Academic literature on the topic 'Stomatal conductance'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Stomatal conductance.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Stomatal conductance"
1
Eensalu, Eve, Priit Kupper, Arne Sellin, Märt Rahi, Anu Sõber, and Olevi Kull. "Do stomata operate at the same relative opening range along a canopy profile of Betula pendula?" Functional Plant Biology 35, no. 2 (2008): 103. http://dx.doi.org/10.1071/fp07258.
Full textAbstract:
Stomatal density and size were measured along the light gradient of a Betula pendula Roth. canopy in relation to microclimatic conditions. The theoretical stomatal conductance was calculated using stomatal density and dimensions to predict to what degree stomatal conductance is related to anatomical properties and relative stomatal opening. Stomatal density was higher and leaf area smaller in the upper canopy, whereas epidermal cell density did not change significantly along the canopy light gradient, indicating that stomatal initiation is responsible for differences in stomatal density. Stomatal dimensions – the length of guard cell on the dorsal side and the guard cell width – decreased with declining light availability. Maximum measured stomatal conductance and modelled stomatal conductance were higher at the top of the crown. The stomata operate closer to their maximum openness and stomatal morphology is a more important determinant of stomatal conductance in the top leaves than in leaves of lower canopy. As stomata usually limit photosynthesis more in upper than in lower canopy, it was concluded that stomatal morphology can principally be important for photosynthesis limitation in upper canopy.
2
Aasamaa, Krõõt, Anu Sõber, and Märt Rahi. "Leaf anatomical characteristics associated with shoot hydraulic conductance, stomatal conductance and stomatal sensitivity to changes of leaf water status in temperate deciduous trees." Functional Plant Biology 28, no. 8 (2001): 765. http://dx.doi.org/10.1071/pp00157.
Full textAbstract:
Some anatomical characteristics in leaves relating to hydraulic conductance and stomatal conductance were examined in six temperate deciduous tree species. The fourth power of the radius of the conducting elements in xylem (r4) and the area of mesophyll and epidermal cells per unit length of leaf cross-section (u) were high in leaves with high hydraulic conductance (L). Stomatal conductance (gs) and stomatal sensitivity to an increase in leaf water potential (si) correlated positively with the length of stomatal pore (l), but negatively with the guard cell width (z) and the length of the dorsal side of the guard cells (ld). Stomatal sensitivity to a decrease in leaf water potential (sd) correlated negatively with l and positively with z and ld. The anatomical characteristics associated with hydraulic conductance (r4 and u) and those associated with stomatal conductance and sensitivity to changes of leaf water potential (l, z and ld) were correlated. We conclude that hydraulic conductance may depend on anatomical characteristics of xylem, mesophyll and epidermis, and stomatal conductance and its sensitivity to changing water potential may depend on anatomical characteristics of stomata. The correlation of shoot hydraulic conductance with stomatal conductance and its sensitivity may be based largely on the correlation between the anatomical characteristics of the water conducting system and stomata in these trees.
3
Shackel, K. A., V. Novello, and E. G. Sutter. "Stomatal Function and Cuticular Conductance in Whole Tissue-cultured Apple Shoots." Journal of the American Society for Horticultural Science 115, no. 3 (1990): 468–72. http://dx.doi.org/10.21273/jashs.115.3.468.
Full textAbstract:
The relative contribution of stomatal and cuticular conductance to transpiration from whole tissue-cultured apple shoots of Malus pumila Mill. M.26 was determined with a modified steady state porometer. When shoots were exposed to 90% RH and high boundary layer conductance, large (73%) and, in some eases, rapid (2 to 3 hours) reductions in leaf conductance occurred, indicating functional stomata. Stomatal closure was also observed microscopically. A maximum estimate for the cuticular conductance of these apple leaves was 18 to 40 mmol·m-2·s-1, which is lower than previous estimates and close to the upper limit of naturally occurring leaf cuticular conductances. Hence, both stomatal and cuticular restrictions of water loss appear to be of importance in determining the water balance of tissue-cultured apple loots. The pathway of water transport in relation to water stress of tissue-cultured shoots is also discussed.
4
Munger, Philip H., James M. Chandler, and J. Tom Cothren. "Effect of Water Stress on Photosynthetic Parameters of Soybean (Glycine max) and Velvetleaf (Abutilon theophrasti)." Weed Science 35, no. 1 (1987): 15–21. http://dx.doi.org/10.1017/s0043174500026722.
Full textAbstract:
Greenhouse experiments were conducted to elucidate the effects of water stress on photosynthetic parameters of soybean [Glycine max(L.) Merr. ‘Hutton′] and velvetleaf (Abutilon theophrastiMedik. # ABUTH). Stomatal conductance of both species responded curvilinearly to reductions in leaf water potential. At leaf water potentials less negative than −2.5 MPa, stomatal conductance, net photosynthetic rate, and transpiration rate were greater in velvetleaf than in soybean. Soybean photosynthetic rate was linearly related to stomatal conductance. Velvetleaf photosynthetic rate increased linearly with stomatal conductances up to 1.5 cm s–1; however, no increase in photosynthetic rate was observed at stomatal conductances greater than 1.5 cm s–1, indicating nonstomatal limitations to photosynthesis. As water stress intensified, stomatal conductance, photosynthetic rate, and transpiration of velvetleaf declined more rapidly than in soybean.
5
Ceulemans, R., I. Impens, and R. Imler. "Stomatal conductance and stomatal behavior in Populus clones and hybrids." Canadian Journal of Botany 66, no. 7 (1988): 1404–14. http://dx.doi.org/10.1139/b88-196.
Full textAbstract:
Responses of abaxial, adaxial, and total leaf conductance to incident photosynthetic photon flux density, solar irradiance, and changing leaf water potential, as well as diurnal and seasonal patterns of stomatal conductances, were examined under field conditions for six Populus clones. Clones belonged to the species P. trichocarpa and to different interspecific crossings including P. deltoides, P. nigra, and P. maximowiczii. Black Cottonwood clone Columbia River showed stomatal behavior different from other clones in many aspects: (i) it was the only clone with hypostomatous leaves; (ii) its stomata remained open for a longer period of time, both diurnally and seasonally; (iii) the hysteresis effect in stomatal response to solar irradiance during the day was less pronounced; and (iv) its stomata showed hardly any response to declining leaf water potential. Leaf area duration and seasonal stomatal activity showed considerable clonal differences, which are in agreement with girth growth increment patterns. Clone Columbia River showed a much longer leaf life-span with considerable stomatal activity near late autumn, which might explain the substantial late-autumn girth growth increment of this clone.
6
Monje, Oscar, and Bruce Bugbee. "Radiometric Method for Determining Canopy Stomatal Conductance in Controlled Environments." Agronomy 9, no. 3 (2019): 114. http://dx.doi.org/10.3390/agronomy9030114.
Full textAbstract:
Canopy stomatal conductance is a key physiological factor controlling transpiration from plant canopies, but it is extremely difficult to determine in field environments. The objective of this study was to develop a radiometric method for calculating canopy stomatal conductance for two plant species—wheat and soybean from direct measurements of bulk surface conductance to water vapor and the canopy aerodynamic conductance in controlled-environment chambers. The chamber provides constant net radiation, temperature, humidity, and ventilation rate to the plant canopy. In this method, stepwise changes in chamber CO2 alter canopy temperature, latent heat, and sensible heat fluxes simultaneously. Sensible heat and the radiometric canopy-to-air temperature difference are computed from direct measurements of net radiation, canopy transpiration, photosynthesis, radiometric temperature, and air temperature. The canopy aerodynamic conductance to the transfer of water vapor is then determined from a plot of sensible heat versus radiometric canopy-to-air temperature difference. Finally, canopy stomatal conductance is calculated from canopy surface and aerodynamic conductances. The canopy aerodynamic conductance was 5.5 mol m−2 s−1 in wheat and 2.5 mol m−2 s−1 in soybean canopies. At 400 umol mol−1 of CO2 and 86 kPa atmospheric pressure, canopy stomatal conductances were 2.1 mol m−2 s−1 for wheat and 1.1 mol m−2 s−1 for soybean, comparable to canopy stomatal conductances reported in field studies. This method measures canopy aerodynamic conductance in controlled-environment chambers where the log-wind profile approximation does not apply and provides an improved technique for measuring canopy-level responses of canopy stomatal conductance and the decoupling coefficient. The method was used to determine the response of canopy stomatal conductance to increased CO2 concentration and to determine the sensitivity of canopy transpiration to changes in canopy stomatal conductance. These responses are useful for improving the prediction of ecosystem-level water fluxes in response to climatic variables.
7
Leuning, R. "Modelling Stomatal Behaviour and and Photosynthesis of Eucalyptus grandis." Functional Plant Biology 17, no. 2 (1990): 159. http://dx.doi.org/10.1071/pp9900159.
Full textAbstract:
Stomatal conductances, CO2 assimilation, transpiration and intercellular CO2 mol fractions of Eucalyptus grandis leaves were measured in the field using a portable, controlled environment cuvette. Test leaves were subjected to a range of temperatures, humidities, photon irradiances and external CO2 mol fractions. An empiral function, gsw = g0 + g1 Ahs/(cs-I'), was able to account for steady- state stomatal conductances g*sw, over a wide range of environmental conditions and leaf photosynthetic capacities. In this equation, termed the stomatal constraint function, A is CO2 assimilation rate, hs and cs are relative humidity and CO2 mol fraction at the leaf surface respectively, I' is the CO2 compensation point, g0 is conductance at A = 0 and gl is an empirical coefficient. Equations describing the supply of CO2 through stomata and demand for CO2 in photosynthesis were solved simultaneously with the constraint function to give a combined model of stomatal conductance, CO2 assimilation and intercellular CO2 mol fraction in terms of external environmental factors and several parameters describing C3 photosynthesis. The model provided a good description of experimental observations.
8
Brodribb, Tim, and Robert S. Hill. "Imbricacy and Stomatal Wax Plugs Reduce Maximum Leaf Conductance in Southern Hemisphere Conifers." Australian Journal of Botany 45, no. 4 (1997): 657. http://dx.doi.org/10.1071/bt96060.
Full textAbstract:
An examination of the relationship between theoretical maximum leaf conductance as calculated from stomatal dimensions, and measured maximum leaf conductance was undertaken in a group of Southern Hemisphere conifers. The relative effects of stomatal wax plugs, found in most species of conifers in the Southern Hemisphere, and imbricate leaf arrangement were expressed as a percentage inhibition of maximum leaf conductance (gmax) calculated from the ratio of measured gmax to theoretical gmax Because of the similar stomatal dimensions of all species, measured gmax was proportional to stomatal density in plugged and unplugged species, with species without wax plugs producing maximum leaf conductances on average 91% of calculated gmax, while in species with plugged stomata measured gmax was on average only 35% of theoretical gmax. There was no effect produced by imbricacy in itself, but when combined with epistomy, gmax was significantly reduced to about 17% of theoretical gmax. This is clearly illustrated by comparisons of juvenile-adult foliage, and closely related imbricate and non-imbricate species. The adaptational advantages of imbricacy and wax plugs, and the potential for inferring gmax of fossil taxa are discussed.
9
Zhang, Qiangqiang, Shaobing Peng, and Yong Li. "Increase rate of light-induced stomatal conductance is related to stomatal size in the genus Oryza." Journal of Experimental Botany 70, no. 19 (2019): 5259–69. http://dx.doi.org/10.1093/jxb/erz267.
Full textAbstract:
Abstract The rapid response of stomatal conductance (gs) to fluctuating irradiance is of great importance to maximize carbon assimilation while minimizing water loss. Smaller stomata have been proven to have a faster response rate than larger ones, but most of these studies have been conducted with forest trees. In the present study, the effects of stomatal anatomy on the kinetics of gs and photosynthesis were investigated in 16 Oryza genotypes. Light-induced stomatal opening includes an initial time lag (λ) followed by an exponential increase. Smaller stomata had a larger maximum stomatal conductance increase rate (Slmax) during the exponential increase phase, but showed a longer time lag and a lower initial stomatal conductance (gs,initial) at low light. Stomatal size was, surprisingly, negatively correlated with the time required to reach 50% of maximum gs and photosynthesis (T50%gs and T50%A), which was shown to be positively correlated with λ and negatively correlated with gs,initial. With a lower gs,initial and a larger λ, small stomata showed a faster decrease of intercellular CO2 concentration (Ci) during the induction process, which may have led to a slower apparent Rubisco activation rate. Therefore, smaller stomata do not always benefit photosynthesis as reported before; the influence of stomatal size on dynamic photosynthesis is also correlated with λ and gs,initial.
10
Zhang, Dandan, Caijuan Tian, Kangquan Yin, Wenyi Wang, and Jin-Long Qiu. "Postinvasive Bacterial Resistance Conferred by Open Stomata in Rice." Molecular Plant-Microbe Interactions® 32, no. 2 (2019): 255–66. http://dx.doi.org/10.1094/mpmi-06-18-0162-r.
Full textAbstract:
Stomata are leaf pores that regulate gas exchange and water transpiration in response to environmental cues. They also function in innate immunity by limiting pathogen entry through actively closing in so-called stomatal defense. However, roles of stomata in plant disease resistance are not fully elucidated, especially in monocots. Here, we report that non–race specific resistance of the rice abscisic acid-deficient mutant Osaba1 to Xanthomonas oryzae pv. oryzae is due to increased stomatal conductance. Reducing stomatal conductance in the Osaba1 mutant increases its susceptibility to X. oryzae pv. oryzae. Artificial opening of stomata in wild-type plants leads to enhanced resistance to X. oryzae pv. oryzae. The rice mutant es1-1 with constitutively higher stomatal conductance exhibits strong resistance to X. oryzae pv. oryzae. Additionally, Osaba1 and es1-1 are resistant to X. oryzae pv. oryzicola. The data support that open stomata confer postinvasive resistance against bacterial pathogens in rice, and such resistance probably results from decreased leaf water potential. Our findings reveal a novel role of stomata in plant immunity through modulation of leaf water status, which provides physiological insight into the interactions between plant, pathogen, and environment.
Dissertations / Theses on the topic "Stomatal conductance"
1
Matsumoto, Kazuho, Takeshi Ohta, and Takafumi Tanaka. "Dependence of stomatal conductance on leaf chlorophyll concentration and meteorological variables." Elsevier, 2005. http://hdl.handle.net/2237/6964.
Full text
2
Dumont, Jennifer. "Rôle de la régulation stomatique et de la capacité de détoxication foliaire dans l'estimation d'un seuil de risque à l'ozone pour la végétation." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0022/document.
Full textAbstract:
L'ozone troposphérique est un polluant atmosphérique majeur qui agit comme une phytotoxine. Il pénètre dans les feuilles par les stomates avant d'être dissout dans l'apoplaste en générant des radicaux libres oxygénés (ROS) provoquant ainsi un stress oxydatif. Deux barrières existent pour restreindre les effets de l'ozone : (i) les stomates qui peuvent limiter les flux entrants par contrôle de la conductance stomatique et (ii) le système de détoxication des ROS issus de la dégradation de l'ozone. Nous avons étudié les effets de l'ozone (120 ppb) sur ces deux moyens de défense chez trois génotypes de peuplier euraméricain (Populus deltoides x Populus nigra) placés en conditions contrôlées dans des chambres phytotroniques. Un effet direct de l'ozone sur la photosynthèse et sur les mouvements stomatiques en réponse à des variations de facteurs environnementaux (ralentissement des phénomènes d'ouverture et de fermeture) a été mis en évidence. Les modèles de calcul de la conductance stomatique, sur lesquels se basent les indicateurs de seuil de risque à l'ozone pour la végétation, doivent donc les prendre en compte. De plus, ces travaux ont mis en évidence le rôle prépondérant des concentrations constitutives en antioxidants dans la tolérance à l'ozone ainsi que la complexité de ces mécanismes de détoxication. La notion de flux effectif d'ozone doit prendre en considération ces deux aspects afin de caractériser au mieux les différences de sensibilité à l'ozone intra et inter spécifique<br>Tropospheric ozone is a major air pollutant that acts as a phytotoxin. It enters the leaf through the stomata before being dissolved in the apoplast by generating reactive oxygen species (ROS) causing oxidative stress. Two defenses exist to restrict the effects of ozone: (i) the stomata which can limit ozone uptake by regulating stomatal conductance and (ii) the detoxification processes of ROS generated by ozone.We studied the effects of ozone (120 ppb) on these two mechanisms of defense in three euramerican poplar genotypes (Populus deltoides x Populus nigra) under controlled conditions in phytotronic chambers. A direct effect of ozone on photosynthesis and stomatal movements in response to changes in environmental factors (by slowing the stomatal opening and closure) has been highlighted. Models of stomatal conductance, on which indicators of critical level of ozone for vegetation are based, must take them into account. In addition, these studies have highlighted the role of constitutive concentrations of antioxidants in tolerance to ozone as well as the complexity of these detoxification mechanisms. The notion of effective ozone flux must consider these two aspects to better characterize the intra-and inter-specific differences in sensitivity to ozone
3
Cornish, Katrina, Phenmin Lu, John W. Radin, Edgar L. Turcotte, and Eduardo Zeiger. "Photosynthetic Rate and Stomatal Conductance are Related to Heat Tolerance in Pima Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/208325.
Full textAbstract:
Breeding for high yield in hot environments (heat tolerance) has tripled the yield of Pirna cotton since 1949. We compared six strains (one primitive non-cultivated line, four cultivars representing advancing stages in the breeding process, and one unreleased advanced line) for their gas exchange properties in the greenhouse. Both photosynthetic rate and stomatal conductance increased with improving genetic yield potential. Photosynthetic rate was enhanced more in the morning than in the afternoon. Stomatal conductance did not limit photosynthesis; rather, the changes resulted from alterations of characteristics of the green mesophyll cells. There is no evidence that increased yield results from the enhanced photosynthetic rates of single leaves. However, the increased stomatal conductance in modem lines was also expressed in the field in 1990, allowing increased transpiration rate and evaporative cooling of leaves. Heat tolerance in Pima cotton may be related to the ability of plants to cool themselves by transpiration.
4
Miranda, Barradas Victor Luis. "Responses to leaf microenvironment dynamics : their implications for photosynthesis and transpiration." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260603.
Full text
5
Ramos, Antônio Mário de Torres. "O papel da histerese no comportamento complexo da condutância estomática." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-06102014-135524/.
Full textAbstract:
Estômatos são poros responsáveis pela troca gasosa entre a folha e o meio externo. A partir da década de 80, experimentos revelaram um complexo padrão espaço temporal na abertura e fechamento dos estômatos. As experiências apontam para uma possível coordenação entre estômatos em algumas áreas da folha chamada de patches. Esse fenômeno é conhecido na literatura como patchy stomatal conductance. Frequentemente a coordenação dinâmica dos estômatos está associada à oscilações temporais na condutãncia estomática (média especial da abertura dos estômatos). Em 1997 Haefner, Buckley e Mott (HBM) publicaram uma análise numérica de um modelo dinâmico para explorar o comportamento complexo dos estômatos. O modelo é baseado em algumas características conhecidas dos estômatos e assume transporte hídrico em uma rede definida por uma geometria simples e bastante restritiva. De acordo com os autores, o modelo reproduz qualitativamente os dados experimentais. Recentemente, Ferraz e Prado mostraram que esse modelo não é capaz de reproduzir os resultados experimentais. Usando ingredientes do modelo sugerido por HBM, Ferraz e Prado sugeriram uma geometria realística de distribuição reservatórios hídricos. Embora essa configuração reproduza os patches, eles permanecem estáticos e nenhuma oscilação é observada. Sem explorar detalhes significativos, Ferraz e Prado afirmaram que a histerese na abertura estomatal poderia explicar vários aspectos dos resultados experimentais. No presente estudo comprovamos, através de uma abordagem computacional baseada em transdutores histeréticos, que a hipótese de histerese na abertura dos estômatos de fato reproduz qualitativamente os dados experimentais. Em nossa abordagem a histerese na abertura dos estômatos é emulada através de operadores chamados de histerons. A robustez da hipótese é testada usando diferentes tipos de histerons. Analisamos a correlação entre os estômatos na rede que simula a superfície da folha. Observamos que a correlação entre estômatos depende da geometria da veia. Uma análise detalhada dos parâmetros envolvidos revela uma dependência entre o período de oscilação na condutância estomática e o déficit de vapor d\'água entre a folha e o meio ambiente. Esta característica subjacente ao modelo pode inspirar novas experiências para testar a hipótese da histerese na abertura dos estômatos.<br>Stomata are pores on the surface of leaves responsible for controlling the exchange of gas between the plant and the environment. Experiments revealed a complex spatial-temporal pattern in the opening and closing mechanism of stomata. The main feature of the phenomenon is that stomata appear to be synchronized into clusters, known as patches. The dynamical coordination of stomata often involves oscillations in stomatal conductance. In 1997 Haefner, Buckley, and Mott (HBM) published a numerical analysis of a dynamic model to explore the complex behavior of stomata. The model is based on some known features of the stomata, and assumes that water diffuses within the leaves according to a simple geometric arrangement. According to the authors, the model reproduces qualitatively the experimental data. Recently, Ferraz and Prado showed that the computational approach of HBM is not able to reproduce the experimental results. Inspired by this model, Ferraz and Prado introduced a new geometric features that leads to static patches of stomata; however no oscillation was observed and the patches remained static. The authors suggested that hysteresis in stomatal aperture could explain several experimental aspects. We now report a further investigation of the changes suggested by Ferraz and Prado in the original model of HBM. The theoretical approach confirmed that hysteresis in the aperture mechanism of pores reproduces a variety of behaviors of stomatal conductance described in experiments. We explore the hysteresis feature through the formalism of hysteretic transducer. The robustness of the hysteretic assumption is tested by different kinds of hysteresis operators. We analyzed the correlation among stomata in the lattice. We observed that the correlation depends on the geometry of the veins. Finally, the analysis of the model reveals a dependence between the period of oscillation in the stomatal conductance time series and water vapor pressure deficits Δω - an external parameter. Further experiments might explore this underlying feature of the model.
6
Sakoda, Kazuma. "Physiological and Genetic Factors for High Leaf Photosynthetic Capacity in Soybean (Glycine max (L.) Merr.)." Kyoto University, 2019. http://hdl.handle.net/2433/242682.
Full text
7
Wehr, Richard, Róisín Commane, J. William Munger, et al. "Dynamics of canopy stomatal conductance, transpiration, and evaporation in a temperate deciduous forest, validated by carbonyl sulfide uptake." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/623091.
Full textAbstract:
Stomatal conductance influences both photosynthesis and transpiration, thereby coupling the carbon and water cycles and affecting surface–atmosphere energy exchange. The environmental response of stomatal conductance has been measured mainly on the leaf scale, and theoretical canopy models are relied on to upscale stomatal conductance for application in terrestrial ecosystem models and climate prediction. Here we estimate stomatal conductance and associated transpiration in a temperate deciduous forest directly on the canopy scale via two independent approaches: (i) from heat and water vapor exchange and (ii) from carbonyl sulfide (OCS) uptake. We use the eddy covariance method to measure the net ecosystem–atmosphere exchange of OCS, and we use a flux-gradient approach to separate canopy OCS uptake from soil OCS uptake. We find that the seasonal and diurnal patterns of canopy stomatal conductance obtained by the two approaches agree (to within ±6 % diurnally), validating both methods. Canopy stomatal conductance increases linearly with above-canopy light intensity (in contrast to the leaf scale, where stomatal conductance shows declining marginal increases) and otherwise depends only on the diffuse light fraction, the canopy-average leaf-to-air water vapor gradient, and the total leaf area. Based on stomatal conductance, we partition evapotranspiration (ET) and find that evaporation increases from 0 to 40 % of ET as the growing season progresses, driven primarily by rising soil temperature and secondarily by rainfall. Counterintuitively, evaporation peaks at the time of year when the soil is dry and the air is moist. Our method of ET partitioning avoids concerns about mismatched scales or measurement types because both ET and transpiration are derived from eddy covariance data. Neither of the two ecosystem models tested predicts the observed dynamics of evaporation or transpiration, indicating that ET partitioning such as that provided here is needed to further model development and improve our understanding of carbon and water cycling.
8
Rzigui, Touhami. "Analyse de la réponse d’un mutant mitochondrial de Nicotiana sylvestris au manque d’eau." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112144/document.
Full textAbstract:
Pour étudier le rôle de la mitochondrie dans la tolérance à la sécheresse, la réponse à la contrainte hydrique a été comparée entre une lignée sauvage (WT) et un mutant CMSII (Cytoplasmic Male Sterile) de Nicotiana sylvestris. Chez le mutant CMSII, le complexe I mitochondrial est absent et la respiration est assurée par les NAD(P)H déshydrogénases alternes et elle est maintenue à un niveau supérieur de l’ordre de 20 à 30% à celui du WT. La différence observée entre les plantes WT et CMSII met en jeu non seulement le fonctionnement mitochondrial, mais également le fonctionnement des chloroplastes. En effet, l’activité photosynthétique du mutant est plus faible que celui du WT et elle est corrélée avec une plus faible conductance stomatique (gs) et mésophyllienne (gm).Après l’arrêt de l’arrosage, on observe que le contenu relatif en eau (RWC) diminue plus lentement chez les feuilles du CMSII. Ceci n’était pas le résultat d’une plus petite surface de transpiration ou d’une masse racinaire d’absorption plus élevé puisque le rapport partie aérienne/racine et la surface foliaire totale ont été similaires au début de l’expérience chez les deux génotypes. De plus la mutation n’a pas induit des changements au niveau des paramètres hydriques (P0, PTLP, RWCTLP) ni au niveau de la densité stomatique. La tolérance des plantes CMSII a été le plus probablement la conséquence de sa plus faible transpiration en conditions bien hydratées et aux premiers jours de déshydratation et non pas d’une meilleure efficacité d’absorption de l’eau puisque le contenu en eau du sol reste plus élevé chez CMSII après l’arrêt de l’arrosage. La plus faible conductance stomatique chez le CMSII bien hydraté a été expliquée par sa plus faible conductance hydraulique. De plus, contrairement au WT, le niveau des acides aminés totaux diminue au cours de la déshydratation lorsque le contenu en protéines solubles augmente chez les feuilles du CMSII, suggérant une accélération de la remobilisation des acides aminés. D’autre part, il a été aussi montré que le mutant CMSII est capable de s’acclimater mieux à la sécheresse que le WT lorsqu’ils ont été maintenus à un RWC de 80 % sur plusieurs jours. Sous ces conditions, la photosynthèse reste plus élevée chez le mutant que chez le WT. Cette meilleure acclimatation corrèle avec une plus forte photorespiration du CMSII sous conditions bien hydratées et sous conditions d’acclimatation. La photorespiration chez CMSII et le WT a été estimée par le transport électronique dévolu à l’oxygénation de RuBP et en plus par l’accumulation des métabolites impliqués dans la photorespiration. D’une part, l’acclimatation à la sécheresse diminue gm plus fortement chez le WT que chez le CMSII. D’autre part, le WT accumule la glycine ce qui laisse supposer que le glycine décarboxylase mitochondrial est plus affectée chez le WT que chez le CMS et inhibe ainsi la photorespiration. En effet, cette plus faible photorespiration chez le WT affecte les réactions primaires de la photosynthèse par une accumulation d’un gradient de protons estimé par le quenching non-photochimique (NPQ) de la fluorescence chlorophyllienne ce qui induit une diminution du transport électronique des réactions primaires de la photosynthèse<br>To investigate the role of mitochondria in drought stress, the response to water deprivation was compared between Nicotiana sylvestris wild type (WT) plants and the CMSII respiratory complex I mutant. In CMSII, alternative NAD(P)H-dehydrogenases bypassing complex 1 allow respiration.. The difference of mitochondrial function between WT and CMSII plants affect also photosynthesis. The CMSII has lower photosynthetic actitvity than the WT and lower stomatal (gs) and internal (gm) conductances to CO2. When watering of plants with similar leaf surface and similar shoot/root ratio was stopped the relative water content (RWC) declined faster in WT as compared to CMSII leaves. Furthermore, CMSII and WT leaves had the same osmotic potential at leaf saturation (P0) and at leaf turgor lost pressure (PTLP) and the same stomatal density. The slower decline of RWC in CMSII, compared to WT leaves, was most likely the consequence of the lower stomatal conductance (gs) under well-watered conditions and during the first days after withholding watering, The lower stomatal conductance of well-watered CMSII leaves correlated with a lower hydraulic conductance of leaves. Remarkably, total free amino acid levels declined and total soluble protein content increased in CMSII leaves, while the opposite was observed in WT leaves. This suggests protein synthesis in CMSII but protein degradation in WT leaves during drought stress. We also show that CMSII leaves better acclimate to drought stress than the WT leaves. After several days at 80 % RWC , photosynthesis is higher in the mutant than in WT. As compared to the WT, the mutant shows higher rates of photorespiration before and after acclimation to drought.The strong accumulation of glycine in the WT suggests that photorespiration may be limited at the level of glycine decarboxylase. In addition, after acclimation to drought gm declined markedly in WT but not in CMSII leaves, thus further limiting CO2 supply for photosynthesis in the WT. The resulting lower photosynthesis and photorespiration in WT leaves affect also the primary reaction of photosynthesis by increasing the non-photochemical fluorescence quenching (NPQ) and decreasing linear electron transport
9
Nwugo, Chika Charles. "Physiological and Molecular Studies on Silicon-Induced Cadmium Tolerance in Rice (Oryza sativa L.)." Oxford, Ohio : Miami University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1216779093.
Full text
10
Vialet-Chabrand, Silvère. "Modélisation des variations journalières de la conductance stomatique : apport d'une approche dynamique et conséquences sur l'efficience intrinsèque d'utilisation de l'eau chez le chêne." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0146/document.
Full textAbstract:
L'efficience intrinsèque d'utilisation de l'eau (Wi) définit comme le rapport de l'assimilation nette de CO2 (A) sur la conductance stomatique à la vapeur d'eau (gs) est un estimateur au niveau foliaire du compromis fait par la plante entre l'accumulation de biomasse et sa consommation en eau. De nombreuses études ont révélé une forte diversité inter et intra-spécifique de ce trait intégré dans le temps dont l'origine est encore mal connue. Les travaux réalisés sur les variations journalières de A et gs ont jusqu'à maintenant révélé un rôle plus important de la diversité de gs dans la diversité de Wi. Une approche de modélisation inversée a permis de décomposer les variations de gs, observées lors de cinétiques journalières, sous la forme de paramètres décrivant les réponses stomatiques aux différentes variables microclimatiques. Comparé aux modèles décrivant les variations de gs en régime permanent, le développement d'un nouveau modèle dynamique a permis d'ajouter une dimension temporelle essentielle décrivant la réponse temporelle des stomates aux variations microclimatiques. La diversité des réponses temporelles des stomates détectée ne semble pas dépendre de leur densité ou de leur taille. Elle présente toutefois une asymétrie entre l'ouverture et la fermeture des stomates qui participe à la diversité des variations journalières de gs et impacte le bilan hydrique journalier au niveau du plant entier. Ainsi, on peut distinguer deux composantes aux variations journalières de Wi liées à gs : une composante temporelle due à la lente réponse des stomates et une autre composante due aux différences de perception des variations du microclimat<br>Intrinsic water use efficiency (Wi), defined as the ratio between net CO2 assimilation rate (A) and stomatal conductance to water vapour (gs), is a leaf level estimator of the trade-off between biomass accumulation and water loss at the plant level. A number of studies have shown a strong inter and intra-specific diversity, usually using a time integrated estimator of this trait. However, the origin of this diversity is not yet well known. Up to now, research on the daily variations of Wi have shown a stronger influence of gs on the diversity of Wi as compared to A. An inverse modelling approach has allowed partitioning the variations of gs observed during daily time-courses into parameters, which describe the stomatal responses to different microclimatic variables. Compared to steady-state gs models, the development of a new dynamic model of gs has allowed adding a necessary temporal dimension, which describes the temporal response of stomata to environmental variations. The observed diversity of these temporal stomatal responses was not related to stomatal density or size. The temporal responses of stomata were shown to be asymmetric between opening and closing, which impacts the observed diversity of gs during daily time courses as well as whole plant water relations. Overall these results suggest two components that determine the variations of Wi related to gs during daily time courses: one component due to the temporal response of stomata in itself, and one component which is due to differences in the sensing of microclimate variations
Books on the topic "Stomatal conductance"
1
Guak, Sunghee. Water relations, stomatal conductance, and abscisic acid content of container-grown apple (Malus domestica Borkh.) plants in response to sorbitol-induced osmotic stress. 1998.
Find full text
2
Lu, Shengjun. Seasonal and diurnal trends of leaf water potential and stomatal conductance of red alder (Alnus rubra Bong) growing along a density gradient in western Oregon. 1989.
Find full text
3
Heidmann, L. J. Effect of prolonged drought on water relations of ponderosa pine seedlings growing in basalt and sedimentary soils. 1992.
Find full textBook chapters on the topic "Stomatal conductance"
1
Overdieck, Dieter. "Water Use Efficiency and Stomatal Conductance." In CO2, Temperature, and Trees. Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1860-2_5.
Full text
2
Tuzet, Andrée J. "Stomatal Conductance, Photosynthesis, and Transpiration, Modeling." In Encyclopedia of Agrophysics. Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3585-1_213.
Full text
3
Burns, I. G., M. A. Escobar-Gutierrez, and A. J. Broadley. "A role for stomatal conductance in nitrogen-limited growth?" In Plant Nutrition. Springer Netherlands, 2001. http://dx.doi.org/10.1007/0-306-47624-x_49.
Full text
4
Olioso, Albert, Olivier Bethenod, Serge Rambal, and Marc Tchamitchian. "Comparison of Empirical Leaf Photosynthesis and Stomatal Conductance Models." In Photosynthesis: from Light to Biosphere. Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0173-5_1108.
Full text
5
Roden, John, Matthias Saurer, and Rolf T. W. Siegwolf. "Probing Tree Physiology Using the Dual-Isotope Approach." In Stable Isotopes in Tree Rings. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_16.
Full textAbstract:
AbstractThe environmental and physiological interpretation of stable isotope variation in organic matter is affected by many different and interacting factors. This is especially true when considering isotope variation in tree rings, which are influenced not only by leaf-level photosynthetic gas exchange processes but also by post-photosynthetic fractionation. It has been proposed that measuring multiple isotopes on the same sample may constrain such interpretations if one isotope provides independent information about important fractionation events that cause variation in another isotope. Here we describe one such “dual-isotope approach” where oxygen isotope variation (δ18O) is used to probe the effects of stomatal conductance on carbon isotope (δ13C) variation for the same sample. This chapter describes the development of this conceptual model, constraints on model applicability, particularly with respect to tree rings, and how it has been utilized to explore aspects of tree physiology.
6
Roden, John, Matthias Saurer, and Rolf T. W. Siegwolf. "Probing Tree Physiology Using the Dual-Isotope Approach." In Stable Isotopes in Tree Rings. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_16.
Full textAbstract:
AbstractThe environmental and physiological interpretation of stable isotope variation in organic matter is affected by many different and interacting factors. This is especially true when considering isotope variation in tree rings, which are influenced not only by leaf-level photosynthetic gas exchange processes but also by post-photosynthetic fractionation. It has been proposed that measuring multiple isotopes on the same sample may constrain such interpretations if one isotope provides independent information about important fractionation events that cause variation in another isotope. Here we describe one such “dual-isotope approach” where oxygen isotope variation (δ18O) is used to probe the effects of stomatal conductance on carbon isotope (δ13C) variation for the same sample. This chapter describes the development of this conceptual model, constraints on model applicability, particularly with respect to tree rings, and how it has been utilized to explore aspects of tree physiology.
7
Araus, Jose Luis, Maria Luisa Buchaillot, and Shawn C. Kefauver. "High Throughput Field Phenotyping." In Wheat Improvement. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-90673-3_27.
Full textAbstract:
AbstractThe chapter aims to provide guidance on how phenotyping may contribute to the genetic advance of wheat in terms of yield potential and resilience to adverse conditions. Emphasis will be given to field high throughput phenotyping, including affordable solutions, together with the need for environmental and spatial characterization. Different remote sensing techniques and platforms are presented, while concerning lab techniques only a well proven trait, such as carbon isotope composition, is included. Finally, data integration and its implementation in practice is discussed. In that sense and considering the physiological determinants of wheat yield that are amenable for indirect selection, we highlight stomatal conductance and stay green as key observations. This choice of traits and phenotyping techniques is based on results from a large set of retrospective and other physiological studies that have proven the value of these traits together with the highlighted phenotypical approaches.
8
Lombardi, Danilo, Kristina Micalizzi, and Marcello Vitale. "Development of a framework for modelling stand evapotranspiration at a local scale in a coastal mediterranean forest under climate change." In Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques. Firenze University Press, 2024. https://doi.org/10.36253/979-12-215-0556-6.21.
Full textAbstract:
This work presents a novel approach for local-scale quantification of stand plant transpiration. The methodology integrates leaf-scale gas exchange, meteorological, and soil water content data with satellite data to upscale results to the stand-scale. Field data enables the calibration of a photosynthesis biochemical model, comprising three modules simulating species-specific net assimilation rates, stomatal conductance, and evapotranspiration rates (ET). ET values, calculated per species, calibrate a forest stand evapotranspiration (ETA) model based on NDVI. ET and ETA, along with other forest system fluxes, compute the forest water balance as soil water content (SWC). Both models effectively simulate SWC (R2species = 0.98, R2satellite = 0.96). Transpiration values and other water balance components are estimated using climate change scenarios (SSP 2.6 and SSP 8.5). Simulated stand evapotranspiration for 2022 is 1387.73 mm, while for SSP 2.6 and SSP 8.5 are 1216.49 mm and 1293.47 mm, respectively.
9
Tardieu, F. "Control of Stomatal Conductance in Droughted Plants by Hydraulic and Chemical Messages from Roots." In Photosynthesis: from Light to Biosphere. Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-0173-5_1039.
Full text
10
Mensah, Eric Opoku, Philippe Vaast, Richard Asare, et al. "Cocoa Under Heat and Drought Stress." In Agroforestry as Climate Change Adaptation. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-45635-0_2.
Full textAbstract:
AbstractCocoa (Theobroma cacao L.) is an important cash crop in many tropical countries, particularly in West Africa. Heat and drought are both known to affect the physiology of cocoa plants through reduced rates of photosynthesis and transpiration, as well as changed physiological processes such as the functions of photosystems, chlorophyll synthesis, stomatal conductance and expression of heat-shock proteins. This in turn leads to decreased yields and increased risks of mortality under severe heat and drought. To help cocoa plants adapt to climate change, the literature suggests agroforestry as a potential farm management practice. It has been argued that the lack of tree cover in cocoa cultivation systems exposes the crop to heat and direct solar radiation, thus increasing evapotranspiration and the risk of drought. Drawing on data generated from two on-field studies, this chapter assesses the shade effect on cocoa’s physiological responses to drought and heat stress to determine whether shade would be beneficial under climate change scenarios. We conclude that shade improves the physiology of cocoa, but that this may not be sufficient to compensate for the negative effects of high temperatures and severe drought exacerbated by climate change in sub-optimal conditions.
Conference papers on the topic "Stomatal conductance"
1
Falagas, Alexandros, Memet Ouzoun, and Konstantinos Karantzalos. "On the Corellation of Remote Estimated ET and Leaf Stomatal Conductance." In IGARSS 2023 - 2023 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2023. http://dx.doi.org/10.1109/igarss52108.2023.10283438.
Full text
2
Zhang, Junxiao, Kantilata Thapa, Nipuna Chamara, Geng Bai, and Yufeng Ge. "Estimating crop stomatal conductance from RGB, NIR, and thermal infrared images." In Autonomous Air and Ground Sensing Systems for Agricultural Optimization and Phenotyping VIII, edited by Christoph Bauer and J. Alex Thomasson. SPIE, 2023. http://dx.doi.org/10.1117/12.2663888.
Full text
3
Pacanoski, Zvonko. "CHEMICAL WEED CONTROL IN CONDITIONS OF CLIMATE CHANGE." In 12. JEEP INTERNATIONAL SCIENTIFIC AGRIBUSINESS CONFERENCE, MAK 2025 – KOPAONIK. Association science and business center WORLD; Institute for plant protection and environmen, 2025. https://doi.org/10.46793/mak2025.035p.
Full textAbstract:
Elevate CO2 levels in the atmosphere might have prominent consequences on weed phenology, subsequently changing herbicide behavior on weeds. Increased atmospheric CO2 concentration strengthens leaf consistency and minimizes number of stomata and their conductivity potentially reducing the absorption of POST-em applied herbicides. On the other side, higher temperature stimulates stomata conductance, reduce the viscosity of epicuticle waxes, thus increasing the penetration and diffusion of herbicides because of modifications in the structure and the penetrability of the cuticle. However, in some circumstances higher temperatures might cause hastened metabolism, which consequently decreases herbicide activity on target plants. In conditions of higher RH, cuticle hydrating and stomatal conductivity increases, consequently increases the penetrability and translocation particularly of hydrophilic herbicides into the leaf surface. Similarly, under higher irradiance, stomata stay open, photosynthetic rate increases consequently increasing absorption, penetration and subsequent phloem translocation of POST-em systemic herbicides in weed plant tissue. Drought might cause increased cuticle thickness and intensify growth of leaf pubescence, with consequent minimization in herbicide absorption in the leaves. Rainfall after POST-em herbicides application might reduce their efficiency through washing out. Increased occurrence and intensiveness of precipitation will have negative consequences on absorption, translocation, and efficacy of PRE-m herbicides.
4
Zhaoquan, Gao, Li Zhiqiang, and Chen Jihu. "Stomatal Conductance Model Establishment and Simulation for Potted Apple Trees under Drought Stress." In 2017 9th International Conference on Measuring Technology and Mechatronics Automation (ICMTMA). IEEE, 2017. http://dx.doi.org/10.1109/icmtma.2017.0083.
Full text
5
"Estimation of stomatal conductance and chlorophyll fluorescence in Croatian grapevine germplasm under water deficit." In Open-GPB. International Viticulture and Enology Society, 2024. http://dx.doi.org/10.58233/dcmv6h2p.
Full text
6
"Response of Cyclopia Subternata to Watering Frequency: Stomatal Conductance, Proline, and Relative Water Content." In Nov. 28-29, 2022 Johannesburg (South Africa). International Institute of Chemical, Biological & Environmental Engineering (IICBEE), 2022. http://dx.doi.org/10.17758/iicbe4.c1122203.
Full text
7
Goins, Gregory D. "Growth, Stomatal Conductance, and Leaf Surface Temperature of Swiss Chard Grown Under Different Artificial Lighting Technologies." In International Conference On Environmental Systems. SAE International, 2002. http://dx.doi.org/10.4271/2002-01-2338.
Full text
8
Alina-Nicoleta, Paraschiv, Dima Milica, Diaconu Aurelia, Enache Viorel, and Fătu Viorel. "PRELIMINARY RESULTS ON THE INFLUENCE OF THE F414 BIOLOGICAL PRODUCT ON SOME PHYSIOLOGICAL INDEXES FOR PEACHES GROWN UNDER THERMO-HYDRIC STRESS." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b1/v3/39.
Full textAbstract:
On the peach species, Springold variety, research was conducted on the influence of the F414 biological product on some physiological indexes and processes carried out on the foliar level, the area of culture being characterized by an accentuated thermo-hydric stress during the summer. Photosynthetic gas exchange, foliar transpiration and stomatal conductance were determined with the portable LC PRO + apparatus, and the leaf water forms were determined gravimetrically, the results obtained being correlated with the meteorological data from the vegetation period. Applying the F414 to the Springold variety resulted in the formation of a pellicle on the surface of the leaves, which, together with the action of the thermo-hydric stress specific to the area, caused stomate closure, reduction of CO2 supply, photosynthesis values being considerably lower compared to the control variant. As for foliar transpiration, the F414 product had a positive effect, the pellicle formed on the surface of the leaves, reducing the amount of water lost to the foliage. The application of this product has positively influenced drought resistance of the Springold variety, the percentages of the bound water being higher (5.1%) compared to the control variant (3.96%).
9
Zhao, Lin, Lin Wang, Jiating Li, Geng Bai, Yeyin Shi, and Yufeng Ge. "Toward accurate estimating of crop leaf stomatal conductance combining thermal IR imaging, weather variables, and machine learning." In Autonomous Air and Ground Sensing Systems for Agricultural Optimization and Phenotyping VI, edited by J. Alex Thomasson and Alfonso F. Torres-Rua. SPIE, 2021. http://dx.doi.org/10.1117/12.2587577.
Full text
10
Engku Azlin Rahayu Engku Ariff, Mohd Nazip Suratman, and Shamsiah Abdullah. "Stomatal conductance, chlorophyll content, diameter and height in different growth stages of rubber tree (Hevea brasiliensis) saplings." In 2011 IEEE Symposium on Business, Engineering and Industrial Applications (ISBEIA). IEEE, 2011. http://dx.doi.org/10.1109/isbeia.2011.6088892.
Full textReports on the topic "Stomatal conductance"
1
Pell, Eva J., Sarah M. Assmann, Amnon Schwartz, and Hava Steinberger. Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7573082.bard.
Full textAbstract:
Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.
2
Swann, Abigail, Gariel Kooperman, Christopher Still, Charles Koven, Forrest Hoffman, and James Randerson. Final Report: Evaluating the Influence of Plants on Hydrologic Cycling: Quantifying and Validating the Role of Plant Processes and Stomatal Conductance. Office of Scientific and Technical Information (OSTI), 2025. https://doi.org/10.2172/2525989.
Full text
3
Fromm, Hillel, Paul Michael Hasegawa, and Aaron Fait. Calcium-regulated Transcription Factors Mediating Carbon Metabolism in Response to Drought. United States Department of Agriculture, 2013. http://dx.doi.org/10.32747/2013.7699847.bard.
Full textAbstract:
Original objectives: The long-term goal of the proposed research is to elucidate the transcription factors, genes and metabolic networks involved in carbon metabolism and partitioning in response to water deficit. The proposed research focuses on the GTLcalcium/calmodulinbindingTFs and the gene and metabolic networks modulated by these TFs in Arabidopsis thaliana. The specific objectives are as follows. Objective-1 (USA): Physiological analyses of GTL1 loss- and gain-of-function plants under water sufficient and drought stress conditions Objective 2 (USA / Israel-TAU): Characterizion of GTL target genes and bioinformatic analysis of data to eulcidate gene-network topology. Objective-3 (Israel-TAU): Regulation of GTLmediated transcription by Ca²⁺/calmodulin: mechanism and biological significance. Objective-4 (Israel-BGU): Metabolic networks and carbon partitioning in response to drought. Additional direction: In the course of the project we added another direction, which was reported in the 2nd annual report, to elucidate genes controlling drought avoidance. The TAU team has isolated a few unhydrotropic (hyd) mutants and are in the process of mapping these mutations (of hyd13 and hyd15; see last year's report for a description of these mutants under salt stress) in the Arabidopsis genome by map-based cloning and deep sequencing. For this purpose, each hyd mutant was crossed with a wild type plant of the Landsberg ecotype, and at the F2 stage, 500-700 seedlings showing the unhydrotropic phenotype were collected separately and pooled DNA samples were subkected to the Illumina deep sequencing technology. Bioinformatics were used to identify the exact genomic positions of the mutations (based on a comparison of the genomic sequences of the two Arabidopsis thaliana ecotypes (Columbia and Landsberg). Background: To feed the 9 billion people or more, expected to live on Earth by the mid 21st century, the production of high-quality food must increase substantially. Based on a 2009 Declaration of the World Summit on Food Security, a target of 70% more global food production by the year 2050 was marked, an unprecedented food-production growth rate. Importantly, due to the larger areas of low-yielding land globally, low-yielding environments offer the greatest opportunity for substantial increases in global food production. Nowadays, 70% of the global available water is used by agriculture, and 40% of the world food is produced from irrigated soils. Therefore, much needs to be done towards improving the efficiency of water use by plants, accompanied by increased crop yield production under water-limiting conditions. Major conclusions, solutions and achievements: We established that AtGTL1 (Arabidopsis thaliana GT-2 LIKE1) is a focal determinant in water deficit (drought) signaling and tolerance, and water use efficiency (WUE). The GTL1 transcription factor is an upstream regulator of stomatal development as a transrepressor of AtSDD1, which encodes a subtilisin protease that activates a MAP kinase pathway that negatively regulates stomatal lineage and density. GTL1 binds to the core GT3 cis-element in the SDD1 promoter and transrepresses its expression under water-sufficient conditions. GTL1 loss-of-function mutants have reduced stomatal number and transpiration, and enhanced drought tolerance and WUE. In this case, higher WUE under water sufficient conditions occurs without reduction in absolute biomass accumulation or carbon assimilation, indicating that gtl1-mediated effects on stomatal conductance and transpiration do not substantially affect CO₂ uptake. These results are proof-of-concept that fine-tuned regulation of stomatal density can result in drought tolerance and higher WUE with maintenance of yield stability. Implications: Accomplishments during the IS-4243-09R project provide unique tools for continued discovery research to enhance plant drought tolerance and WUE.
4
Hochman, Ayala, Thomas Nash III, and Pamela Padgett. Physiological and Biochemical Characterization of the Effects of Oxidant Air Pollutants, Ozone and Gas-phase Nitric Acid, on Plants and Lichens for their Use as Early Warning Biomonitors of these Air Pollutants. United States Department of Agriculture, 2011. http://dx.doi.org/10.32747/2011.7697115.bard.
Full textAbstract:
Introduction. Ozone and related oxidants are regarded as the most important phytotoxic air pollutant in many parts of the western world. A previously unrecognized component of smog, nitric acid, may have even greater deleterious effects on plants either by itself or by augmenting ozone injury. The effects of ozone on plants are well characterized with respect to structural and physiological changes, but very little is known about the biochemical changes in plants and lichens exposed to ozone and/or HNO3. Objectives.To compare and contrast the responses of crop plants and lichens to dry deposition of HNO3 and O3., separately, and combined in order to assess our working hypothesis that lichens respond to air pollution faster than plants. Lichens are most suitable for use as biomonitors because they offer a live-organism-based system that does not require maintenance and can be attached to any site, without the need for man-made technical support systems. Original Immediate aims To expose the tobacco (Nicotiana tabacum L.) cultivar Bel-W3 that is ozone supersensitive and the ozone sensitive red kidney bean (Phaseolusvulgaris) and the lichen Ramalinamenziesii to controlled HNO3 and O3 fumigations and combined and to follow the resulting structural, physiological and biochemical changes, with special reference to reactive oxygen species related parameters. Revised. Due to technical problems and time limitations we studied the lichen Ramalinamenziesii and two cultivar of tobacco: Bel-W3 that is ozone supersensitive and a resistant cultivar, which were exposed to HNO3 and O3 alone (not combined). Methodology. Plants and lichens were exposed in fumigation experiments to HNO3 and O3, in constantly stirred tank reactors and the resulting structural, physiological and biochemical changes were analyzed. Results. Lichens. Exposure of Ramalinamenziesiito HNO3 resulted in cell membrane damage that was evident by 14 days and continues to worsen by 28 days. Chlorophyll, photosynthesis and respiration all declined significantly in HNO3 treatments, with the toxic effects increasing with dosage. In contrast, O3 fumigations of R. menziesii showed no significant negative effects with no differences in the above response variables between high, moderate and low levels of fumigations. There was a gradual decrease in catalase activity with increased levels of HNO3. The activity of glutathione reductase dropped to 20% in thalli exposed to low HNO3 but increased with its increase. Glucose 6-phosphate dehydrogenase activity increase by 20% with low levels of the pollutants but decreased with its increase. Tobacco. After 3 weeks of exposure of the sensitive tobacco cultivar to ozone there were visible symptoms of toxicity, but no danmage was evident in the tolerant cultivar. Neither cultivar showed any visible symptoms after exposure to HNO3.In tobacco fumigated with O3, there was a significant decrease in maximum photosynthetic CO2 assimilation and stomatal conductance at high levels of the pollutant, while changes in mesophyll conductance were not significant. However, under HNO3 fumigation there was a significant increase in mesophyll conductance at low and high HNO3 levels while changes in maximum photosynthetic CO2 assimilation and stomatal conductance were not significant. We could not detect any activity of the antioxidant enzymes in the fumigated tobacco leaves. This is in spite of the fact that we were able to assay the enzymes in tobacco leaves grown in Israel. Conclusions. This project generated novel data, and potentially applicable to agriculture, on the differential response of lichens and tobacco to HNO3 and O3 pollutants. However, due to experimental problems and time limitation discussed in the body of the report, our data do not justify yet application for a full, 4-year grant. We hope that in the future we shall conduct more experiments related to our objectives, which will serve as a basis for a larger scale project to explore the possibility of using lichens and/or plants for biomonitoring of ozone and nitric acid air pollution.
5
Paterson, Andrew H., Yehoshua Saranga, and Dan Yakir. Improving Productivity of Cotton (Gossypsum spp.) in Arid Region Agriculture: An Integrated Physiological/Genetic Approach. United States Department of Agriculture, 1999. http://dx.doi.org/10.32747/1999.7573066.bard.
Full textAbstract:
Objectives: We seek to establish the basis for improving cotton productivity under arid conditions, by studying the water use efficiency - evaporative cooling interrelationship. Specifically, we will test the hypothesis that cotton productivity under arid conditions can be improved by combining high seasonal WUE with efficient evaporative cooling, evaluate whether high WUE and/or evaporative cooling are based on specific physiological factors such as diurnal flexibility in stomatal conductance, stomatal density, photosynthetic capacity, chlorophyll fluorescence, and plant water status. Genes influencing both WUE and evaporative cooling, as well as other parameters such as economic products (lint yield, quality, harvest index) of cotton will also be mapped, in order to evaluate influences of water relations on these parameters. Approach: Carbon isotope ratio will be used to evaluate WUE, accompanied by additional parameters to elucidate the relationship between WUE, evaporative cooling, and cotton productivity. A detailed RFLP map will be used to determine the number, location, and phenotypic effects of genes underlying genetic variation in WUE between cultivated cottons, as well as test associations of these genes with traits of economic importance such as harvest index, lint yield, and lint quality. Major Conclusions: Productivity and quality of cotton grown under well-watered versus water-limited conditions was shown to be partly accounted for by different quantitative trait loci (QTLs). Among a suite of physiological traits often found to differ between genotypes adapted to arid versus well-watered conditions, genetic mapping implicated only reduced plant osmotic potential in improved cotton productivity under arid conditions. Our findings clearly implicate OP as a major component of cotton adaptation to arid conditions. However, testing of further physiological hypotheses is clearly needed to account for additional QTL alleles conferring higher seed-cotton yield under arid conditions, such as three of the five we found. Near-isogenic lines being made for QTLs discovered herein will offer a powerful new tool useful toward identification of the underlying gene(s) by using fine-scale mapping approaches (Paterson et al 1990). Implications: Adaptation to both arid and favorable conditions can be combined into the same genotype. We have identified diagnostic DNA markers that are being applied to creation of such desirable genotypes. Simultaneous improvement of productivity (and/or quality) for both arid and irrigated conditions will require more extensive field testing and the manipulation of larger numbers of genes, reducing the expected rate of genetic gain These difficulties may be at least partly ameliorated by efficiencies gained through identification and use of diagnostic DNA markers. Genomic tools and approaches may expedite adaptation of crops to arid cultivation, help to test roles of additional physiological factors, and guide the isolation of the underlying genes that protect crop performance under arid conditions.
6
da Silva Filho, Adilson Aderito. Effect of the “Cultivation of the future” on Alstroemeria production, stomata conductance and photosynthesis capacity. Stichting Wageningen Research, Wageningen Plant Research, Business unit Glastuinbouw, 2022. http://dx.doi.org/10.18174/568309.
Full text
7
Practical Field Guide. Functional Crop Monitoring for Early Stress Detection: Stomatal Conductance and Infrared Thermography as Key Measurement Tools. International Potato Center, 2021. http://dx.doi.org/10.4160/9789290606253.
Full text