scholarly journals Growth and Photosynthetic Responses of Seedlings of Japanese White Birch, a Fast-Growing Pioneer Species, to Free-Air Elevated O3 and CO2

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 675
Author(s):  
Mitsutoshi Kitao ◽  
Evgenios Agathokleous ◽  
Kenichi Yazaki ◽  
Masabumi Komatsu ◽  
Satoshi Kitaoka ◽  
...  
Keyword(s):  
Light Intensity ◽  
Elevated Co2 ◽  
Biomass Allocation ◽  
Photosynthetic Acclimation ◽  
Total Biomass ◽  
White Birch ◽  
Elevated O3 ◽  
Free Air ◽  
Young Leaves ◽  
Photosynthetic Responses

Plant growth is not solely determined by the net photosynthetic rate (A), but also influenced by the amount of leaves as a photosynthetic apparatus. To evaluate growth responses to CO2 and O3, we investigated the effects of elevated CO2 (550–560 µmol mol−1) and O3 (52 nmol mol−1; 1.7 × ambient O3) on photosynthesis and biomass allocation in seedlings of Japanese white birch (Betula platyphylla var. japonica) grown in a free-air CO2 and O3 exposure system without any limitation of root growth. Total biomass was enhanced by elevated CO2 but decreased by elevated O3. The ratio of root to shoot (R:S ratio) showed no difference among the treatment combinations, suggesting that neither elevated CO2 nor elevated O3 affected biomass allocation in the leaf. Accordingly, photosynthetic responses to CO2 and O3 might be more important for the growth response of Japanese white birch. Based on A measured under respective growth CO2 conditions, light-saturated A at a light intensity of 1500 µmol m−2 s−1 (A1500) in young leaves (ca. 30 days old) exhibited no enhancement by elevated CO2 in August, suggesting photosynthetic acclimation to elevated CO2. However, lower A1500 was observed in old leaves (ca. 60 days old) of plants grown under elevated O3 (regulated to be twice ambient O3). Conversely, light-limited A measured under a light intensity of 200 µmol m−2 s−1 (A200) was significantly enhanced by elevated CO2 in young leaves, but suppressed by elevated O3 in old leaves. Decreases in total biomass under elevated O3 might be attributed to accelerated leaf senescence by O3, indicated by the reduced A1500 and A200 in old leaves. Increases in total biomass under elevated CO2 might be attributed to enhanced A under high light intensities, which possibly occurred before the photosynthetic acclimation observed in August, and/or enhanced A under limiting light intensities.

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

Climate ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 117 ◽  
Author(s):  
Tobita ◽  
Komatsu ◽  
Harayama ◽  
Yazaki ◽  
Kitaoka ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Biomass Allocation ◽  
Plant Biomass ◽  
Leaf Age ◽  
Ambient Air ◽  
Co2 Assimilation ◽  
Fagus Crenata ◽  
Elevated O3 ◽  
Net Co2 Assimilation ◽  
Elevated Co2 And O3

We examined the effects of elevated CO2 and elevated O3 concentrations on net CO2 assimilation and growth of Fagus crenata in a screen-aided free-air concentration-enrichment (FACE) system. Seedlings were exposed to ambient air (control), elevated CO2 (550 µmol mol−1 CO2, +CO2), elevated O3 (double the control, +O3), and the combination of elevated CO2 and O3 (+CO2+O3) for two growing seasons. The responses in light-saturated net CO2 assimilation rates per leaf area (Agrowth-CO2) at each ambient CO2 concentration to the elevated CO2 and/or O3 treatments varied widely with leaf age. In older leaves, Agrowth-CO2 was lower in the presence of +O3 than in untreated controls, but +CO2+O3 treatment had no effect on Agrowth-CO2 compared with the +CO2 treatment. Total plant biomass increased under conditions of elevated CO2 and was largest in the +CO2+O3 treatment. Biomass allocation to roots decreased with elevated CO2 and with elevated O3. Elongation of second-flush shoots also increased in the presence of elevated CO2 and was largest in the +CO2+O3 treatment. Collectively, these results suggest that conditions of elevated CO2 and O3 contribute to enhanced plant growth; reflecting changes in biomass allocation and mitigation of the negative impacts of O3 on net CO2 assimilation.

scholarly journals Photosynthetic Responses of Canola and Wheat to Elevated Levels of CO2, O3 and Water Deficit in Open-Top Chambers

Plants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 171 ◽  
Author(s):  
Bheki G. Maliba ◽  
Prabhu M. Inbaraj ◽  
Jacques M. Berner
Keyword(s):  
Water Deficit ◽  
Elevated Co2 ◽  
Photosynthetic Efficiency ◽  
Jip Test ◽  
Drought Effect ◽  
Open Top Chambers ◽  
Non Invasive ◽  
Elevated O3 ◽  
Photosynthetic Responses ◽  
Chlorophyll A Fluorescence Transients

The effects of elevated CO2 (700 ppm) and O3 (80 ppb) alone and in combination on the photosynthetic efficiency of canola and wheat plants were investigated in open-top chambers (OTCs). The plants were fumigated for four weeks under well-watered and water-stressed (water deficit) conditions. The fast chlorophyll a fluorescence transients were measured after 2 and 4 weeks of fumigation, as well as in control plants, and analyzed by the JIP-test, which is a non-destructive, non-invasive, informative, very fast and inexpensive technique used to evaluate the changes in photosynthetic efficiency. Biomass measurements were taken only after 4 weeks of fumigation. The performance index (PItotal), an overall parameter calculated from the JIP-test formulae, was reduced by elevated CO2 and O3 under well-watered conditions. In the absence of any other treatment, water stress caused a decrease of the PItotal, and it was partly eliminated by fumigation with elevated CO2 and CO2 + O3. This finding was also supported by the biomass results, which revealed a higher biomass under elevated CO2 and CO2 + O3. The decrease in biomass induced by elevated O3 was likely caused by the decline of photosynthetic efficiency. Our findings suggest that elevated CO2 reduces the drought effect both in the absence and presence of O3 in canola and wheat plants. The study also indicates that elevated O3 would pose a threat in future to agricultural crops.

scholarly journals Effect of elevated CO2 and elevated temperature on growth and biomass accumulation in Valeriana jatamansi Jones. under different nutrient status in the western Himalaya

2021 ◽  
Vol 22 (4) ◽  
pp. 419-428
Author(s):  
MUNISH KAUNDAL ◽  
RAKESH KUMAR
Keyword(s):  
Elevated Temperature ◽  
Leaf Area ◽  
Elevated Co2 ◽  
Growth Parameters ◽  
Co2 Enrichment ◽  
Biomass Accumulation ◽  
Leaf Biomass ◽  
Total Biomass ◽  
Free Air ◽  
Valeriana Jatamansi

Valeriana jatamansi is an important medicinal and aromatic plant used as sedative in modern  and traditional medicines butthere is dearth of literature regarding how elevated CO2 and temperature affect on this plant. Therefore,an experiment was conducted to study the effect of elevated CO2 (550±50 µmol mol-1) and elevated temperature (2.5±0.5°C above ambient) and vermicompost on growth, phenology and biomass accumulation in V. jatamansi under Free Air CO2 Enrichment (FACE) and Free Air TemperatureIncrement (FATI) facilities at Palampur, India, during 2013-2015. Growth parameters and biomass accumulation into different parts were observed at 4, 12 and 16 months after exposure (MAE). Plant height, total dry biomass and leaf area plant -1 increased in elevated CO2 treatment applied with vermicompost as compared to the other treatments. Elevated CO2 significantly enhanced leaf area (3.5-23.5%), leaf biomass (12.7-33.2%), stem (15.3-15.6%), root (3.2-72.5%), rhizome (2.1-42.2%) and total biomass (7.7-52.7%), whereas elevated temperature increased aboveground biomass (15.0-45.3%), belowground biomass (11.6-55.5%) and total biomass (12.4-7.9%), respectively, as compared to ambient. Phenological stages were advanced by 1.2-3.9 days under FACE and FATI as compared to ambient. The results indicate that aboveground, belowground and total biomass increased under elevated CO2 and elevated temperature as compared to ambient. 

Warm air temperatures increase photosynthetic acclimation to elevated CO2 concentrations in rice under field conditions

2021 ◽  
Vol 262 ◽  
pp. 108036
Author(s):  
Manman Yuan ◽  
Chuang Cai ◽  
Xiaozhong Wang ◽  
Gang Li ◽  
Gang Wu ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Field Conditions ◽  
Photosynthetic Acclimation ◽  
Co2 Concentrations ◽  
Air Temperatures

Biomass allocation in tomato (Lycopersicon esculentum) plants grown under partial rootzone drying: enhancement of root growth

2004 ◽  
Vol 31 (10) ◽  
pp. 971 ◽  
Author(s):  
Darren M. Mingo ◽  
Julian C. Theobald ◽  
Mark A. Bacon ◽  
William J. Davies ◽  
Ian C. Dodd
Keyword(s):  
Lycopersicon Esculentum ◽  
Root System ◽  
Biomass Allocation ◽  
Root Biomass ◽  
Leaf Water ◽  
Total Biomass ◽  
Split Root ◽  
Split Root System ◽  
Partial Rootzone Drying ◽  
And Control

Tomato (Lycopersicon esculentum Mill.) plants were grown in either a glasshouse (GH) or a controlled environment cabinet (CEC) to assess the effects of partial rootzone drying (PRD) on biomass allocation. Control and PRD plants received the same amounts of water. In control plants, water was equally distributed between two compartments of a split-root system. In PRD plants, only one compartment was watered while the other was allowed to dry. At the end of each drying cycle, wet and dry compartments were alternated. In the GH, total biomass did not differ between PRD and control plants after four cycles of PRD, but PRD increased root biomass by 55% as resources were partitioned away from shoot organs. In the CEC, leaf water potential did not differ between treatments at the end of either of two cycles of PRD, but stomatal conductance of PRD plants was 20% less at the end of the first cycle than at the beginning. After two cycles of PRD in the CEC, biomass did not differ between PRD and control plants, but PRD increased root biomass by 19% over the control plants. The promotion of root biomass in PRD plants was associated with the alternation of wet and dry compartments, with increased root biomass occurring in the re-watered compartment after previous exposure to soil drying. Promotion of root biomass in field-grown PRD plants may allow the root system to access resources (water and nutrients) that would otherwise be unavailable to control plants. This may contribute to the ability of PRD plants to maintain similar leaf water potentials to conventionally irrigated plants, even when smaller irrigation volumes are supplied.

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