The effectiveness of seed priming with synthetic zinc-amino acid chelates in comparison with soil-applied ZnSO4 in improving yield and zinc availability of wheat grain

The effect of soil applied zinc (Zn) sulfate and seed priming with Zn-glutamine [Zn(Gln)₂], Zn-glycine [Zn(Gly)₂], Zn-arginine [Zn(Arg)₂], and Zn-histidine [Zn(His)₂] on yield and grain nutritional quality of two bread (Triticum aestivum L. cvs. Back Cross and Kavir) and a durum wheat genotype (Triticum durum L. cv. Durum) was investigated. Seed priming with [Zn(Gly)₂] and [Zn(Gln)₂] increased grain yield of wheat over soil applied Zn-sulfate treatment by 46 and 14%, respectively. Seed priming with [Zn(Gln)₂], [Zn(Arg)₂], and [Zn(His)₂] significantly increased grain protein content of wheat in comparison with control treatment. Seed priming with [Zn(Arg)₂] and [Zn(His)₂] resulted in higher Zn and Fe accumulation in wheat grain as compared with the other Zn treatments. Priming seeds with [Zn(Arg)₂] reduced phytic acid to Zn molar ratio of wheat grain. Seed priming with [Zn(Arg)₂] and [Zn(His)₂] might be used as an alternative approach for soil application of Zn-sulfate to overcome Zn deficiency in calcareous soils.     

Subcritical soil hydrophobicity in the presence of native and exotic arbuscular mycorrhizal species at different soil salinity levels

Soil salinity and arbuscular mycorrhizal fungi (AMF) influence the soil hydrophobicity. An experiment was performed to determine the effects of soil salinity and AMF species on soil water repellency (SWR) under wheat (Triticum aestivum L.) crop. Six AMF treatments, including four exotic species (Rhizophagus irregularis, Funneliformis mosseae and Claroideoglomus claroideum, a mix of three species), one mix native AMF species treatment and an AMF-free soil in combination with four salinity levels (1, 5, 10, and 15 dS m^?1) were used. The soil repellency index (RI) increased with salinity increment ranging from 2.4 to 10.5. The mix of three exotic and native AMF treatments enhanced the RI significantly compared to AMF-free soil in all salinity levels with one exception for native treatment at 1 dS m^?1. Among individual AMF species, the C. claroideum treatment at 10 dS m^?1 increased the RI by 67% compared to AMF-free soil. The native AMF treatment was more efficient in root colonization, glomalin production and SWR development at 10 and 15 dS m^?1, compared to exotic species. In addition to the net positive effect of salinity on SWR, the AMF influences on the RI were greatly dependent on salinity levels.     

Salt-affected soils,reclamation, carbon dynamics,and biochar: a review

Purpose

This paper reviews chemical, physical, and biological problems of salt-affected soils and different reclamation methods applied to rehabilitate these soils.

Methods

Methods to increase C stocks in these lands are discussed with a focus on biochar application as a potential new approach to not only to increase the C content but also to improve soil properties. Gaps in research knowledge in this field are then identified.

Results

Given the concern on the continued worldwide expansion of salt-affected lands and the focus on C sequestration processes, this review has evaluated current knowledge on salt-affected soils and their remediation with organic materials and plants. The review of the published literature has highlighted important gaps in knowledge, which limit our current understanding of rehabilitation of salt-affected soils with organic amendments specially biochar and the associated carbon dynamic. Knowledge about application of biochar in salt-affected soils is scant, and to date, most studies have evaluated biochar use only in nonsalt-affected soils.

     

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.     

COMPARATIVE ANALYSIS OF SOME PHYSIOLOGICAL RESPONSES OF RICE SEEDLINGS TO COLD,SALT, AND DROUGHT STRESSES

Rice (Oryza sativa L.) is one of the most sensitive crops to drought, salt and cold stresses, particularly at post germination stage. The effects of these stresses on some physiological responses of two (a salt tolerant and a sensitive) rice cultivars ‘FL478’ and ‘IR29’ were investigated in this study. Two-day seedlings were transferred to MS media complemented with iso-osmotic concentrations of sodium chloride (NaCl; 0, 50, 100, and 150 mM) or mannitol (0, 100, 180, and 275 mM) at 25°C or four and 15°C for 10 days. Experiments were carried out based on completely randomized design, with at least three replicates. All three stresses decreased shoot growth, chlorophylls, carotenoids and root starch while increased shoot soluble sugars. The effect of exerted cold stress on growth, hydrogen peroxide (H₂O₂) and malonyldialdehyde levels, electrolyte leakage, chlorophylls and carotenoids contents was more than or comparable with drought, but greater than salinity. The results also indicated higher tolerance of ‘‘FL478’’ not only to salinity but also to drought compared to ‘‘IR29’’. Therefore, a mechanism for osmotic stress adjustment is probable in ‘‘FL478’’ in addition to low sodium (Na⁺) to potassium (K⁺) ratio in shoot tissues under salinity.     

Effects of foliar spray of two kinds of zinc oxide on the growth and ion concentration of sunflower cultivars under salt stress

This study investigated the effects of foliar application of normal and nano-sized zinc oxide on the response of sunflower cultivars to salinity. Treatments included five cultivars (‘Alstar’, ‘Olsion’, ‘Yourflor’, ‘Hysun36’ and ‘Hysun33’), two salinity levels [0 and 100 mM sodium chloride (NaCl)], and three levels of fertilizer application. Fertilizer treatments were the foliar application of normal and nano-sized zinc oxide (ZnO). Foliar application of ZnO in either forms increased leaf area, shoot dry weight, net carbon dioxide (CO₂) assimilation rate (A), sub-stomatal CO₂ concentration (Ci), chlorophyll content, Fv/Fm, and Zn content and decreased Na content in leaves. The extent of increase in chlorophyll content, Fv/Fm and shoot weight was greater as nano-sized ZnO was applied to the normal form. The results show that the nano-sized particles of ZnO compared to normal form has greater effect on biomass production of sunflower plants.     

The application of polyamines by pressure or immersion as a tool to maintain functional properties in stored pomegranate arils

Pomegranate fruits were treated with putrescine (Put) or spermidine (Spd) at 1 mM either by pressure infiltration or by immersion and then were stored at 2 degrees C for 60 days. Samples were taken biweekly and were further stored 3 days at 20 degrees C for shelf life study. The treatments were effective on maintaining the concentration of ascorbic acid, total phenolic compounds, and total anthocyanins in arils at higher levels than in control samples. In addition, the two ways of polyamine application increased the levels of total antioxidant activity (TAA) during storage, especially when polyamines were applied by pressure infiltration. Moreover, Spd showed the best results on increasing TAA through maintenance of total phenolic compounds.     

The role of root plasma membrane ATPase and rhizosphere acidification in zinc uptake by two different Zn-deficiency-tolerant wheat cultivars in response to zinc and histidine availability

ABSTRACT

We investigated the effect of histidine (His) and Zn deficiency on H⁺-ATPase activity and H⁺ release from wheat roots. Two bread wheat (Triticum aestivum L. cvs. Kavir and Back Cross Roshan) were grown in a nutrient solution for four weeks before being transferred to treatment solutions consisting of two concentrations of His (0 and 50 µM) and two concentrations of Zn (0 and 10 μM). The Zn-only and the Zn+His treatments were observed to release more H⁺ in the root media than did the control ones, with the highest achieved under the Zn+His treatment which was roughly 2.1 times higher than that under the control conditions. The H⁺ release from wheat roots increased slightly but significantly in the presence of only His when compared with the control solutions. The hydrolytic and transport activities of H⁺-ATPase were affected by both Zn deficiency and His supply. In both cultivars, application of Zn and His resulted in a higher hydrolytic activity of H⁺-ATPase when compared with the control solutions. The highest hydrolytic activity of H⁺-ATPase in the root plasma membrane vesicles was achieved with the Zn+His treatment. The ‘Back Cross Roshan’ exhibited a higher (PM) H⁺-ATPase activity and H⁺ pumping than did ‘Kavir’.     

CONTROLLED RELEASE OF FERTILIZER MICROCAPSULES USING ETHYLENE VINYL ACETATE POLYMER TO ENHANCE MICRONUTRIENT AND WATER USE EFFICIENCY

There have as yet been no detailed studies of micronutrient release from polymer coated fertilizers (PCFs). In this research, slow release microcapsules containing iron fertilizer was made and its release pattern evaluated. Three polymers ethyl cellulose (EC), glycerol mono stearate (GMS) and Compritol 888 ATO, were mixed with avicel and lactose and the microcaopsules were made by extrusion/spheronization method. The dissolution test carried out to determine the Fe release rate versus time. The results showed that, microcaopsules containing Compritol 888 ATO, released iron ions slower than that of EC and GMS. The release rate reached 85% after 7 days. In order to reduce the release rate, these microcaopsules were coated with ethylene vinyl acetate (EVA) polymer by dip coating method. It is concluded that the combination of matrix type formulation and the coating with EVA polymer caused a significant decrease in the release rate of iron.     

Improvement in estimation of soil water retention using fractal parameters and multiobjective group method of data handling

Soil water retention characteristic is required for modeling of water and substance movement in unsaturated soils and need to be estimated using indirect methods. Point pedotransfer functions (PTFs) for prediction of soil water content at matric suctions of 1, 5, 25, 50, and 1500 kPa were developed and validated using a data-set of 148 soil samples from Hamedan and Guilan provinces, Iran, by multiobjective group method of data handling (mGMDH). In addition to textural and structural properties, fractal parameters of the power-law fractal models for both particles and aggregates distributions were also included as predictors. Their inclusion significantly improved the PTFs’ accuracy and reliability. The aggregate size distribution fractal parameters ranked next to the particle size distribution (PSD) in terms of prediction accuracy. The mGMDH-derived PTFs were significantly more reliable than those by artificial neural networks but their accuracies were practically the same. Similarity between the fractal behavior of particle and void size distributions may contribute to the improvement of the derived PTFs using PSD fractal parameters. It means that both distributions of the pore and particle size represent the fractal behavior and can be described by fractal models.