Trend analysis of reference evapotranspiration in the western half of Iran

Reference evapotranspiration (ET_o) is an important element of the hydrological cycle, and changes in ET_o are of great significance for agricultural water use planning, irrigation system design and management. In this study, annual, seasonal and monthly trends in the Penman-Monteith ET_o at 20 meteorological stations during 1966-2005 in the western half of Iran were examined using the Mann-Kendall test, the Sen's slope estimator and the linear regression. Annual analysis of the ET_o series indicated a positive trend in 70% of the stations according to the Mann-Kendall test and the Sen's slope estimator and in 75% of the stations according to the linear regression. The magnitude of significant positive trends in annual ET_o varied from (+)11.28 to (+)2.30 mm/year. On the seasonal scale, stronger increasing trends were identified in ET_o data in winter and summer compared with those in autumn and spring. Meanwhile, the highest numbers of stations with significant trends were found in the monthly ET_o series in February, while the lowest numbers of stations with significant trends were observed in November. Analysis of the impact of climatic variables on the significant increasing trend in ET_o showed that the increasing trend was mainly caused by a significant increase in air temperature during the study period.     

The effect of zeolite,selenium and silicon on qualitative and quantitative traits of onion grown under salinity conditions

Considering the importance of onion and its cultivation in saline soils, a two-year experiment was carried out to investigate the effects of soil applied zeolite and foliar application of selenium (Se) and silicon (Si) on onion yield, qualitative traits and physiological attributes, under salinity stress. An experiment was performed at three-way factorial design with three replications as follows: zeolite at three levels (0, 4 and 8 ton ha-1), Se at three levels (0, 0.5 and 1 kg ha-1) and Si at three levels (0, 200 and 400 kg ha-1). The results indicated that the effect of year was significant on all studied traits except for soluble solids, bulb nitrogen, leaf sodium and potassium, chlorophyll content and peroxidase activity. Number of small-sized bulbs decreased with increasing zeolite, Se and Si application. Dry matter, soluble solids, nitrogen content, nitrate concentration as well as protein content significantly increased due to zeolite, Se and Si application. Leaf sodium content and enzyme activity decreased due to zeolite, Se and Si application. Overall, 8 ton ha-1 zeolite along with 1 kg ha-1 Se and 400 kg ha-1 Si caused the maximum onion yield and qualitative and physiologic traits including soluble solids, potassium, protein, chlorophyll and photosynthesis .     

Assessment of heavy metal uptake and translocation in Dyera costulata for phytoremediation of cadmium contaminated soil

Abstract

Heavy metal pollution is a widespread global problem causing serious environmental concern. Cadmium, one of the heavy metals, is water soluble and can be transferred from soil to plants and enter into the food chain. It is detrimental to human health because it accumulates in the body and can cause renal tubular dysfunction, pulmonary emphysema and osteoporosis. This heavy metal needs to be cleaned up for a clean and safe environment. An experiment was conducted to evaluate the potential of Dyera costulata as a phytoremediator to absorb cadmium from contaminated soils. Dyera costulata seedlings were planted on six different growth media (soil + different levels of cadmium): Control, 25 ppm Cd, 50 ppm Cd, 75 ppm Cd, 100 ppm Cd and 150 ppm Cd. The highest growth performance mainly height, basal diameter and number of leaves were in the control, 50 ppm Cd and 25 ppm Cd treatments, respectively. The highest accumulation of cadmium (52.9 ppm) was in the 75 ppm Cd treatment. Among the plant parts, leaves showed the highest concentration of cadmium. Dyera costulata showed high translocation factor and low bioconcentration factor values in soil at high cadmium concentrations and was also able to tolerate and accumulate high concentrations of cadmium. The roots of Dyera costulata were found to be suitable for the absorption of cadmium in contaminated soils. This species can be an efficient phytoremediator for soils contaminated with cadmium.     

Role of Silicon in Mediating Heat Shock Tolerance in Soybean

The present experiment was conducted to assess the role of silicon (Si; 0, 100, 200, and 300?mg L^?1 Na₂SiO₃) in mitigating heat stress-induced growth deficiency, photosynthesis inhibition, and oxidative damage in soybean cultivars. Heat stress lowered root and shoot dry weights, which were noticeably improved by Si supplementation. Exposition to 200?mg L^?1 Si caused a 45 and 34% increase in chlorophyll and Fv/Fm, respectively, compared to plants that received no Si. Net photosynthetic rate, intercellular CO₂, and stomatal conductance were lowered due to heat stress and Si supplementation mitigated the adverse effect of heat stress on these attributes. Furthermore, lipid peroxidation, hydrogen peroxide generation, and electrolyte leakage were higher in heat-stressed soybean cultivars without Si as compared to those supplemented with Si. Accumulation of osmolytic cytosolutes such as proline and glycine betaine was also boosted by Si supplementation. In addition, Si treatment alleviated the destructive effects of heat stress by 63, 64, and 50% increases in total phenol, flavonol, and tocopherol contents, respectively. Interestingly, including Si in the heat-stressed soybean cultivars improved protein content and enhanced the activities of catalase, phenylalanine ammonia lyase, and lipoxygenase, while the activities of superoxide dismutase, peroxidase, and polyphenol oxidase were lowered by 30, 56, and 54%, respectively, compared to non-Si-treated cultivars. In conclusion, Si alleviated the adverse effect of heat stress in soybean cultivars by modulating photosynthesis, further accumulating osmolytes, and regulating the antioxidant system. However, large-scale and long-term field trials must be carried out to investigate the economic feasibility of Si application for alleviating heat shock stress.

     

Endocrine disrupting effects of 4-nonylphenol on plasma vitellogenin,reproductive system and histology in koi carp (Cyprinus carpio)

International Aquatic Research - This study aimed to assess the effect of 4-nonylphenol (4-NP), a ubiquitous aquatic micro-chemical pollutant substance on some on some reproductive parameters and...     

Impact of Methylenetetrahydrofolate Reductase C677T Polymorphism on the Risk of Gastric Cancer and Its Interaction with Helicobacter pylori Infection

Background

Attempts for early detection of gastric cancer have recently focused on host''s genetic susceptibility factors and gene-environment interactions. We have, herein, studied the association of MTHFR C677T single nucleotide polymorphism (SNP) and its interaction with Helicobacter pylori infection, smoking, age and gender on the risk of gastric cancer among an Iranian population.

Methods

Gastric cancer patients (n = 450) and cancer-free controls (n = 780) were studied for serum H. pylori-specific IgG antibodies by ELISA and MTHFR C677T polymorphism (SNP) by PCR-RFLP. Demographic and life style data were collected through patient interviews. Unconditional logistic regression model estimated odds ratio (OR) and the corresponding 95% confidence intervals (CI).

Results

The interactions of MTHFR genotype with H. pylori infection (P = 0.03), age (P = 0.049) and gender (P = 0.007) were statistically significant. Accordingly, MTHFR C677T carriers who were also positive for H. pylori infection exhibited 80% (OR = 1.8, 95% CI = 1.0-2.9) significant excess risk of non-cardia gastric cancer. Furthermore, subjects over the age of 50 or female subjects carrying MTHFR C677T SNP showed 40 (OR = 1.4, 95% CI = 1.0-2.0) and 100 (OR = 2.0, 95% CI = 1.2-3.2) percent increased risk of gastric cancer, respectively.

Conclusion

MTHFR C677T SNP seems to increase the risk of gastric cancer and the effect is significantly inflated by interactions with H. pylori infection, age and gender. Key Words: Helicobacter pylori, Smoking, Gender identity, Age group, Methylenetetrahydrofolate reductase     

2个伊朗椰枣品种的体细胞胚胎发生

从2个椰枣(Phoenix dactylifera L)栽培品种,即Khanizi和Mordarsing成龄植株的孽生枝(已生长3-4年)上切取茎尖外植体接种到含有MS无机盐的改良MS培养基上进行培养.12个月之后,将其转移到3种不同生长调节剂处理的培养基之中.5个月后观察发现,培养在含有453um 2,4-二氯苯氧乙...     

Accumulation of Ions in Shoot and Seed of Quinoa (Chenopodium ‎quinoa Willd.) Under Salinity Stress

Quinoa (Chenopodium quinoa Willd.) is a high-nutrient halophyte suitable for ?cultivating in semi-arid climates and saline soils. The current study investigated the ?effect of various water salinities (EC_i) (i.e., 0.3, 10, 15, 20, and 25 dS m^?1) and different ?irrigation methods (IMs) on accumulation of calcium (Ca), magnesium (Mg), ?sodium (Na), and chloride (Cl) ions in shoot (stem+leaves) of quinoa at the end of vegetation (onset of flowering) and seed at the end of seed-filling. Therefore, 30 pots (five EC_i and two IM in three replications) were prepared with similar conditions. Considering that the salinity threshold value (STV) of quinoa varies during growth and is 8, 20 and 15 dSm^?1 at each of ?establishment, flowering, and seed-filling growth stages, the two IMs consisted of considering STV at each growth stage (T) and permanent irrigation by ?constant levels of EC_i(P). Results indicated that by increasing the EC_i from 0.3 to 25 dSm^?1 the amount of Na, Cl, and Mg in shoot increased 82.2%, 75.8%, and 8.7%, respectively, while Ca decreased 37.2%. In seeds, Na and Cl increased 43.3% and 50%, respectively, while Mg increased 8% and Ca did not change significantly. An increase in EC_i ?significantly changed ion accumulation content, especially at EC_i higher than STV, ?because it is the onset of damage due to salinity stress and particularly in? ??shoot compared to seed due to the halophytic properties of quinoa. The T ?method of irrigation was preferred due to less accumulation of Na and Cl in ?shoot and seed, and therefore less damage and loss, especially at higher ?salinities.?