scholarly journals Seasonal change in response of stomatal conductance to vapor pressure deficit and three phytohormones in three tree species

2019 ◽  
Vol 14 (12) ◽  
pp. 1682341 ◽  
Author(s):  
Jing Li ◽  
Gui-Zhai Zhang ◽  
Xia Li ◽  
Yu Wang ◽  
Fang-Zhi Wang ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Vapor Pressure ◽  
Seasonal Change ◽  
Tree Species ◽  
Vapor Pressure Deficit

scholarly journals Role of Species and Planting Configuration on Transpiration and Microclimate for Urban Trees

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 825
Author(s):  
Dan Zhao ◽  
Quanhuan Lei ◽  
Yajie Shi ◽  
Mengdi Wang ◽  
Sibo Chen ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Vapor Pressure ◽  
Transpiration Rate ◽  
Tree Species ◽  
Vapor Pressure Deficit ◽  
Physiological Parameters ◽  
Urban Trees ◽  
Deciduous Tree ◽  
Deciduous Trees ◽  
Urban Microclimate

Research Highlights: To demonstrate the effectiveness of configuration modes and tree types in regulating local microclimate. Background and Objectives: Urban trees play an essential role in reducing the city’s heat load. However, the influence of urban trees with different configurations on the urban thermal environment has not received enough attention. Herein we show how spatial arrangement and foliage longevity, deciduous versus evergreen, affect transpiration and the urban microclimate. Materials and Methods: We analyzed the differences between physiological parameters (transpiration rate, stomatal conductance) and meteorological parameters (air temperature, relative humidity, vapor pressure deficit) of 10 different species of urban trees (five evergreen and five deciduous tree species), each of which had been planted in three configuration modes in a park and the campus green space in Xi’an. By manipulating physiological parameters, crown morphology, and plant configurations, we explored how local urban microclimate could be altered. Results: (1) Microclimate regulation capacity: group planting (GP) > linear planting (LP) > individual planting (IP). (2) Deciduous trees (DT) regulated microclimate better than evergreen trees (ET). Significant differences between all planting configurations during 8 to 16 h were noted for evergreen trees whereas for deciduous trees, all measurement times were significantly different. (3) Transpiration characteristics: GP > LP > IP. The transpiration rate (E) and stomatal conductance (Gs) of GP were the highest. Total daily transpiration was ranked as group planting of deciduous (DGP) > linear planting of deciduous (DLP) > group planting of evergreen (EGP) > linear planting of evergreen (ELP) > isolated planting of deciduous (DIP) > isolated planting of evergreen (EIP). (4) The microclimate effects of different tree species and configuration modes were positively correlated with E, Gs, and three dimensional green quantity (3DGQ), but weakly correlated with vapor pressure deficit (VpdL). (5) A microclimate regulation capability model of urban trees was developed. E, Gs, and 3DGQ could explain 93% variation of cooling effect, while E, Gs, VpdL, and 3DGQ could explain 85% variation of humidifying effect. Conclusions: This study demonstrated that the urban heat island could be mitigated by selecting deciduous broadleaf tree species and planting them in groups.

scholarly journals Ecophysiological Vulnerability to Climate Change in Mexico City’s Urban Forest

2021 ◽  
Vol 9 ◽  
Author(s):  
Victor L. Barradas ◽  
Manuel Esperon-Rodriguez
Keyword(s):  
Climate Change ◽  
Stomatal Conductance ◽  
Vapor Pressure ◽  
Water Potential ◽  
Tree Species ◽  
Environmental Variables ◽  
Vapor Pressure Deficit ◽  
Urban Forest ◽  
Urban Climate ◽  
Vulnerability To Climate Change

Urban forests play an important role in regulating urban climate while providing multiple environmental services. These forests, however, are threatened by changes in climate, as plants are exposed not only to global climate change but also to urban climate, having an impact on physiological functions. Here, we selected two physiological variables (stomatal conductance and leaf water potential) and four environmental variables (air temperature, photosynthetically active radiation, vapor pressure deficit, and water availability) to compare and evaluate the ecophysiological vulnerability to climate change of 15 dominant tree species from Mexico City’s urban forest. The stomatal conductance response was evaluated using the boundary-line analysis, which allowed us to compare the stomatal response to changes in the environment among species. Our results showed differential species responses to the environmental variables and identified Buddleja cordata and Populus deltoides as the least and most vulnerable species, respectively. Air temperatures above 33°C and vapor pressure deficit above 3.5 kPa limited the stomatal function of all species. Stomatal conductance was more sensitive to changes in leaf water potential, followed by vapor pressure deficit, indicating that water is a key factor for tree species performance in Mexico City’s urban forest. Our findings can help to optimize species selection considering future climate change by identifying vulnerable and resilient species.

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

HortScience ◽  
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.

Response of Stomatal Conductance to Vapor Pressure Deficit in Leaves of Four Trees at the Campus of Shandong University

2014 ◽  
Vol 522-524 ◽  
pp. 1055-1058
Author(s):  
Jing Li ◽  
Xiao Guang Wang ◽  
Gui Zhai Zhang ◽  
Xue Wei Hou ◽  
Xiao Ming Li
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Response Pattern ◽  
Populus Deltoides ◽  
Shandong Province ◽  
Populus Euramericana ◽  
Parabolic Curve

Response of gas exchange to VPD in leaves of four trees (Prunus serrulata, Prunus lannesiana, Populus deltoides I-69 (I-69) and Populus × euramericana Neva (I-107)) at the campus of Shandong University in Jinan, Shandong Province were measured. The result showed that: the stomatal conductance increased with increasing VPD, and gs reached gs-max at intermediate VPD, and a steady decline in gs with further increases in VPD. This response pattern was fitted by a parabolic curve (gs=aD2+bD+c, D=VPD, R2>0.52). The gs-max at intermediate VPD with changing VPD showed that there was an optimal VPD (or RH) to plants. Therefore, while VPD (or RH) was higher or lower than the optimal VPD (or RH) of plant, gs would decrease. The response of gs to VPD in I-69 and I-107 were much more sensitive than P. serrulata and P. lannesiana.

Near stream groundwater table fluctuations impact transpiration rates of riparian plants: a field study with stomatal conductance and dendrometry measurements

2021 ◽  
Author(s):  
Stefano Martinetti ◽  
Simone Fatichi ◽  
Marius Floriancic ◽  
Paolo Burlando ◽  
Peter Molnar
Keyword(s):  
Stomatal Conductance ◽  
Vapor Pressure ◽  
Water Table ◽  
Vapor Pressure Deficit ◽  
Growing Season ◽  
Groundwater Table ◽  
Short Term ◽  
Riparian Plants ◽  
Gravel Bed ◽  
Riparian Trees

<p>Vegetation establishment, growth, and succession in riparian ecosystems are linked to river and groundwater dynamics. This is especially true in Alpine gravel-bed rivers with wide floodplains and a strong river-aquifer exchange. Here we provide data evidence of riparian plant response to short-term groundwater table fluctuations in a braided gravel-bed river (Maggia). We used indirect physiological variables for photosynthesis and transpiration – stomatal conductance g<sub>s</sub> and daily variation in stem diameter ΔD<sub>d</sub> – which we measured at six mature riparian trees of the Salicaceae family, one Populus nigra and one Alnus incana specimen at two sites during two growing seasons. The site where g<sub>s</sub> measurements were conducted showed a greater depth to groundwater with higher variability compared to the site were dendrometers were placed.</p><p>We analysed the data by means of two different random forest regression algorithms for the two study sites. One with the transpiration-induced daily tree diameter drop during the growing season 2017 as the dependent variable, and one with the raw g<sub>s</sub> measurement sequence, obtained on 10 days throughout the growing season 2019, as the dependent variable. In both algorithms the independent variables consisted of meteorological measures (locally measured and at valley scale) and of groundwater and river stages near the individual plants. We also separated the g<sub>s</sub> measurements into low and high groundwater stage conditions observed during the g<sub>s</sub> field campaign and applied traditional regression analysis of g<sub>s </sub>on vapor pressure deficit VPD and global radiation r<sub>g</sub> for the 2 groundwater stage conditions separately.</p><p>The data analyses demonstrate that:</p><p>(a) short-term variation of the groundwater table affects riparian vegetation: at the site with deeper groundwater, the water table depth was the best predictor of g<sub>s</sub> variability, while at the site with shallower groundwater, temperature and vapor pressure deficit were the best predictors of ΔD<sub>d</sub>  variability;</p><p>(b) instantaneous stomatal conductance is related to vapor pressure deficit (VPD), but conditioned by groundwater levels, with higher stomatal conductance for the same radiative input and VPD when the water table was higher.</p><p>(c) local micro-climate measured at tree locations had a stronger predictive power for g<sub>s</sub> than valley scale climate, suggesting local climate may be an important control on vegetated stands on gravel bars.</p><p>Even though the considered plants are located in close proximity to the river and could be considered to be unaffected by water stress, our analysis provides evidence of riparian trees undertaking physiological adjustments to transpiration in response to groundwater stage, depending on their riparian floodplain settings. In the heavily regulated Maggia river this has implications on the minimum flow release by dams, as prolonged periods of low water stage in the river will lead to a decrease in groundwater stage, and subsequently in reduced growth of phreatophytic riparian plants on the floodplain. We argue such plant-scale measurements should be helpful for the optimisation of flow release levels in regulated riparian systems.</p>

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