Soil Biology, Biochemistry and Biotechnology
Morvarid HemmatiTabar; Setareh َAmanifar; Elaheh Vatankhah; Elham Malekzadeh
Abstract
Introduction Nickel (Ni) is a fundamental micronutrient in plants but hampers plant growth and metabolism at elevated levels in the soil. Ni toxicity to plants is manifested mainly by the decrease in germination efficiency, the inhibition of growth and root branching, damage to the photosynthetic apparatus, ...
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Introduction Nickel (Ni) is a fundamental micronutrient in plants but hampers plant growth and metabolism at elevated levels in the soil. Ni toxicity to plants is manifested mainly by the decrease in germination efficiency, the inhibition of growth and root branching, damage to the photosynthetic apparatus, and the induction of oxidative stress. In recent years, the use of arbuscular mycorrhiza (AM) has gained importance for its role in enabling plants to tolerate Ni toxicity. However, information about their effectiveness in alleviating Ni stress is scanty. The process of element transport in plants may be assumed to be different among heavy metal concentrations in the substrate. Consequently, whether AM fungi enhance the metal transport to shoots (phytoextraction) or immobilize them in the roots (phytostabilization) mainly depends on metal concentration in the substrate. Moreover, Ni has been reported to compete with other micronutrients for absorption sites, which would trigger different changes of elements concentrations. The aim of this study was to investigate the role of AM fungus in alleviating Ni stress and its possible function in plant nutrition.Materials and Methods In this study, the effects of mycorrhizal inoculation of corn plants with Claroideoglomus etunicatum on alleviation of Ni impact on plant were evaluated. Some growth characteristics of the plant, phosphorus content, micronutrients (iron, zinc, and copper), concentration of nickel in shoot and root, and Bradford reactive soil glomalin (BRSG) were assessed. Accordingly, a two-factor experiment (AM inoculation × Ni levels) in completely randomized design was done. The factors included the different concentrations of nickel (control (Ni0), 50 (Ni50), 100 (Ni100) and 250 (Ni250) mg kg-1), and the levels of fungal application (control without inoculation (NM) and inoculated with C. etunicatum (AM)). Plants were grown in the greenhouse for 90 days and then the growth parameters were recorded. The concentration of phosphorus was measured spectrophotometrically and the concentration of iron, zinc, copper, and nickel in digested plant samples was determined by ICP-OES. Bio-concentration factor and translocation factor were also calculated. The colorimetric method was used to quantify Bradford-reactive soil glomalin. The Bradford protein assay was utilized to determine the concentration of easily extractable and total Bradford-reactive soil glomalin using bovine serum albumin (BSA) as a standard.Results and Discussion Increasing the nickel concentration in soil decreased the dry weight of root and shoot, and this decrease was significant in both inoculated and non-inoculated plants at Ni250 treatment (p≤0.05). Plants inoculated with AM fungus showed significantly higher height and dry weight of shoots than plants without inoculation (p≤0.05), but the effect of mycorrhizal inoculation on the dry weight of roots was not statistically significant. The effect of nickel on the colonization percentage of roots and easily extractable Bradford-reactive soil glomalin (EE-BRSG) was significant. EE-BRSG was higher at all levels of nickel in inoculated plants than in non-inoculated ones. Moreover, with the increase of nickel concentration in soil up to 100 mg Kg-1, total Bradford reactive soil glomalin (T-BRSG) increased. The concentration of phosphorus in the shoots and roots of inoculated plants was higher than in non-inoculated plants. Mycorrhizal inoculation significantly increased the concentration of zinc and copper in the aerial part. Moreover, nickel treatment did not show a statistically significant effect on the concentration of copper in the aerial part and iron in the roots. Inoculation with AM fungus showed a significant impact on the nickel concentration of the shoots and roots, and the concentration of nickel in the roots of inoculated plants at Ni250 level was significantly higher than plants without inoculation by 29% (p<0.05). Mycorrhizal plants had lower nickel concentrations in the aerial part at Ni100 and Ni250 by 30% and 33% respectively, compared to the NM plants. The translocation factors in inoculated plants at Ni100 and Ni250 levels were significantly lower than that in non-inoculated plants, which indicates the role of fungi in preventing the transfer of nickel to the aerial parts and its accumulation in the roots. Moreover, inoculated plants in the Ni100 and Ni250 treatments showed a significantly lower bio-concentration factor by 36% and 22%, respectively, compared to non-inoculated plants.Conclusion The results showed that AM colonization can help to reduce the toxicity of nickel by increasing plant growth and uptake of phosphorus, zinc and copper. AM colonization had a prominent impact in preventing the nickel transfer to the aerial parts and its accumulation in the roots. It seems that AM fungi can be used for phytostabilization of heavy metals in soils.
gholamreza Adim; Elham Malekzadeh; Esmael Dordipour; Farshad Kiani; Hassan Mokhtarpour; seraj Moazzemi
Abstract
Introduction In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Although the use of chemical fertilizers has a high yield of plants, ...
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Introduction In recent years, ensuring the continuous and sustainable production of healthy food products along with environmental protection and paying attention to agricultural economic and environmental problems is very important. Although the use of chemical fertilizers has a high yield of plants, its destructive effects in the long-term are known on the soil biological, physical and chemical properties and environmental pollution. Therefore, a strategy must be considered that can improve soil health and quality as well as produce a high plant yield. Organic manures increase the growth, yield and quality of plants by improving soil conditions and the balance of essential elements. An integrated plant nutrition management system by reducing the use of chemical fertilizers is known as one of the ways to achieve the expected yield and meanwhile, minimize the adverse environmental effects of chemical fertilizers in the world.Materials and Methods The objective of this study was to evaluate the effect of single and combined use of chemical fertilizer (urea, triple superphosphate, potassium sulfate as NPK) with organic and biological fertilizers on the yield and yield components of transplanted canola (Brassica napus L.). Experiment was conducted in a randomized complete block design with six treatments and three replications (18 experimental units) in the 2019-2020 crop year at the Iraqi Agricultural Research Station in Gorgan, Iran. Treatments included: 1) Control (without fertilizer, T1), 2) Chemical fertilizer (T2), 3) Poultry manure (T3), 4) Compost (T4), 5) 50% Chemical fertilizer+ 50% Poultry manure+ 50% Compost (T5), 6) 50% Chemical fertilizer+ 50% Poultry manure+ 50% Compost+ Biofarm-1 biofertilizer (T6). Chemical fertilizer was applied based on soil test including nitrogen equivalent to 250 kg/ha urea was added in three stages during planting, stem elongation, before flowering; phosphorus equivalent to 150 kg/ha of triple super phosphate; potassium equivalent to 50 kg/ha of potassium sulfate, respectively. Organic fertilizers were calculated based on their total nitrogen contents and the equivalent of pure nitrogen recommended based on the soil test for chemical fertilizer and by assuming 50% mineralization rate of organic fertilizers in the soil. Biofertilizer was applied as seed inoculation plus spraying on the plant base in two stages of 4 to 8 leaves and stem elongation. Chlorophyll index was measured in the middle of the flowering stage by using SPAD. After physiological maturity, yield and yield components including pods per plant, numbers of seeds per pod, pod length, 1000-seed weight, seed yield, protein and oil contents of grain were recorded. Results and Discussion The results showed that the effect of fertilizer treatments was significant on yield and yield components (p <0.01). The highest 1000-seed weight, grain yield, protein content of the seed, number of seeds per pod, pod length and pods per plant were recorded in the treatment of 50% chemical fertilizer+ 50% Poultry manure+ 50% Compost+ Biofertilizer (T6) which increased by 21.9%, 43.7%, 33.8%, 29.2%, 37.2% and 37.6%, respectively, in compared to the control treatment (with the lowest values). The pods per plant, 1000-seed weight and grain yield were not significantly different between the combined treatments of chemical fertilizer+bio-organic fertilizers (T6) and integrated use of chemical and organic (T5) fertilizers (p <0.05). The control treatment (T1) by 2248.37 Kg/ha of grain yield (the minimum amount) decreased by 43.7% and 38.3% compared to T6 and T5 treatments, respectively. The chemical treatment (T2) and integrated application of chemical fertilizer+ bio-organic fertilizers (T6) showed the most positive effect on the chlorophyll index compared to other fertilizer and control treatments (with the lowest index, 43.66). Chlorophyll index in the T2 and T6 treatments increased by 35.6% and 33.7% compared to the control treatment (T1), respectively. The treated plants by alone use of organic fertilizers (T3 and T4) without notable difference produced the highest grain oil (by an average of 45.73%) which increased by 6.6% compared to the chemical fertilizer (T2) and control (T1) treatments by an average of 42.7%.Conclusion Combined use of chemical fertilizer with bio-organic fertilizers had the most positive effect on yield and yield components, and often showed significant difference with the single application of chemical and organic fertilizer treatments (T2, T3 and T4). Therefore, the combination use of chemical and bio-organic fertilizers is a better option to increase the yield and yield components of transplanted canola than the single use of chemical fertilizers. The highest pods per plant, pod length, number of seeds per pod, chlorophyll index, protein content, chlorophyll, 1000-seed weight, and grain yield were related to the integrated application of chemical fertilizer with bio-organic fertilizers (T6 and T5), so it can be inferred that the use of a mixture of organic, biological and chemical fertilizers is an effective approach to reduce the using of chemical fertilizers and their destructive environmental effects, as well as increase the yield of transplanted rapeseed
Ghasem Ghorbani Nasrabadi; Esmaeil Dordipour; mojtaba Barani; Elham Malekzadeh; Abdolreza Gharanjiki
Abstract
Introduction Salinity is one of the most important environmental stresses limiting agricultural production in arid and semi-arid regions, which occupies a relatively large area of arable land. Nutrient availability is decreased in saline conditions in soil solution and plant nutrient balance is changed. ...
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Introduction Salinity is one of the most important environmental stresses limiting agricultural production in arid and semi-arid regions, which occupies a relatively large area of arable land. Nutrient availability is decreased in saline conditions in soil solution and plant nutrient balance is changed. Nitrogen fertilizer management as an essential nutrient for plant growth is very important under salinity stress. Also, salicylic acid is a plant growth regulator involved in defense mechanisms of plants against biotic and abiotic stresses. Therefore, the aim of this study was to investigate the effect of salinity on the concentration of nutrients in wheat in response to salicylic acid consumption at different levels of nitrogen.Materials and Methods In order to investigate the effects of salicylic acid and nitrogen fertilizer application rates at different salinity levels on nutrient concentration of wheat cv. Morvarid, an experiment was conducted as a split plot factorial based on a randomized complete block design with four replications in the fields of Mazraeh-E-Nemooneh located in Anbarolum, Aq Qala city, Golestan province. The main factor included three soil salinity levels (3-4 below wheat tolerance threshold (control), 9-11 and 13-15 dS.m-1) and sub factors included two levels of salicylic acid (0 and 1.5 mM) and three levels of N fertilizer (from urea source, 46% N) were 1) N based on soil test recommendation, 2) 30% N more than soil test recommendation and 3) 30% N less than soil test recommendation, respectively. Salicylic acid was foliar applied twice for about 2 weeks in the tillering stage and 10 days after the second stage spraying, content in them was determined. Nitrogen treatments were applied in three stages - one third before planting with ammonium sulfate (21% N) and remains top-dressed with urea (46% N) at tillering and stem elongation stages. At the emergence stage of the cluster or the beginning of flowering of wheat, the amount of nitrogen in the flag leaf was measured. The concentrations of nitrogen, potassium and sodium in grain and straw were also measured by standard methods.Results and Discussion The results showed that by increasing salinity, the flag leaf N concentration, N and K concentration of wheat staw and seed decreased. However, Na concentration of straw and seeds increased. With increasing N and salicylic acid consumption, the concentration of N flag leaf, the seed and straw N and K concentrations increased, but the concentration of Na in seed and straw decreased.The interaction of salinity, salicylic acid and nitrogen on seed N and K concentrations and also on flag leaf N concentration was significant but there was no significant effect on other measured elements. Comparison of the mean of simple effects of salinity on the evaluated elements indicates a significant reduction of all studied elements due to salinity treatment. Also, comparison of the mean of simple effects of nitrogen fertilizer showed that all elements were affected by the treatment. The results of mean comparison showed a positive and significant effect of salicylic acid on the leaf N concentration of the flag leaf, so that the N concentration in the flag leaf in a 1.5 mM salicylic acid treatment was significantly increased compared to the non-use treatment.Conclusion according to the results, more nitrogen consumption at moderate salinity can have a positive effect on plant nutrition, and vice versa, at high salinity levels, it is better to reduce nitrogen consumption. The interactions of salicylic acid and nitrogen showed that in general nitrogen treatments with salicylic acid increased the N concentration of seed and straw. Nitrogen fertilization at higher and medium salinity levels increased the concentration of N and K in straw and seeds; However, at high salinity, less nitrogen fertilization improved the concentration of N and K. Also, nitrogen application with salicylic acid improved these traits under saline conditions. Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Key words: Salicylic acid, salinity stress, wheat, Nitrogen fertilizer management
