AUTHOR=Zhu Congfei , Luo Handong , Luo Laicong , Wang Kunying , Liao Yi , Zhang Shun , Huang Shenshen , Guo Xiaomin , Zhang Ling 

TITLE=Nitrogen and Biochar Addition Affected Plant Traits and Nitrous Oxide Emission From Cinnamomum camphora

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.905537

DOI=10.3389/fpls.2022.905537

ISSN=1664-462X

ABSTRACT=<p>Atmospheric nitrous oxide (N<sub>2</sub>O) increase contributes substantially to global climate change due to its large global warming potential. Soil N<sub>2</sub>O emissions have been widely studied, but plants have so far been ignored, even though they are known as an important source of N<sub>2</sub>O. The specific objectives of this study are to (1) reveal the effects of nitrogen and biochar addition on plant functional traits and N<sub>2</sub>O emission of <italic>Cinnamomum camphora</italic> seedlings; (2) find out the possible leaf traits affecting plant N<sub>2</sub>O emissions. The effects of nitrogen and biochar on plant functional traits and N<sub>2</sub>O emissions from plants using <italic>C. camphora</italic> seedlings were investigated. Plant N<sub>2</sub>O emissions, growth, each organ biomass, each organ nutrient allocation, gas exchange parameters, and chlorophyll fluorescence parameters of <italic>C. camphora</italic> seedlings were measured. Further investigation of the relationships between plant N<sub>2</sub>O emission and leaf traits was performed by simple linear regression analysis, principal component analysis (PCA), and structural equation model (SEM). It was found that nitrogen addition profoundly increased cumulative plant N<sub>2</sub>O emissions (+109.25%), which contributed substantially to the atmosphere’s N<sub>2</sub>O budget in forest ecosystems. Plant N<sub>2</sub>O emissions had a strong correlation to leaf traits (leaf TN, <italic>P</italic><sub><italic>n</italic></sub>, <italic>G</italic><sub><italic>s</italic></sub>, <italic>C</italic><sub><italic>i</italic></sub>, <italic>T</italic>r, WUE<sub><italic>L</italic></sub>, α, <italic>ETR</italic><sub>max</sub>, <italic>I</italic><sub><italic>k</italic></sub>, <italic>Fv/Fm</italic>, <italic>Y</italic>(II), and <italic>SPAD</italic>). Structural equation modelling revealed that leaf TN, leaf TP, <italic>P</italic><sub><italic>n</italic></sub>, <italic>C</italic><sub><italic>i</italic></sub>, <italic>T</italic>r, WUE<sub><italic>L</italic></sub>, α, <italic>ETR</italic><sub>max</sub>, and <italic>I</italic><sub><italic>k</italic></sub> were key traits regulating the effects of plants on N<sub>2</sub>O emissions. These results provide a direction for understanding the mechanism of N<sub>2</sub>O emission from plants and provide a theoretical basis for formulating corresponding emission reduction schemes.</p>