Nitrogen Fertilization Modified the Responses of Schima superba Seedlings to Elevated CO2 in Subtropical China

Zhan Chen; Siyuan Ye; Jixin Cao; He Shang

doi:10.3390/plants10020383

Nitrogen Fertilization Modified the Responses of Schima superba Seedlings to Elevated CO₂ in Subtropical China

Plants (Basel). 2021 Feb 17;10(2):383. doi: 10.3390/plants10020383.

Authors

Zhan Chen¹, Siyuan Ye¹, Jixin Cao¹, He Shang¹

Affiliation

¹ Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.

Abstract

There are very few studies about the effects of relatively higher CO₂ concentration (e.g., 1000 μmol·mol^-1) or plus N fertilization on woody plants. In this study, Schima superba seedings were exposed to ambient or eCO₂ (550, 750, and 1000 μmol·mol^-1) and N fertilization (0 and 10 g·m^-2·yr^-1, hereafter: low N, high N, respectively) for one growth season to explore the potential responses in a subtropical site with low soil N availability. N fertilization strongly increased leaf mass-based N by 118.38%, 116.68%, 106.78%, and 138.95%, respectively, in different CO₂ treatments and decreased starch, with a half reduction in leaf C:N ratio. Leaf N was significantly decreased by eCO₂ in both low N and high N treatments, and N fertilization stimulated the decrease of leaf N and mitigated the increase of leaf C:N by eCO₂. In low N treatments, photosynthetic rate (Pn) was maximized at 733 μmol·mol^-1 CO₂ in August and September, while, in high N treatments, Pn was continuously increased with elevation of CO₂. N fertilization significantly increased plant biomass especially at highly elevated CO₂, although no response of biomass to eCO₂ alone. These findings indicated that N fertilization would modify the response of S. superba to eCO₂.

Keywords: N fertilization; biomass; elevated CO2; leaf N; photosynthesis.

Abstract

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