Effects of ozone on soil respiration rate of Siebold’s beech seedlings grown under different soil nutrient conditions

Abstract

Ozone O 3 is an air pollutant that negatively affect carbon budget in woody plants. In the present study, we aimed to clarify the effects of ozone on soil respiration rate of Siebold's beech seedlings Fagus crenata grown under different soil-nutrient conditions. Seedlings were grown under three levels of O 3 fumigation charcoal-filtered air or O 3 at 1.0 or 1.5 times ambient concentration in combination with three levels of nutrient supplies non-, low-or high-fertilised for two growing seasons. We determined soil respiration rate in July, August, September, and October of the second growing season. The seedlings were harvested to determine the dry mass in October. Significant effect of O 3 on soil respiration rate was not observed in all measurements. There was a significant interaction between O 3 and nutrient supply for whole-root dry mass. The dry mass in non-fertilised and low-fertilised treatments was reduced by O 3 , whereas O 3 did not affect dry mass in the high-fertilised treatment. On the other hand, neither significant effects of O 3 , nor a significant interaction between O 3 and nutrient supply for the biomass allocations were observed. Coefficient of positive correlation in the relation of soil respiration rate with dry mass of fine-root across the all treatments was higher than that in the relation of soil respiration rate with coarse-root and whole-root dry mass. These results indicate that no significant effect of O 3 on soil respiration was mainly attributable to no response of fine root dry mass to elevated O 3 . Soil nutrient supply decreased soil respiration rate in August. Our results emphasize the importance of fine root in the response of soil respiration to elevated O 3 . To clarify the response of soil respiration to elevated O 3 , future researches on the effect of O 3 on fine root dynamics including turnover and indirect effect on soil microbial respiration are needed.

Nitrogen Use Efficiency for Growth of Fagus crenata Seedlings Under Elevated Ozone and Different Soil Nutrient Conditions

“…The exposure to O 3 significantly decreased ∆W in NF treatment, whereas there was no significant O 3 -induced reduction in ∆W in the LF and HF treatments ( Table 2). This result was in agree with the tendency in dry mass of the seedlings at the end of this experiment [26,42]. Similar results of lower O 3 susceptibility under higher nutrient condition were reported in the other studies on larch [30,43] and aspen [22] seedlings, although several studies demonstrated nitrogen supply-induced enhance of the susceptibility to O 3 in Siebold's beech [24] and Scots pine [44].…”

“…The reduction in MRT by soil nutrient supply indicated a smaller increase in PND as compared to that of ∆N (Table 2). In this experiment, the dry mass ratio of fine roots to coarse roots was decreased by increased soil nutrient supply [42], indicating the possibility of lower N uptake efficiency. However, the contribution of lower nitrogen uptake efficiency was smaller compared to that of the greater soil N availability under the high fertilisation condition because we observed a clear increase in the ∆N of the seedlings with an increase in soil nutrient supply.…”

Effects of Combined CO2 and O3 Exposures on Net CO2 Assimilation and Biomass Allocation in Seedlings of the Late-Successional Fagus Crenata

“…However, in mature Fagus species, different responses to elevated O 3 were also observed, such as stimulation of root growth [66,67] and no changes in carbon allocation into belowground tissues [68]. In addition, soil nutrient supply mitigated the negative impacts of O 3 on biomass allocation in F. crenata seedlings [69,70].…”

Observation of vertical profiles of NO, O<SUB>3</SUB>, and VOCs to estimate their sources and sinks by inverse modeling in a Japanese larch forest

“…Trace gases such as ozone O 3 and nitrogen oxides NO x in the biosphere influence forest growth and carbon storage Ollinger et al, 2002 . O 3 results in a reduction of carbon fixation and biomass production Reich, 1987;Izuta et al, 1999;Watanabe et al, 2015Watanabe et al, , 2019Tani et al, 2017 , and atmospheric nitrogen deposition can result in increased growth of terrestrial ecosystems Vitousek and Howarth, 1991 . Biogenic volatile organic compounds BVOCs generate secondary organic aerosols that can affect the climate by affecting cloud formation Kanakidou et al, 2005 . Forest ecosystems are also an important sink and source of trace gases and particle matters in the atmosphere Slemr and Seiler, 1984;Yamaguchi et al, 2019 ; thus, observations of trace gas fluxes, such as O 3 Mikkenlsen et al, 2004;Gerosa et al, 2005;Matsuda et al, 2005 , NO x Rummel et al, 2002;Horii et al, 2004;Farmer et al, 2006, and BVOCs Guenther and Hills, 1998: Tani et al, 2002: Mochizuki et al, 2015 in forest ecosystems have been conducted.…”