The nonallosteric regulation mechanism of enzyme reaction velocity assumes that the substrate and enzyme interact via a metal cation and form simple and mixed, mono- and multi-nuclear complexes. A solution of equations for individual cases gives a function of initial reaction velocity at any given substrate or modifier concentration. This function can describe kinetic effects that are considered allosteric, as well as phenomena omitted by commonly-accepted models.
In pot experiments with lettuce, the effect of chelated and mineral forms of manganese on the fresh matter of plants and on the content of Mn, Cu, Zn and Fe in lettuce leaves were compared. Lettuce plants were grown in a peat substrate where the manganese content was differentiated in four levels: 10, 20, 30, and 60 mg Mn‧dm⁻³. Independent of the form of the applied manganese, no differences were found in fresh matter of lettuce heads at manganese levels of 10 to 30 mg Mn‧dm⁻³ substrate. When the plants were nourished with the mineral form of manganese, then in comparison with the chelated form of manganese, the content of manganese in lettuce leaves was higher. The differentiated fertilization with manganese exerted an effect on the nutritional status of plants with copper, zinc and iron. After the application of chelated manganese, there was more copper and iron in the lettuce, but a lesser amount of zinc than in case of manganous sulphate application. The increase of manganese content in the substrate caused an increase of this component in the plants.
A greenhouse experiment aimed at investigating the effect of four chelates, differing in percentage of Fe content and the kind of Fe bonding ligand: Fe 8 Forte (EDTA+ +HEEDTA), Fe 9 Premium (DTPA), Fe 13 Top (EDTA) and Librel Fe DP7 (DTPA), on the state of iron nutrition of Merkury F1 cultivar greenhouse tomato grown traditionally in peat substrate. The second factor was iron content in the growing medium, which was established to reach the following levels: 50, 75 and 100 mg Fe⋅dm-3, while in the control object Fe values ranged 17.9 Fe⋅dm-3 (after peat liming). The experiment was established in a two-factorial design with three replications including four plants cultivated on one plot. The iron content was assayed in plant index parts according to the ASA method. On the basis of the results, significant differences were found in the state of greenhouse tomato nutrition under the influence of the examined iron chelates. The highest content of iron in tomato leaves was determined when chelate Fe 9 Premium (DTPA) was used, which points to the fact that it was the best source of Fe. The lowest iron level was recorded after the application of Fe 13 Top (EDTA). The highest mean Fe content for the years and dates of analyses appeared in leaves of plants cultivated in the growing medium containing 75 mg Fe⋅dm-3. In June, after the plants began to yield, there was a considerable decrease in the Fe content in plant index parts in comparison to the stage of fruit maturation and the end of yielding. The study did not demonstrate any symptoms of phytotoxicity or visible disorders regarding tomato growth and development due to the examined Fe chelates introduced in the doses of 32.1, 57.1 and 82.1 mg Fe⋅dm-3 to the substrate, whose initial Fe concentration after peat liming was on average 17.9 mg Fe⋅dm-3.
Badania przeprowadzono na 2 grupach indorów typu Big-6 podczas 16-tygodniowego odchowu. Czynnikiem doświadczalnym był dodatek miedzi w formie chelatu z lizyną w ilości 10 mg Cu-dm-3H2O. Celem badań było określenie wpływu miedzi jako dodatku do wody pitnej na masę ciała oraz kumulację składników mineralnych w wybranych tkankach indyków. Wykazano, że dodatek chelatu spowodował zwiększenie końcowej masy ciała indorów, natomiast nie wpłynął w znaczący sposób na masę analizowanych tkanek. Stwierdzono, że zastosowanie Cu wpłynęło na wzrost zawartości Cu, Zn i Fe we wszystkich badanych tkankach. Największą retencję Cu wykazano w przypadku wątroby, natomiast najmniejsze ilości tego pierwiastka kumulowały się w mięśniach piersiowych ptaków. Długotrwała aplikacja miedzi nie spowodowała nadmiernej kumulacji tego składnika w nerkach i mięśniach indyków, co nie stanowiło zagrożenia dla zdrowia konsumentów, gdyż jej zawartość nie przekraczała dopuszczalnych norm (5 mg-kg-1; wg PN-A-86524:1994).
An experiment conducted in the years 1991-1994 in Garlica Murowana Experimental Station concerned the effects of foliar fertilization with chelates on the content of mineral constituents in leaves and fruits of Golden Delicious apple trees. The applied chelates were LS-Fe (5.0% + 8.0% of urea), LS-Mg (4.88%), LS-B (2.10%), and LS-4 (Fe — 1.0%, Cu — 2.0%, Zn — 2.0%, and B — 5.0%). The chelates did not increase the yield or weight of fruit. LS-4, LS-Mg, and LS-B, positively affected the hardness, extract, and pH of fruit. Foliar fertilization of trees with chelates LS-B and LS-Mg is justified since their introduction to plants increases the content of nitrogen, boron, phosphorus and magnesium in leaves. The extra-root fertilization of apple trees with chelates LS-Fe, LS-Mg, and LS-B effected an increase in the content of nitrogen, phosphorus, potassium, boron, and magnesium in fruit.
We współczesnym rolnictwie poszukuje się nowych form wnoszenia do gleby składników odżywczych, m.in. azotu i mikroelementów. Azot może być dostarczany także przez stosowanie nawozów o przedłużonym działaniu. Znane są nawozy otoczkowane, nawozy powstające w wyniku kondensacji mocznika z aldehydami oraz z innymi substancjami o znaczeniu nawozowym, nawozy na nośnikach organicznych i polimerowych, nawozy zawierające inhibitory nitryfikacji. Mikroelementy stosowane są często w postaci soli, kompleksów i chelatów. Prowadzono wiele badań nad otrzymaniem i właściwościami kompleksów metali przejściowych z mocznikiem i jego pochodnymi. Stwierdzono, że jako nośniki mikroelementów mogą być stosowane także spolimeryzowane pochodne mocznika.
In pot experiments, in spring 2006 and 2007, a comparison was made between the chelated and the mineral forms of copper on the yielding of lettuce and on the content of Cu, Zn, Mn and Fe in lettuce leaves. Plants were grown in peat substrate supplemented with Cu doses of 5, 25, 50 and 75 mg∙dm⁻³. A greater mass of lettuce heads was obtained after the application of the mineral form of copper. In the range of doses: 5–50 mg Cu∙dm⁻³, the mean yields of lettuce did not differ. In the second year of studies, the application of copper chelates in the dose of 75 mg∙dm⁻³ caused a high reduction of yield. The mean copper content in lettuce, after the application of the chelated Cu form, was twice higher than after the use of the mineral Cu form. Iron content in lettuce after the application of copper chelates was higher than after the use of copper sulphate, while the contents of zinc and manganese were smaller.