The effect of silver nanoparticle on Fenugreek seed germination under salinity levels

A study was conducted to evaluate the effect s of silver nanoparticles for ameliorating negative effects of salinity on germination and growth of Fenugreek seeds. In order to investigate salinity stress on Fenugreek germination indices, an experiment was carried out in Iran from October 2014 to November 2014 at Ferdowsi University of Mashhad, in the biotechnology Laboratory, to create salinity stress, sodium chloride (NaCl) at the levels of 0 (as control), 5, 10, 15 and 20 dS/m and Five levels of silver nanoparticles (0, 10, 20, 30 and 40 μg mL^–1) on Fenugreek seed (Trigonella foenum-graecum); were tested Germination characteristics such as total germination (GT), Germination Speed Index (GSI), Shoot and Root of seedling long, Fresh Mass and Dry Mass were measured. Results showed the great effects of silver nanoparticles to improve salinity stress on Fenugreek seed germination. Results showed a significant reduction in germination percent and seedling growth due to the salinity stress while significantly increased with silicon nano-particles application. In without silver nanoparticle low level of salinity (0 dS/m) increased seed germination percentage, while the high levels (5, 10, 15 and 20 dS/m) inhibited the seed germination significantly. The results showed that the effect of AgNPs was significant on germination percentage in P ≤ 0.05. Overall, application of AgNPs was beneficial in improving salinity tolerance in the Fenugreek seedling and its application may stimulate the differences defense mechanisms of plants against salt toxicity.     

Impact of drought stress on yield,photosynthesis rate,and sugar alcohols contents in wheat after anthesis in semiarid region of Iran

Owing to the importance of after anthesis water deficit in Mediterranean regions (such as Iran), this study has focused on harmful impact of after anthesis drought stress on grain yield (GY), photosynthesis, and some physiological characteristics of wheat. To this aim, a factorial experiment based on randomized complete block design with three replications was used in greenhouse conditions in Razi University in Kermanshah city of Iran, during 2010–2011 growing season. Two bread wheat genotypes, “Zagros” (tolerant to drought) and “Marvdasht” (sensitive to drought) were grown in normal water supply condition (100% of field capacity) and drought stress from anthesis until maturity (50% of field capacity). The results indicated that after anthesis water deficit considerably reduced grain and biological yields, thousand grain weight (TGW) and a number of grains per spike (NGS) among different traits in genotypes. Under well-watered and drought-treated conditions, genotypes in terms of all evaluated traits had considerable variations. Water deficit caused more reduction of net photosynthesis rate (Pn), stomatal conductance (gs), relative water content (RWC) of leaf, chlorophyll a, b (Chl), and soluble proteins content in sensitive genotype; values were respectively 66.3, 73.2, 14.6, 32.1, 46.2, and 25.6%. Better performance of tolerant genotype under water deficit was associated with a great ability in production of some osmoprotectants as inositol, glycerol, and erythritol sugars. Rather adaptation of tolerant genotype to water deficit may be attributable to having maximum soluble protein, sugar alcohols, Chl content, RWC, gs and Pn in drought stress, and with respect to the results, wheat might not be able to synthesize mannitol. Transfer of gene(s) producing mannitol may cause more improvement of growth performance of wheat under stresses.     

The response of Stevia (Stevia rebaudiana Bertoni) to nitrogen supply under greenhouse condition

Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions.     

Positive effects of Penconazole on growth of Brassica napus under drought stress

The aim of the present study was to compare the effects of drought on some physiological and biochemical parameters and to assess the inducing effects of Penconazole (PEN) on drought tolerance in two cultivars (RGS003 as a drought tolerant and Sarigol as a drought sensitive) of canola. Plants were treated with various PEG concentrations (0, 5, 10, and 15%) without or with PEN (15 mg l^?1). Decrease in fresh weight (FW) and dry weight (DW) in Sarigol under drought was higher than that of RGS003. Surprisingly, PEN reversed prominently the negative effects of drought on FW and DW in RGS003. Concomitantly, PEN treatment decreased malondialdehyde content in RGS003 under drought. Moreover, higher content of proline in RGS003 under all drought levels could be considered as a factor for drought tolerance of this cultivar. Superoxide dismutase (SOD), catalase (CAT) and Polyphenol oxidase (PPO) activities were induced by PEN in both cultivars under drought. Inducing effects of PEN on phenylalanine ammonia lyase and thyrosine ammonia lyase activities decreased by increasing of drought levels in both cultivars. In summary, PEN alleviated the negative effects of drought in RGS003 cultivar by inducing activities of SOD, CAT and PPO and proline content comparing to Sarigol.     

Ocimum basilicum L. growth and nutrient status as influenced by biochar and potassium-nano chelate fertilizers

In sustainable agriculture, the protection of environment against pollution is the main goal for consumers. Nowadays, the overuse of pesticides and chemical fertilizers, are one of the main causes of environmental pollution. It is claimed that incorporation of organic compound into soil enhances nutrient availability and plant productivity. A greenhouse experiment was conducted to determine the effects of 0%, 1.5% and 3% cattle manure biochar and 0, 300 and 600 mg K-nano chelate kg^?1 soil on agronomic properties and nutrient status of Ocimum basilicum L. Biochar increased leaf area and plant height, significantly. Application of 1.5% and 3% biochar increased fresh weight by 40% and 42% and dry weight by 50% and 49%, respectively. Addition of 3% biochar increased P, K and Mn concentrations by 45%, 17% and 109%, respectively. Biochar increased N, P, K, Zn and Mn uptake, significantly. Addition of 300 mg K increased dry weight by 15%; while application of 600 mg K decreased it. Application of 300 and 600 mg K-nano chelate increased K and Zn concentration and K uptake significantly. Furthermore, 300 mg K increased Cu and Zn uptake. In order to achieve sustainable agricultural productions, biochar application is recommended especially in the soils of arid and semiarid regions.     

A new ENU-induced mutant mouse with defective spermatogenesis caused by a nonsense mutation of the syntaxin 2/epimorphin (Stx2/Epim) gene

Repro34 is an N-ethyl-N-nitrosourea (ENU)-induced mutation in mice showing male-specific infertility caused by defective spermatogenesis. In the present study, we investigated pathogenesis and molecular lesions in relation to spermatogenesis in the repro34/repro34 homozygous mouse. Histological examination of the testis showed that the seminiferous epithelium of the repro34/repro34 mouse contained spermatogonia and spermatocytes but no round and elongating spermatids. Instead of these haploid cells, multinucleated giant cells occupied the niche of the seminiferous tubules. Immunohistochemical staining for Hsc70t, an elongating spermatid specific protein, confirmed the absence of elongating spermatids. Furthermore, RT-PCR showed that there were significantly reduced expressions of the marker genes specifically expressed in the spermatid and that there was no difference in the expressions of the spermatocyte specific marker genes. These findings indicated interruption of the spermatogenesis during transition from the spermatocyte to spermatid in the repro34/repro34 mouse. The repro34 locus has been mapped on a 7.0-Mb region of mouse chromosome 5 containing the Syntaxin 2/Epimorphin (Stx2/Epim) gene, and targeted disruption of this gene has been reported to cause defective spermatogenesis. We therefore sequenced the entire coding region of the Stx2/Epim gene and found a nucleotide substitution that results in a nonsense mutation of this gene. The expression pattern of the Stx2/Epim gene during the first wave of spermatogenesis, increased expression at later stages of spermatogenesis, was in agreement with the affected phase of spermatogenesis in the adult repro34/repro34 testis. We therefore concluded that the male infertility of the repro34/repro34 mouse is caused by the interruption of spermatogenesis during transition from the spermatocyte to spermatid and that the nonsense mutation of the Stx2/Epim gene is responsible for the interruption of spermatogenesis.     

Study of reproductive performance and related factors in four dairy herds in Fars province (southern Iran) by Cox proportional-hazard model

Our objective was to characterize the current reproductive performance and factors which may be related to it in the Fars province dairy herds in southern Iran. We collected retrospective data from four commercial herds in the region. All 256 cows with history of calving between 21 March 2004 and 20 March 2005 were followed until subsequent pregnancy, culling or death. Effects of risk factors on days open were investigated in a Cox proportional-hazards model. The overall median calving interval, dry period and days open were 388, 68, and 120 days, respectively. First-service conception risk and overall-service conception risk were 45 and 42%, respectively. Average numbers of insemination per pregnant and all cows were 2 and 2.1, respectively. Cows without incidence of any disorder during the lactation (but before conception, and including metabolic disorders) had 2.1-times greater hazard of conception than cows with incidence of disease. No significant association between calving interval, dry period, parity of dam, and sex and weight of calves with days open was observed.     

Dissection of additive genetic variability for quantitative traits in chickens using SNP markers

The aim of this study was to separate marked additive genetic variability for three quantitative traits in chickens into components associated with classes of minor allele frequency (MAF), individual chromosomes and marker density using the genomewide complex trait analysis (GCTA) approach. Data were from 1351 chickens measured for body weight (BW), ultrasound of breast muscle (BM) and hen house egg production (HHP), each bird with 354 364 SNP genotypes. Estimates of variance components show that SNPs on commercially available genotyping chips marked a large amount of genetic variability for all three traits. The estimated proportion of total variation tagged by all autosomal SNPs was 0.30 (SE 0.04) for BW, 0.33 (SE 0.04) for BM, and 0.19 (SE 0.05) for HHP. We found that a substantial proportion of this variation was explained by low frequency variants (MAF <0.20) for BW and BM, and variants with MAF 0.10–0.30 for HHP. The marked genetic variance explained by each chromosome was linearly related to its length (R² = 0.60) for BW and BM. However, for HHP, there was no linear relationship between estimates of variance and length of the chromosome (R² = 0.01). Our results suggest that the contribution of SNPs to marked additive genetic variability is dependent on the allele frequency spectrum. For the sample of birds analysed, it was found that increasing marker density beyond 100K SNPs did not capture additional additive genetic variance.     

Assessing cadmium availability of contaminated saline-sodic soils as influenced by biochar using the adsorption isotherm models

ABSTRACT

In arid/semi-arid regions, soil salinization, sodification and contamination by heavy metals (HMs) are the main constrains to plant growth, crop production and human health. Biochar can affect soil behaviors, e.g. adsorption of HMs that is one of the most effective techniques for reducing their bioavailability. Effect of three levels (0%, 2% and 4% wt) of sugarcane bagasse-derived biochar and two cadmium (Cd) levels (0 and 50 mg Cd kg^?1 soil as Cd(NO₃)₂) on Cd adsorption of saline, sodic, saline-sodic and normal soils were evaluated through studying adsorption isotherms. Six isotherm models were fitted to the data and the best model were chosen. The maximum Cd adsorption (694 mg kg^?1) obtained in sodic soils without biochar treatment. Cadmium removal decreased when dosage of the applied biochar increased. The minimum Cd removal obtained as 17%, 21%, and 23% in control, 2% and 4% biochar-treated saline soils, respectively. Biochar increased Cd adsorption in salt-affected soils. Increasing pH in soil solution after biochar addition resulted in an increase in net negative surface charge and the affinity of soil particles for Cd adsorption. Consequently, 2% biochar could ameliorate Cd contamination. However, Cd adsorption decreased when dosage of the applied biochar increased from 2% to 4%.     

Measuring and simulating pH buffer capacity of calcareous soils using empirical and mechanistic models

ABSTRACT

We studied (i) the pH buffer capacity (pHBC) of calcareous soils varied widely in calcite and texture, (ii) the contribution of soil properties to pHBC and (iii) the significance of using a model based on calcite dissolution to estimate the pHBC of calcareous soils. The pHBC of soils was measured by adding several rates of HCl to soils (100–6500 mM H⁺ kg^–1), in a 0.01 M CaCl₂ background and an equilibration time of 24 h. The pHBC (mM H⁺ kg^–1 pH^?1) varied from 55 to 3383, with the mean of 1073. The pHBC of the soils was strongly correlated with soil CaCO₃ equivalent (calcite) (r = 0.94), sand (r = ?0.72), silt (r = 0.60), EC (r = 0.63), pH (r = 0.55), and weakly (r = 0.37) but significantly with clay content. The attained pHBC values indicated that calcite was probably the main buffer system in these soils. The chemical equilibrium model successfully predicted pH titration curves based on calcite dissolution, indicating buffering of acid inputs in the calcareous soils is dominated by calcite dissolution. The model can be used to simulate acidification of calcareous soils and to provide information for making environmental management decisions.