Open AccessJournal Article
Stomatal and mesophyll conductances control CO2 transfer to chloroplasts in leaves of grapevine (Vitis vinifera L.)
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TLDR
It is hypothesized that both stomatal and mesophyll conductance are involved in the adaptation of the CO 2 supply to the CO 2 demand at the site of carboxylation in chloroplasts.Abstract:
From simultaneous determination of net CO 2 assimilation and transpiration at the abaxial side and of the photosynthetic electron transport rate at the adaxial side of fieldgrown, light-saturated leaves of grapevine (cv. Riesling) photorespiration, stomatal conductance for CO2, mesophyll conductance and the CO 2 concentration in intercellular spaces (Ci) and in chloroplasts (Cc) were estimated. CO 2 assimilation was saturated at about Ci = 340 ppm. At increasing ambient CO 2 concentration (Ca) photorespiration decreased (less negative values); stomatal conductance decreased significantly (- 45 %) limiting CO2 uptake into intercellular spaces. Rates of total photosynthetic electron transport were constant between Ci = 340 and 800 ppm and decreased by 34 % at low Ci. Electron flow to carboxylation was closely correlated to CO 2 assimilation rates (R 2 = 0.999). When Ca was raised, the CO 2 concentration in chloroplasts (Cc) increased but at smaller rates than Ci. Presumably due to the distinct decline of the mesophyll conductance Cc remained constant at Ci >340 ppm. At Ca = 400 ppm the Cc/Ca ratio was 0.46 - 0.48, corroborating data reported for other species (CORNIC and FRESNEAU 2002). At 2 % ambient O 2 and 400 ppm CO 2 decreased rates of photorespiration (- 69 %) were associated with a decline of total photosynthetic electron flow (- 6 %); higher stomatal and mesophyll conductances, however, led to increases of Cc and CO2 assimilation rates (+ 49 %). It is hypothesized that both stomatal and mesophyll conductance are involved in the adaptation of the CO 2 supply to the CO 2 demand at the site of carboxylation in chloroplasts.read more
Citations
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Mesophyll conductance to CO2: current knowledge and future prospects
TL;DR: There is now evidence that g(liq) and, in some cases, g(w), are the main determinants of g(m).
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Mesophyll diffusion conductance to CO2: an unappreciated central player in photosynthesis
Jaume Flexas,Margaret M. Barbour,Oliver Brendel,Hernán M. Cabrera,Marc Carriquí,Antonio Díaz-Espejo,Cyril Douthe,Erwin Dreyer,Juan Pedro Ferrio,Jorge Gago,Alexander Gallé,Jeroni Galmés,Naomi Kodama,Hipólito Medrano,Ülo Niinemets,José Javier Peguero-Pina,Alicia Pou,Miquel Ribas-Carbo,Magdalena Tomás,Tiina Tosens,Charles R. Warren +20 more
TL;DR: New evidence shows that anatomical traits, such as cell wall thickness and chloroplast distribution are amongst the stronger determinants of mesophyll conductance, although rapid variations in response to environmental changes might be regulated by other factors such as aquaporin conductance.
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Rapid variations of mesophyll conductance in response to changes in CO2 concentration around leaves
Jaume Flexas,Antonio Díaz-Espejo,Jeroni Galmés,Ralf Kaldenhoff,Hipólito Medrano,Miquel Ribas-Carbo +5 more
TL;DR: Transgenic tobacco plants differing in the amounts of aquaporin NtAQP1 showed different slopes of the gm-Ci response, suggesting a possible role for aquaporins in mediating CO2 responsiveness of gm, and the importance of these findings is discussed in terms of their effects on parameterization of AN-CI curves.
Journal ArticleDOI
Tobacco aquaporin NtAQP1 is involved in mesophyll conductance to CO2 in vivo
Jaume Flexas,Miquel Ribas-Carbo,David T. Hanson,Josefina Bota,Beate Otto,Josep Cifre,Nate G. McDowell,Hipólito Medrano,Ralf Kaldenhoff +8 more
TL;DR: Evidence is provided for the in vivo involvement of aquaporin NtAQP1 in mesophyll conductance to CO(2) using plants either deficient in or overexpressing Nt aqP1.
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Physiological and structural tradeoffs underlying the leaf economics spectrum.
Yusuke Onoda,Ian J. Wright,John R. Evans,Kouki Hikosaka,Kaoru Kitajima,Ülo Niinemets,Hendrik Poorter,Tiina Tosens,Mark Westoby +8 more
TL;DR: In this article, the authors investigated physiological and structural mechanisms underpinning the leaf economics spectrum (LES) by analysing a novel data compilation incorporating rarely considered traits such as the dry mass fraction in cell walls, nitrogen allocation, mesophyll CO2 diffusion and associated anatomical traits for hundreds of species covering major growth forms.
References
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Journal ArticleDOI
Limitation to Photosynthesis in Water‐stressed Leaves: Stomata vs. Metabolism and the Role of ATP
TL;DR: Decreasing relative water content of leaves progressively decreases stomatal conductance (gs), slowing CO2 assimilation (A) which eventually stops, after which CO2 is evolved.
Journal ArticleDOI
Theoretical Considerations when Estimating the Mesophyll Conductance to CO2 Flux by Analysis of the Response of Photosynthesis to CO2
TL;DR: It is concluded that both methods can be used to determine mesophyll conductance and each method has particular strengths and will prove useful in the future.
Journal ArticleDOI
Relationship between photosystem II activity and CO2 fixation in leaves
John P. Krall,Gerald E. Edwards +1 more
TL;DR: In this paper, a measure of the quantum yield of photosystem II, ΦII (electron/photon absorbed by PSII), can be obtained in leaves under steady-state conditions in the light using a modulated fluorescence system.
Journal ArticleDOI
Effects of drought on photosynthesis in grapevines under field conditions: an evaluation of stomatal and mesophyll limitations.
TL;DR: The apparent carboxylation efficiency and the compensation point for CO2 remained unchanged under severe drought when analysed on a Cc, rather than a Ci, basis, suggesting that previously reported metabolic impairment was probably due to decreased gmes.