Metabolic Adjustments in Urban Lawns in Response to Soil Salinization

Soil salinization is typical for urban environment where de-icing agents are released in considerable amounts. Urban lawns with turf grasses are the primary components of the urban green infrastructure and are exposed to different rates of soil salinity, depending on the distance to the paved surfaces where de-icing agents are released. Plant metabolic adjustments supported by nutrients availability in soil are the key parameters necessary to cope with soil salinity. In this study we evaluated the mechanisms activated at a plant level in response to low and moderate soil salinity in a popular turf-grass mixture used for urban lawn greening. Carbohydrates and starch content as well as content of chloride were measured in plant biomass after 2.5 months of continuous irrigation with salt solution. Nutrients availability and plant-soil interactions were assessed by analyzing extracellular soil enzymatic activity in the rhizosphere and N content of plant tissues. Plants increased the amount of compounds involved in the osmotic regulation in expense of storage compounds and isolated the toxic ions to old tissues. Increased plant demand for N at soil salinity was accompanied by an increase in the activity of chitinase in the rhizospheric soil, suggesting no potential restrictions for future accumulation of osmotic N-containing compounds in vegetation.