مژده اسدی

Harvest at inappropriate time is the most important factor in reducing the fruit quality, marketability, and postharvest life of kiwifruit. In this study, the effect of different harvest times on fruit quality, nutritional value, and organoleptic characteristics of two novel kiwifruits of yellow and red flesh was investigated. Fruits from promising genotypes were harvested at 130, 140, 150, 160, 170, and 180 days after full bloom (DAFB). The results showed that fruits harvested after 180 DAFB showed higher weight, length, diameter, dry matter, soluble solids content, and total soluble sugars. Meanwhile, titratable acidity was lower than fruits harvested earlier. The values of soluble solid content ranged from 6.80 to 11.66° brix in golden kiwifruit and from 6.90 to 13.70° brix in red flesh kiwifruit. With delayed harvest, total phenols, ascorbic acid content, DPPH and FRAP antioxidant capacity and hue angle in outer and inner pericarp decreased in both genotypes. Ascorbic acid content in the red-fleshed genotype decreased from 90.34 to 75.57 mg/100 g and in the golden genotype from 74.83 to 50.62 mg/100 g. Fruits from the red-fleshed genotype had the higher antioxidant capacity and nutritional value compared to the golden genotype. There was a positive significant correlation between ascorbic acid content and antioxidant capacity measured by DPPH (r=0.98) and FRAP (r=0.95) methods. In conclusion, novel golden and red flesh kiwifruit genotypes reached the minimum soluble solid content and hue angle for commercial harvest with favorable organoleptic properties only at 170 DAFB and the delay in harvest increased the organoleptic properties in both genotypes. However, the content of their antioxidant capacity was slightly lower compared to the early harvest.

The relative values of secondary metabolites may be impacted by harvesting time and post-harvest drying methods.

The effects of various harvesting stages of flower and drying methods were investigated on the quality and quantity of secondary metabolites of A. chamissonis Less. grown in the field.

The flowers were harvested in early May, June and July from four different developmental stages (stage 1: opening bud; stage 2: all radial florets or less than half of tubular florets opened; stage 3: all radial and tubular florets opened; stage 4: radial florets withering and seed formation). Also, the maximum collection of inflorescences during two years of trial was considered for drying method treatments (shade and sun drying, oven drying at 40 and 50 °C, and microwave drying at 500 and 1000 W power).

Results showed that the highest and the lowest total phenols were obtained in the second and first harvest date at flower maturity stages of 3 and 4, respectively. However, the highest luteolin and apigenin contents were obtained in the third harvest time at flower development stage 1. In the second experiment, the flower heads treated by shade contained the highest total phenols content followed by oven drying at 40°C. Moreover, oven drying was the most favorable method for preserving of other main secondary metabolites including total flavonoid, rutin, luteolin and apigenin.

Different harvesting dates at various flower bud phenological stages had significant effect on total phenols, flavonoids, rutin, luteolin and apigenin contents.

The genus Arnica L. comprises of 32 species predominantly confined to the boreal and montane region of the northern hemisphere. Arnica species are rhizomatous perennial herbs belonging to the daisy family, with simple or branched stems bearing opposite leaves, and large, single or cymose heads of yellow flowers. A. chamissonis is distributed over North America from Alaska to New Mexico, and due to its low ecological demand it is easier to cultivate than A. montana. Arnica is a source of sesquiterpene lactones, flavonoids, essential oils, terpenoids, and phenolic acids and exhibits antiseptic, anti-inflammatory, antiradical, antibacterial, anti-sclerotic, antifungal, and antioxidant activities. The flower heads and other parts of the plant of two of the species have been used therapeutically: A. montana and A. chamissonis, both of them containing sesquiterpene lactones as pharmacologically active compounds. Arnica species are used in as many as 300 drug preparations in Europe and about 20 products in Canada. Moreover, A. chamissonisis a good source of bioactive compounds a valuable source of herbal raw material and a pharmaceutical substitute for the endangered mountain arnica. A. chamissonis extracts exhibit potent anti-inflammatory and anti-radical activity and possesses high antioxidant abilities that might be helpful in preventing or slowing the progress of free radicaldependent diseases. Low pH soil is one of the principal ecological requirements of Arnica. Good plant growth and flower yield was achieved on acid soils with a pH of 6.8 and below. After nitrogen, phosphorus and potassium, sulfur is considered as fourth major element in most crops. Rate of sulfur oxidation in soils vary and depend on population Thiobacillus bacteria in soil, particle size and environmental conditions.

This study was conducted as a complete randomized block design with three replications and four treatments including different levels of bentonite sulfur (0, 250, 500 and 750 kg/ha) combined with the bacterium Thibacillus thiooxidans. Traits such as height and width of plants, number of flowers on each plant, inflorescence diameter, fresh and dry yield of flowers in each plant per square meter and total phenols, total flavonoids, rutin, luteolin and apigenin content in flowers were measured. High-Performance Liquid Chromatography method (HPLC) was used to separate rutin, luteolin and apigenin. HPLC grade methanol and distilled water, each with 0.02% added TFT were used as solvents.

The results showed that A. chamissonis is compatible with Tehran’s climate and it can be cultivated in regions with a similar climate. The use of elemental sulfur has a significant role in reducing soil pH and soil pH decreased more rapidly with increasing sulfur. Thiobacillus bacteria by oxidation of sulfur produced some to sulfuric acid and at low buffered properties can considerably reduce pH. Different levels of sulfur fertilizer had a significant effect (P ≤0.01) on soil acidity (pH), electrical conductivity, and sulfur, iron, zinc and manganese levels. The use of 750 kg sulfur bentonite with Thiobacillus caused to reduce soil acidity by about 0.9 units, and it increased the electrical conductivity of the soil to 7.33 dS/m. The amount of soil sulfate as a result of oxidation of sulfur fertilizers increased linearly. The highest amounts of iron, zinc and manganese were measured in the treatment of 750 kg sulfur as 3.38, 3.84 and 27.94 mg /kg, respectively. In this study, supplying 250 kg of sulfur plus bio-sulfur caused to improve the morphological traits and the highest flower yield (20.67 g / plant) compared to control (3.66 g / plant). Also, it increased the amount of sulfur and microelements in the soil, but in the treatment of 500 and 750 kg sulfur per hectare due to increased electrical conductivity and soil salinity, the growth of Chamisso Arnica decreased. Therefore, these levels of sulfur are not suitable for this plant. Sulfur Bentonite is oxidized by Thiobacillus bacteria and other microorganisms and sulfuric acid is produced. Reducing acidity and, as a result, the release of stabilized and insoluble nutrients can increase their uptake capacity and improve plant growth and development. Due to the increased salinity and osmotic imbalance in the soil by the treatments of 500 and 750 g /kg sulfur, vegetation growth will be incomplete and plants quickly enter to the reproductive phase and produce fewer and smaller flowers. The highest content of rutin was measured in plants grown in soil treated with 750 Kg/ha sulfur while soil treatment with 500 Kg/ha sulfur resulted in highest content of luteolin and apigenin, both showing significant difference to the control.

Results of this study indicated that the Chamisso Arnica showed adaptability to the planting location and it can be mass-cultivated under similar conditions.

Chia (Salvia hispanica L.) is an herbaceous annual plant of the Lamiaceae family. Chia seeds are rich source of omega-3 fatty acids (a-linoleic acid), proteins, soluble and insoluble fibers, vitamins, minerals and natural antioxidants. Study of growth, development, yield and oil quality of white and black Chia seeds in different planting dates. In order to study the possibility of Chia production in Iran, a factorial field trial was carried out based on a completely randomized block design with four replications, at Safiabad Agriculture Research Center (Dezful). Treatments included two different varieties of Chia (black and white) and six planting dates. Planting date altered vegetative and reproductive characteristics of both Chia varieties. The best yield from both Chia varieties was observed in plants grown from the first planting date (October). Black Chia showed better yield in terms of seed production (76.68 g/m2) and oil content (36.6%) compared to the white variety. α-linolenic acid was the major component of both black (54.0%) and white Chia (61.0%). Both varieties of Chia showed suitable adaptation in the climate of Dezful. By planting on October, Chia plants could receive enough short days and produce seeds. Suitable oil yield and quality was obtained for both Chia varieties. By optimizing of other parameters, economic seed yield will be achievable.

Arnica chamissonis Less. ssp. foliosa is a herbaceous perennial belonging to the Asteraceae family and endemic to north America and Canada. Inducing genetic mutation is a practical approach to increase genetic diversity for breeding purposes. Effect of different gamma radiation doses (0, 100, 200, 300, 400 and 500 gray) on seed germination and seedling growth of A chamissonis (e. g. plumule and rootlet length, germination percentage, speed and mean, seedling vigor, plumule fresh and dry weight, rootlet fresh and dry weight was measured and the proper dose for mutation induction was assessed. Gamma radiation caused significant effect on parameters such as plumule and rootlet length, germination percentage, germination rate, seedling vigor, rootlet fresh weight, plumule fresh and dry weight (P≤0.01) and also rootlet dry weight (P≤0.05). Radiation with 200 gray showed the most promising effects on germination parameters of this species. Compared to the control treatment, radiation with 300 gray and higher caused adverse effects on all mentioned parameters which may be caused by producing free radicals. An LD50 of 226.275 gray was estimated for this species and the best estimated dose to induce highest genetic mutation was 181.02 gray.

Plasmid mediated AmpC β-lactamase resistance in Escherichia coli is an emerging problem worldwide. Phenotypic methods are commonly used for detection of resistance production in Gram-negative isolates, but molecular data about the prevalence of plasmid-mediated AmpC-type resistance at the national level are needed. Hence, a prospective study was undertaken to determine of antibiotic resistance and detection of plasmid-mediated AmpC beta-lactamases among clinical isolates of Escherichia coli from Patients of Vali-e-Asr hospital in Qom city.

In this cross-sectional, descriptive study (conducted between 20 March and 20 May, 2016), 61 specimens of E. coli were collected from patients visiting Vali-e-asr Hospital in Qom, Iran, using conventional microbiological methods. To determine antibiotic resistance of the specimens, antibiogram obtained from disk diffusion test was used. Then, the screened strains were examined for PCR amplification of (CITM, FOX)-type plasmid-mediated AmpC beta-lactamases- producing genes. The results were analyzed by using SPSS software.

Among 61 E. coli specimens, 54 specimens (88.5%) were associated with urine and the rest (11.5%) with blood. In terms of gender, 49 patients (80.3%) were female and 12 patients (19.7%) were male. Among the specimens, the highest and least antibiotic resistance was observed against amoxicillin and imipenem, respectively. Resistance to ceftazidime was seen in 27 specimens (69.2%). From the results, CITM was identified in 7.4% of specimens, but FOX was not detected in specimens.

Results showed that the prescription of antibiotics for patients with plasmid-mediated AmpC beta-lactamases -producing strains not only did not stimulate recovery, but also led to the formation of resistant strains. In addition, the phenotypic methods do not produce the actual number of AmpC β-lactamase strains. Therefore, the conduction of genotypic studies in society leads to effective and faster treatment of patients, and prevents the spread of resistant bacterial isolates.