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Aminochelate fertilizers are the latest novelties regarding plant nutrition in agricultural production systems. They are part of the modern formulae of fertilizers which are synthesized based on various amino acids, mainly glycine. In recent years, they have had a rapid growth in the marketplace. Their rapid growth in formulations, manufacturing, diversity and application is mainly due to the novel understandings regarding diverse roles of amino acids in plant metabolism. Compared to routine fertilizers or other commercially synthetic chelators such as EDTA; however, aminochelates represent a safer and more efficient form of fertilizer, resulting in better plant performance and less environmental risks. Aminochelates represent effective fertilizers for both soil and particularly for foliar applications. Despite, aminochelates having quickly dominated the fertilizer markets in many countries, there is not enough scientific data and information regarding detailed responses of crops to these types of fertilizers. This in part, may be due to their mixed composition of several nutrient elements, giving various nutrients effects, meaning that conducting scientific experiments and concluding remarks, , would be very difficult. This review provides information concerning different aspect of aminochelate fertilizers including their history, structure, types, value and effects on agricultural crops.

Amino acids have various roles in plant metabolism, and exogenous application of amino acids may have benefits and stimulation effects on plant growth and quality. In this study, the growth and nutrient uptake of Romain lettuce (Lactuca sativa subvar Sahara) were evaluated under spray of glycine or glutamine at different concentrations of 0 (as control), 250, 500 and 1000 mg.L-1, as well as a treatment of 250 mg.L-1 glycine+250 mg.L-1 glutamine. The results showed that there was significant increase in leaf total chlorophyll content under Gly250+Glu250, Gly250 and Glu1000 mg.L-1treatments, and in leaf carotenoids content under 250 mg.L-1 glutamine spray compared with the control plants. Shoot fresh and dry weights were highest under 500 mg.L-1 glycine, whereas root fresh weight was highest under 250 mg.L-1 glycine spray. Foliar application of glycine and glutamine had no significant increase in leaf mineral concentrations except for iron, in which 1000 mg.L-1Gly spray resulted in significantly higher leaf Fe concentration compared with the control plants. Leaf vitamin C was increased at 250 and particularly 500 mg.L-1 spray of glycine and glutamine compared with the control. Nevertheless, different amino acid treatments had no significant effect on plant height, leaf SPAD value, root dry weight, and leaf concentrations of N, K, Ca, Mg and Zn. The results indicate that foliar application of glycine and glutamine amino acids can have beneficial effects on lettuce growth, as higher fresh yield, leaf chlorophyll content and vitamin C were obtained by low to moderate concentrations of glycine and/or glutamine amino acids.

Background: Soil salinity is a real challenge in nowadays crop production in many regions. Various strategies have been applied to increase plant salinity tolerance. Salicylic acid (SA) frequently has been reported to increase plant salinity tolerance; however, the comparative efficiency of soil (root) or foliar application of SA has not been well tested yet. In this study, the effects of root or leaf pretreatment, and leaf treatment with 100 mg L −1 salicylic acid were evaluated on growth characteristics of tomato seedlings (Solanum lycopersicum Mill) under salinity stress. The plants were grown 3 weeks in sand that were fed with Hoagland nutrient solution with or without 100 mM NaCl. Results: The results showed that salinity significantly reduced tomato seedling growth and traits of plant height, leaf area, shoot fresh weight, and nutrient concentration of potassium, calcium, iron and zinc compared to control plants. However, leaf SPAD value, root fresh and dry weights, leaf concentration of sodium, proline and soluble sugars were significantly increased under 100 mM NaCl salinity compared to control plants. Application of salicylic acid particularly by foliar pretreatment increased the tomato plant growth and those traits that were reduced by NaCl salinity. Application of SA, particularly foliar pretreatment, also increased the root fresh and dry weights, leaf proline and soluble sugars concentrations as compared with salinity alone. Foliar SA pretreatment significantly increased leaf K and Fe concentrations, whereas leaf Ca was significantly increased by either root or leaf pretreatment with SA under salinity. Conclusion: The results indicate that the most to least effective method of SA application was leaf pretreatment, root pretreatment and leaf treatment, respectively, to recover the reduced growth parameters of tomato plant under salinity stress.

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