Elevated atmospheric temperature and CO2 altered the growth, carbon, and nitrogen distribution and the rhizosphere properties of Platanus occidentalis L. seedlings

Authors: VENECIO U. ULTRA JR., SIM-HEE HAN

Abstract: The effects of elevated atmospheric temperature and CO₂ on the growth and plant carbon and nitrogen allocation of Platanus occidentalis L. and their influence on rhizosphere and soil microbial properties were evaluated through a rhizobag experiment in an environmentally controlled chamber. Seedlings of P. occidentalis L. were established in the central compartment of a rhizobag filled with forest soil and exposed to four treatment combinations (control (25 °C, 400 μmol mol^-1 CO₂), T2 (30 °C, 400 μmol mol^-1 CO₂), T3 (25 °C, 800 μmol mol^-1 CO₂), and T4 (30 °C, 800 μmol mol^-1 CO₂)) for 20 weeks. Elevated temperature and CO₂ enhanced the growth and dry matter yield and altered the C and N distribution of P. occidentalis. The pH, electrical conductivity, and concentration of dissolved sugar and organic carbon in soil solution were also altered, as well as the microbial activity and carbon utilization potential of soil microorganisms in the rhizosphere of P. occidentalis. Overall, the results showed that the changes in plant growth and physiology of P. occidentalis due to exposure to elevated temperature and carbon dioxide extended to the soil biological properties via plant-induced changes in substrate quality and quantity in the rhizosphere.

Keywords: Carbon acquisition, carbon and nitrogen allocation, dissolved sugars, rhizosphere, soil microorganisms, soil solution

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