Seasonal Patterns of Photosynthesis and Stomatal Conductance in Lowbush Blueberry Plants Managed in a Two-year Production Cycle

Seasonal patterns of CO2 assimilation (ACO2), leaf water potential (ψ1) and stomatal conductance (g1) were studied in three clones (`Augusta', `Brunswick', and `Chignecto') of lowbush blueberry (Vaccinium angustifolium Ait.) over two growing seasons. Plants were managed in a 2-year cycle of fruiting (year 1) and burn-prune (year 2). In the fruiting year, ACO2 was lowest in mid-June and early September. Rates peaked between 10 and 31 July and declined after fruit removal in late August. Compared with the fruiting year, ACO2 in the prune year was between 50% and 130% higher in the early season, and between 80% and 300% higher in mid-September. In both years, however, mid-season maximum ACO2 for each clone was between 9 and 10 μmol·m–2·s–1CO2. Assimilation of CO2 increased with increasing photosynthetic photon flux (PPF) to between 500 and 600 μmol·s–1·m–2 in `Augusta' and `Brunswick', and to between 700 and 800 μmol·s–1·m–2 in `Chignecto'. Midday ψ1 was generally lower in the prune year than in the fruiting year, reflecting year-to-year differences in soil water content. Stomatal conductance (g1), however, was generally higher in the prune year than in the fruiting year over similar vapor pressure deficit (VPD) ranges, especially in June and September when prune year g1 was often twice that observed in the fruiting year. In the fruiting year, g1 declined through the day in response to increasing VPD in June, but was quite constant in mid-season. It tended to be higher in `Augusta' than in the other two clones. Stomatal closure imposes limitations on ACO2 in lowbush blueberries, but not all seasonal change in C-assimilative capacity can be explained by changes in g1.

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Characteristic of Stomatal Conductance and Optimal Stomatal Behaviour in an Arid Oasis of Northwestern China

Sustainability ◽

10.3390/su14020968 ◽

2022 ◽

Vol 14 (2) ◽

pp. 968

Author(s):

Tuo Han ◽

Qi Feng ◽

Tengfei Yu ◽

Xiaofang Zhang ◽

Xiaomei Yang ◽

...

Keyword(s):

Stomatal Conductance ◽

Land Surface ◽

Vapor Pressure Deficit ◽

Hysteresis Loops ◽

Growing Seasons ◽

Biological Variables ◽

Seasonal Characteristics ◽

Surface Models ◽

Desert Oasis ◽

Water Use Strategy

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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Effects of changes in the photosynthetic photon flux density on net gas exchange of Citrus limon and Nicotiana tabacum

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202004000200002 ◽

2004 ◽

Vol 16 (2) ◽

pp. 77-82 ◽

Cited By ~ 4

Author(s):

Carlos Pimentel ◽

Rafael Vasconcelos Ribeiro ◽

Mauro Guida dos Santos ◽

Ricardo Ferraz de Oliveira ◽

Eduardo Caruso Machado

Keyword(s):

Nicotiana Tabacum ◽

Stomatal Conductance ◽

Gas Exchange ◽

Stomatal Closure ◽

Woody Species ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Citrus Limon ◽

Photosynthetic Photon Flux

The objective of this study was to evaluate the effects of changes in the photosynthetic photon flux density (PPFD) on net gas exchange of Citrus limon, a woody species, and Nicotiana tabacum, an herbaceous species. When PPFD was increased from 50 to 350 mumol.m-2.s-1 and returned to 50 mumol.m-2.s-1 after 60 min, the CO2 assimilation rate (A) increased and stabilized after 15 min in both species. Stomatal conductance (g s), however, continued to increase. After returning to low PPFD, A immediately diminished to a low value for both lemon and tobacco. Stomatal conductance of lemon diminished slowly over 60 min, whereas g s for tobacco took only 15 min to decrease. This difference in behavior is probably due to over-sensitivity of stomata of woody species, such as Citrus, when exposed to high light, retarding stomatal closure on return to low PPFD. Furthermore, when lemon, growing at a PPFD of 300 mumol.m-2.s-1, was submitted to a step increase of 600 mumol.m-2.s-1, there was an oscillatory behavior of A and g s requiring 150 min to stabilize. The causes of this behavior are discussed with respect to improved intrinsic water use efficiency by stomatal closure.

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Stomatal Conductance Responses of Acacia caven to Seasonal Patterns of Water Availability at Different Soil Depths in a Mediterranean Savanna

Water ◽

10.3390/w10111534 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1534 ◽

Cited By ~ 1

Author(s):

Marcelo Sepulveda M. ◽

Horacio Bown ◽

Bonifacio Fernandez L.

Keyword(s):

Stomatal Conductance ◽

Water Availability ◽

Vapor Pressure Deficit ◽

Root Zone ◽

Seasonal Patterns ◽

Wet Season ◽

Central Chile ◽

Seasonally Dry ◽

Acacia Caven ◽

Plant Water Use

Soil water availability controls plant productivity in seasonally dry ecosystems, although plant water use at different soil depths and times is, to the best of our knowledge, not clearly understood. Environmental variables at the canopy level and the soil volumetric water content (VWC) at five different soil depths were continuously recorded for three years (2011–2014) in an Acacia caven savanna site in central Chile. Stomatal conductance ( g s ) was measured every hour during daytime for 42 days distributed across the study period. Values of g s were weakly controlled by photosynthetically active radiation, vapor pressure deficit, and leaf temperature when considering the whole series. The variance proportion being explained increased from 5% to 20% if the whole series was partitioned into a dry and a wet season. According to the above, A. caven exhibited a more anisohydric behavior than previously thought. When we added the VWC in the root zone, to the g s atmospheric variables model, R2 increased to 47% when separately considering the dry and wet seasons. However, we did not find a differentiated use of water in the root zone, but instead a joint activity of the radicular system within the top 100 cm of the soil controlling g s .

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Assessment of Canopy Conductance Responses to Vapor Pressure Deficit in Eight Hazelnut Orchards Across Continents

Frontiers in Plant Science ◽

10.3389/fpls.2021.767916 ◽

2021 ◽

Vol 12 ◽

Author(s):

Gaia Pasqualotto ◽

Vinicio Carraro ◽

Eloy Suarez Huerta ◽

Tommaso Anfodillo

Keyword(s):

Gas Exchange ◽

Vapor Pressure ◽

Vapor Pressure Deficit ◽

Leaf Gas Exchange ◽

Stomatal Closure ◽

Thermal Dissipation ◽

Canopy Conductance ◽

Correct Identification ◽

Potential Productivity ◽

Growing Seasons

A remarkable increase in vapor pressure deficit (VPD) has been recorded in the last decades in relation to global warming. Higher VPD generally leads to stomatal closure and limitations to leaf carbon uptake. Assessing tree conductance responses to VPD is a key step for modeling plant performances and productivity under future environmental conditions, especially when trees are cultivated well outside their native range as for hazelnut (Corylus spp.). Our main aim is to assess the stand-level surface canopy conductance (Gsurf) responses to VPD in hazelnut across different continents to provide a proxy for potential productivity. Tree sap flow (Fd) was measured by Thermal dissipation probes (TDP) probes (six per sites) in eight hazelnut orchards in France, Italy, Georgia, Australia, and Chile during three growing seasons since 2016, together with the main meteorological parameters. We extracted diurnal Fd to estimate the canopy conductance Gsurf.. In all the sites, the maximum Gsurf occurred at low values of VPD (on average 0.57 kPa) showing that hazelnut promptly avoids leaf dehydration and that maximum leaf gas exchange is limited at relatively low VPD (i.e., often less than 1 kPa). The sensitivity of the conductance vs. VPD (i.e., -dG/dlnVPD) resulted much lower (average m = −0.36) compared to other tree species, with little differences among sites. We identified a range of suboptimal VPD conditions for Gsurf maximization (Gsurf > 80% compared to maximum) in each site, named “VPD80,” which multiplied by the mean Gsurf might be used as a proxy for assessing the maximum gas exchange of the orchard with a specific management and site. Potential gas exchange appeared relatively constant in most of the sites except in France (much higher) and in the driest Australian site (much lower). This study assessed the sensitivity of hazelnut to VPD and proposed a simple proxy for predicting the potential gas exchange in different areas. Our results can be used for defining suitability maps based on average VPD conditions, thus facilitating correct identification of the potentially most productive sites.

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Effect of Mycorrhizal Fungi on Gas Exchange of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment

HortScience ◽

10.21273/hortsci.33.3.501c ◽

1998 ◽

Vol 33 (3) ◽

pp. 501c-501

Author(s):

Andrés A. Estrada-Luna ◽

Jonathan N. Egilla ◽

Fred T. Davies

Keyword(s):

Tissue Culture ◽

Stomatal Conductance ◽

Gas Exchange ◽

Vapor Pressure ◽

Mycorrhizal Fungi ◽

Vapor Pressure Deficit ◽

Psidium Guajava ◽

Glomus Etunicatum ◽

Plant Establishment ◽

Use Efficiency

The effect of mycorrhizal fungi on gas exchange of micropropagated guava plantlets (Psidium guajava L.) during acclimatization and plant establishment was determined. Guava plantlets (Psidium guajava L. cv. `Media China') were asexually propagated through tissue culture and acclimatized in a glasshouse for eighteen weeks. Half of the plantlets were inoculated with ZAC-19, which is a mixed isolate containing Glomus etunicatum and an unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 (g P/ml. Gas exchange measurements included photosynthetic rate (A), stomatal conductance (gs), internal CO2 concentration (Ci), transpiration rate (E), water use efficiency (WUE), and vapor pressure deficit (VPD). Measurements were taken at 2, 4, 8 and 18 weeks after inoculation using a LI-6200 portable photosynthesis system (LI-COR Inc. Lincoln, Neb., USA). Two weeks after inoculation, noninoculated plantlets had greater A compared to mycorrhizal plantlets. However, 4 and 8 weeks after inoculation, mycorrhizal plantlets had greater A, gs, Ci and WUE. At the end of the experiment gas exchange was comparable between noninoculated and mycorrhizal plantlets.

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Light Quality Affects Water Use of Sweet Basil by Changing Its Stomatal Development

Agronomy ◽

10.3390/agronomy11020303 ◽

2021 ◽

Vol 11 (2) ◽

pp. 303

Author(s):

Sungeun Lim ◽

Jongyun Kim

Keyword(s):

Stomatal Conductance ◽

Blue Light ◽

Water Use ◽

Growth Parameters ◽

Stomatal Density ◽

Photon Flux ◽

Photon Flux Density ◽

Stomatal Development ◽

Sweet Basil ◽

Stomatal Responses

Different light qualities affect plant growth and physiological responses, including stomatal openings. However, most researchers have focused on stomatal responses to red and blue light only, and the direct measurement of evapotranspiration has not been examined. Therefore, we quantified the evapotranspiration of sweet basil under various red (R), green (G), and blue (B) combinations using light-emitting diodes (LEDs) and investigated its stomatal responses. Seedlings were subjected to five different spectral treatments for two weeks at a photosynthetic photon flux density of 200 µmol m−2 s−1. The ratios of the RGB light intensities were as follows: R 100% (R100), R:G = 75:25 (R75G25), R:B = 75:25 (R75B25), R:G:B = 60:20:20 (R60G20B20), and R:G:B = 31:42:27 (R31G42B27). During the experiment, the evapotranspiration of the plants was measured using load cells. Although there were no significant differences in growth parameters among the treatments, the photosynthetic rate and stomatal conductance were higher in plants grown under blue LEDs (R75B25, R60G20B20, and R31G42B27) than in the R100 treatment. The amount of water used was different among the treatments (663.5, 726.5, 728.7, 778.0, and 782.1 mL for the R100, R75G25, R60G20B20, R75B25, and R31G42B27 treatments, respectively). The stomatal density was correlated with the blue light intensity (p = 0.0024) and with the combined intensity of green and blue light (p = 0.0029); therefore, green light was considered to promote the stomatal development of plants together with blue light. Overall, different light qualities affected the water use of plants by regulating stomatal conductance, including changes in stomatal density.

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Transpiration Response to Vapor Pressure Deficit in Field Grown Peanut

Peanut Science ◽

10.3146/ps11-13.1 ◽

2012 ◽

Vol 39 (1) ◽

pp. 53-61 ◽

Cited By ~ 6

Author(s):

Maria Balota ◽

Steve McGrath ◽

Thomas G. Isleib ◽

Shyam Tallury

Keyword(s):

Vapor Pressure ◽

Soil Water ◽

Water Deficit ◽

Water Conservation ◽

Vapor Pressure Deficit ◽

Stomatal Closure ◽

Genotypic Variation ◽

Moisture Stress ◽

Breeding Lines ◽

Wide Range

Abstract Water deficit, i.e., rainfall amounts and distribution, is the most common abiotic stress that limits peanut production worldwide. Even though extensive research efforts have been made to improve drought tolerance in peanut, performance of genotypes largely depends upon the environment in which they grow. Based on greenhouse experiments, it has been hypothesized that stomata closure under high vapor pressure deficit (VPD) is a mechanism of soil water conservation and it has been shown that genotypic variation for the response of transpiration rate to VPD in peanut exists. The objective of this study was to determine the relationship between stomatal conductance (gs) and VPD for field grown peanut in Virginia-Carolina (VC) rainfed environments. In 2009, thirty virginia-type peanut cultivars and advanced breeding lines were evaluated for gs at several times before and after rain events, including a moisture stress episode. In 2010, eighteen genotypes were evaluated for gs under soil water deficit. In 2009, VPD ranged from 1.3 to 4.2 kPa and in 2010 from 1.78 to 3.57 kPa. Under water deficit, genotype and year showed a significant effect on gs (P = 0.0001), but the genotype × year interaction did not. During the water deficit episodes while recorded gs values were relatively high, gs was negatively related to VPD (R2 = 0.57, n = 180 in 2009; R2 = 0.47, n = 108 in 2010), suggesting that stomata closure is indeed a water conservation mechanism for field grown peanut. However, a wide range of slopes among genotype were observed in both years. Genotypes with significant negative relationships of gs and VPD under water deficit in both years were Florida Fancy, Gregory, N04074FCT, NC-V11, and VA-98R. While Florida Fancy, Gregory, and NC-V11 are known to be high yielding cultivars, VA-98R and line N04074FCT are not. The benefit of stomatal closure during drought episodes in the VC environments is further discussed in this paper.

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Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202004000300005 ◽

2004 ◽

Vol 16 (3) ◽

pp. 155-161 ◽

Cited By ~ 38

Author(s):

Mara de Menezes de Assis Gomes ◽

Ana Maria Magalhães Andrade Lagôa ◽

Camilo Lázaro Medina ◽

Eduardo Caruso Machado ◽

Marcos Antônio Machado

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Stomatal Conductance ◽

Water Potential ◽

Leaf Water Potential ◽

Acid Content ◽

Stomatal Closure ◽

Leaf Water ◽

Orange Trees ◽

Abscisic Acid Content

Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

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Leaf Temperature and Vapour Pressure Deficit (VPD) Driving Stomatal Conductance and Biochemical Processes of Leaf Photosynthetic Rate in a Subtropical Evergreen Coniferous Plantation

Sustainability ◽

10.3390/su10114063 ◽

2018 ◽

Vol 10 (11) ◽

pp. 4063 ◽

Cited By ~ 2

Author(s):

Yue Li ◽

Lei Zhou ◽

Shaoqiang Wang ◽

Yonggang Chi ◽

Jinghua Chen

Keyword(s):

Stomatal Conductance ◽

Photosynthetic Rate ◽

Vapour Pressure Deficit ◽

Leaf Temperature ◽

Slash Pine ◽

Seasonal Patterns ◽

Subtropical China ◽

Biochemical Processes ◽

Leaf Photosynthetic Rate ◽

Positive Effect

Photosynthesis is arguably the most important biochemical process on Earth, which is dramatically influenced by environmental conditions. How environmental factors drive stomatal conductance and biochemical processes of leaf photosynthetic rate has not been sufficiently investigated in subtropical China. In this study, we analysed the effects of stomatal and biochemical parameters on the photosynthetic rate of native Masson’s pine (Pinus massoniana Lamb.) and exotic slash pine (Pinus elliottii Engelm.) in response to leaf temperature and vapour pressure deficit (VPD) in subtropical China, based on leaf gas exchange measurements in 2016. Our results showed that there was no significant difference in the light-saturated photosynthetic rate (Asat) between native Masson’s pine and exotic slash pine. The seasonal patterns of maximum rate of the carboxylation (Vcmax25) were basically consistent with seasonal patterns of Asat for both species. The positive effect of leaf temperature on Asat was mainly produced through its positive effect on Vcmax25. Leaf temperature had no significant effect on stomatal conductance. Vcmax25 and gs simultaneously affected Asat in response to VPD. Our results highlighted the importance of biochemical processes in limiting leaf photosynthetic rate in response to environmental conditions in subtropical evergreen coniferous plantations.

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Environmental controls over methanol emission from leaves

Biogeosciences Discussions ◽

10.5194/bgd-4-2593-2007 ◽

2007 ◽

Vol 4 (4) ◽

pp. 2593-2640 ◽

Cited By ~ 3

Author(s):

P. Harley ◽

J. Greenberg ◽

Ü. Niinemets ◽

A. Guenther

Keyword(s):

Stomatal Conductance ◽

Leaf Growth ◽

Dry Mass ◽

Leaf Temperature ◽

Photon Flux ◽

Photon Flux Density ◽

Emission Model ◽

Production Term ◽

Methanol Production ◽

Environmental Controls

Abstract. Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation. Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.3 to 38 μg g (dry mass)−1 h−1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.4 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b), with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production. Although the short-term dynamics of methanol emissions can be successfully modeled only if stomatal conductance and compound solubility are taken into account, emissions on longer time scales will be determined by rates of methanol production, controls over which remain to be investigated.

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