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Reduced growth and development of plants on acid soils is an effect of worsening of chemical, physical and biological properties of soils and in consequence toxic influence of some elements on plant and restricted uptake of plant nutrients. To more important factors reduced the yield of plants on acid soils could be included: toxic action of Al., Mn and H ions on plants, restriction in uptake of many nutrients by plants, precipition beyond the root system of phosphorus and molybdenum, diminishing of soil sorption capacity and others. Counteraction to these results could be take by application of lime to the optimal level of pH for particular plant species. Individual species and also varieties have different immunity mechanism on excessive acidity of the soil. In that case detrimental effect of soil acidity could be diminished not only by liming but also by assortment of species and varieties as well as by application some chemical compounds (gypsum, compounds of Mg, F, nitrates and others). Mentioned factors are discussed in this paper.
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Till now the chemical changes in the rhizosphere have not been well known due to difficulties in precise separation of all roots and rhizosphere from bulk soil. In this review paper, the authors describe major chemical changes in the rhizosphere and propose methods of their investigation. These processes may be studied in plants, grown in soil, in sloped (at 45°) rhizoboxes with removable plexiglass lids. On the side of the transparent lid the roots and soil is covered with agar sheet or filter-paper containing specific reagents and indicators. From colour reactions in contactwith root released substances it is possible to assess the following rhizosphere processes: - pH changes (using a prefixed thin agar sheet - 1% agar containing bromocresol purple or bromocresol green - 1% as pH indicator). - Activity of Al (using complexation of Al by the decolouration of polyacrylamide gel or agar containing Aland aluminon). - Mn⁴⁺ to Mn²⁺ reduction (indicated by the decolouration of filter paper impregnated with Mn oxide). - Fe³⁺ to Fe²⁺ reduction (indicated by the formation of a red coloured complex between Fe²⁺ EDTA and BPDS in an agar medium). - The activity of acid phosphatase (indicated by the formation of a red complex on filter paper containing 1-naphtyl phosphate as substrate and Fast Red TR as specific indicator).
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Rola rizosfery w mineralnym odzywianiu sie roslin

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The biology and chemistry of the soil-root interface (rhizosphere) has recently received increased attention. Of special interest is the identification and quantification of organic and inorganic root exudates, which may alter the flow of nutrients in the rhizosphere mainly via soil pH and ionic concentration changes in the rhizosphere soil. Release of inorganic ions, such as H⁺ abd HCO₃⁻ , resulted from ion uptake by roots directly affects the pH of rhizosphere soil what can modify the acquisition of nutrients by plants. Exudation of organic compounds by roots may influence the ion solubility and uptake through their indirect effects on microbial activity, physical properties of rhizosphere and dynamics of root growth and directly through the acidification, chelation, precipitation and oxidation-reduction reactions in the rhizosphere. Plant roots release a variety of organic substances; however, the water soluble compounds are most readily decomposable substances which serve as a source of nutrients for microbial populations of microorganisms colonizing root surface. The microorganisms in turn can affect the growth and physiology of plants either directly via various microbial metabolites or by modifying the soil-root interface environment. Although the rhizosphere studies are difficult, understanding the biology and chemistry of rhizosphere is essential to determining the mobility and availability of mineral elements at the soil-root interface and their impact on plant nutrition.
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