干旱区生态环境知识资源中心

The chemical and biochemical composition of leaf tissue from 24 mezquites (Prosopis articulata) was correlated with the ion content of soils and ground waters from six separate sites supporting plant growth. The peroxidase responses varied at different salinities; however, this enzyme activity decreased as the electrical conductivity of the ground water increased. Chlorophyll content of the leaves increased with the electrical conductivity (EC) of the well water, but the response was not statistically significant. The ion concentration (Ca++, Mg++, Na+, HCO3-, and Cl-), pH, and SAR (sodium adsorption ratio) in leaf tissue showed no correlation with their corresponding values for soil and ground water, confirming earlier reports on the ion-exclusion mechanism of the mezquite root system. Likewise, low molecular weight metabolites such as glycerol, amino acids, and hexoses showed no correspondence with the salt content in ground waters. Of all the studied ions, chemical parameters, and biochemical compounds, EC in the ground water, leaves, and soil in the open field midway between mezquites, as well as peroxidase activity of foliar extracts showed the highest correlation with the salinity of ground water. The results of this research suggest that measuring EC and biochemical mezquite parameters may provide an alternative to drilling to evaluate ground-water quality.