potential of pomegranate after long-term storage at 2 degrees C.

Oxalic acid at three concentrations (2, 4, and 6 mM) was applied by dipping to pomegranate fruits of cv. Mollar de Elche, which were then stored for 84 days at 2 degrees C. Pomegranate is a chilling-sensitive fruit and, thus, control fruits exhibited chilling injury (CI) symptoms after long-term storage at 2 degrees C that were accompanied by increased respiration rate, weight loss, and electrolyte leakage (EL). The CI symptoms were significantly reduced by oxalic acid treatment, especially for the 6 mM concentration. In addition, control pomegranates showed significant reduction in the content of total phenolics and ascorbic acid as well as in total antioxidant activity (TAA), in both hydrophilic (H-TAA) and lipophilic (L-TAA) fractions. The application of oxalic acid led to lower losses of total phenolics and significant increase in both ascorbic acid content and H-TAA, whereas L-TAA remained unaffected. Thus, oxalic acid could be a promising postharvest treatment to alleviate CI and increase antioxidant potential.