Mineral uptake

Damage to epicuticular waxes Altered photosynthesis Increased water loss Accumulation of acidic anions Leaching of ions, sugars, etc. Mineral imbalances Altered metabolism Increased susceptibility to winter freezing injury Death of fine roots Destabilization of trees Reduced water/mineral uptake Reduced water uptake Cations leached below roots Accumulation of acidic anions Altered structure/texture Altered microflora Reduced litter decomposition Altered N transformations Solubilization of metal ions... 

Accumulation in soil solutions Altered microflora Reduced litter decomposion Metal ions accumulate Reduced water/mineral uptake Reduction in mycorrhizae Reduced vigor/resistance... 

Effects of Allelochemicals on Mineral Uptake and Associated Physiological Processes... 

Allelopathic inhibition of mineral uptake results from alteration of cellular membrane functions in plant roots. Evidence that allelochemicals alter mineral absorption comes from studies showing changes in mineral concentration in plants that were grown in association with other plants, with debris from other plants, with leachates from other plants, or with specific allelochemicals. More conclusive experiments have shown that specific allelochemicals (phenolic acids and flavonoids) inhibit mineral absorption by excised plant roots. The physiological mechanism of action of these allelochemicals involves the disruption of normal membrane functions in plant cells. These allelochemicals can depolarize the electrical potential difference across membranes, a primary driving force for active absorption of mineral ions. Allelochemicals can also decrease the ATP content of cells by inhibiting electron transport and oxidative phosphorylation, which are two functions of mitochondrial membranes. In addition, allelochemicals can alter the permeability of membranes to mineral ions. Thus, lipophilic allelochemicals can alter mineral absorption by several mechanisms as the chemicals partition into or move through cellular membranes. Which mechanism predominates may depend upon the particular allelochemical, its concentration, and environmental conditions (especially pH). 

One of the primary bases for the hypothesis that allelochemicals affect mineral uptake rests with the fact that the concentration of minerals In receiver plants can be altered by donor plants by a mechanism other than competition for minerals. In general, studies In support of this hypothesis have Involved measuring the amount of mineral present per weight of a particular plant part following absorption of minerals by the roots of the Intact receiver. 

Specific Chemicals. Very few studies have tested directly the Influence of specific allelochemlcals on mineral uptake by plants. 

A Relationship between net photosynthesis, foliage age, and foliage retention B Effect ofplant moisture stress on net photosynthesis C Relationship between mineral uptake and net photosynthesis D Relationship between net photosynthesis and carbohydrate storage E Relationship between water uptake and mineral nutrition F Relationship between carbohydrate storage and bark characteristics G Relationship between carbohydrate storage and wood H Relationship between carbohydrate storage and cone production... 

Roots modify their environment quite extensively in many ways. The most important of these are pH change, exudation and microbiological activity in the rhizosphere. Root exudates contain compounds such as hydroxycarboxylic acids and amino acids and these are capable of complexing trace metals. Bowling (1976), Farago (1986) and Streit and Stumm (1993) have discussed the theories of mineral uptake by plant roots the first suggests that there are four links in the uptake chain movement of ions or complexes in the soil to the roots uptake into the root transport across the root to the vascular system and movement to the shoot. 

The search for the exact sites of ion and compound deposition in plants and the nature of the chemical species involved has been carried out with a number of aims The elucidation of various mechanisms of phytochemical importance mineral uptake and utilisation toxicity and tolerance exhibited by many individual species and the study of plants that accumulate or hyperaccumulate metals. The literature for a number of individual elements to the late 1970s has been reviewed (Farago, 1981) and the phytochemistry of metal hyperaccumulators has been reviewed by Baker and Brooks (1989). 

Balke, N. E. 1985. Effects of allelochemicals on mineral uptake and associated physiological processes. ACS Symposium Series 268, 161-178... 

Mineral absorption studies that compared the absorption of the micro-nutrients, Cu, Fe, and Zn, from human milk versus experimental infant formulae confirmed that mineral uptake is more closely linked to the chemical interactions between the components in milk and formulae, than to mineral solubility alone (Glahn et al., 1998 Hendricks et al., 2001). 

Reader, J. P, N. C. Everall, M. D. J. Sayer, and R. Morris. 1989. The effects of eight trace metals in acid soft water on survival, mineral uptake and skeletal calcium deposition in yolk-sac fry of brown trout, Salmo trutta L. J. Fish. Biol. 35 187-198. 

Galls and other swellings on stems and roots are due to overstimulated cell development. Root swellings can interfere with water and mineral uptake, resulting in yellowing and wilting of the aboveground portions of the plants. 

Endocytosis constitutes the pathway by which extracellular material is carried into a cell by membrane invagination and internalization.1 3 Endocytosis occurs in virtually all eukaryotic cells,4 5 and can assist in such diverse processes as hormone signaling and removal, vitamin and mineral uptake, extracellular solute uptake, pathogen removal, and even simple membrane turnover. In fact, endocytosis is so active in some cells that the entire plasma membrane is internalized and replaced in less than 30 minutes.6... 

Dr. Heinerman furnishes still other evidence about the advantages of a vegetarian diet, such as the fact that crucifraous vegetables reduce the incidence of colon and rectum cancers. At the same time it is cautioned that some oth factors may play a part, such as a defidracy in mineral uptake by the body. 

Strontium-89, a radioisotope, is used in the relief of metastatic bone pain. Strontium-89 chloride is a radiopharmaceutical. Following IV injection, soluble strontium compounds behave like their calcium analogs, clearing rapidly from blood and selectively locahzing in bone mineral. Uptake of strontium by bone occurs preferentially in sites of active osteogenesis. It selectively irradiates sites of primary metastatic bone involvement with minimal effect on soft tissues distant from bone lesions. It is indicated for painful skeletal metastases. 

In addition to change of concentration by mixing processes, the relative concentrations of lanthanides may be changed by oxidation-reduction reactions followed by diflFerential mineral uptake (as for manganese nodules (4, JO), or phosphorites (4)), or by diflFerential solubility or ion-exchange processes aflFected by variations in ionic radius. The lanthanides are the group of elements for which such processes are known to be least effective only two, cerium and europium, are expected to exhibit stable ions other than trivalent, and as summarized by Moeller et aL (13), lanthanide complexes are typically weak, and show within the series, only modest variations in strength. 

Dambrine, E., Martin, E, Carisey, N., Granier, A., Hallgren, J.-E., Bishop, K., 1995. Xylem sap composition A tool for investigating mineral uptake and cycling in adult spruce. Plant Soil 168-169, 233-241. 

Equations (6.42), (6.43), (6.44), and (6.45) are established for the system which is not affected by precipitation of minerals such as Fe- and Mn-hydroxides, adsorption of dissolved species, colloids and fine grained particles onto minerals, uptake of elements by organisms and dissolution of sediments. Figure 6.17 shows an example of the system which is not affected by these processes. Observed concentration is in agreement with the calculated concentration based on Eq. (6.45) (Fig. 6.17). 

NISHITA H., KOWALEWSKY B.W. and LARSON K.H. 1956. Influence of soil organic matter on mineral uptake by barley seedlings. Soil Science, 82, 307-318. 

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