Temporal variation of total and DTPA-extractable heavy metal contents as influenced by sewage sludge and perlite in a calcareous soil

Continuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties.     

Contribution to the knowledge of the genetic diversity and taxonomy of some Iranian Trifolium species

Genetic Resources and Crop Evolution - Trifolium (Fabaceae) is widely distributed with more than 255 species. The current study contributed to the knowledge of the diversity and genetic population...     

Optimal Design of Dilution Experiments Under Volume Constraints

The paper develops methods to construct a one-stage optimal design of dilution experiments under the total available volume constraint typical for biomedical applications. We consider various design criteria based on the Fisher information both in Bayesian and non-Bayesian settings and show that the optimal design is typically one-atomic meaning that all the dilutions should be of the same size. The main tool is variational analysis of functions of a measure and the corresponding steepest descent-type numerical methods. Our approach is generic in the sense that it allows for inclusion of additional constraints and cost components, like the cost of materials and of the experiment itself.     

Monitoring the photosystem II behavior of wild and cultivated barley in response to progressive water stress and rehydration using OJIP chlorophyll a fluorescence transient

To study the effects of progressive drought stress on photosystem II behavior of wild type (Spantaneum) and cultivated barley (Morocco), different levels of soil water availability, including control, moderate, mild, and severe water stress (70%, 50%, 30%, and 10% water holding capacity of soil, respectively) and rehydration were used. Polyphasic OJIP fluorescence transient of Morocco plants exhibited a considerable increase in fluorescence intensity at O, J, and I steps under mild and severe stress relative to slight increase in wild barley. Values of fluorescence parameters and quantum efficiencies, including minimal fluorescence, relative variable fluorescence at phase J and I, maximal quantum yield of photosystem II (PSII), performance index, electron transport yield, and excitation transfer efficiency were influenced by water stress in both genotypes. These parameters were significantly less affected in wild type barley by progressive drought stress compared to Morocco. After re-watering, both genotypes were able to restore from severe drought in most of the traits. Based on our findings, highly correlated values of relative water content (RWC) and independent JIP-test parameters (P < 0.01) indicate that the chlorophyll a fluorescence induction technique is sensitive to plant water status and performance index represent an accurate and reliable indicator for early stress detection and also explore plant vitality under water stress.     

Copper and zinc uptake by celery plants grown on acidic soil amended with biosolids

For trace elements, such as copper (Cu) and zinc (Zn), the bioavailability of these elements, Cu and Zn, in biosolids is important because both are essential elements and both are potential contaminants when biosolids are land applied. A greenhouse study was conducted in factorial experiment based on a completely randomized design (CRD) with four replications on a soil treated with four rates of Cu (0, 50, 100, and 150 mg/kg) and four rates of Zn (0, 150, 300, and 450 mg/kg) on celery plants to investigate the distribution and mobility of these elements as well as growth and antioxidant changes of celery. The results of antioxidant changes were inconclusive due to irregular changes with Zn and Cu applications. However, generally the results show that Cu did not affect superoxide dismutase (SOD) or peroxidase (POD) activities in most of the treatments. On the other hand, Zn stimulated SOD and POD activities in most of the treatments. The photosynthesis rate decreased with the applications of Cu and Zn at the rates above 100 and 300 mg/kg and increased in low Cu concentration (50 mg/kg) compared to S (soil without biosolid).     

Sex steroids in the seminal fluid and milt quality indices in the endangered Caspian brown trout,Salmo trutta caspius

In this study, the relationships between the seminal fluid sex steroids sperm quality parameters (i.e. sperm motility and sperm production were investigated in the endangered Caspian brown trout. According to results, the variation of sex steroid concentrations was comparatively high. The seminal fluid levels of 17α‐Hydroxyprogesterone (OHP) had positive correlation with percentage and duration of sperm motility. Similar correlation was found between the seminal fluid concentration of testosterone (T) and estradiol‐17β (E2) with sperm concentration. As well as, there was no significant correlation between progesterone (P) with sperm quality indices. The significant correlation of some steroids i.e. OHP, T and E2 and sperm quality parameters of Caspian brown trout confirms the key role of these steroids in acquisition of the potential of motility during final stage of the maturation.     

Metabolomic analysis of Ranunculus spp. as potential agents involved in the etiology of equine grass sickness

Identification of toxic or harmful agents continues to be a key goal in agricultural chemistry. This paper reports a metabolomic analysis of Ranunculus repens and related species, which were recently postulated to be cocausative agents in the etiology of equine grass sickness (EGS). Specifically, samples collected at EGS sites were compared with those from non-EGS sites. Furthermore, interspecific and seasonal variations and the species' response to edaphic and climatic factors were investigated. (1)H NMR spectroscopy in combination with multivariate data analysis was applied to the crude methanol extracts of the Ranunculus samples, as well as their chloroform fractions. Samples from EGS sites were significantly different from control samples. The metabolite composition varied greatly between different Ranunculus species. No significant changes could be observed between samples collected in different seasons. This work provides strong evidence that Ranunculus is involved in the etiology of EGS and has implications for agricultural management of pastures.     

Screening drought-tolerant genotypes in bread wheat (Triticum aestivum L.) using different multivariate methods

Wheat (Triticum aestivum L.) is one of the most widely cultivated crops in rainfed areas of Iran, where drought is the main limiting factor on yield. The object of this study was the identification of drought-tolerant genotypes in bread wheat. Forty bread wheat genotypes were tested in separate experiments under drought stress and normal conditions in two years (2009–2010 and 2010–2011). Nine drought-tolerance/susceptibility indices including stress susceptibility index (SSI), mean productivity (MP), tolerance (TOL), stress tolerance index (STI), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), linear regression coefficient (β) and drought response index (DRI) were determined. Simultanously applied factor analysis used two factors instead of nine indices in this study. Mahdavi was recognized as the most drought-tolerant genotype in both years based on factor analysis. In this study an equation was developed for estimating the Stress Tolerance Score (STS). The results of the equation were identical to those of factor analysis in both years. The equation was much easier to use than factor analysis and is suggested as a screening tool for the identification of drought-tolerant genotypes. In this study, Mahdavi was the most drought-tolerant genotype also corresponding to this equation.     

Improvement of Antioxidant System and Decrease of Lignin by Nickel Treatment in Tea Plant

The effect of nickel (Ni) on the activities of antioxidant enzymes was evaluated in suspension-cultured cells of tea (Camellia sinensis L. cv. ‘Yabukita’) and two-year-old rooted cuttings of tea (Camellia sinensis L. assamica × sinensis). Suspension-cultured cells were grown in B5 medium and treated with 40 μM of Ni for 24 h. Tea plants were grown in a modified Hoagland solution and treated for one week with 40 μM of Ni. The activities of superoxide dismutase, catalase, ascorbate peroxidase, and ionically wall-bound peroxidase of both Ni-treated tea cells and Ni-treated tea plants increased compared with those of control groups. The activities of soluble peroxidase and covalently wall-bound peroxidase, as well as the lignin content of both tea cells and tea plants, decreased under Ni treatment. Thus it seems that Ni may have beneficial effects on tea plants via elevation of antioxidant activity and decrease of lignification of the walls.     

Preparation of PAN-based electrospun nanofiber webs containing Ni-ZnO as high performance visible light photocatalyst

The one dimensional (1D) Ni-ZnO nanoparticles have been synthesized by a simple hydrothermal method. A novel photocatalyst of nanostructured Ni-ZnO which immobilized on polyacrylonitrile nanofibers were successfully fabricated using electrospinnig technique. The structures of nanofibers were characterized by various techniques including Scanning Electron Microscope (SEM), X-ray powder Diffraction (XRD), Fourier transform infrared (FT-IR), UV-Vis diffuse reflectance (DR) and thermogravimetric analys (TGA). The Ni-ZnO/PAN nanofibers photodegradation efficiency was optimized with factorial design method in order to act highly effective in the photocatalytic degradation of Methyle orange (MO). The highest decolorizing efficiencies using introduced material were achieved by 0.8 g l ^-1 of catalyst and 10 mg l ^-1 of MO at natural pH under visible light irradiation. The obtained results exhibited that Ni-ZnO/PAN nanofibers have high visible light photocatalitic activities. Overall, the presented material can be used as an efficient, low cost and healthily secure photocatalyst in the field of water treatment.