الفهرس 
2. Review of literatureOnly 14 pages are availabe for public view
 |  | from | 95 |  |  |
| | | from | 95 | | |
Abstract
4.8. Effect of the applied P, Biofertilizers and S on the Cu uptake values of the different organs of marigold (Calendula offcinalis) plant grown on a calcareous soil.
Data presented in Table 9 reveal that values of Cu uptake by roots, shoots and flowers increased due to application of the mineral P fertilizer .However, Cu uptake values by roots were shown to be the highest whereas the corresponding ones shown by flowers were the lowest. The influence of P application on Cu transportation from root to grain should be receiving much more attention. Quantitative study is required in the field to analyze whether P fertilizer application influences Cu uptake efficiency by roots, or its translocation to the other organs. Efficient uptake by the roots is the key to acquiring soil nutrients, and root growth (especially root morphology) is thought to significantly affect the root uptake of mineral elements. The application of phosphorus (P) fertilizer in intensive agriculture production is a crucial measure for increasing grain yield (Banj et al., 2006). but it may affect the micronutrient contents in grain. The antagonistic effects between P-Cu have long been observed before (Wang et al, 2012, Ova et al., 2015). showed that, under field conditions, the root dry weight and root length density (length of roots/unit volume of soil) increased as the P application rate increased up to a critical level, but did not increase further once the rate exceeded that critical level. However, the changes in plant root morphology caused by P application influence Cu uptake has not been reported.
Application of the bio-fertilizers caused values of Cu uptake by roots, shoots and flowers to increase significantly, however, the Bacillus megaterium bio-fertilizer was of more pronounced effect on Cu uptake by the plant roots. PSB play a vital role in transformation and accumulation of P to plant roots that re-translocated in seeds and fruits. These bacteria have ability to produce low molecular weight organic acids in the rhizosphere such as acetic, citric, gluconic, lactic, succinic, propionic and oxalic acids, that well-recognized and widely accepted approach as principal mechanism for P-solubilization (Khan et al., 2014). Also, PSB can facilitate growth via changing the concentration of plant growth promoting like substances such as indoleacetic acid (IAA), synthesizing siderophores, symbiotic N2 fixation, biocontrol activity, produce antibiotics and cyanide, synthesizing 1-aminocyclopropane-1- carboxylate (ACC) deaminase that can modulate plant ethylene levels and helping in bioremediation process (Abd El-Azeem et al., 2007;Aarab et al., 2019).The final product of such processes is decreasing the soil pH and consequently the increase in availability of Cu and hence its uptake by plant. On the other hand, the bio-fertilizer Myccorhiza was more efficient in increasing Cu uptake by each of shoots and roots. Mycorrhizal fungi, upon root colonization, develop an external mycelium which is a bridge connecting the root with the surrounding soil microhabitats. Therefore, the mycorrhizal symbiosis, by linking the biotic and geochemical portions of the ecosystem, can contribute to nutrient capture and supply (Jeffries and Barea,1994) .Particularly, the arbuscular mycorrhizal (AM) symbiosis plays a direct role in nutrient cycling rates and patterns in agroecosystems and natural environments (Jackson,1994) . The establishment of the AM symbiotic status affects the chemical composition of root exudates while the development of a mycorrhizal soil mycelium also introduces physical modifications in the environment surrounding the roots. These changes affect the rhizospheric microbial communities in the so-called mycorrhizosphere.
The sulfur applied in its elemental form, generally, caused Cu uptake by roots ,shoots and flowers of the plant to increase significantly .This result can be attributed to the acidifying effect of the sulfuric acid formed due to oxidation of sulfur by thiobacillus thioxidance then the reaction of the formed sulfuric acid with soil moisture forming sulfuric acid. Ionization of this acid produces free H+ in the soil solution. Exchangeable H+ from cation-exchange surfaces also contributes to acidity. The relative contribution of exchangeable H+ is influenced by the total osmotic strength of the soil solution; the more concentrated the extracting solution, the greater the amount of H+ that is exchanged. Hence, extractability of Cu increases and consequently its uptake by plant increases.