Korean <Emphasis Type="Italic">Brassica oleracea</Emphasis> germplasm offers a novel source of qualitative resistance to blackleg disease

Blackleg disease, caused by the hemibiotrophic fungal pathogen Leptosphaeria maculans, is one of the most devastating disease of Brassica species worldwide. To date, a total of 20 race-specific blackleg resistance (R) genes have been reported and all of those loci are located in either the A or B genomes of various Brassica species. The B. oleracea genome (CC) shares a high ancestral synteny with the A genome of B. rapa, suggesting the presence of qualitative (race specific) resistance to blackleg disease is also possible in B. oleracea germplasm. In the present study the C genome of Korean B. oleracea germplasm was screened for the presence of blackleg R genes. Thirty-two inbred cabbage lines with unknown resistance profiles, along with five control B. napus lines with well-characterised race-specific R genes, were assessed for cotyledon resistance against two L. maculans isolates with known and highly-contrasting avirulence gene (Avr) profiles. Two cabbage accessions were identified which produced a strong resistance when challenged with either isolate, demonstrating the presence of effective blackleg R genes in the cabbage C genome. Additionally, 16 microsatellite markers linked to seven different R genes of the B. napus A genome were converted into markers for their homologous regions on the B. oleracea C genome. These markers were used to screen all B. oleracea lines to assess if the novel C genome R genes were syntenous to known R gene-homologous regions of the A genome. The resistant cabbage lines offer C genome R genes for the protection of B. oleracea varieties against incursion of blackleg disease, as well as novel additional resistance sources for introgression into B. napus and B. carinata breeding material.     

Nutritional status of Washington Navel orange orchards in arid lands of southern Iran

Nutrient deficiency may be a reason for citrus decline in many countries. In the current investigation, soil and leaf samples of 63 Washington Navel orange orchards in arid lands of southern Iran (Darab region) were analyzed to study the nutritional status of orange orchards and to find relationships between soil properties and nutrients content of soils and orange leaves. The soils differed widely in clay content (3–37%), pH value (7.04–7.95), calcium carbonate equivalent (18–86%), and organic matter content (0.3–12%). These soils represented a wide range of plant nutrients concentration. Majority of the studied soils had sufficient concentrations of all nutrients (except Fe). Results indicated that pH, organic matter, clay, and calcium carbonate contents are the most important characteristics that control the soil nutrients availability. The mean contents of N, K, P, Fe, Mn, Zn, and Cu in leaves were 2.59, 0.84, and 0.14% and 66, 44, 17, and 12?mg?kg^?1, respectively. Most orchards showed K, Fe, and Zn deficiencies. We found no relationships between nutrients content in leaf and soil (except for K, Mn, and Zn); and this indicated that soil analysis may not be a reliable method for most nutrient deficiency diagnosis.     

High Velocity Impact Response of Basalt Fibers/Epoxy Composites Containing Graphene Nanoplatelets

The effects of adding surface modified graphene nanoplatelets (GNPs) in various weight percentages (0, 0.1, 0.2, 0.3, 0.4, 0.5 with respect to matrix) on the high velocity impact response of basalt fibers/epoxy composites were evaluated. High speed mechanical stirrer and ultrasonic waves were used for the dispersion of GNPs in the epoxy matrix, and hand layup method was utilized for the fabrication of the composite samples. High velocity impact testing was performed using a conical projectile. The results demonstrated that the maximum improvement in the impact limit velocity and energy absorption occurred in the 0.3 wt.% GNPs nanocomposite, i.e., 11 and 23 %, respectively. Also, the electron microscopy studies revealed that the addition of GNPs contributed in improving the impact properties by influencing the matrix and thus enhancing the interfacial characteristics between the basalt fibers and the matrix.     

Effect of Cattle Manure and Sulfur on Yield and Oil Composition of Pumpkin (Cucurbita pepo var. Styriaca) Inoculated with Thiobacillus thiooxidans in Calcareous Soil

The effect of cattle manure and sulfur fertilizer on seed yield and oil composition of pumpkin (Cucurbita pepo var. Styriaca) under inoculated with Thiobacillus thiooxidans was investigated in a factorial study based on a randomized complete block design. Experimental factors consisted of cattle manure (M) (M₀: 0, M₁: 10; and M₂: 20 t ha^?1), sulfur (S) (S₀: 0, S₁: 250; and S₂: 500 kg ha^?1) and T. thiooxidans (B): inoculated (B₁) and non-inoculated (B₀). Results demonstrated that the application of T. thiooxidans, cattle manure, and S fertilizer decreased the soil pH. The largest number of seed per fruit (367), highest fruit yield (70.57 t ha^?1), seed iron (Fe) content (16.26 mg 100 g^?1), and seed yield (111 kg ha^?1) was obtained when 20 t ha^?1 manure was applied in combination with 500 kg ha^?1 S inoculated with T. thiooxidans. In this condition, the content of S, Fe, phosphorus (P), and nitrogen (N) in plant shoots was increased by 44.8%, 22.58%, 33.89%, and 10.38%, respectively, compared to the control. Moreover, the highest content of seed protein was observed in 10 t ha^?1 manure and 500 kg ha^?1 S fertilizer inoculated with T. thiooxidans. When 250 kg ha^?1 S fertilizer was applied, 20 t ha^?1 manure decreased seed P content sharply. At the rate of 500 kg ha^?1 S fertilizer, the highest content of seed P was obtained from 20 t ha^?1 manure. Totally, 20 t ha^?1 cattle manure, along with 500 kg ha^?1 S fertilizer as well as T. thiooxidans inoculation, improved oil and seed yield of medicinal pumpkin.     

Application of Zeolites for Sustainable Agriculture: a Review on Water and Nutrient Retention

Developing urbanization, water shortage, watercourse pollution, and demands for more food due to population growth require a more efficient water irrigation and fertilizer application. Retaining nutrients and water in agricultural soils brings about higher crop yields and prevents pollution of water courses. Among different solutions, zeolites, which are environmental friendly, ubiquitous, and inexpensive, have been extensively employed in agricultural activities. These minerals are considered as soil conditioners to improve soil physical and chemical properties including infiltration rate, saturated hydraulic conductivity (K _s), water holding capacity (WHC), and cation exchange capacity (CEC). Natural and surface-modified zeolites can efficiently hold water and nutrients including ammonium (NH₄ ⁺), nitrate (NO₃ ^?) and phosphate (PO₄ ^3?), potassium (K⁺), and sulfate (SO₄ ^2?) in their unique porous structures. Their application as slow-release fertilizers (SRFs) are reported as well. Therefore, zeolite application can improve both water use efficiency (WUE) and nutrient use efficiency (NUE) in agricultural activities and consequently can reduce the potential of surface and groundwater pollution. This review paper summarizes findings in the literature about the impact of zeolite applications on water and nutrient retention in the agriculture. Furthermore, it explores benefits and drawbacks of zeolite applications in this regard.

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Effects of nanoclay on physical and mechanical properties of wood-plastic composites

Effects of nanoclay (NC) on physical and mechanical properties of wood-plastic composite (WPC) were studied here. Virgin, recycled, and mixed (50/50% of virgin/recycled) polyvinyl chloride (PVC) were used as the matrix in the WPC. Specimens with three NC contents of 1.5%, 3%, and 5% were manufactured; they were then compared with control specimens. Totally, 12 treatments were manufactured. The physical and mechanical properties were measured in accordance with the ASTM standards. The highest properties were found in specimens made from virgin PVC. Addition of recycled PVC resulted in significant decrease in all properties. NC improved all physical and mechanical properties studied in the present research project; the highest properties were observed in specimens with 5% of NC content. The improvement in properties was as a result of formation of bonds between the hydroxyl groups of NC with the wood flour components. It was concluded that NC would significantly improve the properties in all the three PVC types of virgin, recycled, and mixed. From an industrial point of view, it was concluded that mixing virgin and recycled PVC can be recommended not only to decrease production costs, but also to partially solve the problem of PVC residue which are not bio-degradable.     

Assimilate and nitrogen remobilization of six-rowed and two-rowed winter barley under drought stress at different nitrogen fertilization

Field experiments were conducted to investigate the effects of irrigation regimes and N levels on assimilate remobilization of two barley cultivars (Yousef_six-rowed and Nimrouz_two-rowed) in 2011 and 2012. There were three levels of water regimes (full irrigation (I₁₀₀), 75% and 50% of I₁₀₀: I₇₅ and I₅₀, respectively) in 2011. Rain-fed treatment (I₀) was included in 2012. Three N levels (0, 60, and 120 kg ha^?1) were used. Grain yield and assimilate remobilization decreased by severe water stress (I₀), however, the reduction of them were intensified by N fertilizer application. The N remobilization was negatively affected by N fertilization and water stress. The two-rowed showed higher N remobilization (10.7%) and contribution of N remobilized to N content of grain (5.8%) than the six-rowed. The two-rowed cultivar showed significantly higher assimilate remobilization and grain yield than the six-rowed under I₅₀ (26.3% and 6.5%, respectively) and I₀ (48.7% and 17.1%, respectively), while the six-rowed had similar or higher performances in terms of these traits under I₁₀₀ and I₇₅. This study showed that optimizing irrigation and N rates (decrease N level with increasing water stress) and selection of the suitable cultivars (Nimrouz_two-rowed) might increase assimilate remobilization and consequently grain yield under drought stress conditions.     

Egyptian broomrape (Phelipanche aegyptiaca) response to silicon nutrition in tomato (Solanum lycopersicum L.)

Egyptian broomrape is a root holoparasitic plant that causes severe damage to tomato in Iran. Experiments were conducted in 2013 to investigate the effect of silicon (Si) nutrition on broomrape response in tomato. Si concentration significantly delayed first appearance of broomrape and decreased number of tubercles in both cultivars, although the magnitude of reduction varied with cultivar and Si concentration. Broomrape infection significantly decreased root and shoot dry weights of tomato cultivars. However, Si nutrition at high concentration considerably reduced damage severity of broomrape compared to the treatment that received no Si. Infection of tomato with broomrape resulted in significant increase in peroxidase and catalase activity in the roots of resistant cultivar which led to enhanced crop resistance to oxidative stress and improved growth in this cultivar.     

Radiosensitivity and repair kinetics of gamma-irradiated leukocytes from sporadic prostate cancer patients and healthy individuals assessed by alkaline comet assay

Background: Impaired DNA repair mechanism is one of the main causes of tumor genesis. Study of intrinsic radiosensitivity of cancer patients in a non-target tissue (e.g. peripheral blood) might show the extent of DNA repair deficiency of cells in affected individuals and might be used a predictor of cancer predisposition. Methods: Initial radiation-induced DNA damage (ratio of Tail DNA/Head DNA), dose-response curves and kinetics of DNA repair in leukocytes from healthy volunteers and prostate cancer patients were assessed using alkaline comet assay after exposure to ⁶⁰Co gamma rays. Results: Results showed that higher levels of baseline and gamma rays induced DNA damage in leukocytes of prostate cancer cases than in controls. A similar dose response was obtained for both groups. After a repair time of 24 h following in vitro irradiation, samples from the healthy individuals showed no residual DNA damage in their leukocytes, whereas prostate cancer patients revealed more than 20%. Although similar initial radiosensitivity was observed for both groups, the repair kinetics of radiation induced DNA damage of leukocytes from prostate cancer cases and healthy subjects were statistically different. Conclusion: These results support the hypothesis that men affected by prostate cancer may have a constitutional genomic instability. Key Words: Leukocytes, DNA damage, Radiosensitivity, Prostate cancer, Comet assay     

Wicking phenomenon in polyacrylonitrile nanofiber yarn

The aim of this paper is to investigate vertical wicking in polyacrylonitrile (PAN) electrospinning nanofiber yarn using image analysis. Colored liquid rising phenomenon into the yarn and the distance of liquid rise were determined as a function of time. The kinetics of capillary rise follows the Lucas-Washburn equation. The results show that capillary rise rate coefficient is being reduced with increasing yarn twist, due to the reduction of continuity and size of capillaries. Increasing heat treatment stretch from 0 % (draw ratio=1) to 50 % (draw ratio=1.5) increases the capillary rise rate coefficient, due to the more homogeneity of capillary spaces in the yarn structure and increasing heat treatment stretch from 50 to 100 % (draw ratio=2) reduces capillary rise rate coefficient, because of the low capillary length. The present study indicates that an appropriate choice in production parameters of nanofiber yarn is all important in obtaining the desired properties of capillary rise.