Reduced ascorbate pool and its maintenance are important determinants of O damage to net photosynthetic rate in Fagus crenata under elevated CO and soil N supply.

Many studies have reported modification in the degree of O damage to photosynthesis by elevated CO and soil N supply. However, the mechanism underlying the modification is unclear. To clarify the important determinants in the degree of O damage to net photosynthetic rate (A) in the leaves of Fagus crenata (Siebold's beech) under elevated CO and with different soil N supply, F.

Differences of stomatal ozone uptake in leaves of mature trees and seedlings of Zelkova serrata.

Ozone uptake through the stomata in tree leaves is an important process for improving air quality by urban trees. Stomatal conductance (g) is a key determinant of stomatal ozone uptake. The parameterization of g models for estimating stomatal ozone uptake of trees has mainly been carried out using g data measured in seedling leaves although the leaf traits may differ between mature trees and seedlings.

Vertical gradient of needle ozone uptake within the canopy of Cryptomeria japonica.

Leaf ozone uptake through the stomata is an important index for the ozone risk assessments on trees. Stomatal conductance (g) and ozone concentration ([O]), determinants of the leaf ozone uptake, are known to show vertical gradients within a tree canopy. However, less is known about the within-canopy vertical gradient of leaf ozone uptake.

Effects of elevated ozone and carbon dioxide on the dynamic photosynthesis of Fagus crenata seedlings under variable light conditions.

Ozone (O) is an air pollutant that is toxic to trees. O reduces steady-state net photosynthetic rate (A), and the adverse effects of O are mitigated under elevated CO condition. However, the combined effects of O and elevated CO on dynamic photosynthesis under variable light conditions have not yet been clarified.

Stomatal ozone uptake of a Quercus serrata stand based on sap flow measurements with calibrated thermal dissipation sensors.

The amount of ozone absorbed by the tree leaves is a critical factor determining the ozone effects on forest trees. Stomatal ozone uptake of a forest canopy can be estimated from the ozone concentration and canopy conductance (g) determined by the sap-flow-based method. This method measures sap flow as a metric of crown transpiration and then derives g.

Relationship between the amount of black carbon particles deposited on the leaf surface and leaf surface traits in nine urban greening tree species.

To select urban greening tree species suitable for the purification of the atmosphere polluted by black carbon (BC) particles, it is necessary to clarify the determinants of the amount of BC particles deposited on the tree leaves. In the present study, we investigated the relationship between the amount of BC particles that were deposited from the atmosphere and firmly adhered to the leaf epicuticular wax, and leaf surface traits in seedlings of nine tree species grown for two years under natural conditions (Fuchu, Tokyo, Japan). There was a significant interspecific difference in the maximum amount of BC particles deposited on the leaf surface, and the order was as follows: > > > > ≒ > ≒ ≒ .

Seasonal variations in the amount of black carbon particles deposited on the leaf surfaces of nine Japanese urban greening tree species and their related factors.

As black carbon (BC) particles can be deposited on the leaf surfaces, urban greening is considered to be effective in purifying urban air. However, little information on the seasonal variations in the amount of BC particles deposited on the leaf surfaces (BC amount on the leaves) is available in Japanese urban greening tree species. Therefore, we investigated seasonal variations in the BC amount on the leaves of evergreen (, , and ) and deciduous (, , , and ) broad-leaved tree species.

Growth and photosynthetic responses to ozone of Siebold's beech seedlings grown under elevated CO and soil nitrogen supply.

Ozone (O) is a phytotoxic air pollutant, the adverse effects of which on growth and photosynthesis are modified by other environmental factors. In this study, we examined the combined effects of O, elevated CO, and soil nitrogen supply on Siebold's beech seedlings. Seedlings were grown under combinations of two levels of O (low and two times ambient O concentration), two levels of CO (ambient and 700 ppm), and three levels of soil nitrogen supply (0, 50, and 100 kg N ha year) during two growing seasons (2019 and 2020), with leaf photosynthetic traits being determined during the second season.

Distributions of photosynthetic traits, shoot growth, and anti-herbivory defence within a canopy of Quercus serrata in different soil nutrient conditions.

The hypothesis of the present study is that not only distributions of leaf photosynthetic traits and shoot growth along light gradient within a canopy of forest trees, but also that of leaf anti-herbivory defence capacities are influenced by soil nutrient condition. To test this hypothesis, we investigated the distributions of photosynthetic traits, shoot growth, anti-herbivory defence and leaf herbivory rate throughout the canopy of Quercus serrata grown in two sites with different soil nutrient conditions. In both sites, photosynthetic traits, shoot growth, and anti-herbivory defence were greater in the upper canopy.

Toward an impact assessment of ozone on plant carbon fixation using a process-based plant growth model: A case study of Fagus crenata grown under different soil nutrient levels.

Ozone (O) in the troposphere, an air pollutant with phytotoxicity, is considered as a driver of global warming, because it reduces plant carbon fixation. Recently, a process-based plant growth model has been used in evaluating the O impacts on plants (Schauberger et al., 2019).

Effects of ozone on the growth and yield of rice (Oryza sativa L.) under different nitrogen fertilization regimes.

To examine whether the sensitivity of growth and yield of rice (Oryza sativa L.) to ozone (O) varies under different nitrogen (N) fertilization conditions, rice cultivar 'Koshihikari' was exposed to O under either standard N (SN) fertilization or no N (NN) fertilization. The rice plants were subjected to three gas treatments (charcoal-filtered air (CF) and O at 1.

Mesophyll conductance to CO in leaves of Siebold's beech (Fagus crenata) seedlings under elevated ozone.

Ozone is an air pollutant that negatively affects photosynthesis in woody plants. Previous studies suggested that ozone-induced reduction in photosynthetic rates is mainly attributable to a decrease of maximum carboxylation rate (V) and/or maximum electron transport rate (J) estimated from response of net photosynthetic rate (A) to intercellular CO concentration (C) (A/C curve) assuming that mesophyll conductance for CO diffusion (g) is infinite. Although it is known that C-based V and J are potentially influenced by g, its contribution to ozone responses in C-based V and J is still unclear.

Photosynthetic responses to ozone of upper and lower canopy leaves of Fagus crenata Blume seedlings grown under different soil nutrient conditions.

We aimed to clarify the effects of ozone (O) on photosynthetic ability of upper and lower canopy leaves of Fagus crenata Blume seedlings grown under different soil nutrient conditions. To accomplish this objective, we analyzed the response of photosynthetic parameters such as maximum carboxylation rate (V) to cumulative stomatal O uptake (ΣF) and reduction rate of V per unit ΣF as an index of detoxification capacity for O. The seedlings of Fagus crenata were grown for two growing seasons (2014-2015) in nine treatments comprised of a combination of three levels of gas treatments (charcoal-filtered air or 1.

Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3.

Ground-level ozone (O3) concentrations are expected to increase over the 21(st) century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive Japanese beech (Fagus crenata), and in a warm temperate deciduous and evergreen forest dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations.

Effect of epicuticular wax crystals on the localization of artificially deposited sub-micron carbon-based aerosols on needles of Cryptomeria japonica.

Elucidation of the mechanism of adsorption of particles suspended in the gas-phase (aerosol) to the outer surfaces of leaves provides useful information for understanding the mechanisms of the effect of aerosol particles on the growth and physiological functions of trees. In the present study, we examined the localization of artificially deposited sub-micron-sized carbon-based particles on the surfaces of needles of Cryptomeria japonica, a typical Japanese coniferous tree species, by field-emission scanning electron microscopy. The clusters (aggregates) of carbon-based particles were deposited on the needle surface regions where epicuticular wax crystals were sparsely distributed.

Effects of ozone on growth, net photosynthesis and yield of two African varieties of Vigna unguiculata.

To assess the effects of O(3)on growth, net photosynthesis and yield of two African varieties of cowpea(Vigna unguiculata L.), Blackeye and Asontem were exposed as potted plants to air that was either filtered to remove O(3) (FA), non-filtered air (NF), non-filtered with added O3 of approximately 50 nL L(-1) (ppb) from 11:00 to 16:00 (NF + O(3)) for 88 days in open-top chambers. The mean O(3) concentration (11:00-16:00) during the exposure period had a range from 16 ppb in the FA treatment to 118 ppb in the NF + O(3) treatment.

Responses of gas-exchange rates and water relations to annual fluctuations of weather in three species of urban street trees.

The frequency of extreme weather has been rising in recent years. A 3-year study of street trees was undertaken in Tokyo to determine whether: (i) street trees suffer from severe water stress in unusually hot summer; (ii) species respond differently to such climatic fluctuations; and (iii) street trees are also affected by nitrogen (N) deficiency, photoinhibition and aerosol pollution. During the study period (2010-12), midsummers of 2010 and 2012 were unusually hot (2.

Modeling of stomatal conductance to estimate stomatal ozone uptake by Fagus crenata, Quercus serrata, Quercus mongolica var. crispula and Betula platyphylla.

To construct stomatal conductance models and estimate stomatal O3 uptake for Fagus crenata, Quercus serrata, Quercus mongolica var. crispula and Betula platyphylla, stomatal conductance (gs) was measured in seedlings of the four tree species. Better estimates of gs were made by incorporating the acute effects of O3 on gs into the models and the models could explain 34-52% of the variability in gs.

Modeling stomatal conductance and ozone uptake of Fagus crenata grown under different nitrogen loads.

A multiplicative stomatal conductance model was constructed to estimate stomatal O3 uptake of Fagus crenata exposed to O3 under different N loads to the soil. Our stomatal conductance model included environmental functions such as the stomatal responses of F. crenata to diurnal changes, chronic O3 stress (AOT0), acute O3 stress (O3 concentration), and nitrogen load to soil.

Evaluation of the effects of ozone on yield of Japanese rice (Oryza sativa L.) based on stomatal ozone uptake.

To evaluate the negative impact of ozone (O3) on Japanese crop plant yield based on cumulative stomatal O3 flux, a Japanese rice cultivar, Koshihikari, was exposed to O3 in O3-exposure chambers. Stomatal diffusive conductance to water vapour were measured during the experimental period. We parameterized and improved a stomatal diffusive conductance model by considering seasonal changes in stomatal diffusive conductance, as well as the acute effects of O3 on this variable.

Relationship between cultivar difference in the sensitivity of net photosynthesis to ozone and reactive oxygen species scavenging system in Japanese winter wheat (Triticum aestivum).

To clarify the relationship between cultivar difference in the sensitivity of net photosynthesis to ozone (O(3)) and the reactive oxygen species (ROS) scavenging system in wheat (Triticum aestivum), we investigated the effects of chronic exposure to ambient levels of O(3) on gas exchange rates, activity and concentration of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), activity of ROS scavenging enzymes and concentration of antioxidants of the flag leaf in two Japanese winter wheat cultivars (Norin 61 and Shirogane-komugi). Although the net photosynthetic rate of the flag leaf in Norin 61 was not significantly reduced by exposure to O(3), that in Shirogane-komugi was significantly reduced by the exposure to O(3) during the anthesis and early grain-filling stages. In the two cultivars, stomatal diffusive conductance to H(2) O of the flag leaf was not significantly affected by the exposure to O(3).

Effects of ozone on growth, yield and leaf gas exchange rates of four Bangladeshi cultivars of rice (Oryza sativa L.).

To assess the effects of tropospheric O3 on rice cultivated in Bangladesh, four Bangladeshi cultivars (BR11, BR14, BR28 and BR29) of rice (Oryza sativa L.) were exposed daily to charcoal-filtered air or O3 at 60 and 100 nl l(-1) (10:00-17:00) from 1 July to 28 November 2008. The whole-plant dry mass and grain yield per plant of the four cultivars were significantly reduced by the exposure to O3.

Effects of ozone on growth, yield and leaf gas exchange rates of two Bangladeshi cultivars of wheat (Triticum aestivum L.).

To clarify the effects of O(3) on crop plants cultivated in Bangladesh, two Bangladeshi wheat cultivars (Sufi and Bijoy) were grown in plastic boxes filled with Andisol and exposed daily to charcoal-filtered air or O(3) at 60 and 100 nl l(-1) (10:00-17:00) from 13 March to 4 June 2008. The whole-plant dry mass and grain yield per plant of the two cultivars at the final harvest were significantly reduced by the exposure to O(3). Although there was no significant effect of O(3) on stomatal diffusive conductance to H(2)O of flag leaf, net photosynthetic rate of the leaf was significantly reduced by the exposure to O(3.

Effects of elevated carbon dioxide and ozone on foliar proanthocyanidins in Betula platyphylla, Betula ermanii, and Fagus crenata seedlings.

Proanthocyanidins (PAs) or condensed tannins are a major group of phenolic compounds in the leaves of birch trees and many other woody and herbaceous plants. These compounds constitute a significant allocation of carbon in leaves and are involved in plant responses to environmental stress factors, such as pathogens or herbivores. In some plants, PA concentrations are affected by atmospheric carbon dioxide (CO(2)) and ozone (O(3)) levels that may influence, for example, species fitness, community structure, or ecosystem nutrient cycling.

Effects of red-yellow soil acidification on seed germination of Chinese pine.

Acid treatments significantly change the physical and chemical properties of red-yellow soil by lowering its pH value and leaching out aluminum(Al) ions that are harmful to the growth of plants. The structure of soil will be damaged, resulting in higher viscosity, higher water retention rate and lower air permeability of the soil. The germination rate of Chinese pine(Pinus tobulacformic Carr.