Soil science
E. Mirparizi; M. Barani Motlagh; S.A. Movahedi Naeini; R. Ghorbani Nasrabadi; S. Bakhtiary
Abstract
Introduction: Iron deficiency is one of the most common nutritional problems of plants in arid and semi-arid soils especially in calcareous soils. Iron is essential to many cellular activities, required for optimum growth and development, however it is insoluble in aerated soils at neutral or basic pH, ...
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Introduction: Iron deficiency is one of the most common nutritional problems of plants in arid and semi-arid soils especially in calcareous soils. Iron is essential to many cellular activities, required for optimum growth and development, however it is insoluble in aerated soils at neutral or basic pH, therefore, iron deficiency is common in these soils. The problem is usually solved by using iron synthetic chelates which is a very expensive option. There is, therefore, a need for cheaper and more effective alternatives to traditional Fe fertilizers. Several reports have shown that application of Fe factory by-product to soil tends to raise the availability of Fe and reduce Fe deficiency in plants. Application of organic compounds to soil may improve the solubility of the minerals containing micronutrients and correct their deficiencies in alkaline and calcareous soils. A large amount of slag is produced annually at the Sarcheshmeh Copper Complex, Kerman Province, Iran. So far, the copper slag, however, has not been tested as an Fe fertilizer in calcareous soils. Since about 53.8% of slag obtained from copper concentrate melting is composed of iron oxides, we, thus, examined the effect of copper slag along with organic compounds on the level of upper leaf iron, photosynthetic pigments, SPAD index, the activity of plant enzymes and the level of active iron in the upper leaves of sorghum by performing a factorial experiment in a completely randomized design.Materials and Methods: In order to study the effect of copper slag (one of by-products of melting copper concentrate in Sarcheshmeh Copper Complex, Kerman Province) and organic compounds (cow manure and pistachio skin) on total leaf iron content, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), antioxidant enzymes activity (Guiacol Peroxidase, Glutathione peroxidase) and concentration of active iron of young leaves developed of sorghum, a pot experiment was conducted in the greenhouse with three replicates per treatment. We applied experimental treatments including 5 levels of organic matter (pistachio skin, cow manure at 2 and 4 wt. % and control sample), and 11 levels of iron (copper slag, copper slag with sulfur, copper slag with sulfur and thiobacillus, acidic slag (each 2 levels each), sequesterine, foliar application of EDTA, and control sample) to a soil sample with low iron content. At the end of the incubation period, sorghum bicolor was cultured in the above treatments. Ten seeds were sown in each pot. Seedlings were thinned to 4 when they were about 10 cm high. During the growth period, pots were irrigated with distilled water as needed. Before harvesting, SPAD, the concentration of photosynthetic pigments, level of active iron and activity of plant enzymes were also measured in fresh plant samples. Furthermore, the concentration of Fe in the leaves was measured. Analysis of variance was performed using software SAS and significant differences were determined based on LSD (Least Significant Difference Test) at p < 0.05 level.Results and Discussion: The interaction between slag treatments and organic compounds showed that treatments of 4 wt. % of cow manure with slag of 4 times of recommended soil test value (C4S4, and 4 wt. % of cow manure with slag of 4 times of recommended soil test value with sulfur and thiobacillus (C4S4S°T), had significant effects on increasing photosynthetic pigments pigments (chlorophyll a, chlorophyll b, total chlorophyll), SPAD index, activity of plant enzymes (Guiacol peroxidase, Glutathione peroxidase) and active iron. The highest active iron level in the young leaves developed (54.06 mg / kg) was observed in (C4S4S°T) treatment which showed a significant increase compared to the control treatment (17.14). Increased concentration of active iron was also observed due to application of treatments (slag, organic compounds and the interaction between treatments) in sorghum young leaves. The photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), SPAD index and activity of plant enzymes (Guiacol peroxidase, Glutathione peroxidase) were more correlated with active iron in young leaves developed compared to total iron concentration in these leaves. This indicates that active iron can be used as an index to detect iron deficiency.Conclusion: The higher level of active iron in the young leaves developed was more associated with physiological indices of sorghum as compared with total Fe concentration in these leaves. Therefore, this parameter can be used as an index to detect iron deficiency. In this study, increasing the level of slag consumed and consequently increasing Fe concentration in the leaf resulted in a significant increase in chlorophyll a, chlorophyll b, total chlorophyll, carotenoids and activation of the plant enzymes.
Taleb Nazari; mojtaba barani; Esmaeil dordipour; Reza Ghorbani nasrabadi; Somayeh Sefidgar shahkolaie
Abstract
Introduction: Fe is the first identified micronutrient for crops and required in higher amount than other micronutrients. Fe plays important roles in enzyme metabolism, protein metabolism, chlorophyll construction, chloroplast evolution, photosynthesis, respiration and reduction-oxidation reaction as ...
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Introduction: Fe is the first identified micronutrient for crops and required in higher amount than other micronutrients. Fe plays important roles in enzyme metabolism, protein metabolism, chlorophyll construction, chloroplast evolution, photosynthesis, respiration and reduction-oxidation reaction as well as organic acids metabolism. Iron, as an essential micronutrient, has great contribution in important antioxidant enzymes activity and through which affects plant tolerance against environmental stresses. Plant enzymes including superoxide dismutase, catalase and glutathione peroxidase are among the most important enzymes scavenging the hydrogen peroxide have iron in their structure, so they affected by iron deficiency. In this study, the effect of soil, foliar and fertigation application of humic acid on iron availability, chlorophyll types and superoxide dismutase, catalase and glutathione peroxidase enzymes in canola (Hyola 308) were evaluated.
Results and Discussion: Results showed that highest total iron content in plant leaves was obtained in 0.4 percent foliar application and the lowest was belonged to control treatment. Highest iron content in plant stem and active iron was obtained in humic acid application through irrigation at 2000 mg L-1 by 85 and 44.86 mg kg-1, respectively, and lowest amounts were obtained in control by 54.62 and 20.40 mg kg-1. Also, greatest concentration of chlorophyll a, chlorophyll b and total chlorophyll were recorded under0.4 percent humic acid foliar application by 3.58, 1.79 and 5.37 and the lowest chlorophyll contents were associated to control. Highest activities for plant enzymes superoxide dismutase and glutathione peroxidase were obtained under0.1 percent foliar application of humic acid by 4.20 and 1.95 (Iu/gr. FW) and the highest activity for catalase enzyme by 4.46 Iu/gr FW in 1000 mg L-1 humic acid through was irrigation and the lowest enzyme activity obtained in control treatment. Findings showed that application of various levels of humic acid increased plant enzyme activity compared to control in all of three application method (soil, foliar and application through irrigation water). Increasing humic acid concentration decreased enzyme activities. Also, there was negative correlation between activity of plant enzymes and concentation of chlorophyll types and active iron.
Conclusions: Active iron and antioxidant enzymes represent iron status within cell cytoplasm. Based on the results of this study, active iron concentration and activity of antioxidant enzymes are appropriate indices for evaluating plant tolerance to iron deficiency compared to assessing total iron content in leaves.
