Reakcja kukurydzy (Zea mays L.) na zanieczyszczenie gleby miedzią w zależności od zastosowanych dodatków neutralizujących

Copper is an essential trace element in living organisms, but its excess interferes with metabolic transformations in plant, animal and human cells. The uptake of copper from contaminated soils can be regulated, for example, by soil liming or application of other substances which enhance soil adsorption capacity and Cu binding in the substrate. The purpose of this study has been to assess the response of maize to soil contamination with copper depending on the applied neutralizing substances. The tested factors were increasing concentrations of Cu in soil: 0, 200, 400 and 600 mg Cu kg ?1 dm, and soil application of mineral (lime, loam and zeolite) and organic (manure, peat and bark) neutralizing substances. Soil contamination with copper within the range of 200 to 600 mg kg ?1 of soil caused reduction in maize yields. Positive influence such as alleviation of the harmful effect of copper contamination was demonstrated by lime and manure, which enhanced yields of maize, especially in the series polluted with 200 and 400 mg Cu kg ?1 . The other soil amending substances, especially peat added in amounts of 400 and 600 mg kg ?1 of soil, caused aconsiderable depression in maize yields. A linear dependence has been demonstrated between the concentration of Cu in maize plants and the content of Cu in the substrate, with the root content of Cu being on average six-fold higher than in aerial organs. Mineral soil amendments significantly decreased the BTC index in maize compared to organic substances, and lime as well as pine bark decreased the BCF index to 2.33 and 1.67 versus the value of 4.21 found in the control treatment without any neutralizing substances. The uptake of copper depended on the volume of yield and ? to a lesser degree ? on the concentration of Cu in plants. The uptake of copper by plants was the highest in treatmentscontaminated with a rate of 200 mg Cu kg ?1 , which was the consequence of higher yields from that treatment than from the plots polluted with 400 or 600 mg Cu kg ?1 of soil

Effect of process variables on Mg-Si particles and extrudability of 6xxx series aluminum extrusions

The Mg-Si particles are one of the major constituents in the microstructure of 6xxx series aluminum alloys. The size, distribution, and morphology of the Mg-Si particle have significant impact on extrudability in terms of mechanical properties and surface quality of aluminum extrusions. The characteristics of the Mg-Si particles are influenced by various process parameters in the production of extrusions. This paper reviews the effects of the major process variables on the Mg-Si particle characteristics and extrudability of aluminum extrusions