Scaling the Wall: understanding structure/function relationships in leaves across scales

John Innes Centre

Friday Seminar – Scaling the Wall: understanding structure/function relationships in leaves across scales with Prof. Andrew Fleming, University of Sheffield

Our Friday Seminar on 26th April at 11:30am is Scaling the Wall: understanding structure/function relationships in leaves across scales with Prof. Andrew Fleming, University of Sheffield

Location: Merton Auditorium and Zoom
(No registration is required to attend in person. If you are attending via Zoom, please register: https://jic.link/FS-Fleming)

Speaker: Andrew Fleming, University of Sheffield

Bio: Andrew Fleming is Professor of Plant Sciences at the University of Sheffield. Initially focussed on plant morphogenesis, Andrew’s research has broadened to integrate elements of plant development, cell biology, biochemistry and physiology, set in the context of understanding how events at the molecular and cellular level influence form and function at the tissue and organ scale of the leaf. His career has encompassed fellowships and positions at universities in the UK, the Netherlands and Switzerland, with current and recent research supported by funding from the BBSRC, Royal Society and Leverhulme Trust.

About: Plant cells are encased in a complex, dynamic composite material- the wall. Using stomatal guard cells as an experimental platform for combined molecular genetic, imaging and computational biology approaches, we are uncovering the links between the molecular composition of the wall and the emergent mechanical properties which allow these cells to undergo repeated, controlled expansion and deflation. Reflecting the core role of stomata in regulating gas flow into and out of the plant, these experiments also allow us to investigate the relationship of leaf structure and physiology linking cell-scale activities to the fundamental processes of photosynthesis and water control at the organ scale. Finally, by applying high-resolution scanning probe technologies, we are investigating the molecular spatial architecture and chemistry of the wall, with the ultimate aim of bridging mechanistic understanding of plant structure/function across scales.

Evaluation of ozone uptake by the rice canopy with the multi-layer model

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评估水稻冠层对臭氧吸收的多层模型

Avaliação da absorção de ozônio pelo dossel de arroz com o modelo de múltiplas camadas.

Evaluación de la absorción de ozono por el dosel de arroz con el modelo de múltiples capas.

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Evaluation of ozone uptake by the rice canopy with the multi-layer model

Oue H., Motohiro S., Inada K., Miyata A., Mano M., Kobayashi K., Zhu J. (2008)

Hiroki OUE, Shingo MOTOHIRO, Kenta INADA, Akira MIYATA, Masayoshi MANO, Kazuhiko KOBAYASHI, Jianguo ZHU,

  • Hiroki OUE : Faculty of Agriculture, Ehime University
  • Shingo MOTOHIRO : Faculty of Agriculture, Ehime University
  • Kenta INADA : Graduate School of Agricultural Science, Ehime University
  • Akira MIYATA : National Institute for Agro-Environmental Science
  • Masayoshi MANO : National Institute for Agro-Environmental Science
  • Kazuhiko KOBAYASHI : Graduate School of Agricultural and Life Sciences, The University of Tokyo
  • Jianguo ZHU : Institute of Soil Science, Chinese Academy of Sciences
  • ===

Journal of Agricultural Meteorology 64: 223-232 – https://doi.org/10.2480/agrmet.64.4.8 –

https://www.jstage.jst.go.jp/article/agrmet/64/4/64_64.4.8/_article

Abstract

The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the ambient and FACE fields, where the concentration of ozone ([O3]) was elevated artificially, during the heading and flowering stages, 2007. The gs sub-model of rice was developed by a multiplicative approach with modifications of PAR, VPD, AOT40 and [O3], while the multi-layer model of the O3 uptake process in the rice canopy was developed by incorporating the gs sub-model.
By the proposed model, vertical profiles of O3 fluxes on a single leaf (FO3) and in each canopy layer were calculated in the conditions 46.0, 40.2 and 43.6 ppb of [O3] at z = 280 cm at 1030, 1200 and 1530 h on August 30. O3 uptake by a single leaf (-FO3) in the upper canopy layer peaked at 1530 h and was smallest at 1200 h. The smallest –FO3 at 1200 h was caused not only by the lowest [O3] but also smaller gs, while the smaller gs at 1200 h was caused by smaller PAR on the flag leaf, even under the largest global solar radiation (SR) condition, because the leaf stands erect. The estimated O3 uptakes in the paddy field were 14.9, 13.7 and 12.1 (nmol m-2 s-1) at 1030, 1200 and 1530 h, respectively.
The predicted FO3 under different [O3] conditions by the model revealed that FO3 would exceed the threshold of -6 nmol m-2 s-1 in more than 60 ppb [O3] at 1030 and 1200 h and in more than 50 ppb at 1530 h. The predicted FO3 under different SR conditions with fixed [O3] of 80 ppb revealed that FO3 would reach the threshold in more than 400 W m-2 of SR at 1030 and 1200 h and more than 200 W m-2 at 1530 h under this relatively high [O3] condition.

Modeling the stomatal conductance and photosynthesis of a flag leaf of wheat under elevated ozone concentration

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对小麦旗叶在升高的臭氧浓度下的气孔导度和光合作用进行建模


Modelando a condutância estomática e a fotossíntese de uma folha de bandeira de trigo sob concentração elevada de ozônio.

Modelando la conductancia estomática y la fotosíntesis de una hoja bandera de trigo bajo una concentración elevada de ozono.

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Modeling the stomatal conductance and photosynthesis of a flag leaf of wheat under elevated O3 concentration

Oue H., Feng Z., Pang J., Miyata A., Mano M., Kobayashi K., Zhu J. (2009)

Hiroki OUE, Zhaozhong FENG, Jing PANG, Akira MIYATA, Masayoshi MANO, Kazuhiko KOBAYASHI, Jianguo ZHU,

  • Hiroki OUE : Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, 790-8566, Japan
  • Zhaozhong FENG : Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
  • Jing PANG : Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
  • Akira MIYATA : National Institute for Agro-Environmental Science, 3-1-3 Kannondai, Tsukuba, 305-8604, Japan
  • Masayoshi MANO : National Institute for Agro-Environmental Science, 3-1-3 Kannondai, Tsukuba, 305-8604, Japan
  • Kazuhiko KOBAYASHI : Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
  • Jianguo ZHU : Institute of Soil Science, Chinese Academy of Sciences, East Beijing Road 71, Nanjing 210008, P. R. China
  • ===

Journal of Agricultural Meteorology 65,: 239-248 – https://doi.org/10.2480/agrmet.65.3.7 –

https://www.jstage.jst.go.jp/article/agrmet/65/3/65_65.3.7/_article

Abstract

In aims to estimate stomatal O3 flux and predict the yield loss of wheat in eastern China, the focus was on developing a stomatal conductance (gs) model and a photosynthesis (P) model of a wheat flag leaf. To date, relationships between the relative yield of European spring wheat and the stomatal O3 flux of the wheat flag leaf have been presented by Pleijel et al. (2000), UNECE (2004) and many researchers with high correlations on the basis of the open-top chamber experiments.
The gs and P of flag leaves and other winter wheat leaves were measured, both in the ambient field and FACE (Free Air Concentration Enrichment) field, whereby the O3 concentration ([O3]) was artificially elevated, on 6 days from before heading to before harvest, 2008. The gs model was developed by a multiplicative approach with a maximum value of gs (gsmax) multiplied by modifications of photosynthetically active radiation incident on the leaf (PARl), accumulated exposure of O3 over a threshold concentration of 40 ppb for daylight hours (AOT40) at the canopy top, phenology, VPD and the time of day. A relationship between gs/gsmax and P/Pmax (Pmax is the maximum value of P) of a flag leaf measured in PARl=2000 μmol m-2 s-1 was represented by a linear regression line with a slope of 1.0 and intercept of 0.0. Therefore, the P model was developed by the multiplicative approach with Pmax multiplied by modifications of PARl for P and the same other parameters as the gs model. The models reproduced the gs and P of a flag leaf and even those of the other leaves successfully.
For the practical use of these models, [O3] at the canopy top ([O3]canopy) and PARl were also modeled. By applying the logarithmic profile of [O3] above the canopy, and modeling the roughness length for [O3] (z0O3) with the wind speed, the [O3]canopy was reproduced successfully. To model PARl, the inclination factor of a leaf (Fl) was decided so that the modeled vertical profile of shortwave radiation within the canopy could fit the measurements using the vertical two streams shortwave radiation model (e.g. Oue, 2003a; 2003b). Fl at z=0.6-0.8 m, where most flag leaves exist, was found to be from 0.4 to 0.6 for a wheat canopy of LAI=5.

Expectations of plant water-savings and reduced stomatal air pollution uptake under rising atmospheric CO(2) may not hold for northern hardwood forests under concurrently rising tropospheric O(3)

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预期随着大气CO(2)上升，植物节水和减少气孔吸收空气污染的情况可能不适用于北方阔叶林，同时大气中的O(3)也在上升。

As expectativas de economia de água das plantas e redução da absorção de poluição do ar pelos estômatos sob o aumento do CO(2) atmosférico podem não se aplicar às florestas de madeira dura do norte, sob o aumento simultâneo do O(3) troposférico.

Las expectativas de ahorro de agua de las plantas y la reducción de la absorción de contaminación del aire por los estomas bajo el aumento del CO(2) atmosférico pueden no aplicarse a los bosques de madera dura del norte bajo el aumento simultáneo del O(3) troposférico.

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Exposure to moderate concentrations of tropospheric ozone impairs tree stomatal response to carbon dioxide

Onandia G., OlssonA.-K., Barth S., King J. S., Uddling J. (2011)

Gabriela Onandia, Anna-Karin Olsson, Sabine Barth, John S King, Johan Uddling,


Department of Plant and Environmental Sciences, University of Gothenburg, PO Box 461, SE-405 30 Göteborg, Sweden.

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Environmental Pollution 159: 2350-2354 – doi: 10.1016/j.envpol.2011.06.001 – Epub 2011 Jul 5 – PMID: 21733606 –

https://pubmed.ncbi.nlm.nih.gov/21733606/

Abstract

With rising concentrations of both atmospheric carbon dioxide (CO(2)) and tropospheric ozone (O(3)), it is important to better understand the interacting effects of these two trace gases on plant physiology affecting land-atmosphere gas exchange. We investigated the effect of growth under elevated CO(2) and O(3), singly and in combination, on the primary short-term stomatal response to CO(2) concentration in paper birch at the Aspen FACE experiment. Leaves from trees grown in elevated CO(2) and/or O(3) exhibited weaker short-term responses of stomatal conductance to both an increase and a decrease in CO(2) concentration from current ambient level. The impairement of the stomatal CO(2) response by O(3) most likely developed progressively over the growing season as assessed by sap flux measurements. Our results suggest that expectations of plant water-savings and reduced stomatal air pollution uptake under rising atmospheric CO(2) may not hold for northern hardwood forests under concurrently rising tropospheric O(3).

Ozone flux-related responsiveness of photosynthesis, respiration, and stomatal conductance to experimentally enhanced free-air ozone exposure

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臭氧通量相关的光合作用、呼吸作用和气孔导度对实验性增强的自由大气臭氧暴露的响应


Responsividade relacionada ao fluxo de ozônio da fotossíntese, respiração e condutância estomática à exposição experimental aprimorada de ozônio livre no ar.


La respuesta relacionada con el flujo de ozono de la fotosíntesis, la respiración y la conductancia estomática a la exposición experimental mejorada de ozono libre en el aire.

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O3 flux-related responsiveness of photosynthesis, respiration, and stomatal conductance of adult Fagus sylvatica to experimentally enhanced free-air O3 exposure

Löw M., Häberle K. H., Warren C. R., Matyssek R. (2007)

Plant Biology 9: 197-206 – PMID: 17357014 – DOI: 10.1055/s-2006-924656 –

https://pubmed.ncbi.nlm.nih.gov/17357014/

Abstract

Knowledge of responses of photosynthesis, respiration, and stomatal conductance to cumulative ozone uptake (COU) is still scarce, and this is particularly the case for adult trees. The effect of ozone (O(3)) exposure on trees was examined with 60-year-old beech trees (FAGUS SYLVATICA) at a forest site of southern Germany. Trees were exposed to the ambient O(3) regime (1 x O(3)) or an experimentally elevated twice-ambient O(3) regime (2 x O(3)). The elevated 2 x O (3) regime was provided by means of a free-air O(3) canopy exposure system. The hypotheses were tested that (1) gas exchange is negatively affected by O(3) and (2) the effects of O(3) are dose-dependent and thus the sizes of differences between treatments are positively related to COU. Gas exchange (light-saturated CO(2) uptake rate A(max), stomatal conductance g (s), maximum rate of carboxylation Vc (max), ribulose-1,5-bisphosphate turnover limited rate of photosynthesis J (max), CO(2) compensation point CP, apparent quantum yield of net CO(2) uptake AQ, carboxylation efficiency CE, day- and nighttime respiration) and chlorophyll fluorescence (electron transfer rate, ETR) were measured IN SITU on attached sun and shade leaves. Measurements were made periodically throughout the growing seasons of 2003 (an exceptionally dry year) and 2004 (a year with average rainfall). In 2004 Vc(max), J(max), and CE were lower in trees receiving 2 x O(3) compared with the ambient O(3) regime (1 x O(3)). Treatment differences in Vc (max), J (max), CE were rather small in 2004 (i.e., parameter levels were lower by 10 – 30 % in 2 x O(3) than 1 x O(3)) and not significant in 2003. In 2004 COU was positively correlated with the difference between treatments in A (max), g (s), and ETR (i.e., consistent with the dose-dependence of O(3)’s deleterious effects). However, in 2003, differences in A(max), g (s), and ETR between the two O(3) regimes were smaller at the end of the dry summer 2003 (i.e., when COU was greatest). The relationship of COU with effects on gas exchange can apparently be complex and, in fact, varied between years and within the growing season. In addition, high doses of O(3) did not always have significant effects on leaf gas exchange. In view of the key findings, both hypotheses were to be rejected.

Both mature forest (MMPP) and young forest (YMPP) have lower sensitivity for stomatal regulation than half-mature forest (HMPP), and the maximum  stomatal conductance (gs) was found in trees with both small and large tree diameters at breast height

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成熟森林（MMPP）和幼稚森林（YMPP）对气孔调节的敏感性都比半成熟森林（HMPP）低，树木的最大气孔导度（gs）在胸径较小和较大的树木中被发现


Tanto a floresta madura (MMPP) quanto a floresta jovem (YMPP) têm menor sensibilidade para regulação estomática do que a floresta meio madura (HMPP), e a condutância estomática máxima (gs) foi encontrada em árvores com diâmetros de tronco pequenos e grandes à altura do peito.

Tanto el bosque maduro (MMPP) como el bosque joven (YMPP) tienen una menor sensibilidad para la regulación estomática que el bosque medio maduro (HMPP), y la conductancia estomática máxima (gs) se encontró en árboles con diámetros de tronco pequeños y grandes a la altura del pecho.

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Transpiration and canopy stomatal conductance dynamics of Mongolian pine plantations in semiarid deserts, Northern China

Deng J., Yao J., Zheng X., Gao G. (2021)

Jifeng Deng ab, Jiaqi Yao ab, Xiao Zheng ac, Guanglei Gao de,

a College of Forestry, Shenyang Agricultural University, Dongling St. 120, Shenyang, Liaoning Province 110866, People’s Republic of China

b Key Laboratory of Forest Tree genetics and Breeding of Liaoning Province, Dongling St. 120, Shenyang, Liaoning Province 110866, People’s Republic of China

c Forestry bureau, Fushun Mining Industry Group Co., Ltd, Qingnian East Road 25#, Fushun, Liaoning Province 210400, People’s Republic of China

d Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Qinghua East Road 35#, Beijing 100083, People’s Republic of China

e Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation (Beijing Forestry University), Beijing 100083, People’s Republic of China

===

Agricultural Water Management 249: 106806 – https://doi.org/10.1016/j.agwat.2021.106806 –

https://www.sciencedirect.com/science/article/abs/pii/S0378377421000718

Highlights

  • •Vapor pressure deficit is the main driving factor that affects transpiration rates.
  • •A canopy is well coupled to the atmosphere and transpiration rate.
  • •Old and young trees showed lower stomatal regulation upon water loss.
  • •Mature and young forests are more susceptible to decline under drought conditions.

Abstract

Mongolian pine (Pinus sylvestris var. mongolica) plantations have ecological significance for desertification control and degraded land restoration in drought-induced regions. To date, knowledge about the dynamics of transpiration and canopy stomatal conductance (gs) of Mongolian pine in the semiarid deserts in Northern China is quite limited. Thus, better understanding its physical response to environmental factors and exploring the mechanisms of forest transpiration can offer a theoretical basis for a reasonable tree planting program in semi-arid regions. In this study, transpiration and gs changes in Mongolian pine plantations for a mature forest (MMPP), half-mature forest (HMPP), and young forest (YMPP) were obtained using sap flow observations, while simultaneously monitoring the atmospheric and soil moisture contents. The results showed that the canopy transpiration per unit leaf area (EL) averaged 0.97 mm d–1, 0.60 mm d–1, and 0.45 mm d–1 in MMPP, HMPP, and YMPP, respectively, and the EL of Mongolian pine could be attributed to evaporative demand, soil moisture status, and gs. EL was obviously affected by air temperature, photosynthetic active radiation (PAR), and vapor pressure deficit (VPD) with the highest determined coefficient. The low values measured for the dimensionless coefficient (Ω = 0.041, 0.15, and 0.18) indicated that the canopy and the atmosphere were highly coupled. gs had more control over EL, and thus gs was more limited by VPD than that PAR. The average gs was 105.27, 105.26, and 99.44 mmol m–2 s–1 for MMPP, HMPP, and YMPP, respectively; Both MMPP and YMPP had lower sensitivity for stomatal regulation than HMPP, and the maximum gs was found in trees with both small and large tree diameters at breast height. Therefore, MMPP and YMPP were suspected to vary based on environmental conditions and were more susceptible to decline under mega drought conditions.

Estimation of the canopy stomatal conductance (gc) and photosynthetic rate (Pc) by first dividing the apple tree canopy into sunlit and shaded leaves and then summing the contribution of sunlit and shaded gl, Pl and leaf area index

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苹果树冠层气孔导度（gc）和光合速率（Pc）的估算首先将苹果树冠分为阳光照射和阴影叶，然后将阳光照射和阴影叶的贡献总和起来，包括光照叶和阴影叶的气孔导度（gl）、光合速率（Pl）和叶面积指数。

Estimativa da condutância estomática do dossel (gc) e da taxa fotossintética (Pc) primeiro dividindo o dossel da árvore de maçã em folhas iluminadas pelo sol e sombreadas e depois somando a contribuição das folhas iluminadas pelo sol e sombreadas, gl, Pl e índice de área foliar.

La estimación de la conductancia estomática del dosel (gc) y la tasa fotosintética (Pc) se realiza primero dividiendo el dosel del árbol de manzana en hojas iluminadas por el sol y sombreadas, y luego sumando la contribución de las hojas iluminadas por el sol y sombreadas, gl, Pl e índice de área foliar.

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Estimating canopy stomatal conductance and photosynthesis in apple trees by upscaling parameters from the leaf scale to the canopy scale in Jinzhong Basin on Loess Plateau

Gao G., Hao Y., Feng Q., Guo X., Shi J., Wu B. (2023)

Guanlong Gao abcd, Yulian Hao a, Qi Feng b, Xiaoyun Guo a, Junxi Shi a, Bo Wu a,

a College of Environment and Resource, Shanxi University, Taiyuan 030006, China

b Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China

c Shanxi Laboratory for Yellow River, Taiyuan 030006, China

d Academy of Water Resources Conservation Forests in Qilian Mountains of Gansu Province, Zhangye 734000, China

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Plant Physiology and Biochemistry 202: 107939 – https://doi.org/10.1016/j.plaphy.2023.107939 –

https://www.sciencedirect.com/science/article/abs/pii/S0981942823004503

Highlights

  • •Modified Jarvis model can estimate apple trees’ leaf stomatal conductance perfectly.
  • •New light–response model can estimate apple trees’ leaf photosynthetic rate ideally.
  • •Canopy conductance/photosynthetic rate can be obtained from sunlit and shaded leaves.

Abstract

The estimations of stomatal conductance and photosynthesis performed by upscaling the parameters from the leaf scale to the canopy scale are key points in the fields of forest ecohydrology and physiology. The foundation for solving this scientific problem is determining the optimal models for calculating the leaf stomatal conductance (gl) and photosynthetic rate (Pl). In this study, we used the Jarvis model combined with modification factors, including leaf–air temperature (ΔT) and CO2 concentration inside and outside the stomata (ΔC), to estimate gl and the new Ye light–response model to estimate the Pl of apple trees in Jinzhong Basin on Loess Plateau. The results show that the modified Jarvis (JarvisΔT-ΔC) model and the new Ye light–response model could estimate gl and Pl, respectively, with very high accuracy, with R2 values of 0.926 and 0.959 for the former, and 0.987 and 0.983 for the latter in 2019 and 2021, respectively. Then, we estimated the canopy stomatal conductance (gc) and photosynthetic rate (Pc) by first dividing the apple tree canopy into sunlit and shaded leaves and then summing the contribution of sunlit and shaded gl, Pl and leaf area index. Our efforts will be a valid reference for estimating the gc and Pc of other tree or crop species in the future.

Jarvis-type model parameterisations for estimating stomatal conductance (gs) in wheat (Triticum aestivum L.) under ambient [CO2] (a[CO2], approximately 390 μmol mol−1) and elevated [CO2] (e[CO2]

===============


Jarvis类型的模型参数化用于估算小麦（Triticum aestivum L.）在环境[CO2]（a[CO2]，约为390 μmol mol−1）和升高[CO2]（e[CO2]）条件下的气孔导度（gs）

Parametrizações do modelo tipo Jarvis para estimar a condutância estomática (gs) no trigo (Triticum aestivum L.) sob [CO2] ambiente (a[CO2], aproximadamente 390 μmol mol−1) e [CO2] elevado (e[CO2]).

Parametrizaciones del modelo tipo Jarvis para estimar la conductancia estomática (gs) en trigo (Triticum aestivum L.) bajo [CO2] ambiente (a[CO2], aproximadamente 390 μmol mol−1) y [CO2] elevado (e[CO2]).

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Modelling stomatal conductance of wheat: An assessment of response relationships under elevated CO2

Houshmandfar A., Fitzgerald G. J., Armstrong R., Macabuhay A. A., Tausz M. (2015)

Alireza Houshmandfar a, Glenn J. Fitzgerald b, Roger Armstrong b, Allene A. Macabuhay a, Michael Tausz c,

a Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, Victoria 3363, Australia

b Agriculture Research Division, Victoria Department of Economic Development, Jobs, Transport and Resources, Horsham, Victoria 3401, Australia

c Department of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, Victoria 3363, Australia

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Agricultural and Forest Meteorology 214–215: 117-123 – https://doi.org/10.1016/j.agrformet.2015.08.249 – 

https://www.sciencedirect.com/science/article/abs/pii/S0168192315006814 

Highlights

  • •Jarvis-type model parameterisations need to be tested for elevated [CO2] conditions.
  • •Model functions are different for ambient and elevated [CO2] grown wheat.
  • •Multiplicative model parametrisation for wheat under elevated [CO2] is proposed.

Abstract

This study proposes Jarvis-type model parameterisations for estimating stomatal conductance (gs) in wheat (Triticum aestivum L.) under ambient [CO2] (a[CO2], approximately 390 μmol mol−1) and elevated [CO2] (e[CO2], approximately 550 μmol mol−1), based on measurements collected in the Australian Grains Free Air CO2 Enrichment (AGFACE) facility. Relationships of gs with phenological and environmental factors were evaluated using a boundary line technique. Results suggest that gs-response functions for vapour pressure deficit (VPD), volumetric soil moisture (VSM) and temperature dependence were different between a[CO2] and e[CO2]: VPD induced stomatal closure at approximately 3 and 2.5 kPa under a[CO2] and e[CO2] respectively, and optimum temperature was 2 °C lower under e[CO2]. Elevated [CO2] decreased maximum gs (gmax) by approximately 35%.

Generalized stomatal response patterns of the herbaceous growth form, the dependence of the variables’ age and ozone dose and the lack of an important factor influencing stomatal response in the model, are suggested as explanations of the poor results of the test

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草本植物生长形态的气孔反应模式普遍存在，变量的年龄和臭氧剂量依赖性以及模型中缺乏重要因素对气孔反应的影响，被认为是测试结果不佳的解释。


Os padrões generalizados de resposta estomática da forma de crescimento herbáceo, a dependência da idade das variáveis e da dose de ozônio, e a falta de um fator importante que influencia a resposta estomática no modelo, são sugeridos como explicações para os resultados insatisfatórios do teste.

Se sugieren los patrones generalizados de respuesta estomática de la forma de crecimiento herbácea, la dependencia de la edad de las variables y la dosis de ozono, así como la falta de un factor importante que influya en la respuesta estomática en el modelo, como explicaciones de los resultados deficientes del test.

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Modelling stomatal responses of spring wheat (Triticum aestivum L. cv. Turbo) to ozone and different levels of water supply

Grüters U., Fangmeier A., Jäger H.-J. (1995)

Institut für Pflanzenökologie, Heinrich-Buff-Ring 38, D-35392 Gießen, Germany

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Environmental Pollution 87(2): 141-149 – https://doi.org/10.1016/0269-7491(94)P2600-E –

https://www.sciencedirect.com/science/article/abs/pii/0269749194P2600E?via%3Dihub

Abstract

Spring wheat (Triticum aestivum L. cv. Turbo) was exposed to different levels of ozone and water supply in open-top chambers in 1991. Air was charcoal filtered (CF), non-filtered (NF) and CF plus proportional addition of ambient or twice ambient ozone (CF1, CF2). Seasonal means of O3, taken over 24 h, were 2·3, 20·6, 17·3, and 34·5 nl litre−1 for CF, NF, CF1 and CF2 treatments, respectively. A split-plot design was used to obtain two levels of water supply: one-half of the pots was irrigated sufficiently not to show any symptoms of drought stress; the others were exposed to low water supply and received 50% of these amounts.

Using a steady-state porometer approximately 800 measurements of stomatal conductance (gs) were made on flag leaves from 68 to 106 days after sowing. The measurements yielded only small differences of maximum conductance between the two levels of water supply. Therefore, low water supply did not protect wheat plants against ozone injury via reduced stomatal uptake in this experiment. To describe the effects of environmental variables on the stomatal behaviour, boundary-line analysis and non-linear regression analysis were used. Besides microclimatic parameters, the ozone dose of flag leaves was introduced as an independent variable affecting stomatal aperture. A well-defined boundary line for ozone dose was found, suggesting that increasing ozone dose caused stomatal closure in wheat flag leaves. But at high ozone doses, co-acting senescence seems also responsible for the decrease in stomatal conductance.

A multiplicative boundary-line model was used to predict stomatal conductance from combinations of environmental variables. In the test carried out with the measurements of stomatal conductance, the model accounted only for 40% of the variation of gs. Generalized stomatal response patterns of the herbaceous growth form, the dependence of the variables’ age and ozone dose and the lack of an important factor influencing stomatal response (water status of the plant) in the model, are suggested as explanations of the poor results of the test.

A loss of ozone-induced stomatal closure after ozone exposure in the late growing season should be considered in modeling stomatal ozone uptake for the assessment of ozone impacts on Siebold’s beech

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致考虑季末致臭氧暴露后的臭氧引发的气孔关闭，在模拟对西奥氏枫的臭氧气孔吸收以评估臭氧对其影响时。


Uma perda de fechamento estomático induzido por ozônio após exposição ao ozônio no final da estação de crescimento deve ser considerada na modelagem da absorção estomática de ozônio para a avaliação dos impactos do ozônio na faia de Siebold.

Una pérdida de cierre estomático inducido por el ozono después de la exposición al ozono en la temporada de crecimiento tardía debería considerarse al modelar la absorción estomática de ozono para la evaluación de los impactos del ozono en el haya de Siebo

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Effects of ozone-induced stomatal closure on ozone uptake and its changes due to leaf age in sun and shade leaves of Siebold’s beech

Hoshika Y., Watanabe M., Inada N., Koike T. (2015)

Journal of Agricultural Meteorology 71: 218–226 – https://doi.org/10.2480/agrmet.D-14-00013 –

https://www.jstage.jst.go.jp/article/agrmet/71/3/71_D-14-00013/_article

Abstract

An estimation of stomatal ozone uptake for the assessment of ozone risks in forest trees can be modified by ozone-induced stomatal closure. We thus examined a seasonal course of stomatal conductance in sun and shade leaves of Siebold’s beech native to northern Japan (Fagus crenata) grown under free-air ozone exposure. A performance of multiplicative stomatal conductance model was also tested, when considering ozone-induced stomatal closure into the model. Ozone caused stomatal closure in both sun and shade leaves (20% and 30-40% reduction of stomatal conductance in sun and shade leaves, respectively) during early summer. However, in autumn, stomatal closure was diminished regardless of canopy positions (approximately 7% and 6% reduction of stomatal conductance in sun and shade leaves, respectively). When observed seasonal course of stomatal closure was taken into account in stomatal conductance model, the model provided a good agreement with measurements even under conditions of elevated ozone. As a result, ozone-induced stomatal closure limited stomatal ozone uptake by 11% and 17% in sun and shade leaves of Siebold’s beech, respectively. In addition, stomatal ozone uptake in shade leaves under elevated ozone was much less than that in sun leaves (35% of the value in sun leaves), indicating better avoidance of ozone stress in shade leaves. Our results suggest that a loss of ozone-induced stomatal closure after ozone exposure in the late growing season should be considered in modeling stomatal ozone uptake for the assessment of ozone impacts on Siebold’s beech.