scholarly journals Effects of long-term exposure to elevated CO2 and N fertilization on the development of photosynthetic capacity and biomass accumulation in Quercus suber L.

2002 ◽  
Vol 25 (1) ◽  
pp. 105-113 ◽  
Author(s):  
J. P. Maroco ◽  
E. Breia ◽  
T. Faria ◽  
J. S. Pereira ◽  
M. M. Chaves
Keyword(s):  
Elevated Co2 ◽  
Photosynthetic Capacity ◽  
Biomass Accumulation ◽  
Quercus Suber ◽  
N Fertilization

scholarly journals Production dynamics of Cenococcum geophilum ectomycorrhizas in response to long-term elevated CO2 and N fertilization

2017 ◽  
Vol 26 ◽  
pp. 11-19 ◽  
Author(s):  
M. Luke McCormack ◽  
Christopher W. Fernandez ◽  
Hope Brooks ◽  
Seth G. Pritchard
Keyword(s):  
Elevated Co2 ◽  
N Fertilization ◽  
Cenococcum Geophilum ◽  
Production Dynamics

Will photosynthetic capacity of aspen trees acclimate after long-term exposure to elevated CO2 and O3?

2010 ◽  
Vol 158 (4) ◽  
pp. 983-991 ◽  
Author(s):  
Joseph N.T. Darbah ◽  
Mark E. Kubiske ◽  
Neil Nelson ◽  
Katre Kets ◽  
Johanna Riikonen ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Photosynthetic Capacity ◽  
Elevated Co2 And O3

Initial observations of increased requirements for light-energy dissipation in ryegrass (Lolium perenne) when source/sink ratios become high at a naturally grazed free air CO2 enrichment (FACE) site

2006 ◽  
Vol 33 (11) ◽  
pp. 1045 ◽  
Author(s):  
Jianmin Guo ◽  
Craig M. Trotter ◽  
Paul C. D. Newton
Keyword(s):  
Elevated Co2 ◽  
Lolium Perenne ◽  
Co2 Fixation ◽  
Photosynthetic Capacity ◽  
Co2 Enrichment ◽  
Free Air ◽  
The Face ◽  
Source Sink ◽  
And Control

Although photosynthetic response to long-term elevated CO2 has been extensively studied, little attention has yet been directed at coordinated adjustments between the use of absorbed light for CO2 fixation, and the dissipation of potentially harmful excess light. In this study, we have performed an initial analysis of photosynthetic light use and excess light dissipation in response to grazing-induced variation in the source / sink ratio in ryegrass (Lolium perenne L.) after 6 years’ exposure to Free Air CO2 Enrichment (FACE). Before grazing, when the source / sink ratio was relatively large, significant down-regulation of photosynthetic capacity (Amax) was observed in the FACE leaves compared with control leaves at the same stage of maturity. The decrease in Amax partly offset the direct stimulation of elevated CO2 on light-saturated photosynthesis, and was accompanied by a reduction in photochemical electron flow that was accompanied by a large increase in susceptibility to photoinhibition. This was indicated by large increases in both non-photochemical quenching (NPQ) and the de-epoxidised state of xanthophyll cycle (DEPS), and also by changes in the photochemical reflectance index (PRI). However, no significant increase in the xanthophyll pool size in FACE leaves was observed, despite the apparent large increase in requirements for photodissipation in FACE leaves. After grazing, when the source / sink ratio was relatively small, the CO2 fixation rates in both the FACE and control leaves were, as expected, significantly higher compared with those before grazing, and there was no down-regulation of photosynthetic capacity in the leaves under FACE conditions. In addition, the extent of photodissipation in the FACE and control leaves was not significantly different. Overall, the profile of leaf physiological and biochemical responses supports the hypothesis that the effect of long-term elevated CO2 can be significantly influenced by short-term variation in the source / sink ratio. As the xanthophyll pool size does not change significantly, this poses the question of whether the increased photodissipative demand observed here under even moderately elevated CO2 concentrations may lead to increased plant susceptibility to photoinhibition, and thus to an increased risk of damage to plant function, under conditions of low sink demand. This question clearly deserves further study.

Elevated CO2 causes different growth stimulation, water and nitrogen use efficiencies and leaf ultrastructure responses in two conifer species under intra- and interspecific competition

2021 ◽  
Author(s):  
Lei Yu ◽  
Haojie Dong ◽  
Zongdi Huang ◽  
Helena Korpelainen ◽  
Chunyang Li
Keyword(s):  
Plant Growth ◽  
Interspecific Competition ◽  
Elevated Co2 ◽  
Morphological Traits ◽  
Photosynthetic Capacity ◽  
Plant Competition ◽  
Biomass Accumulation ◽  
Leaf Ultrastructure ◽  
Nitrogen Use ◽  
Ectomycorrhizal Infection

Abstract The continuously increasing atmospheric carbon dioxide concentration ([CO2]) has substantial effects on plant growth, and on the composition and structure of forests. However, how plants respond to elevated [CO2] (e[CO2]) under intra- and interspecific competition has been largely overlooked. In this study, we employed Abies faxoniana and Picea purpurea seedlings to explore the effects of e[CO2] (700 ppm) and plant–plant competition on plant growth, physiological and morphological traits, and leaf ultrastructure. We found that e[CO2] stimulated plant growth, photosynthesis and nonstructural carbohydrates (NSC), affected morphological traits and leaf ultrastructure, and enhanced water and nitrogen use efficiencies in A. faxoniana and P. purpurea. Under interspecific competition and e[CO2], P. purpurea showed a higher biomass accumulation, photosynthetic capacity and rate of ectomycorrhizal infection, and higher water and nitrogen use efficiencies compared with A. faxoniana. However, under intraspecific competition and e[CO2], the two conifers showed no differences in biomass accumulation, photosynthetic capacity, and water and nitrogen use efficiencies. In addition, under interspecific competition and e[CO2], A. faxoniana exhibited higher NSC levels in leaves as well as more frequent and greater starch granules, which may indicate carbohydrate limitation. Consequently, we concluded that under interspecific competition, P. purpurea possesses a positive growth and adjustment strategy (e.g., a higher photosynthetic capacity and rate of ectomycorrhizal infection, and higher water and nitrogen use efficiencies), while A. faxoniana likely suffers from carbohydrate limitation to cope with rising [CO2]. Our study highlights that plant–plant competition should be taken into consideration when assessing the impact of rising [CO2] on the plant growth and physiological performance.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

scholarly journals Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modelling analysis

2015 ◽  
Vol 12 (1) ◽  
pp. 79-101 ◽  
Author(s):  
Y. Wu ◽  
C. Blodau ◽  
T. R. Moore ◽  
J. Bubier ◽  
S. Juutinen ◽  
...  
Keyword(s):  
Ecosystem Respiration ◽  
Model Performance ◽  
Net Ecosystem Exchange ◽  
N Fertilization ◽  
N Deposition ◽  
Competitive Advantages ◽  
Long Term Effects ◽  
N Content ◽  
Modelling Analysis

Abstract. Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to explore impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behaviour. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to factors that can be related to differences in vegetation distribution (e.g. shrubs vs. graminoid vegetation) and to high tolerance of vascular plants to N deposition in the model. Model performance regarding the 8-year response of GEP and NEE to N input was improved by introducing an N content threshold shifting the response of photosynthetic capacity (GEPmax) to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub–Sphagnum-dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m−2 yr−1, whereas this was not the case when it became graminoid-dominated. The modelling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

scholarly journals Incubation methods for assessing mineralizable nitrogen in soils under sugarcane

2013 ◽  
Vol 37 (2) ◽  
pp. 450-461 ◽  
Author(s):  
Eduardo Mariano ◽  
Paulo Cesar Ocheuze Trivelin ◽  
José Marcos Leite ◽  
Michele Xavier Vieira Megda ◽  
Rafael Otto ◽  
...  
Keyword(s):  
N Mineralization ◽  
Standard Technique ◽  
Extraction Methods ◽  
N Fertilization ◽  
Chemical Extraction ◽  
Net N Mineralization ◽  
Anaerobic Incubation ◽  
Aerobic Incubation ◽  
Mineralizable N

Considering nitrogen mineralization (N) of soil organic matter is a key aspect for the efficient management of N fertilizers in agricultural systems. Long-term aerobic incubation is the standard technique for calibrating the chemical extraction methods used to estimate the potentially mineralizable N in soil. However, the technique is laborious, expensive and time-consuming. In this context, the aims of this study were to determine the amount of soil mineralizable N in the 0-60 cm layer and to evaluate the use of short-term anaerobic incubation instead of long-term aerobic incubation for the estimation of net N mineralization rates in soils under sugarcane. Five soils from areas without previous N fertilization were used in the layers 0-20, 20-40 and 40-60 cm. Soil samples were aerobically incubated at 35 ºC for 32 weeks or anaerobically incubated (waterlogged) at 40 ºC for seven days to determine the net soil N mineralization. The sand, silt and clay contents were highly correlated with the indexes used for predicting mineralizable N. The 0-40 cm layer was the best sampling depth for the estimation of soil mineralizable N, while in the 40-60 cm layer net N mineralization was low in both incubation procedures. Anaerobic incubation provided reliable estimates of mineralizable N in the soil that correlated well with the indexes obtained using aerobic incubation. The inclusion of the pre-existing NH4+-N content improved the reliability of the estimate of mineralizable N obtained using anaerobic incubation.

scholarly journals Effect of long-term N fertilization on ca saturation and soil quality in a calcareous soil in a semiarid to sub-humid region

2014 ◽  
Vol 9 (1) ◽  
pp. 80-93
Author(s):  
Hai, XU, ◽  
Yi-quan WANG, ◽  
Xiao-yun LI, ◽  
Hao WANG, ◽  
Yong-jian WANG, ◽  
...  
Keyword(s):  
Soil Quality ◽  
Calcareous Soil ◽  
N Fertilization ◽  
Humid Region
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