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Journal articles on the topic 'Stomatal conductance'
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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.
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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.
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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 (May 1990): 468–72. http://dx.doi.org/10.21273/jashs.115.3.468.
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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 (January 1987): 15–21. http://dx.doi.org/10.1017/s0043174500026722.
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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 (July 1, 1988): 1404–14. http://dx.doi.org/10.1139/b88-196.
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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 (February 27, 2019): 114. http://dx.doi.org/10.3390/agronomy9030114.
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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.
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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.
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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 (May 30, 2019): 5259–69. http://dx.doi.org/10.1093/jxb/erz267.
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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 (February 2019): 255–66. http://dx.doi.org/10.1094/mpmi-06-18-0162-r.
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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.
11
Meinzer, FC, DA Grantz, and B. Smit. "Root Signals Mediate Coordination of Stomatal and Hydraulic Conductance in Growing Sugarcane." Functional Plant Biology 18, no. 4 (1991): 329. http://dx.doi.org/10.1071/pp9910329.
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Root hydraulic conductance and total stomatal conductance on a per plant basis changed in parallel during growth of sugarcane. Changes in root system water and solute transport properties were evaluated to determine the role of changes in root xylem sap composition in this coordination of vapour and liquid phase conductances. Stomatal conductance of excised leaf strips supplied with root exudate declined with increasing leaf area of the exudate donor plants. Leaf strips from plants of different sizes responded similarly to exudate from each donor plant, indicating that there were no inherent differences in leaf stomatal properties. The effect of xylem sap from plants of increasing size paralleled the decline in stomatal conductance of intact plants of similarly increasing plant size. Delivery rates per unit leaf area of K+, Ca2+, abscisic acid, and zeatin riboside (ZR) in xylem sap declined with increasing plant size. Patterns of delivery of ZR and K+ were consistent with a role in the plant size-dependent regulation of stomatal conductance, although additional xylem constituents are likely to be involved. Developmental patterns of stomatal conductance in intact sugarcane plants may be linked to plant hydraulic properties by the composition and flux of xylem sap arriving at the stomatal complexes in leaves.
12
Lawson, Tracy, and Jack Matthews. "Guard Cell Metabolism and Stomatal Function." Annual Review of Plant Biology 71, no. 1 (April 29, 2020): 273–302. http://dx.doi.org/10.1146/annurev-arplant-050718-100251.
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The control of gaseous exchange between the leaf and external atmosphere is governed by stomatal conductance ( gs); therefore, stomata play a critical role in photosynthesis and transpiration and overall plant productivity. Stomatal conductance is determined by both anatomical features and behavioral characteristics. Here we review some of the osmoregulatory pathways in guard cell metabolism, genes and signals that determine stomatal function and patterning, and the recent work that explores coordination between gs and carbon assimilation ( A) and the influence of spatial distribution of functional stomata on underlying mesophyll anatomy. We also evaluate the current literature on mesophyll-driven signals that may coordinate stomatal behavior with mesophyll carbon assimilation and explore stomatal kinetics as a possible target to improve A and water use efficiency. By understanding these processes, we can start to provide insight into manipulation of these regulatory pathways to improve stomatal behavior and identify novel unexploited targets for altering stomatal behavior and improving crop plant productivity.
13
Büssis, Dirk, Uritza von Groll, Joachim Fisahn, and Thomas Altmann. "Stomatal aperture can compensate altered stomatal density in Arabidopsis thaliana at growth light conditions." Functional Plant Biology 33, no. 11 (2006): 1037. http://dx.doi.org/10.1071/fp06078.
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Stomatal density of transgenic Arabidopsis thaliana plants over-expressing the SDD1 (stomatal density and distribution) gene was reduced to 40% and in the sdd1-1 mutant increased to 300% of the wild type. CO2 assimilation rate and stomatal conductance of over-expressers and the sdd1-1 mutant were unchanged compared with wild types when measured under the light conditions the plants were exposed to during growth. Lower stomatal density was compensated for by increased stomatal aperture and conversely, increased stomatal density was compensated for by reduced stomatal aperture. At high light intensities the assimilation rates and stomatal conductance of SDD1 over-expressers were reduced to 80% of those in wild type plants. Areas beneath stomata and patches lacking stomata were analysed separately. In areas without stomata, maximum fluorescence yield (Fv / Fm) and quantum yield of photosystem II (Φ PSII) were significantly lower than in areas beneath stomata. In areas beneath stomata, Fv / Fm and Φ PSII were identical to levels measured in wild type leaves. At high light intensities over-expressers showed decreased photochemical quenching (qP) compared with wild types. However, the decrease of qP was significantly stronger in areas without stomata than in mesophyll areas beneath stomata. At high CO2 partial pressures and high light intensities CO2 assimilation rates of SDD1 over-expressers did not reach wild type levels. These results indicate that photosynthesis in SDD1 over-expressers was reduced because of limiting CO2 in areas furthest from stomata at high light.
14
Pezeshki, S. R., and J. L. Chambers. "Stomatal and photosynthetic response of drought-stressed cherrybark oak (Quercusfalcata var. pagodaefolia) and sweet gum (Liquidambarstyraciflua)." Canadian Journal of Forest Research 16, no. 4 (August 1, 1986): 841–46. http://dx.doi.org/10.1139/x86-148.
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The effects of water stress on stomatal conductance and net photosynthesis of cherrybark oak (Quercusfalcata var. pagodaefolia Ell.) and sweet gum (Liquidamberstyraciflua L.) seedlings were studied under controlled environment conditions during the 1983 growing season. Drought stress induced stomatal closure and significant declines in net photosynthesis for both species. Stomatal conductance declined by as much as 43% in cherrybark oak and 82% in sweet gum compared with predrought levels. Net photosynthetic rates also declined 85% from predrought levels in sweet gum and fell below zero in cherrybark oak. The remarkable decline in net photosynthesis in cherrybark oak while stomata remained partially open suggests that in addition to a stomatal effect, nonstomatal factors were involved in the reduction of net photosynthesis. In sweet gum, however, stomatal limitation of net photosynthesis seems to be the dominant factor. The greater relative decline in mean leaf conductance in sweet gum suggests a greater reaction to drought by this species through effective and rapid stomatal closure resulting in avoidance of leaf desiccation. Stomata of cherrybark oak, on the other hand, were less sensitive to low leaf water potentials; therefore, stomatal closure occurred at significantly lower (more negative) leaf water potentials when compared with sweet gum.
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Hernández, María J., Sven Mutke, Fernando Montes, and Pilar Pita. "Early testing for improving growth under water shortage in Eucalyptus globulus Labill." Forest Systems 33, no. 1 (March 14, 2024): e01. http://dx.doi.org/10.5424/fs/2024331-20868.
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Aim of study: We aimed at identifying differences in the response to water shortage between Eucalyptus globulus clones.
Area of study: The greenhouse experiment was performed in SW Spain.
Material and methods: Potted plants from six clones were grown in a greenhouse for 53 days under two watering regimes. Two clones were F0 genotypes and the other four were F1 (hybrid) genotypes, including one inbred clone. Differences in stomatal conductance, hydraulic traits, growth and specific leaf area (SLA) were analyzed.
Main results: Water shortage decreased SLA, growth in height and leaf area and leaf-specific hydraulic conductivity (KLmax). We measured the highest growth in F1 genotypes and the lowest in the clone in which SLA was lowest. The inbred clone showed the highest growth reduction under water shortage. There was substantial hysteresis between leaf water potential (Y) and native embolism, most probably a result of combined cavitation and refilling. High losses of hydraulic conductance were compatible with high stomatal conductances. Maximum values of stomatal conductance decreased with the soil water content estimated from predawn Y and were lowest in the inbred clone, showing less plasticity and a diminished ability to cope with high temperatures, which could explain its poor development under field conditions.
Research highlights: Soil water content and predawn Y appeared as critical factors controlling stomata closure, while stomatal conductance and SLA could be useful to predict differences in growth and survival from early trials.
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Goknur, Atilla B., and Theodore W. Tibbitts. "Association of Dark Opening of Stomata with Air Pollution Sensitivity of Irish Potatoes." Journal of the American Society for Horticultural Science 126, no. 1 (January 2001): 37–43. http://dx.doi.org/10.21273/jashs.126.1.37.
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The magnitude of dark opening of stomata on leaves of Irish potato (Solanum tuberosum L.) was studied to determine if this opening was related to the high sensitivity of these plants to air pollutants. Stomatal opening was studied over diurnal periods both in the field and in controlled environments. In both environments, stomatal conductance decreased rapidly at the initiation of dark to 0.1 cm·s-1 but then increased to 0.2 cm·s-1 over the dark period. However conductance was always less in the dark than in the light (0.3 to 0.9 cm·s-1). During the early part of the dark period, stomatal conductance in controlled environments was not as great as in the field, but conductance was similar in both environments over the latter part of the dark period. Cultivars Norchip and Kennebec had smaller conductances during the first hours of the dark than Haig or Katahdin, and all cultivars increased in conductance over the dark period. `Haig' showed slightly higher conductance than the other three during the last 4 hours of the dark period. Injury to `Haig' from 3-hour fumigations with sulfur dioxide (SO2) or ozone (O3) demonstrated that exposures during the day generally produced more injury than during the night, although exposures with SO2 during the last 3 hours of the light period produced similar injury to exposures at the end of the dark period. Thus, although partial opening during the dark may be permitting some pollution injury, it is concluded that previous published reports of similar opening of stomata on Irish potatoes during the light and dark periods, and equal or greater pollution injury during the dark compared with the light period, were not substantiated and apparently resulted from procedural artifacts.
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Paoletti, Elena, Nancy E. Grulke, and Rainer Matyssek. "Ozone Amplifies Water Loss from Mature Trees in the Short Term But Decreases It in the Long Term." Forests 11, no. 1 (December 31, 2019): 46. http://dx.doi.org/10.3390/f11010046.
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We measured whole-tree transpiration of mature Fagus sylvatica and Picea abies trees exposed to ambient and twice-ambient O3 regimes (1xO3 and 2xO3 free-air fumigation). After eight years, mean daily total transpiration did not vary with the O3 regime over the 31 days of our study, even though individual daily values increased with increasing daily O3 peaks in both species. Although the environmental parameters were similar at 1xO3 and 2xO3, the main factors affecting daily transpiration were vapour pressure deficit in 2xO3 spruce and O3 peaks in beech. For a mechanistic explanation, we measured O3-induced sluggish stomatal responses to variable light (sunflecks) by means of leaf-level gas exchange measurements only in the species where O3 was a significant factor for transpiration, i.e., beech. Stomata were always slower in closing than in opening. The 2xO3 stomata were slower in opening and mostly in closing than 1xO3 stomata, so that O3 uptake and water loss were amplified before a steady state was reached. Such delay in the stomatal reaction suggests caution when assessing stomatal conductance under O3 pollution, because recording gas exchange at the time photosynthesis reached an equilibrium resulted in a significant overestimation of stomatal conductance when stomata were closing (ab. 90% at 1xO3 and 250% at 2xO3). Sun and shade leaves showed similar sluggish responses, thus suggesting that sluggishness may occur within the entire crown. The fact that total transpiration was similar at 1xO3 and 2xO3, however, suggests that the higher water loss due to stomatal sluggishness was offset by lower steady-state stomatal conductance at 2xO3. In conclusion, O3 exposure amplified short-term water loss from mature beech trees by slowing stomatal dynamics, while decreased long-term water loss because of lower steady-state stomatal conductance. Over the short term of this experiment, the two responses offset each other and no effect on total transpiration was observed.
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Buckley, Thomas N. "Modeling Stomatal Conductance." Plant Physiology 174, no. 2 (January 6, 2017): 572–82. http://dx.doi.org/10.1104/pp.16.01772.
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Lloyd, J., and H. Howie. "Salinity, Stomatal Responses and Whole-Tree Hydraulic Conductivity of Orchard 'Washington Navel' Orange, Citrus sinensis (L.) Osbeck." Functional Plant Biology 16, no. 2 (1989): 169. http://dx.doi.org/10.1071/pp9890169.
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Diurnal patterns in stomatal conductance and bulk water potentials were measured over a 6-month period for spring flush leaves on 24-year-old Washington Navel orange trees that had been irrigated with water containing either 5 mol m-3 NaCl or 20 mol m-3 NaCl for 5 years prior to measurements. During summer and autumn, at early morning measurement times, stomatal conductances of leaves on trees irrigated with 20 mol m-3 were significantly below those on trees irrigated with 5 mol m-3 NaCl. Lower values on high salinity trees were not attributable to more negative water potentials or lower turgor pressures but were apparently due to an inability of stomata on leaves from salinised trees to open in response to low vapour pressure deficits (VPDs). There was little effect of salinity on stomatal conductances during afternoon measurements when high vapour pressure deficits prevailed. Laboratory studies confirmed that stomata on salinised trees are less responsive to VPD than those from unsalinised trees. When measurements were made during winter months there was no effect of salinity on diurnal patterns of stomatal conductances but leaf water potentials were less negative for leaves of salinised trees during daylight hours. Hydraulic conductance (G) of trees to liquid water flow was greater for trees irrigated with 5 mol m-3 NaCl in summer, but seasonal reductions in G for trees irrigated with 5 mol m-3 NaCl occurred to a far greater extent than for trees irrigated with 20 mol m-3 NaCl. This may have been a consequence of a reduction in leaf areas of salinised trees during summer and autumn without concomitant decreases in root length.
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Kimura, Haruki, Mimi Hashimoto-Sugimoto, Koh Iba, Ichiro Terashima, and Wataru Yamori. "Improved stomatal opening enhances photosynthetic rate and biomass production in fluctuating light." Journal of Experimental Botany 71, no. 7 (February 25, 2020): 2339–50. http://dx.doi.org/10.1093/jxb/eraa090.
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Abstract It has been reported that stomatal conductance often limits the steady-state photosynthetic rate. On the other hand, the stomatal limitation of photosynthesis in fluctuating light remains largely unknown, although in nature light fluctuates due to changes in sun position, cloud cover, and the overshadowing canopy. In this study, we analysed three mutant lines of Arabidopsis with increased stomatal conductance to examine to what extent stomatal opening limits photosynthesis in fluctuating light. The slac1 (slow anion channel-associated 1) and ost1 (open stomata 1) mutants with stay-open stomata, and the PATROL1 (proton ATPase translocation control 1) overexpression line with faster stomatal opening responses exhibited higher photosynthetic rates and plant growth in fluctuating light than the wild-type, whereas these four lines showed similar photosynthetic rates and plant growth in constant light. The slac1 and ost1 mutants tended to keep their stomata open in fluctuating light, resulting in lower water-use efficiency (WUE) than the wild-type. However, the PATROL1 overexpression line closed stomata when needed and opened stomata immediately upon irradiation, resulting in similar WUE to the wild-type. The present study clearly shows that there is room to optimize stomatal responses, leading to greater photosynthesis and biomass accumulation in fluctuating light in nature.
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Anderegg, William R. L. "Quantifying seasonal and diurnal variation of stomatal behavior in a hydraulic-based stomatal optimization model." Journal of Plant Hydraulics 5 (December 22, 2018): e001. http://dx.doi.org/10.20870/jph.2018.e001.
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Plant responses to drought occur across many time-scales, with stomatal closure typically considered to be a critical short-term response. Recent theories of optimal stomatal conductance linked to plant hydraulic transport have shown promise, but it is not known if stomata update their hydraulic “shadow price” of water use (marginal increase in carbon cost with a marginal drop in water potential) over days, seasons, or in response to recent drought. Here, I estimate the hydraulic shadow price in five species – two semi-arid gymnosperms, one temperate and two tropical angiosperms – at daily timescales and in wet and dry periods. I tested whether the shadow prices varies predictably as a function of current and/or lagged drought conditions. Diurnal estimates of the hydraulic shadow price estimated from observed stomatal conductance, while variable, did not vary predictably with environmental variables. Seasonal variation in shadow price was observed in the gymnosperm species, but not the angiosperm species, and did not meaningfully influence prediction accuracy of stomatal conductance. The lack of systematic variation in shadow price and high predictive ability of stomatal conductance when using a single set of parameters further emphasizes the potential of hydraulic-based stomatal optimization theories.
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Israel, Walter Krystler, Alexander Watson-Lazowski, Zhong-Hua Chen, and Oula Ghannoum. "High intrinsic water use efficiency is underpinned by high stomatal aperture and guard cell potassium flux in C3 and C4 grasses grown at glacial CO2 and low light." Journal of Experimental Botany 73, no. 5 (October 28, 2021): 1546–65. http://dx.doi.org/10.1093/jxb/erab477.
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Abstract We compared how stomatal morphology and physiology control intrinsic leaf water use efficiency (iWUE) in two C3 and six C4 grasses grown at ambient (400 µmol mol–1) or glacial CO2 (180 µmol mol–1) and high (1000 µmol m–2 s–1) or low light intensity (200 µmol m–2 s–1). C4 grasses tended to have higher iWUE and CO2 assimilation rates, and lower stomatal conductance (gs), operational stomatal aperture (aop), and guard cell K+ influx rate relative to C3 grasses, while stomatal size (SS) and stomatal density (SD) did not vary according to the photosynthetic type. Overall, iWUE and gs depended most on aop and density of open stomata. In turn, aop correlated with K+ influx, stomatal opening speed on transition to high light, and SS. Species with higher SD had smaller and faster-opening stomata. Although C4 grasses operated with lower gs and aop at ambient CO2, they showed a greater potential to open stomata relative to maximal stomatal conductance (gmax), indicating heightened stomatal sensitivity and control. We uncovered promising links between aop, gs, iWUE, and K+ influx among C4 grasses, and differential K+ influx responses of C4 guard cells to low light, revealing molecular targets for improving iWUE in C4 crops.
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Hunt, Lena, Michal Fuksa, Karel Klem, Zuzana Lhotáková, Michal Oravec, Otmar Urban, and Jana Albrechtová. "Barley Genotypes Vary in Stomatal Responsiveness to Light and CO2 Conditions." Plants 10, no. 11 (November 21, 2021): 2533. http://dx.doi.org/10.3390/plants10112533.
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Changes in stomatal conductance and density allow plants to acclimate to changing environmental conditions. In the present paper, the influence of atmospheric CO2 concentration and light intensity on stomata were investigated for two barley genotypes—Barke and Bojos, differing in their sensitivity to oxidative stress and phenolic acid profiles. A novel approach for stomatal density analysis was used—a pair of convolution neural networks were developed to automatically identify and count stomata on epidermal micrographs. Stomatal density in barley was influenced by genotype, as well as by light and CO2 conditions. Low CO2 conditions resulted in increased stomatal density, although differences between ambient and elevated CO2 were not significant. High light intensity increased stomatal density compared to low light intensity in both barley varieties and all CO2 treatments. Changes in stomatal conductance were also measured alongside the accumulation of pentoses, hexoses, disaccharides, and abscisic acid detected by liquid chromatography coupled with mass spectrometry. High light increased the accumulation of all sugars and reduced abscisic acid levels. Abscisic acid was influenced by all factors—light, CO2, and genotype—in combination. Differences were discovered between the two barley varieties: oxidative stress sensitive Barke demonstrated higher stomatal density, but lower conductance and better water use efficiency (WUE) than oxidative stress resistant Bojos at saturating light intensity. Barke also showed greater variability between treatments in measurements of stomatal density, sugar accumulation, and abscisic levels, implying that it may be more responsive to environmental drivers influencing water relations in the plant.
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A. Baqasi, Laila, Huda A. Qari, Nihal Al-Nahhas, Reem H. Badr, Wafaa K. Taia, Rehab El-Dakkak, and Ibrahim A. Hassan. "Effects of Low Concentrations of Ozone (O3) on Metabolic and Physiological Attributes in Wheat (Triticum aestivum L.) Pants." Biomedical and Pharmacology Journal 11, no. 2 (June 20, 2018): 929–34. http://dx.doi.org/10.13005/bpj/1450.
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Growth, yield, protein content, net photosynthetic rates, stomatal conductance and amino acid profiles were determined in wheat (Triticum aestivum L) plants in response to 50 ppb O3 during the growing season. This concentration is similar to the concentrations of O3 in ambient air. O3 decreased photosynthetic rates (24%) and stomatal conductance (25%), which were reflected in lower growth and yield in terms of number of grains and 100 grain weight. Scanning electron microscopy showed a collapse in the epidermal cells adjacent to stomata that led to stomatal closure and consequently reductions in stomatal conductance. The significance of O3-induced impairment of growth, yield and alteration in amino acid contents are discussed. To the best of our knowledge, this is the first study reporting impact of ozone on protein content, amino acids and yield of wheat in Saudi Arabia.
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Mott, Keith A., and Thomas N. Buckley. "Patchy stomatal conductance: emergent collective behaviour of stomata." Trends in Plant Science 5, no. 6 (June 2000): 258–62. http://dx.doi.org/10.1016/s1360-1385(00)01648-4.
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Passos, Edson Eduardo Melo, and Jorge Vieira Da Silva. "Fonctionnement des stomates de Cocotier (Cocos nucifera) au champ." Canadian Journal of Botany 68, no. 2 (February 1, 1990): 458–60. http://dx.doi.org/10.1139/b90-059.
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The behavior of coconut (Cocos nucifera L.) stomata was studied under field conditions in adult plants. Hourly determination of relative stomatal opening and of stomatal conductance values revealed that coconut stomata were opened maximally between 0800 and 1600; by the end of this period, the stomata closed rapidly as solar radiation decreased. Changes in temperature and relative humidity of the air did not affect stomatal behavior. The maximum relative stomatal opening occurred at midday, when the water potential of the leaf is at its lowest point, showing that stomatal behavior depends mostly on solar radiation and does not control water loss efficiently under conditions of water stress.
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Santrucek, J., and RF Sage. "Acclimation of Stomatal Conductance to a CO2-Enriched Atmosphere and Elevated Temperature in Chenopodium album." Functional Plant Biology 23, no. 4 (1996): 467. http://dx.doi.org/10.1071/pp9960467.
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Acclimation of stomatal conductance to different CO2 and temperature regimes was determined in Chenopodium album L. plants grown at one of three treatment conditions: 23�C and 350 μmol CO2 mol-1 air; 34�C and 350 μmol mol-1; and 34�C and 750 μmol mol-1. Stomatal conductance (gs) as a function of intercellular CO2 (Ci) was determined for each treatment at 25 and 35�C, and these data were used to estimate gains of the feedback loops linking changes in intercellular CO2 with stomatal conductance and net CO2 assimilation. Growth temperature affected the sensitivity of stomata to measurement temperature in a pattern that was influenced by intercellular CO2. Stomatal conductance more than doubled at intercellular CO2 varying between 200 and 600 μmol mol-1 as leaf temperature increased from 25 to 35�C for plants grown at 23�C. In contrast, stomatal conductance was almost unaffected by measurement temperature in plants grown at 34�C. Elevated growth CO2 attenuated the response of stomatal conductance to CO2, but growth temperature did not. Stomatal sensitivity to Ci was extended to higher Ci in plants grown in elevated CO2. As a result, plants grown at 750 μmol mol-1 CO2 had higher Ci/Ca at ambient CO2 values between 300 and 1200 �mol mol-1 than plants grown at 350 �mol mol-1 CO2. The gain of the stomatal loop was reduced in plants grown at elevated CO2 or at lower temperature when compared to plants grown at 350 μmol mol-1 and 34°C. Both photosynthetic and stomatal loop gains acclimated to elevated CO2 in proportion so that their ratio, integrated over the range of Ci in which the plant operates, remained constant. Water use efficiency (WUE) more than doubled after a short-term doubling of ambient CO2. However, the WUE of plant grown and measured at elevated CO2 was only about 1.5 times that of plant transiently exposed to elevated CO2, due to stomatal acclimation. An optimal strategy of water use was maintained for all growth treatments.
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Sun, Ruifeng, Juanjuan Ma, Xihuan Sun, Shijian Bai, Lijian Zheng, and Jiachang Guo. "Study on a Stomatal Conductance Model of Grape Leaves in Extremely Arid Areas." Sustainability 15, no. 10 (May 21, 2023): 8342. http://dx.doi.org/10.3390/su15108342.
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Stomata are essential for regulating the exchange of water and energy between plants and the atmosphere. In the context of climate warming, especially in extremely arid regions, the knowledge of stomatal conductance variation patterns is fundamental to the study of crop evapotranspiration, productivity and drought resistance characteristics. The accurate simulation of stomatal conductance in this region is an important prerequisite for the optimal regulation of the crop growth environment. In this study, a two-year field experiment was carried out in vineyards in an extremely arid region. The Jarvis model and BWB model were used to evaluate the daily changes in stomatal conductance. The results showed that stomatal conductance was significantly correlated with environmental factors (temperature difference between leaf and air (ΔT), photosynthetically active radiation and air temperature). The Jarvis and BWB models performed well. However, the response function of the environment factor in the Jarvis model can affect the model performance. The ΔT effectively improved the model, and the modified Jarvis model outperformed the modified BWB model. The R2 and model slope b of the modified Jarvis model increased by 45.18–70.37% and 2.51–3.12%, respectively. RMSE and MAE decreased by 38.98–43.12% and 42.69–44.35%, respectively. Overall, the Jarvis3–ΔT model had a good effect on the simulation of the daily change of stomatal conductance during the critical period of grape growth, and the Jarvis3–ΔT model was the best stomatal conductance model in this study. The results of the study are of great significance for further improving the sustainable use of water resources in grapevines in extremely arid regions.
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Tang, Zhenmin, and Samuel B. Land. "Photosynthesis and Leaf Water Relations in Four American Sycamore Clones." Forest Science 41, no. 4 (November 1, 1995): 729–43. http://dx.doi.org/10.1093/forestscience/41.4.729.
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Abstract Photosynthesis, transpiration, stomatal conductance, and xylem pressure potential were studied to examine clonal variation and clone-by-season interactions in rooted cuttings of four sycamore clones (Platanus occidentalis L.). These physiological parameters were measured during June through November of the second and third growing seasons in the field. Stomatal conductance, xylem pressure potential, and photosynthesis were higher in June-July than in August-November. The four clones did not differ significantly in yearly average photosynthetic rates, but clone 11 tended to have higher rates early in each growing season (June-July) than did the other three clones. Dry periods during August-September of the second season and during October of the third season apparently caused clone 11 to close its stomata more than clone 17, as indicated by significant clone-by-season interactions for reductions in stomatal conductance and transpiration late in the morning. Clone 17 was generally able to maintain high xylem pressure potential, stomatal conductance, and transpiration throughout the growing season, probably because of its large root system. For. Sci. 41(4):729-743.
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Maroco, João P., João S. Pereira, and M. Manuela Chaves. "Stomatal Responses to Leaf-to-Air Vapour Pressure Deficit in Sahelian Species." Functional Plant Biology 24, no. 3 (1997): 381. http://dx.doi.org/10.1071/pp96062.
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Stomatal response to leaf-to-air vapour pressure deficit (LAVPD) was studied in the annual arid zone C4 grasses Schoenefeldia gracilis, Dactyloctenium aegyptium and Eragrostis tremula and in the C3 species, convolvulus, Ipomoea pes-tigridis and Ipomoea vagans. Stomatal responses to LAVPD were consistent with the drought survival strategies adopted by the different species. In drought resistant species (S. gracilis, I. vagansand I. pes-tigridis) stomatal conductance showed a negative response to increasing LAVPD whereas, in drought escaping species (D. aegyptium and E. tremula), stomatal conductance was independent of LAVPD. These observations suggest that resistance to drought was associated with stomatal closure as LAVPD increased, thus reducing the negative effect of a higher evaporative demand on water use efficiency, whereas in drought escaping species stomata showed no response to increasing evaporative demand in the atmosphere.
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Espinoza, Sergio, Samuel Ortega-Farías, and Luis Ahumada-Orellana. "Characterization of stomatal density and size of different vitis vinifera L. cultivars growing in Mediterranean climate conditions." Ciência e Técnica Vitivinícola 39, no. 1 (2024): 196–208. http://dx.doi.org/10.1051/ctv/ctv2024390114.
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The stomatal traits of 13 red and white grapevine cultivars of Vitis vinifera L. established in a cultivar collection garden in central Chile were characterized in this study. The cultivars examined were ‘Cabernet Franc’, ‘Cabernet Sauvignon’, ‘Carmenere’, ‘Cot’, ‘Grenache’, ‘Merlot’, ‘Mourvedre’, ‘Pinot Noir’, ‘Syrah’, ‘Chardonnay’, ‘Marzanne’, ‘Roussane’, and ‘Sauvignon Blanc’. Transparent nail polish peel prints in four adult leaves per vine were obtained and examined under a light microscope at 10 ×. The number of stomata in 0.196 mm2 was counted, and their length and width were measured using image analysis software. With these variables, the stomatal area and stomatal density were obtained. The ‘Cot’ cultivar had the largest stomata and stomatal area, while the ‘Mourvedre’ cultivar had the smallest stomata and stomatal area. ‘Chardonnay’ had the highest number of stomata and stomatal density, while ‘Carmenere’ had the lowest. The red grapevine cultivars exhibited larger and fewer stomata than the white grapevine cultivars, corroborating different adaptations for the environmental modulation of stomatal conductance and transpiration.
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Han, Tuo, Qi Feng, Tengfei Yu, Xiaomei Yang, Xiaofang Zhang, and Kuan Li. "Characteristic of Stomatal Conductance and Optimal Stomatal Behaviour in an Arid Oasis of Northwestern China." Sustainability 14, no. 2 (January 15, 2022): 968. http://dx.doi.org/10.3390/su14020968.
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Stomatal conductance (gs), the process that governs plant carbon uptake and water loss, is fundamental to most Land Surface Models (LSMs). With global change accelerating, more attention should be paid to investigating stomatal behavior, especially in extremely arid areas. In this study, gas exchange measurements and environmental/biological variables observations during growing seasons in 2016 and 2017 were combined to investigate diurnal and seasonal characteristics of gs and the applicability of the optimal stomatal conductance model in a desert oasis vineyard. The results showed that the responses of gs to environmental factors (photosynthesis active radiation, PAR; vapor pressure deficit, VPD; and temperature, T) formed hysteresis loops in the daytime. The stomatal conductance slope, g1, a parameter in the unified stomatal optimal model, varied in different growing seasons and correlated with the soil-to-leaf hydraulic conductance (KL). These results indicated the potential bias when using a constant g1 value to simulate gs and highlighted that the water-use strategy of oasis plants might not be consistent throughout the entire growing season. Our findings further help to achieve a better understanding of stomata behavior in responding to climate change and encourage future efforts toward a more accurate parameterization of gs to improve the modeling of LSMs.
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Costa, Marcus Vinicius de Lima, Pedro Antônio de Lima Félis, Kelvin Jean Santos Masselani, Túlio Lopes Marinho Linard, Luis Alberto Bucci, and Willyam de Lima Vieira. "Organization of leaf vascular system and gas exchange in seedlings of Guazuma ulmifolia Lam. in different light conditions." Scientific Electronic Archives 14, no. 7 (July 1, 2021): 68–73. http://dx.doi.org/10.36560/14720211366.
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In tropical forests, different physiological characteristics of leaves in tree species are evidenced by variations in different incident light conditions. We aim to evaluate gas exchange and organization of leaf vascular system in Guazuma ulmifolia Lam. seedlings under different light conditions. Seedlings were obtained from seeds germinated under greenhouse conditions with controlled environment. Ninety days after germination, seedlings in 8kg pots were transferred to the experimental site to allow acclimatization under sun and shade conditions. The experimental design was completely randomized, with two treatments: full sunlight and artificial shading, limiting the luminosity to about 5% of irradiance. Seedlings were maintained under these conditions for 120 days before measuring gas exchange parameters. We measured photosynthetic rate, stomatal conductance, sub-stomatic CO2 concentration, transpiration, and chlorophyll content. Anatomical analysis measured distance between veins, distance from veins to abaxial epidermis, distance from veins to adaxial epidermis, distance from veins to stomata, total leaf thickness, abaxial epidermis thickness, adaxial epidermis thickness, palisade parenchyma thickness, and spongy parenchyma thickness of foliar gas exchange of G. ulmifolia which presented significant differences between light environments. Photosynthetic rate and stomatal conductance were reduced by 78% and 39%, respectively, in shade, while stomatal conductance increased by 31% in full sunlight. Transpiration showed no significant difference between the two treatments, but chlorophyll content was 30% lower in full sunlight. Distance between veins and distance from veins to stomata showed no difference between treatments, but the other parameters increased in full sunlight. Thus, the results showed that the pioneer species G. ulmifolia presented leaf gas exchange acclimated to environments with high luminosity.
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Buchholcerová, Anna, Peter Fleischer, Dušan Štefánik, Svetlana Bičárová, and Veronika Lukasová. "Specification of Modified Jarvis Model Parameterization for Pinus cembra." Atmosphere 12, no. 11 (October 23, 2021): 1388. http://dx.doi.org/10.3390/atmos12111388.
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The high ambient ozone concentrations cause impairing effects on vegetation leading to plant injuries. The potential ozone uptake to vegetation through open stomata can be quantified using stomatal conductance measurements under the local environmental conditions. This study compares the ozone stomatal conductance to vegetation obtained with a modified Jarvis formula adopted from the Vegetation Manual of United Nations Economic Commission for Europe, and experimental field measurements’ data. The stomatal conductance was measured by a portable photosynthesis and gas exchange analyzer system LiCOR6400. The measurements were performed in the submontane environment of the High Tatra Mountains in Slovakia on Swiss pine (Pinus cembra), as a native species of the local flora. According to previous studies, Swiss pine is considered as an ozone-sensitive species. The modified Jarvis model for the ozone stomatal conductance is compared with the field measurements. The suitable parameterization of the modified Jarvis model for Swiss pine is obtained. The parameterization of stomatal conductance for Swiss pine in the local environment would help understand its specificity and similarity to other conifer species. In the case of using parameterization for a boreal coniferous from the Vegetation Manual of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops, validation of the model with the measurements without temperature adjustment of the conifer chamber achieved a coefficient of determination of R2=0.75. This result is not in contradiction with the previous researches. With the optimal set of parameters, obtained in this paper, the Jarvis model reaches R2=0.85. The data suggest that Jarvis-type models with appropriate parameterization are applicable for stomatal conductance estimation for Pinus cembra when the measurements do not modify the temperature regime.
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Hart, Miranda, E. H. Hogg, and V. J. Lieffers. "Enhanced water relations of residual foliage following defoliation in Populus tremuloides." Canadian Journal of Botany 78, no. 5 (May 1, 2000): 583–90. http://dx.doi.org/10.1139/b00-032.
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Stomatal conductance and leaf water potential of aspen (Populus tremuloides Michx.) were measured in response to defoliation intensity, both in the field and under controlled conditions. There was evidence of increased stomatal conductance in trees with 50 and 98% defoliation, but no change in leaf water potential. Under controlled conditions, stomatal conductance and rate of photosynthesis were measured under high and low vapour pressure deficits (VPD). Under high VPD, overall stomatal conductance and rates of photosynthesis were greatly reduced. However, in both VPD treatments, there was evidence of increased stomatal conductance and compensatory photosynthesis following defoliation. These findings may be due to increases in leaf specific hydraulic conductance following defoliation.Key words: defoliation, stomatal conductance, leaf water potential, compensatory photosynthesis.
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Drake, Paul L., Ray H. Froend, and Peter J. Franks. "Smaller, faster stomata: scaling of stomatal size, rate of response, and stomatal conductance." Journal of Experimental Botany 64, no. 2 (January 2013): 495–505. http://dx.doi.org/10.1093/jxb/ers347.
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Susilo, Agung Wahyu, Sobir Sobir, Adinda Wuriandani, and Desta Wirnas. "Seedling performance of cocoa genotypes (Theobroma cacao L.) in Drought Stress Condition." Pelita Perkebunan (a Coffee and Cocoa Research Journal) 35, no. 3 (December 31, 2019): 167–76. http://dx.doi.org/10.22302/iccri.jur.pelitaperkebunan.v35i3.375.
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Drought stress can affect changes in physiological, morphological, biochemical,and molecular of plant. Plant in drought stress showed slower growthand development than in normal condition. This research aimed to determine the response of cocoa genotypes in seedling phase to drought stress in morphological and stomata character. This research conducted with split-plot design with main plot were water regimes (25% and 100% available water content). Eleven genotypes were used in this research consisted of six genotypes crosses and five genotypes parents. Variables observed were stem diameter, root volume, root length, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, root/shoot ratio, and stomatal conductance. Drought stress decreased values associated with all observed morphological characters and stomata characters. Root/shoot ratio and stomatal conductance can be used to determine genotype with tolerance to drought. Sulawesi 3 x ICCRI 09 showed heighest in root/shoot ratio and stomatal conductance. Sulawesi 3 x ICCRI 09 can be used as candidate of plant material tolerant to drought.
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Carter, Gregory A., and Alan H. Teramura. "Nonsummer stomatal conductance for the invasive vines kudzu and Japanese honeysuckle." Canadian Journal of Botany 66, no. 12 (December 1, 1988): 2392–95. http://dx.doi.org/10.1139/b88-325.
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A field study was conducted in Maryland to estimate nonsummer stomatal conductances on clear days for two invasive woody vine species common to the southeastern United States. Before the first frost in late October, stomatal conductances were similar for kudzu (Pueraria lobata) and Japanese honeysuckle (Lonicera japonica). When minimum predawn air temperature fell to −0.6 °C, kudzu leaves were irreversibly damaged, whereas maximum daily conductance in honeysuckle was unaffected. Maximum conductances in honeysuckle increased to 14 mm s−1 in late November and mid-December, similar to late-spring and summer values. When minimum air temperatures decreased to −2.8 °C in January, conductance still remained above 5 mm s−1. Maximum daily conductance was lowest in early March, corresponding with low leaf temperatures. By mid-April, maximum conductance increased to 10 mm s−1. Conductances suggested that rates of leaf gas exchange in honeysuckle during fall, winter, and spring were relatively high. Carbon gain during this period might thus contribute substantially to the invasive growth characteristic of the species.
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Kangur, Ott, Kathy Steppe, Jeroen D. M. Schreel, Jonas S. von der Crone, and Arne Sellin. "Variation in nocturnal stomatal conductance and development of predawn disequilibrium between soil and leaf water potentials in nine temperate deciduous tree species." Functional Plant Biology 48, no. 5 (2021): 483. http://dx.doi.org/10.1071/fp20091.
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It is widely acknowledged that many plant species can keep stomata open during night. We examined how nocturnal stomatal conductance differs among potted saplings of nine temperate tree species from diverse native habitats in wet and dry soil conditions, and how it affects plant predawn water status. Nocturnal stomatal conductance in dry soil conditions was low in all the species (with a maximum value of 14.6 mmol m–2 s–1); in wet conditions, it was the highest in Populus tremula L., a fast-growing and anisohydric pioneer species, and the lowest in Quercus robur L., a late-successional and isohydric species. Relatively high nocturnal stomatal conductance in wet conditions in P. tremula compared with the other species resulted in the highest difference in water potential values between the leaves and soil at predawn. As drought progressed, different species tended to keep stomata almost closed at night, and the observed differences between anisohydric and isohydric species disappeared. At an ample soil water supply, nocturnal stomatal behaviour was species dependent and varied according to both the water-use and the life strategies of the species. Keeping that in mind, one should therefore be careful when using predawn leaf water potential as a proxy for soil water potential, sampling different species.
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Iacobelli, Antonio, and J. Harry McCaughey. "Stomatal conductance in a northern temperate deciduous forest: temporal and spatial patterns." Canadian Journal of Forest Research 23, no. 2 (February 1, 1993): 245–52. http://dx.doi.org/10.1139/x93-033.
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Stomatal conductance measurements were obtained in the summer of 1989 in a deciduous forest near Chalk River, Ontario. Seasonal changes in stomatal conductance of trembling aspen (Populustremuloides Michx.) and white birch (Betulapapyrifera Marsh.) were related to changes in soil water content. Rehydration of water stores in trees following each of the two major rain events observed over the growing season likely influenced the magnitude of stomatal conductance. Diurnal changes in stomatal conductance were found to be related primarily to changes in solar radiation, vapour-pressure deficit, and air temperature. There was considerable vertical variation in stomatal conductance, such that the canopy could be divided into a total of five layers. There was also considerable variation in stomatal conductance trees.
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Wang, Tiange, Linna Zheng, Dongliang Xiong, Fei Wang, Jianguo Man, Nanyan Deng, Kehui Cui, Jianliang Huang, Shaobing Peng, and Xiaoxia Ling. "Stomatal Ratio Showing No Response to Light Intensity in Oryza." Plants 12, no. 1 (December 23, 2022): 66. http://dx.doi.org/10.3390/plants12010066.
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Stomata control carbon and water exchange between the leaves and the ambient. However, the plasticity responses of stomatal traits to growth conditions are still unclear, especially for monocot leaves. The current study investigated the leaf anatomical traits, stomatal morphological traits on both adaxial and abaxial leaf surfaces, and photosynthetic traits of Oryza leaves developed in two different growth conditions. Substantial variation exists across the Oryza species in leaf anatomy, stomatal traits, photosynthetic rate, and stomatal conductance. The abaxial stomatal density was higher than the adaxial stomatal density in all the species, and the stomatal ratios ranged from 0.35 to 0.46 across species in two growth environments. However, no difference in the stomatal ratio was observed between plants in the growth chamber and outdoors for a given species. Photosynthetic capacity, stomatal conductance, leaf width, major vein thickness, minor vein thickness, inter-vein distance, and stomatal pore width values for leaves grown outdoors were higher than those for plants grown in the growth chamber. Our results indicate that a broad set of leaf anatomical, stomatal, and photosynthetic traits of Oryza tend to shift together during plasticity to diverse growing conditions, but the previously projected sensitive trait, stomatal ratio, does not shape growth conditions.
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Yuza, Steve C., Art L. Youngman, and John C. Pair. "Leaf Conductance and Xylem Water Potential of Ecotypes and Cultivars of Acer saccharum and A. nigrum." HortScience 31, no. 4 (August 1996): 649a—649. http://dx.doi.org/10.21273/hortsci.31.4.649a.
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This study examined physical factors and physiological responses of five different ecotypes and cultivars of Acer saccharum and A. nigrum. The objective was to determine variations in leaf conductance and xylem water potential and correlations associated with their natural geographic distribution. Compared were two ecotypes of sugar maple, Caddo and Wichita Mountains, native to Oklahoma with cultivars Green Mountain and Legacy, plus black maple seedlings from Iowa. Measurements taken included leaf conductance, xylem water potential and soil water potential in a replicated block of 15-year-old trees. The two ecotypes had consistently higher photosynthetic rates, stomatal conductance and transpiration rates than other selections. Xylem water potentials were significantly higher for Caddo maples than Green Mountain, Legacy and Acer nigrum in both predawn and midday samples. This difference in water availability can be associated with a tendency for Caddo to vary its stomatal conductance. The other tree types maintained stable stomatal conductances.
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Li, Ting-Yu, Qi Shi, Hu Sun, Ming Yue, Shi-Bao Zhang, and Wei Huang. "Diurnal Response of Photosystem I to Fluctuating Light Is Affected by Stomatal Conductance." Cells 10, no. 11 (November 11, 2021): 3128. http://dx.doi.org/10.3390/cells10113128.
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Upon a sudden transition from low to high light, electrons transported from photosystem II (PSII) to PSI should be rapidly consumed by downstream sinks to avoid the over-reduction of PSI. However, the over-reduction of PSI under fluctuating light might be accelerated if primary metabolism is restricted by low stomatal conductance. To test this hypothesis, we measured the effect of diurnal changes in stomatal conductance on photosynthetic regulation under fluctuating light in tomato (Solanum lycopersicum) and common mulberry (Morus alba). Under conditions of high stomatal conductance, we observed PSI over-reduction within the first 10 s after transition from low to high light. Lower stomatal conductance limited the activity of the Calvin–Benson–Bassham cycle and aggravated PSI over-reduction within 10 s after the light transition. We also observed PSI over-reduction after transition from low to high light for 30 s at the low stomatal conductance typical of the late afternoon, indicating that low stomatal conductance extends the period of PSI over-reduction under fluctuating light. Therefore, diurnal changes in stomatal conductance significantly affect the PSI redox state under fluctuating light. Moreover, our analysis revealed an unexpected inhibition of cyclic electron flow by the severe over-reduction of PSI seen at low stomatal conductance. In conclusion, stomatal conductance can have a large effect on thylakoid reactions under fluctuating light.
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Lu, Zhenmin, Miguel A. Quiñones, and Eduardo Zeiger. "Temperature dependence of guard cell respiration and stomatal conductance co-segregate in an F2 population of Pima cotton." Functional Plant Biology 27, no. 5 (2000): 457. http://dx.doi.org/10.1071/pp98128.
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In Pima cotton (Gossypium barbadense L.), stomatal conductance shows a strong response to temperature. At high temperature (40˚C), the stomatal conductance of greenhouse- and growth chamber-grown leaves is three and four times higher than that measured at lower temperature (25ºC), respectively. The segregation of stom-atal conductance observed in an F2 population obtained from a cross between a primitive cotton (B368) and a modern Pima line (Pima S-6) increased substantially with temperature in both light and darkness. Furthermore, F2 segregants with high stomatal conductance at high temperature were more sensitive to temperature, showing larger changes in conductance in response to an increase in temperature when compared to F2 segregants having low stomatal conductance. Rates of guard cell respiration measured in enzymatically-cleaned epidermal peels, mechanically isolated from the same F2 plants, showed the same temperature dependence. The temperature-induced respiration enhancement was higher in guard cells with high respiration rates. There were positive correlations between stomatal conductance and guard cell respiration rates, and between stomatal conductance and the sensitivity of respiration to changes in temperature. These results imply that guard cell respiration and stomatal conductance co-segregate in Pima cotton plants, suggesting that guard cell respiration is a component of the sensory transduction pathway controlling stomatal responses to temperature.
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RAHMAN, H. U. "Genetic analysis of stomatal conductance in upland cotton (Gossypium hirsutum L.) under contrasting temperature regimes." Journal of Agricultural Science 143, no. 2-3 (June 2005): 161–68. http://dx.doi.org/10.1017/s0021859605005186.
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Stomatal conductance plays an important role in the heat avoidance mechanism of crop plants. Stomatal conductance in cotton is genetically determined and has been shown to be associated with heat resistance and higher yields. Experiments were carried out with six generations (parental, F1, F2 and back crosses) of three upland cotton crosses under heat-stressed and non-stressed greenhouse and field regimes, to understand the inheritance pattern of stomatal conductance as affected by contrasting temperature regimes. The results revealed significant variation for stomatal conductance due to generations and generation×temperature regime interaction in the three crosses. In general, heat stress reduced stomatal conductance and available genetic variability. Temperature regimes exerted a significant effect on the expression of the genes responsible for stomatal conductance. High temperature or heat stress favoured the expression of genes having additive effects, while absence of heat stress favoured those having dominant effects in two of the three crosses evaluated. The third cross showed the opposite reaction. The results suggest that genes controlling stomatal conductance in the parents of the first two crosses (MNH-552, HR109-RT, CIM-448, CRIS-19) were different from those controlling stomatal conductance in FH-900 and N-Karishma, the parents of the third cross. The selection efficiency of stomatal conductance in segregating populations was likely to be affected by the complexity of its inheritance, environmental dependency, and presence of substantial non-allelic and genotype×temperature regime interactions.
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Ramos-Vázquez, Alfredo, and Víctor L. Barradas. "El effecto del microambiente en la conductividad estomática de Buddleia cordata H. B. K., en la Reserva del Pedregal de San Ángel." Botanical Sciences, no. 62 (May 20, 2017): 63. http://dx.doi.org/10.17129/botsci.1551.
Full textAbstract:
Precipitation seasonality and substratum in Pedregal de San Angel can play a key role on plant water status. Therefore, stomatal conductance (g), water potential (Ψ h), photosynthetically photon flux density (Q), air temperature (Ta) and leaf-air vapour pressure difference (VPD), were measured on leaves of Buddleia cordata H.B.K., because its perennial character and its dominance in the Pedregal. These measurements were carried out during the wet and dry seasons in the Pedregal which is a plant community developing in a lava substratum. The highest values of stomatal conductance were registered in the wet season (330 mmol m-2 s-1), however during the dry season, stomatal conductance was reduced by 54%. Upper limit enveloping curve technique and multiple regression analysis were performed to the data in order to study how g responded to the microenvironment and (Ψ h). Results clearly showed that there was a significant effect of Q, Ta and VPD on g and stomata were more sensitive on humid season than during dry season. (Ψ h), effect was not significant during the humid season, nor the dry season, but annually. Results from these kind of analysis may be very useful during the formulation of mathematics models to simulate or predict stomatal conductance.
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Gándara, José, Silvia Ross, Gastón Quero, Dellacassa Gonzalo, Dellepiane Joaquín, Gonzalo Figarola, and Luis Viega. "Differential water-use efficiency and growth among Eucalyptus grandis hybrids under two different rainfall conditions." Forest Systems 29, no. 2 (July 8, 2020): e006. http://dx.doi.org/10.5424/fs/2020292-16011.
Full textAbstract:
Aim of the study: To analyze the course of leaf water status, water-use efficiency and growth in Eucalyptus grandis and hybrids throughout seasons with different rainfall.Area of study: The study was conducted in northern Uruguay.Methods: A randomized block trial was established containing E. grandis (ABH17), E. grandis × Eucalyptus camaldulensis (GC172), E. grandis × Eucalyptus tereticornis (GT529), and E. grandis × Eucalyptus urophylla (GU08). Predawn leaf water potential (Ψpd) and midday leaf water potential (Ψmd) were measured every six weeks from the age of 16 months, throughout two growing seasons. Stomatal conductance (gs), net photosynthetic rate (A), and leaf-level transpiration (E) were measured once in each growing season, along with leaf carbon isotope discrimination (∆13C) and tree growth. Stomatal density and distribution were studied.Results: ABH17 and GU08 had the lowest daily fluctuation of leaf water potential and showed stronger stomatal regulation; they were hypostomatic, and stomata on the adaxial leaf surfaces remained immature. GC172 and GT529 (Red-Gum hybrids) were amphistomatic and transpired more intensively; they were less efficient in instantaneous and intrinsic water use and grew faster under high soil moisture (inferred from rainfall). Under such conditions, GC172 reached the highest gas-exchange rate due to an increase in tree hydraulic conductance. ABH17 and GU08 were hypostomatic and used water more efficiently because of stronger stomatal regulation.Research highlights: Red-Gum hybrids evidenced less water use efficiency due to lower stomatal regulation, different stomatal features, and distinct growth patterns as a function of soil moisture (inferred from rainfall).Keywords: Eucalypt hybrids; stomatal conductance; water-use efficiency; transpiration.Abbreviations used: Ψpd:predawn leaf water potential;Ψmd: midday leaf water potential; ΔΨ: daily fluctuation of leaf water potential ( ; A: net photosynthetic rate, E: leaf transpiration rate, gs: stomatal conductance, WUE: instantaneous water-use efficiency; WUEi: integrated water-use efficiency; A/E: leaf photosynthesis-to-leaf transpiration ratio; ∆13C: leaf carbon isotope discrimination; K: tree hydraulic conductance; E/∆Ψ: ratio between leaf transpiration and daily fluctuation of leaf water potential; δ13C: natural abundance of 13C.
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Young, Donald R. "Crown architecture, light interception, and stomatal conductance patterns for sympatric deciduous and evergreen species in a forest understory." Canadian Journal of Botany 63, no. 12 (December 1, 1985): 2425–29. http://dx.doi.org/10.1139/b85-346.
Full textAbstract:
Within a mixed deciduous forest in central Virginia, daily patterns of light interception and stomatal conductance were related to crown architecture for the deciduous Asimina triloba and the evergreen Ilex opaca. For A. triloba, branches were up to 54% longer, the bifurcation ratio was 15% lower, branch internode lengths were 15% greater, and leaf angles were closer to the horizontal plane (9 vs. 22°) than for I. opaca, possibly contributing to a greater percentage of sunlit leaves for A. triloba at 1100 and 1400 (22.4 vs. 10.0 and 30.0 vs. 10.1%, respectively). Maximum stomatal conductances to water vapor diffusion were 4.0 and 4.6 mm∙s−1 for sunlit leaves of A. triloba and I. opaca, respectively. Sunlit and shaded leaf stomatal conductances were similar in A. triloba throughout the day, but in I. opaca, values for sunlit leaves were up to 1.3 mm∙s−1 greater than values measured in shaded leaves. In addition, stomatal conductances for shaded leaves of A. triloba remained approximately 1.0 mm∙s−1 greater than for I. opaca throughout most of the afternoon. Therefore, within a forest understory environment, sympatric deciduous and evergreen species may differ in crown architecture, light interception, and stomatal conductance patterns.
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Henson, IE, CR Jensen, and NC Turner. "Leaf Gas Exchange and Water Relations of Lupins and Wheat. III. Abscisic Acid and Drought-Induced Stomatal Closure." Functional Plant Biology 16, no. 5 (1989): 429. http://dx.doi.org/10.1071/pp9890429.
Full textAbstract:
Changes in the content of endogenous abscisic acid (ABA) were followed in glasshouse experiments during stomatal closure induced by drought in leaves of lupin (Lupinus cosentinii Guss. cv. Eregulla) and wheat (Triticum aestivum L. cvv. Gamenya and Warigal), species which differ in stomatal sensitivity to changes in leaf water potential. Increases in bulk leaf ABA concentration were closely correlated with decreases in leaf conductance in both species. In lupin, substantial increases in ABA and decreases in conductance occurred over a very narrow range of leaf water potential. ABA concentrations in wheat leaves were highly negatively correlated with bulk leaf turgor, but there was no significant relationship between ABA and turgor in lupin. However, ABA accumulated progressively in the leaves of both species as soil water content decreased. Stomatal closure in lupin could be induced by supplying exogenous ABA to detached leaves via the transpiration stream at concentrations of 10-4 to 10-2 mol m-3 of (+)-ABA. Abaxial stomata closed more readily than those on the adaxial surface in response to both drought and applied ABA. Stomatal response to ABA was not affected by the presence of the cytokinin zeatin, and zeatin by itself had no effect on conductance. When treatments designed to reduce endogenous cytokinin concentrations were imposed (prolonged leaf detachment or prior drought), stomatal response to low concentrations of ABA was enhanced. However, such treatments did not significantly change the stomatal response to high ABA concentrations, nor affect the stomatal conductance of leaves supplied with water alone. It is concluded that drought-induced stomatal closure could be mediated by ABA in both wheat and lupin, despite the initially small change in leaf water status in the latter species.
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Robinson, SP, WJR Grant, and BR Loveys. "Stomatal Limitation of Photosynthesis in Abscisic Acid-Treated and in Water-Stressed Leaves Measured at Elevated CO2." Functional Plant Biology 15, no. 4 (1988): 495. http://dx.doi.org/10.1071/pp9880495.
Full textAbstract:
Feeding 10-5M (�)-abscisic acid (ABA) via the petioles of detached leaves of apricot (Prunus armeniaca) or sunflower (Helianthus annuus) decreased stomatal conductance and assimilation rate but not the calculated intercellular CO2 concentration (Ci) suggesting non-stomatal as well as stomatal inhibition of photosynthesis. Evidence for non-stomatal inhibition was not observed in spinach (Spinacia oleracea). There was no significant decrease in rates of electron transport nor ribulosebisphosphate carboxylase (Rubisco) activity in intact chloroplasts isolated from ABA-treated sunflower leaves. Oxygen evolution by leaf discs with 3% CO2 in the gas phase was inhibited in ABA- treated sunflower and apricot leaves but not in spinach; the inhibition was only half as great as the inhibition of assimilation rate at ambient CO2. The quantum yield of oxygen evolution decreased in ABA-treated sunflower leaves in proportion to the decrease in the light-saturated rate. There was no significant difference in room temperature chlorophyll fluorescence of ABA-treated leaves compared to controls. Stomatal conductance of sunflower leaves decreased by more than 90% when the CO2 concentration was increased from 340 ppm to 1000 ppm but at much higher CO2 concentrations the stomata appeared to reopen. Stomatal conductance at 2-3% CO2 (20 000-30 000 ppm) was 50% that at ambient CO2. This reopening of stomata at high CO2 was inhibited in previously water-stressed or ABA-treated plants. In unstressed leaves, the maximum rate of oxygen evolution occurred at 0.5-2% CO2 but in ABA-treated leaves 10-15% CO2 was required for maximum rates. It is suggested that stomatal closure may limit photosynthesis in ABA-treated or previously water-stressed leaves even at the relatively high CO2 concentrations normally used in the leaf disc oxygen electrode. The inhibition of photosynthesis by ABA is largely overcome at saturating CO2. The apparent non-stomatal inhibition suggested by gas exchange measurements and the decreased quantum yield could be explained by patchy stomatal closure in response to ABA.