AB 23:119-127 (2015)  -  DOI: https://doi.org/10.3354/ab00605

ABSTRACT: Inorganic carbon and temperature are 2 important factors that regulate the growth of submerged macrophytes. However, experimental evidence regarding the eco-physiological changes that occur in submerged macrophytes in response to elevated CO₂ and temperature is still limited. To investigate how the submerged macrophyte Vallisneria natans (Hydrocharitaceae), a common species in the waters of the middle and lower reaches of the Yangtze River, responds to these factors, we conducted a mesocosm experiment using simulated CO₂ elevation (by bubbling CO₂ into experimental water) and ambient temperature warming systems. During the 60 d experiment, CO₂ elevation significantly increased the inorganic carbon concentration in the water column. The warming systems elevated average water temperature by approximately 3°C. The elevation of CO₂ levels significantly enhanced the photosynthetic performance, growth and clonal propagation of V. natans. When combined with an increase in CO₂, elevated temperatures also promoted photosynthesis and growth. The individual ramet biomass of V. natans decreased with increasing temperature, but only significantly under ambient CO₂ levels. CO₂ elevation increased both stolon elongation and bud number. At elevated CO₂ concentration, more biomass was allocated to the stolons, roots and buds, while less biomass was allocated to the leaves. These results indicate that the eco-physiological responses of V. natans should increase its stress tolerance in aquatic plant communities under future spatial and temporal variation in CO₂ levels, however, further research is required.

KEY WORDS: CO₂ elevation · Biomass allocation · Photosynthetic performance · Submerged macrophyte · Warming

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Cite this article as: Cao J, Ruan H (2015) Responses of the submerged macrophyte Vallisneria natans to elevated CO2 and temperature. Aquat Biol 23:119-127. https://doi.org/10.3354/ab00605 Export citation Share:    Facebook - - linkedIn