Determination of the growth and herbicide sensitivity of some invasive plants under different carbon dioxide, temperature and nitrogen conditions

Global climate changes are supposed to impact the global ecosystems including those of plants. Invasive plants present a serious threat to plants, environment and, human and animal health. The global climate changes may impact the growth, invasion and management of invasive weed species. Hence, these studies were conducted to investigate the impact of recent climate changes on growth, control and nitrogen uptake of invasive species. In these two-years glasshouse experiments, we studied the effects of temperature, carbon dioxide (CO2), nitrogen and herbicide application on biomass, growth, control and leaf tissue nitrogen concentration of four invasive weed species. High CO2-concentration, high CO2-concentration+high temperature improved the biomass and growth parameters of weeds including Bromus tectorum L., Hordeum murinum L., and Lactuca serriola L., while Capsella bursa-pastoris (L.) Medik. responded differently to climatic conditions compared with the other weeds. In general, high temperature had a negative or neutral effect on all the weed species in our studies. Nitrogen application had little effects on grasses while the broadleaved weeds mostly had a positive response to nitrogen application. Climatic conditions had no effect on activity of herbicide (glyphosate). This research work conclude that high-CO2 concentration improved the growth of most of the invasive weeds in the experiment while elevated temperature mostly had negative or neutral effect on invasive weeds. Herbicide application provided equal and effective weed control under either of the CO2 or temperature levels while N fertilization had improved very few growth parameters of invasive weeds under different climatic conditions.