Variation of nitric oxide emission potential in plants: a possible link to leaf N content and net photosynthetic activity

Aims Ecological systems, especially soils, have been recently recognized as an important source of atmospheric nitric oxide (NO). However, the study on the contribution of plants to atmospheric NO budget is significantly lagged. The specific objectives of this study are to reveal the phylogenetic variation in NO emission potential existing in various plant species and find out the possible leaf traits affecting NO emission potential. Methods We measured NO emission potential, leaf N and C content, C: N ratio, specific leaf area, net photosynthetic rate (P-n) and estimated photosynthetic N use efficiency (PNUE) of 88 plant species. Further investigation of the relationships between NO emission potential and leaf traits were performed by simple linear regression analysis and pair-wise correlation coefficients analysis. Important Findings Major results are as follows: (1) NO emission from plant species exhibited large variations, ranging from 0 to 41.7 nmol m(-2) h(-1), and the species frequency distributions of NO emission potential could be fitted to a log-normal curve. (2) Among 88 species, NO emission potential was the highest in Podocarpus macrophyllus, but lowest in Zanthoxylum nitidum and Vernicia montana. (3) NO emission potential has strong correlation to leaf N content, P-n and PNUE. The variations in NO emission potential among diverse plant species may be closely related to leaf N level and net photosynthetic ability.