Canopy development and hydraulic function in Eucalyptus tereticornis grown in drought in CO2-enriched atmospheres

2007 ◽  
Vol 34 (12) ◽  
pp. 1137 ◽  
Author(s):  
Brian J. Atwell ◽  
Martin L. Henery ◽  
Gordon S. Rogers ◽  
Saman P. Seneweera ◽  
Marie Treadwell ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Shoot Growth ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Shoot Biomass ◽  
Eucalyptus Tereticornis ◽  
Growth Responses ◽  
Ambient Conditions ◽  
Long Distance ◽  
Pipe Model

We report on the relationship between growth, partitioning of shoot biomass and hydraulic development of Eucalyptus tereticornis Sm. grown in glasshouses for six months. Close coordination of stem vascular capacity and shoot architecture is vital for survival of eucalypts, especially as developing trees are increasingly subjected to spasmodic droughts and rising atmospheric CO2 levels. Trees were exposed to constant soil moisture deficits in 45 L pots (30–50% below field capacity), while atmospheric CO2 was raised to 700 μL CO2 L–1 in matched glasshouses using a hierarchical, multi-factorial design. Enrichment with CO2 stimulated shoot growth rates for 12–15 weeks in well-watered trees but after six months of CO2 enrichment, shoot biomasses were not significantly heavier (30% stimulation) in ambient conditions. By contrast, constant drought arrested shoot growth after 20 weeks under ambient conditions, whereas elevated CO2 sustained growth in drought and ultimately doubled the shoot biomass relative to ambient conditions. These growth responses were achieved through an enhancement of lateral branching up to 8-fold due to CO2 enrichment. In spite of larger transpiring canopies, CO2 enrichment also improved the daytime water status of leaves of droughted trees. Stem xylem development was highly regulated, with vessels per unit area and cross sectional area of xylem vessels in stems correlated inversely across all treatments. Furthermore, vessel numbers related to the numbers of leaves on lateral branches, broadly supporting predictions arising from Pipe Model Theory that the area of conducting tissue should correlate with leaf area. Diminished water use of trees in drought coincided with a population of narrower xylem vessels, constraining hydraulic capacity of stems. Commensurate with the positive effects of elevated CO2 on growth, development and leaf water relations of droughted trees, the capacity for long-distance water transport also increased.

High vapour pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment

1998 ◽  
Vol 25 (3) ◽  
pp. 287 ◽  
Author(s):  
Saman P. Seneweera ◽  
Oula Ghannoum ◽  
Jann Conroy
Keyword(s):  
Soil Water ◽  
Elevated Co2 ◽  
Vapour Pressure ◽  
Shoot Growth ◽  
Vapour Pressure Deficit ◽  
C4 Grasses ◽  
Growth Responses ◽  
High Co2 ◽  
C4 Grass ◽  
Shoot Mass

The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.

Seasonal changes in tissue elasticity and water transport efficiency in three co-occurring Mediterranean shrubs under natural long-term CO2 enrichment

2002 ◽  
Vol 29 (9) ◽  
pp. 1097 ◽  
Author(s):  
Roberto Tognetti ◽  
Antonio Raschi ◽  
Mike B. Jones
Keyword(s):  
Elevated Co2 ◽  
Seasonal Changes ◽  
Water Movement ◽  
Co2 Enrichment ◽  
Co2 Concentration ◽  
Tissue Elasticity ◽  
Ambient Conditions ◽  
Mediterranean Shrubs ◽  
Competitive Relations

Seasonal changes in hydraulic properties and tissue elasticity were evaluated in Erica arborea L., Myrtus�communis L. and Juniperus communis L., three Mediterranean shrubs that differ in adaptations to drought. These parameters were analysed over 12 months under field conditions, by comparing plants grown in the proximity of a natural CO2 spring (about 700 μmol mol–1 atmospheric CO2 concentration, [CO2]) with plants in ambient conditions. Plants at the CO2-spring site have been growing for generations at elevated [CO2]. At both sites, stem hydraulic and structural properties followed the prevailing climatic constraints. However, these shrub species co-occurring in the same environment differed in their capacity to tolerate water deficits, in xylem efficiency, and in strategies for regulating water movement between plant compartments. Either an increase or a decrease in tissue elasticity was effective in promoting resistance to drought stress, depending on the species. Long-term elevated [CO2] influenced all the studied parameters. Species-dependent differences existed in hydraulic architecture between the CO2-spring plants and control plants of E. arborea and M. communis, while J. communis plants rarely showed differences between sites. Less distinct differences between sites were observed for wood structure. The three species showed somewhat lower tissue elasticity under elevated [CO2], in particular during stress periods. The effects of elevated [CO2] on stem hydraulic pathway and structure and shoot elastic properties persist in the long term, but differ in absolute values and sign among the studied species and with the seasonal course, and thus might alter competitive relations between these shrubs.

Soil development under elevated CO2 affects plant growth responses to CO2 enrichment

2003 ◽  
Vol 4 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Grant R. Edwards ◽  
Harry Clark ◽  
Paul C.D. Newton
Keyword(s):  
Plant Growth ◽  
Elevated Co2 ◽  
Co2 Enrichment ◽  
Soil Development ◽  
Growth Responses

scholarly journals Elevated Atmospheric CO2 Concentration Improved C4 Xero-Halophyte Kochia prostrata Physiological Performance under Saline Conditions

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 491
Author(s):  
Zulfira Rakhmankulova ◽  
Elena Shuyskaya ◽  
Kristina Toderich ◽  
Pavel Voronin
Keyword(s):  
Osmotic Stress ◽  
Elevated Co2 ◽  
Stress Responses ◽  
Dark Respiration ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Shoot Biomass ◽  
Elevated Co2 Concentration ◽  
Elevated Atmospheric Co2 ◽  
Atmospheric Co2 Concentration

A significant increase in atmospheric CO2 concentration and associated climate aridization and soil salinity are factors affecting the growth, development, productivity, and stress responses of plants. In this study, the effect of ambient (400 ppm) and elevated (800 ppm) CO2 concentrations were evaluated on the C4 xero-halophyte Kochia prostrata treated with moderate salinity (200 mM NaCl) and polyethylene glycol (PEG)-induced osmotic stress. Our results indicated that plants grown at elevated CO2 concentration had different responses to osmotic stress and salinity. The synergistic effect of elevated CO2 and osmotic stress increased proline accumulation, but elevated CO2 did not mitigate the negative effects of osmotic stress on dark respiration intensity and photosystem II (PSII) efficiency. This indicates a stressful state, which is accompanied by a decrease in the efficiency of light reactions of photosynthesis and significant dissipative respiratory losses, thereby resulting in growth inhibition. Plants grown at elevated CO2 concentration and salinity showed high Na+ and proline contents, high water-use efficiency and time required to reach the maximum P700 oxidation level (PSI), and low dark respiration. Maintaining stable water balance, the efficient functioning of cyclic transport of PSI, and the reduction of dissipation costs contributed to an increase in dry shoot biomass (2-fold, compared with salinity at 400 ppm CO2). The obtained experimental data and PCA showed that elevated CO2 concentration improved the physiological parameters of K. prostrata under salinity.

scholarly journals Ecosystem feedbacks from subarctic wetlands: vegetative and atmospheric CO<sub>2</sub> controls on greenhouse gas emissions

2016 ◽  
Author(s):  
Matthew J. Bridgman ◽  
Barry H. Lomax ◽  
Sofie Sjogersten
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Elevated Co2 ◽  
Atmospheric Co2 ◽  
Carbon Substrate ◽  
Total Biomass ◽  
Growth Responses ◽  
Gas Emissions ◽  
Ch4 Emissions ◽  
Species Specific

Abstract. Wetland vegetation provide strong controls on greenhouse gas fluxes but impacts of elevated atmospheric carbon dioxide (CO2) levels on greenhouse gas emissions from wetlands are poorly understood. This study aims to investigate if elevated atmospheric CO2 enhance methane (CH4) emissions from subarctic wetlands and to determine if responses are comparable or species specific within the Cyperaceae, an important group of artic wetland plants. To achieve this we carried out a combined field and laboratory investigation to measure of CO2 and CH4 fluxes. The wetland was a CH4 source with comparable fluxes from areas with and without vegetation and across the different sedge communities. In contrast, the net ecosystem exchange of CO2 differed with sedge species. Within the laboratory experiment plants grown at double ambient (800 ppm) CO2, total biomass of Eriophorum vaginatum and Carex brunnescens increased, whereas the total biomass of E. angustifolium and C. acuta decreased, compared to the control (400 ppm CO2). These changes in biomass were associated with corresponding changes in CH4 flux. E. vaginatum and C. brunnescens mesocosms produced more CH4 when grown in 800 ppm atmospheric CO2 when compared to 400 ppm CO2 with E. angustifolium and C. acuta producing less. Additionally, redox potential and carbon substrate availability in the pore water differed among the plant treatments and in response to the elevated CO2 treatment. Together, this suggests species specific controls of CH4 emissions in response to elevated CO2, which facilitate differential plant growth responses and modification of the rhizosphere environments. Our study highlights species composition as an important control of greenhouse gas feedbacks in a CO2 rich future, which need to be considered in models aiming to predict how ecosystems respond to climate change.

scholarly journals Soybean-BioCro: A semi-mechanistic model of soybean growth

2021 ◽  
Author(s):  
Megan L Matthews ◽  
Amy Marshall-Colón ◽  
Justin M McGrath ◽  
Edward B Lochocki ◽  
Stephen P Long
Keyword(s):  
Elevated Co2 ◽  
Mechanistic Model ◽  
Co2 Enrichment ◽  
Field Measurements ◽  
Atmospheric Co2 ◽  
Growth And Yield ◽  
Elevated Atmospheric Co2 ◽  
Crop Models ◽  
Growing Seasons ◽  
Or Gene

Abstract Soybean is a major global source of protein and oil. Understanding how soybean crops will respond to the changing climate and identifying the responsible molecular machinery, are important for facilitating bioengineering and breeding to meet the growing global food demand. The BioCro family of crop models are semi-mechanistic models scaling from biochemistry to whole crop growth and yield. BioCro was previously parameterized and proved effective for the biomass crops miscanthus, coppice willow, and Brazilian sugarcane. Here, we present Soybean-BioCro, the first food crop to be parameterized for BioCro. Two new module sets were incorporated into the BioCro framework describing the rate of soybean development and carbon partitioning and senescence. The model was parameterized using field measurements collected over the 2002 and 2005 growing seasons at the open air [CO2] enrichment (SoyFACE) facility under ambient atmospheric [CO2]. We demonstrate that Soybean-BioCro successfully predicted how elevated [CO2] impacted field-grown soybean growth without a need for re-parameterization, by predicting soybean growth under elevated atmospheric [CO2] during the 2002 and 2005 growing seasons, and under both ambient and elevated [CO2] for the 2004 and 2006 growing seasons. Soybean-BioCro provides a useful foundational framework for incorporating additional primary and secondary metabolic processes or gene regulatory mechanisms that can further aid our understanding of how future soybean growth will be impacted by climate change.

Effect of elevated CO2 on Vigna radiata and two weed species: yield, physiology and crop–weed interaction

2018 ◽  
Vol 69 (6) ◽  
pp. 617 ◽  
Author(s):  
Jay Prakash Awasthi ◽  
Kamlesh Singh Paraste ◽  
Meenal Rathore ◽  
Mayank Varun ◽  
Disha Jaggi ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Elevated Co2 ◽  
Vigna Radiata ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Green Gram ◽  
Weed Species ◽  
Test Species ◽  
Antioxidant Defence System ◽  
Species Specific

A field experiment was conducted in a free-air CO2 enrichment (FACE) facility to investigate the effect of elevated atmospheric CO2 on growth and physiology of green gram (Vigna radiata (L.) R.Wilczek) and associated weed species (Euphorbia geniculata Ortega and Commelina diffusa Burm.f.). Physiological and reproductive behaviour and interaction of the crop and two weed species under elevated CO2 was also studied. Plants were grown under ambient (390 ± 5 ppmv) and elevated (550 ± 50 ppmv) CO2. The results showed that growth, photosynthesis and carbonic anhydrase activity increased in all the test species. Stomatal conductance and transpiration decreased in V. radiata (5.1% and 30.5%, respectively) and C. diffusa (19% and 13.7%) but increased in E. geniculata (6.5% and 27.6%), suggesting a unique adaptive potential of E. geniculata at elevated CO2. Higher accumulation of reactive oxygen species (hydrogen peroxide and superoxide) was noticed at elevated CO2 in V. radiata than in E. geniculata and C. diffusa. Potential of E. geniculata to maintain redox homeostasis in its original state may provide an advantage over two other species in adaptation to climate change. Isoenzyme patterns of superoxide dismutase and stronger activity of antioxidant enzymes suggest species-specific differential regulation and induction of new isoforms under elevated CO2. Enrichment of atmospheric CO2 at a competitive density of weeds lowered the yield (12.12%) and quality of green gram seed, with diminished protein content (16.14% at ambient CO2 to 15.42% at elevated CO2) and enhanced carbohydrate content (3.11%). From the study, it may be concluded that a rise in atmospheric CO2 concentration affects plant performance in a species-specific manner. Among the three species, E. geniculata emerged as most responsive to elevated CO2, showing higher transpiration and stomatal conductance and a stronger antioxidant defence system in a higher CO2 atmosphere. At elevated CO2, weed–crop interaction altered in favour of weeds leading to considerable yield loss of green gram seed.

scholarly journals Leveraging genome-enabled growth models to study shoot growth responses to water deficit in rice

2020 ◽  
Vol 71 (18) ◽  
pp. 5669-5679
Author(s):  
Malachy T Campbell ◽  
Alexandre Grondin ◽  
Harkamal Walia ◽  
Gota Morota
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Shoot Growth ◽  
Growth Models ◽  
Shoot Biomass ◽  
Model Parameters ◽  
Growth Responses ◽  
Genome Wide ◽  
A Genome

Abstract Elucidating genotype-by-environment interactions and partitioning its contribution to phenotypic variation remains a challenge for plant scientists. We propose a framework that utilizes genome-wide markers to model genotype-specific shoot growth trajectories as a function of time and soil water availability. A rice diversity panel was phenotyped daily for 21 d using an automated, high-throughput image-based, phenotyping platform that enabled estimation of daily shoot biomass and soil water content. Using these data, we modeled shoot growth as a function of time and soil water content, and were able to determine the time point where an inflection in the growth trajectory occurred. We found that larger, more vigorous plants exhibited an earlier repression in growth compared with smaller, slow-growing plants, indicating a trade-off between early vigor and tolerance to prolonged water deficits. Genomic inference for model parameters and time of inflection (TOI) identified several candidate genes. This study is the first to utilize a genome-enabled growth model to study drought responses in rice, and presents a new approach to jointly model dynamic morpho-physiological responses and environmental covariates.

Sink Strength May Be the Key to Growth and Nitrogen Responses in N-Deficient Wheat at Elevated CO2

1996 ◽  
Vol 23 (3) ◽  
pp. 253 ◽  
Author(s):  
GS Rogers ◽  
PJ Milham ◽  
M Gillings ◽  
JP Conroy
Keyword(s):  
Elevated Co2 ◽  
Protein Concentration ◽  
Shoot Growth ◽  
Co2 Enrichment ◽  
Sink Strength ◽  
High Co2 ◽  
N Supply ◽  
N Concentration ◽  
Ambient Co2 ◽  
Leaf N

The influence of elevated CO2 (350, 550 and 900 μL L-1) and N supplies ranging from deficient to excess (0-133 mg N kg-1 soil week-1) on the leaf N concentration and shoot growth of wheat (Triticum aestivum L.), cultivar Hartog, was investigated. Shoot growth was 30 % greater at 550 μL L-1 compared to ambient CO2 at all levels of N supply. When the CO2 concentration was increased to 900 μL L-1, there was no increase in shoot growth at low N supply but it more than doubled at high N supply (67 mg N kg-1 soil week-1). Growth effects were closely matched by changes in sink development, suggesting that sink strength, mediated through N supply controlled the shoot growth response to elevated CO2. The shoot N concentration was lower at each level of CO2 enrichment and the greatest effect (30% reduction) occurred at 900 μL CO2 L-1, 33 mg N kg-1 soil week-1. The effect of high CO2 on shoot N concentration diminished as N supply increased and, at the highest N addition rate, there was only a 7% reduction. Changes in foliar N concentration due to CO2 enrichment were closely correlated with lower soluble protein concentration, accounting for 58 % of the total leaf N reduction. Ribulose- IS-bisphosphate carboxylase/oxygenase (Rubisco) levels were also reduced at high CO2 and N was allocated away from Rubisco and into other soluble proteins at high CO2 when N supply was low. Non- structural carbohydrate concentration (dry weight basis) was greatest at 900 μL CO2 L-1 and low N supply and may have reduced Rubisco concentration via a feed-back response. Critical foliar N concentrations (N concentration at 90 % of maximum shoot growth) were reduced from 43 mg g-1 at ambient CO2 to 39 and 38 mg g-1 at 550 and 900 μL CO2 L-1, respectively. Elevated CO2, at N supplies of 0-17 mg N kg-1 soil week-1, reduced flour protein concentration by 9-13 %.

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