CO2 diffusion across stomata and mesophyll

Carbon dioxide diffusion across stomata and mesophyll and photo-biochemical processes as affected by growth CO₂ and phosphorus nutrition in cotton

by Singh S. K., Badgujar G., Reddy V. R., Fleisher D. H., Bunce J. A. (2013)

Shardendu K. Singh, ^ab Girish Badgujar, ^bc Vangimalla R. Reddy, ^b David H. Fleisher, ^b James A. Bunce, ^b

^a Wye Research and Education Center, University of Maryland, MD, USA

^b Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, USA

^c Asian Institute of Technology, Pathumthani, Thailand

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In J. Plant Physiol. 170: 801–813 – https://doi.org/10.1016/j.jplph.2013.01.001 –

https://www.sciencedirect.com/science/article/pii/S0176161713000187?via%3Dihub

Abstract

Nutrients such as phosphorus may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO₂), which is projected to double by the end of the 21st century. Elevated CO₂ may overcome the diffusional limitations to photosynthesis posed by stomata and mesophyll and alter the photo-biochemical limitations resulting from phosphorus deficiency. To evaluate these ideas, cotton (Gossypium hirsutum) was grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.2, 0.05 and 0.01 mM) and two levels of CO₂ concentration (ambient 400 and elevated 800 μmol mol⁻¹) under optimum temperature and irrigation. Phosphate deficiency drastically inhibited photosynthetic characteristics and decreased cotton growth for both CO₂treatments. Under Pi stress, an apparent limitation to the photosynthetic potential was evident by CO₂diffusion through stomata and mesophyll, impairment of photosystem functioning and inhibition of biochemical process including the carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxyganase and the rate of ribulose-1,5-bisphosphate regeneration. The diffusional limitation posed by mesophyll was up to 58% greater than the limitation due to stomatal conductance (g_s) under Pi stress. As expected, elevated CO₂ reduced these diffusional limitations to photosynthesis across Pi levels; however, it failed to reduce the photo-biochemical limitations to photosynthesis in phosphorus deficient plants. Acclimation/down regulation of photosynthetic capacity was evident under elevated CO₂ across Pi treatments. Despite a decrease in phosphorus, nitrogen and chlorophyll concentrations in leaf tissue and reduced stomatal conductance at elevated CO₂, the rate of photosynthesis per unit leaf area when measured at the growth CO₂ concentration tended to be higher for all except the lowest Pi treatment. Nevertheless, plant biomass increased at elevated CO₂ across Pi nutrition with taller plants, increased leaf number and larger leaf area.

Reduction in photosynthesis at high transpiration rate without stomatal closure

Nonstomatal inhibition of photosynthesis by water stress. Reduction in photosynthesis at high transpiration rate without stomatal closure in field-grown tomato

by Bunce J. A. (1988)

• James A. Bunce, Plant Photobiology Laboratory USDA-Agricultural Research Service, Beltsville, USA

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In Photosynthesis Research 18: 357-362 – https://doi.org/10.1007/BF00034840 –

https://link.springer.com/article/10.1007%2FBF00034840#citeas

Abstract

Large underestimates of the limitation to photosynthesis imposed by stomata can occur because of an error in the standard method of calculating average substomatal pressures of carbon dioxide when heterogeneity of those pressures occurs across a leaf surface.

Most gas exchange data supposedly indicating nonstomatal inhibition of photosynthesis by water stress could have this error. However, if no stomatal closure occurs, any reduction in photosynthesis must be due to nonstomatal inhibition of photosynthesis.

Net carbon dioxide exchange rates and conductances to water vapor were measured under field conditions in upper canopy leaves of tomato plants during two summers in Beltsville, Maryland, USA. Comparisons were made near midday at high irradiance between leaflets in air with the ambient water vapor content and in air with a higher water content.

The higher water content, which lowered the leaf to air water vapor pressure difference (VPD), was imposed either one half hour or several hours before measurements of gas exchange. In both seasons, and irrespective of the timing of the imposition of different VPDs, net photosynthesis increased 60% after decreasing the VPD from 3 to 1 kPa.

There were no differences in leaf conductance between leaves at different VPDs, thus transpiration rates were threefold higher at 3 than at 1 kPa VPD. It is concluded that nonstomatal inhibition of photosynthesis did occur in these leaves at high transpiration rate.

Stomatal adjustment under fluctuating and stressed environments

The physiology and genetics of stomatal adjustment under fluctuating and stressed environments

by Qu M., Hamdani S., Bunce J. A. (2016)

Mingnan Qu, Saber Hamdani, James A. Bunce,

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In Applied Photosynthesis – New Progress, Mohammad Mahdi Najafpour, IntechOpen, DOI: 10.5772/62223.

Available from: https://www.intechopen.com/books/applied-photosynthesis-new-progress/the-physiology-and-genetics-of-stomatal-adjustment-under-fluctuating-and-stressed-environments

Sections

Chapter and author info

• 1.Introduction
• 2.External environments
• 3.Internal signals
• 4.Natural variation and heritability of stomatal conductance
• 5.Relation of stomatal profiling with life histories
• 6.Theoretical modeling for describing stomatal delays

Abstract

Stomata are pores in the leaf that allow gas exchange where water vapor leaves the plant and carbon dioxide enters. Under natural condition, plants always experience at a fluctuating light regime (shade-/sun-fleck) and due to global climate change, occasionally extreme high temperature and CO2 enrichment will be inevitable occurred, which dramatically affects stomatal response, and trade-off between water-use efficiency and photosynthesis.

Response of stomata to fluctuating and stressed environments determines optimized strategy of plants directing to water save or photosynthesis. Dynamic adjustments of stomata play an equivalent role as steady-state stomatal characteristics.

Evolutionary approach indicated that stomatal-dynamic adjustments interacting with historical environments or life histories could be genetically controlled and environmentally selected.

In this article, we reviewed physiological response of stomatal dynamic to changing environments including our previous works, and discussed the possibility of genetic improvements on stomatal adjustments by estimating broad-sense heritability and SNP heritability of stomatal pattern. To gain insight into the framework of stomatal genetics, we highlighted the importance of combining multidisciplinary techniques, such as mathematic modeling, quantitative genetics, molecular biology and equipments developments.

New Gas Exchange Methods to Estimate Mesophyll Conductance and Non-stomatal Inhibition of Photosynthesis

 

 

Using New Gas Exchange Methods to Estimate Mesophyll Conductance and Non-stomatal Inhibition of Photosynthesis Caused by Water Deficits

by Bunce J. A. (2012)

James A. Bunce

Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville Agricultural Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705-2350

 

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in HortScience 47(6): 687-690 – 

http://hortsci.ashspublications.org/content/47/6/687.full

Abstract

Soil water deficits remain one of the most important factors reducing the yield of crop plants and may become even more limiting with changes in the global climate and competition for fresh water resources. Soil water deficits reduce plant growth partly by reducing photosynthesis. However, it remains unclear how important non-stomatal factors are in limiting photosynthesis under moderate water stress and whether rising atmospheric carbon dioxide may alter which processes limit photosynthesis under water stress.

The conductance to CO₂ from the substomatal air space to the site of carboxylation inside chloroplasts in C₃ plants is now termed mesophyll conductance. Because of the competition between CO₂ and O₂ for RuBisco, the carbon dioxide concentration at the chloroplast can be estimated from the O₂ sensitivity of photosynthesis, providing a new method of estimating mesophyll conductance. It has also recently been realized that partial stomatal closure resulting from water stress can often be reversed by exposing leaves to low CO₂.

This provides a new means of assessing the non-stomatal component of the inhibition of photosynthesis by water stress.

These methods were applied to four C₃ species and revealed that mesophyll conductance decreased substantially with water stress in two of the four species and that reopening of stomata did not eliminate the reduction in photosynthesis caused by moderate water stress at either the current ambient or elevated CO₂ concentrations.

Stomatal responses to light, humidity and temperature at 3 CO2 concentrations

 

 

Responses of stomatal conductance to light, humidity and temperature in winter wheat and barley grown at three concentrations of carbon dioxide in the field

by Bunce J. A. (2000)

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in Global Change Biology 6: 371-382 –

https://pubag.nal.usda.gov/pubag/downloadPDF.xhtml?id=40374&content=PDF

Responses of stomatal conductance to elevated CO2

 

 

Direct and acclimatory responses of stomatal conductance to elevated carbon dioxide in four herbaceous crop species in the field

by Bunce J. A. (2001)

James A. Bunce, United States Department of Agriculture, Washington, D.C., United States

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in Global Change Biology 7: 323-331 – DOI: 10.1046/j.1365-2486.2001.00406.x –

Google Scholar CrossRef –

https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2486.2001.00406.x

Summary

In order to separate the net effect of growth at elevated [CO₂] on stomatal conductance (g_s) into direct and acclimatory responses, mid‐day values of g_swere measured for plants grown in field plots in open‐topped chambers at the current ambient [CO₂], which averaged 350 μmol mol⁻¹ in the daytime, and at ambient + 350 μmol mol⁻¹[CO₂] for winter wheat, winter barley, potato and sorghum.

The acclimatory response was determined by comparing g_smeasured at 700 μmol mol⁻¹[CO₂] for plants grown at the two [CO₂]. The direct effect of increasing [CO₂] from 350 to 700 μmol mol⁻¹ was determined for plants grown at the lower concentration.

Photosynthetic rates were measured concurrently with g_s. For all species, growth at the higher [CO₂] significantly reduced g_s measured at 700 μmol mol⁻¹[CO₂]. The reduction in g_s caused by growth at the higher [CO₂] was larger for all species on days with low leaf to air water vapour pressure difference for a given temperature, which coincided with highest conductances and also the smallest direct effects of increased [CO₂] on conductance.

For barley, there was no other evidence for stomatal acclimation, despite consistent down‐regulation of photosynthetic rate in plants grown at the higher [CO₂]. In wheat and potato, in addition to the vapour pressure difference interaction, the magnitude of stomatal acclimation varied directly in proportion to the magnitude of down‐regulation of photosynthetic rate through the season. In sorghum, g_sconsistently exhibited acclimation, but there was no down‐regulation of photosynthetic rate.

In none of the species except barley was the direct effect the larger component of the net reduction in g_s when averaged over measurement dates. The net effect of growth at elevated [CO₂] on mid‐day g_sresulted from unique combinations of direct and acclimatory responses in the various species.

Leaf hydraulics limiting stomatal conductance

 

 

How do leaf hydraulics limit stomatal conductance at high water vapour pressure deficits?

by Bunce J. A. (2006)

J. A. Bunce, USDA-Agricultural Research Service, Washington D.C. USA

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in Plant Cell Environ. 29: 1644–1650 – DOI 10.1111/j.1365-3040.2006.01541.x –

Google Scholar CrossRef –

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.2006.01541.x/full

ABSTRACT

A reduction in leaf stomatal conductance (g) with increasing leaf-to-air difference in water vapour pressure (D) is nearly ubiquitous. Ecological comparisons of sensitivity have led to the hypothesis that the reduction in g with increasing D serves to maintain leaf water potentials above those that would cause loss of hydraulic conductance. A reduction in leaf water potential is commonly hypothesized to cause stomatal closure at high D. The importance of these particular hydraulic factors was tested by exposing Abutilon theophrasti, Glycine max, Gossypium hirsutum and Xanthium strumarium to D high enough to reduce g and then decreasing ambient carbon dioxide concentration ([CO₂]), and observing the resulting changes in g, transpiration rate and leaf water potential, and their reversibility. Reducing the [CO₂] at high D increased g and transpiration rate and lowered leaf water potential. The abnormally high transpiration rates did not result in reductions in hydraulic conductance. Results indicate that low water potential effects on g at high D could be overcome by low [CO₂], and that even lower leaf water potentials did not cause a reduction in hydraulic conductance in these well-watered plants. Reduced g at high D in these species resulted primarily from increased stomatal sensitivity to [CO₂] at high D, and this increased sensitivity may mediate stomatal responses to leaf hydraulics at high D.

Stomatal conductance and elevated concentration of CO2

 

 

Stomatal conductance, photosynthesis and respiration of temperate deciduous tree seedlings grown outdoors at an elevated concentration of CO2

by Bunce J. A. (1992)

James. A. Bunce, Climate Stress Laboratory, Natural Resources Institute, USDA-Agricultural Research Service, Beltsville Maryland 20705, USA

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in Plant, Cell and Environment 15(5): 541-549 – DOI: 10.1111/j.1365-3040.1992.tb01487.x –

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3040.1992.tb01487.x/abstract

ABSTRACT

Seedlings of temperate deciduous tree species were grown outdoors at ambient and at an elevated concentration of carbon dioxide to examine how aspects of their gas exchange would be altered by growth at elevated carbon dioxide concentration. Leaf conductances to water vapour and net carbon dioxide exchange rates were determined periodically near midday. Whole-plant carbon dioxide efflux rates in darkness were also determined. The stomatal conductance of leaves of plants grown and measured at 700 cm³ m⁻³ carbon dioxide did not differ from that of plants grown and measured at 350 cm³ m⁻³ in Malus domestica, Quercus prinus and Quercus robur at any measurement time. In Acer saccharinum, lower conductances occurred for plants grown and measured at elevated carbon dioxide concentration only at measurement temperatures above 33°C. Photo-synthetic adjustment to elevated carbon dioxide concentration was evident only in Q. robur. All species examined had lower rates of dark respiration per unit of mass when grown and measured at elevated carbon dioxide concentration.

 

CO2 diffusion across stomata, photo-biochemical processes and P-nutrition

Photo credit Google – Gossypium hirsutum – https://images-na.ssl-images-amazon.com/images/I/31XtrC2XWNL._SX300_.jpg

 

Carbon dioxide diffusion across stomata and mesophyll and photo-biochemical processes as affected by growth CO2 and phosphorus nutrition in cotton.

by Singh S. K., Badgujar G., Reddy V., Fleisher D. H., Bunce J. A. (2013)

Shardendu K. Singh, Girish Badgujar, Vangimalla R. Reddy, David H. Fleisher, James A. Bunce

Shardendu K. Singh, Wye Research and Education Center, University of Maryland, MD, USA

Girish Badgujar, Asian Institute of Technology, Pathumthani, Thailand

Vangimalla R. Reddy, Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, USA

————

in Journal of Plant Physiology. 170(9): 801-813 – DOI10.1016/j.jplph.2013.01.001 –

https://www.infona.pl/resource/bwmeta1.element.elsevier-f42d3a31-616d-3f08-8e0e-220107f61ce0

 

Abstract

Nutrients such as phosphorus may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO₂ ), which is projected to double by the end of the 21st century. Elevated CO₂ may overcome the diffusional limitations to photosynthesis posed by stomata and mesophyll and alter the photo-biochemical limitations resulting from phosphorus deficiency.

To evaluate these ideas, cotton (Gossypium hirsutum) was grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.2, 0.05 and 0.01mM) and two levels of CO₂ concentration (ambient 400 and elevated 800μmolmol ⁻¹ ) under optimum temperature and irrigation.

Phosphate deficiency drastically inhibited photosynthetic characteristics and decreased cotton growth for both CO₂ treatments. Under Pi stress, an apparent limitation to the photosynthetic potential was evident by CO₂ diffusion through stomata and mesophyll, impairment of photosystem functioning and inhibition of biochemical process including the carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxyganase and the rate of ribulose-1,5-bisphosphate regeneration.

The diffusional limitation posed by mesophyll was up to 58% greater than the limitation due to stomatal conductance (g _s ) under Pi stress.

As expected, elevated CO₂ reduced these diffusional limitations to photosynthesis across Pi levels; however, it failed to reduce the photo-biochemical limitations to photosynthesis in phosphorus deficient plants. Acclimation/down regulation of photosynthetic capacity was evident under elevated CO₂ across Pi treatments.

Despite a decrease in phosphorus, nitrogen and chlorophyll concentrations in leaf tissue and reduced stomatal conductance at elevated CO₂ , the rate of photosynthesis per unit leaf area when measured at the growth CO₂ concentration tended to be higher for all except the lowest Pi treatment. Nevertheless, plant biomass increased at elevated CO₂ across Pi nutrition with taller plants, increased leaf number and larger leaf area.