الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Despite the growing industrial and technological development in the present time, agriculture is still one of the primary sectors of Egypt. Cereals such as maize and wheat are commonly deficient in P and Zn due to soils in the growing regions having incredibly low amounts of plant-available P and Zn. Zinc is an essential co-factor and structural component of proteins and enzymes involved in many metabolic pathways, including the production of energy, Krebs cycle, and resistance to infection by specific pathogens. Crops lacking in zinc exhibit chlorotic and necrotic patches, leaf bronzing, deformed and dwarf leaves, and generally stunted plant growth. About one-third of the world’s population is known to experience zinc nutritional deficiencies due to a diet lacking in zinc that is based on plants. Eco-friendly and affordable agro-technologies are required to boost agricultural productivity and lessen Zn deficiency. Plants require zinc in amounts between 5 and 100 mg/kg, but most soils have very low Zn concentrations. Nearly all pastures and crops suffer from zinc deficiency, which causes significant yield losses and nutritional inadequacies. In low-income nations, the problems are significantly worse, pushing farmers to use extensive cultivation techniques to meet the food demand. Zinc fertilizers are not practical economically nor environmentally beneficial, as they
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are converted into insoluble complex forms within 7 days. Two approaches to correct soil Zn deficiency have been partially successful: using fertilizers to fortify crops and developing Zn dense cereals producing crops through breeding programs or genetic engineering. Microbial inoculants are an eco-friendly alternative to chemical fertilizers. Twenty different bacteria were isolated from five soil samples collected from different fields in Egypt for the current study. Three bacterial isolates were chosen because they were effective at solubilizing zinc oxide and zinc carbonate and could tolerate high concentrations of soluble zinc. Zea mays plants grown with selected isolates of Acinetobacter calcoaceticus and ZnCO3 demonstrated higher growth parameters and greater zinc content in both free and immobilized forms, and can be used as biofertilizers to increase soil fertility. Only three strains of bacteria were able to withstand 500 mg kg-1 of soluble zinc, while the rest of isolates were able to tolerate up to 400 mg kg-1. Three bacteria; B3 (Acinetobacter calcoaceticus), B5 (Bacillus proteolyticus), and C6 (Stenotrophomonas pavanii) were chosen for further investigation based on their capacity to solubilize zinc in various forms and their tolerance to high zinc concentrations. Three of the isolates demonstrated plant-growth-promoting characteristics during a pot experiment carried out in a greenhouse, including the increase in fresh and dry weight of
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plant root and stem as well as an increase in zinc content in plants. The viability of sodium alginate agents was examined during storage at room temperature and in the refrigerator. The results demonstrated that sodium alginate persisted in both storage environments for three months, and enhanced plant growth characteristics during a pot experiment carried out in a greenhouse.