The effects of elevated ozone on the accumulation and allocation of poplar biomass depend strongly on water and nitrogen availability

• Published in: The Science of the total environment Vol. 665; pp. 929 - 936
• Main Authors: Li, Pin, Zhou, Huimin, Xu, Yansen, Shang, Bo, Feng, Zhaozhong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.05.2019
• Subjects: Biomass; Biomass allocation; Dose-Response Relationship, Drug; Fine roots; Nitrogen - analysis; Nutrient availability; Ozone; Ozone - administration & dosage; Ozone - metabolism; Poplar; Populus - drug effects; Populus - growth & development; Populus - metabolism; Seasons; Soil - chemistry; Water - analysis; Water limitation; Water limitation; Poplar; Fine roots; Nutrient availability; Ozone; Biomass allocation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.02.182

Ozone (O3) pollution can alter carbon allocation and reduce tree growth - both above and below ground, but the extent of these effects depends on the variation in soil water and nutrient availability. Here we present the accumulation and allocation of biomass in poplar clone 546 (Populus deltoides cv. ‘55/56’ × P. deltoides cv. ‘Imperial’) for one growing season at two O3 concentrations (charcoal-filtered air [CF] and non-filtered air + 40 ppb of O3 [E-O3]), two watering regimes (well-watered [WW] and reduced watering at 40% of WW irrigation [RW]) and two soil nitrogen addition treatments (no addition [N0] and the addition of 50 kg N ha−1 year−1 [N50]). We found that the deleterious effects of E-O3 depended on the supply of water and nitrogen. Specifically, when the supplies of water and/or N (WW and/or N50) were abundant, E-O3 significantly reduced whole plant biomass by >15% but had no significant effect on biomass when these supplies were limited (RW and N0). A significant reduction of biomass by E-O3 occurred earlier in fine roots than in other plant organs, indicating greater sensitivity of fine root to E-O3. These results suggest that rising O3 concentrations may not ubiquitously lead to a large reduction in plant biomass since plant growth is often jointly constrained by water and nutrients. [Display omitted] •The negative effects of O3 depend on the amount of available water and nitrogen.•O3-induced the reduction in biomass was limited under low water and nutrient availability.•Biomass decreased but root to shoot ratios increased with the number of limiting factors.•Fine root biomass was significantly decreased by elevated O3 at low O3 dose.