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001-es BibID:	BIBFORM096204
Első szerző:	Makleit Péter (növényélettanász)
Cím:	Role of magnesium in plant's life / Makleit Péter, Fári Miklós Gábor, Kovács Szilvia, Domokos-Szabolcsy Éva, Bákonyi Nóra, Veres Szilvia
Dátum:	2021
Megjegyzések:	Magyar Magnézium szimpózium (17.)(2021.08.31.)(Debrecen, Magyarország). Adequately supplied plants contain 0.15-0.35 wt % magnesium (Mg) on the basis of their dry wieght (macronutrient). In case of deficiency Mg is transported from older to younger parts of plants. The process called retranslocation takes place in the phloem, that's why magnesium can be detected from phloem sap in concentration of about 0,1 mg/ml. Plants take up Mg from the soil solution in the form of divalent cation. Nonspecific ion chanels or H+/Mg2+ antiporters facilitate Mg uptake of plant cells, depending on the outside concentration. Its quantity in the cytoplasm is 2-10 mM, but vacuoles contain in higher quantity (about 13-17 mM). H+/Mg2+ antiporters allow the transport of Mg through the tonoplast into the vacuole. The relatively high concentration of Mg in the vacuole increase solute potential and water uptake ability of the cells. Functions of Mg in the plant cells connected with its ability of forming ionic bond with highly nucleophilic ligands (e.g. phosphpryl group), complex forming and occasionally, forming of covalent bonds. Mg is the central atom of chlorophyll molecule, where the enzime Mg chelatase builds in. Only 6-25 % of total Mg bounded to the chlorophyll depending on the environmental conditions (Mg-supply; light intensity). Chlorophyll molecules have key role in the photosynthesis light reactions, their quantity and the productivity of plants correlates positively. 5-15 % of the total Mg content is in bounded form, on one hand in the form of pectate in the cell wall, on other hand in the form of insoluble Mg-salts (e.g. phosphates) in the vacuole. Beside the bounded forms, the rest of Mg in the plant cells is in ionic form (60-90 % of total Mg-content). The divalent magnesium ions excert influence on the operation of several enzimes. Mg has emphasized importance in energy conservation and comsumption. The substrate of ATP-ases is Mg-ATP rather than free ATP. In case of ATP synthesis the forming of connection between the enzyme and ADP require ionic form of Mg. Glutamine synthetase which is the member of nitrogen assimilation enzyme system, also require ionic form of Mg to its operation. Mg activate pyruvate dehydrogenase which is a key enzyme in dark respiration. Mg also activate several enzymes of the Calvin?cycle (Rubisco; Fructose-1,6-biphoshatase; Sedoheptulose-1,7-biphosphatase; Phosphoribulokinase) when its concentration rises in the stroma of chloroplasts for the effect of illumination. Mg has significant function in protein synthzesis too. The subunits of ribosomes join by the help of Mg, and the enzyme RNA-polymerase and termination are activated by effect of Mg.
Tárgyszavak:	Agrártudományok Növénytermesztési és kertészeti tudományok nem besorolt egyéb
További szerzők:	Fári Miklós (1953-) (kertészmérnök) Kovács Szilvia Domokos-Szabolcsy Éva (1978-) (molekuláris biológus) Bákonyi Nóra (1985-) (agrármérnök) Veres Szilvia (1972-) (biológus, biológia középiskolai tanár, angol-magyar szakfordító)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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