Effects of Ca++ on plant sensitivity to high NaCl concentrations
SummaryNaCl reduced growth ofHordeum vulgare much more at low than at high nutrient, due solely to the Ca++-status of the medium.
Salt Tolerance in Aquatic Macrophytes: Ionic Relation and Interaction
Effects of seawater salinity (SWS) and pure NaCl on the intracellular contents of Na+, K+, Mg2+, Ca2+, chlorophylls (Chl) and carotenoids (Car) were studied in three submerged aquatic macrophytes, Hydrilla verticillata, Najas indica and Najas gramenia, which differed in their tolerance to salinity. NaCl resulted in significant increase in Chl/Car ratio in the salt-sensitive H. verticillata and moderately salt-tolerant N. indica, but not in the salt-tolerant N. gramenia. SWS treatment did not result in any significant change in the ratio. The intracellular content of Na+ increased significantly in all the test plants upon exposure to both NaCl and SWS. The content of K+ decreased significantly in these plants upon salinity treatment, except in N. gramenia. The contents of Ca2+ and Mg2+ decreased significantly upon NaCl treatment and remained unchanged or increased upon SWS treatment. No relationship between salt tolerance and K+/Na+ ratio was observed. The maintenance of a minimal level of K+ was observed to be the most probable requirement of salt tolerance in aquatic macrophytes.
Evolution of carbide precipitates in Hastelloy N joints during welding and post weld heat treatment
Abstract The effects of welding and post weld heat treatment (PWHT) on the morphology, composition and lattice parameter of the precipitates in the welding joints of Hastelloy N alloy have been investigated. Joint samples were prepared using a gas tungsten arc welding process with ERNiMo-2 fillers, and then solid-solution treated at 1100 °C for 20 min. After welding, eutectic M6C carbides can be observed in the heat affected zones (HAZ) and weld zones (WZ). These eutectic M6C carbides become spheroidized during the following PWHT. The concentration of Si decreases during the transformation from the primary ones to eutectic ones, and then increases during the spheroidizing process. The total concentration of Si + Cr in M6C carbides remains stable during welding and PWHT. At the same time, the heat leads to the outward diffusion of Mo from the M6C carbides, which results in a decrease of the lattice parameter.