scholarly journals Supplementary material to "Observations of Aerosol-Vapor Pressure Deficit-Evaporative Fraction coupling over India"

2021 ◽  
Author(s):  
Chandan Sarangi ◽  
Tirthankar Chakraborty ◽  
Sachchidanand Tripathi ◽  
Mithun Krishnan ◽  
Ross Morrison ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Evaporative Fraction ◽  
Supplementary Material

scholarly journals A Recent Systematic Increase in Vapor Pressure Deficit over Tropical South America

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Armineh Barkhordarian ◽  
Sassan S. Saatchi ◽  
Ali Behrangi ◽  
Paul C. Loikith ◽  
Carlos R. Mechoso
Keyword(s):  
South America ◽  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Climate Feedback ◽  
Evaporative Fraction ◽  
Surface Energy Fluxes ◽  
Detection Analysis ◽  
Attribution Analysis ◽  
Positive Climate ◽  
Tropical South America

Abstract We show a recent increasing trend in Vapor Pressure Deficit (VPD) over tropical South America in dry months with values well beyond the range of trends due to natural variability of the climate system defined in both the undisturbed Preindustrial climate and the climate over 850–1850 perturbed with natural external forcing. This trend is systematic in the southeast Amazon but driven by episodic droughts (2005, 2010, 2015) in the northwest, with the highest recoded VPD since 1979 for the 2015 drought. The univariant detection analysis shows that the observed increase in VPD cannot be explained by greenhouse-gas-induced (GHG) radiative warming alone. The bivariate attribution analysis demonstrates that forcing by elevated GHG levels and biomass burning aerosols are attributed as key causes for the observed VPD increase. We further show that There is a negative trend in evaporative fraction in the southeast Amazon, where lack of atmospheric moisture, reduced precipitation together with higher incoming solar radiation (~7% decade−1 cloud-cover reduction) influences the partitioning of surface energy fluxes towards less evapotranspiration. The VPD increase combined with the decrease in evaporative fraction are the first indications of positive climate feedback mechanisms, which we show that will continue and intensify in the course of unfolding anthropogenic climate change.

scholarly journals Observations of Aerosol-Vapor Pressure Deficit-Evaporative Fraction coupling over India

2021 ◽  
Author(s):  
Chandan Sarangi ◽  
Tirthankar Chakraborty ◽  
Sachchidanand Tripathi ◽  
Mithun Krishnan ◽  
Ross Morrison ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Gross Primary Production ◽  
Stomatal Closure ◽  
Aerodynamic Resistance ◽  
North India ◽  
Physiological Control ◽  
Evaporative Fraction ◽  
Aerosol Loading ◽  
Depth Analysis

Abstract. North India is a densely populated subtropical region with heavy aerosol loading, frequent heatwaves and strong atmosphere-biosphere coupling, making it ideal for studying the impacts of aerosols and temperature variation on latent heat flux (LH) and evaporative fraction (EF). Here, using in situ observations during the onset of the summer monsoon over a semi-natural grassland site in this region, we confirm that strong co-variability exists among aerosols, LH, air temperature (Tair) and vapor pressure deficit (VPD). Since the surface evapotranspiration is strongly controlled by both physical (available energy and moisture demand) and physiological (canopy and aerodynamic resistance) factors, we separately analyze our data for different combinations of aerosols and Tair/VPD changes. We find that aerosol loading and heatwave conditions both reduces SH. Further, we find that an increase in atmospheric VPD, tends to decrease the gross primary production (GPP) and thus LH, most likely as a response to stomatal closure of the dominant grasses at this location. In contrast, under heavy aerosol loading, LH is enhanced partly due to the physiological control exerted by the diffuse radiation fertilization effect (thus increasing EF). Moreover, LH and EF are positively associated with aerosol loading even under heatwave conditions, indicating a decoupling of plant’s response to VPD enhancement (stomatal closure) in presence of high aerosol conditions. With heat-stress, VPD and aerosols expected to increase in future India, our results warrant in-depth analysis of aerosol-plant-temperature-EF continuum and its impact on Indian monsoon dynamics and crop vulnerability.

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.

scholarly journals Is There Daily Growth Hysteresis versus Vapor Pressure Deficit in Cherry Fruit?

Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 131
Author(s):  
Matteo Zucchini ◽  
Arash Khosravi ◽  
Veronica Giorgi ◽  
Adriano Mancini ◽  
Davide Neri
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Fruit Growth ◽  
Hysteresis Curve ◽  
Growth Stages ◽  
Fourth Stage ◽  
The Third ◽  
Third Stage ◽  
Rainy Days ◽  
Clockwise Hysteresis

The growth of cherry fruit is generally described using a double sigmoid model, divided into four growth stages. Abiotic factors are considered to be significant components in modifying fruit growth, and among these, the vapor pressure deficit (VPD) is deemed the most effective. In this study, we investigated sweet cherry fruit growth through the continuous, hourly monitoring of fruit transversal diameter over two consecutive years (2019 and 2020), from the beginning of the third stage to maturation (forth stage). Extensometers were used in the field and VPD was calculated from weather data. The fruit growth pattern up to the end of the third stage demonstrated three critical steps during non-rainy days: shrinkage, stabilization and expansion. In the third stage of fruit growth, a partial clockwise hysteresis curve of circadian growth, as a response to VPD, appeared on random days. The pattern of fruit growth during rainy days was not distinctive, but the amount and duration of rain caused a consequent decrease in the VPD and indirectly boosted fruit growth. At the beginning of the fourth stage, the circadian growth changed and the daily transversal diameter vs VPD formed fully clockwise hysteresis curves for most of this stage. Our findings indicate that hysteresis can be employed to evaluate the initial phenological phase of fruit maturation, as a fully clockwise hysteresis curve was observable only in the fourth stage of fruit growth. There are additional opportunities for its use in the management of fruit production, such as in precision fruit farming.

scholarly journals Towards In Vivo Monitoring of Ions Accumulation in Trees: Response of an in Planta Organic Electrochemical Transistor Based Sensor to Water Flux Density, Light and Vapor Pressure Deficit Variation

2021 ◽  
Vol 11 (11) ◽  
pp. 4729
Author(s):  
Davide Amato ◽  
Giuseppe Montanaro ◽  
Filippo Vurro ◽  
Nicola Coppedé ◽  
Nunzio Briglia ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Flux Density ◽  
Precision Agriculture ◽  
Vapor Pressure Deficit ◽  
Accumulation Rate ◽  
Xylem Sap ◽  
Water Flux ◽  
Electrochemical Transistor ◽  
Olive Trees

Research on organic electrochemical transistor (OECT) based sensors to monitor in vivo plant traits such as xylem sap concentration is attracting attention for their potential application in precision agriculture. Fabrication and electronic aspects of OECT have been the subject of extensive research while its characterization within the plant water relation context deserves further efforts. This study tested the hypothesis that the response (R) of an OECT (bioristor) implanted in the trunk of olive trees is inversely proportional to the water flux density flowing through the plant (Jw). This study also examined the influence on R of vapor pressure deficit (VPD) as coupled/uncoupled with light. R was hourly recorded in potted olive trees for a 10-day period concomitantly with Jw (weight loss method). A subgroup of trees was bagged in order to reduce VPD and in turn Jw, and other trees were located in a walk-in chamber where VPD and light were independently managed. R was tightly sensitive to diurnal oscillation of Jw and at negligible values of Jw (late afternoon and night) R increased. The bioristor was not sensitive to the VPD per se unless a light source was coupled to trigger Jw. This study preliminarily examined the suitability of bioristor to estimate the mean daily nutrients accumulation rate (Ca, K) in leaves comparing chemical and sensor-based procedures showing a good agreement between them opening new perspective towards the application of OECT sensor in precision agricultural cropping systems.

Effect of vapor pressure deficit on the photosynthesis, growth, and nutrient absorption of tomato seedlings

2021 ◽  
pp. 110736
Author(s):  
Juping Ding ◽  
Xiaocong Jiao ◽  
Ping Bai ◽  
Yixin Hu ◽  
Jiayu Zhang ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Nutrient Absorption ◽  
Tomato Seedlings

Transpiration Response to Vapor Pressure Deficit in Field Grown Peanut

2012 ◽  
Vol 39 (1) ◽  
pp. 53-61 ◽  
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.

scholarly journals Transpiration in an oil palm landscape: effects of palm age

2015 ◽  
Vol 12 (12) ◽  
pp. 9209-9242 ◽  
Author(s):  
A. Röll ◽  
F. Niu ◽  
A. Meijide ◽  
A. Hardanto ◽  
A. Knohl ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Eddy Covariance ◽  
Water Use ◽  
Oil Palm ◽  
Vapor Pressure Deficit ◽  
Ground Vegetation ◽  
Sap Flux ◽  
Stand Transpiration ◽  
Oil Palms ◽  
Water Use Rates

Abstract. Oil palm (Elaeis guineensis Jacq.) plantations cover large and continuously increasing areas of humid tropical lowlands. Landscapes dominated by oil palms usually consist of a mosaic of mono-cultural, homogeneous stands of varying age, which may be heterogeneous in their water use characteristics. However, studies on the water use characteristics of oil palms are still at an early stage and there is a lack of knowledge on how oil palm expansion will affect the major components of the hydrological cycle. To provide first insights into hydrological landscape-level consequences of oil palm cultivation, we derived transpiration rates of oil palms in stands of varying age, estimated the contribution of palm transpiration to evapotranspiration, and analyzed the influence of fluctuations in environmental variables on oil palm water use. We studied 15 two- to 25 year old stands in the lowlands of Jambi, Indonesia. A sap flux technique with an oil palm specific calibration and sampling scheme was used to derive leaf-, palm- and stand-level water use rates in all stands under comparable environmental conditions. Additionally, in a two- and a 12 year old stand, eddy covariance measurements were conducted to derive evapotranspiration rates. Water use rates per leaf and palm increased 5-fold from an age of two years to a stand age of approx. 10 years and then remained relatively constant. A similar trend was visible, but less pronounced, for estimated stand transpiration rates of oil palms; they varied 12-fold, from 0.2 mm day−1 in a 2 year old to 2.5 mm day−1 in a 12 year old stand, showing particularly high variability in transpiration rates among medium-aged stands. Confronting sap flux and eddy-covariance derived water fluxes suggests that transpiration contributed 8 % to evapotranspiration in the 2 year old stand and 53 % in the 12 year old stand, indicating variable and substantial additional sources of evaporation, e.g. from the soil, the ground vegetation and from trunk epiphytes. Diurnally, oil palm transpiration rates were characterized by an early peak between 10 and 11 a.m.; there was a pronounced hysteresis in the leaf water use response to changes in vapor pressure deficit for all palms of advanced age. On the day-to-day basis this resulted in a relatively low variability of oil palm water use regardless of fluctuations in vapor pressure deficit and radiation. We conclude, that oil palm dominated landscapes show some spatial variations in (evapo)transpiration rates, e.g. due to varying age-structures, but that the temporal variability of oil palm transpiration is rather low. Stand transpiration rates of some studied oil palm stands compared to or even exceed values reported for different tropical forests, indicating a high water use of oil palms under certain site or management conditions. Our study provides first insights into the eco-hydrological characteristics of oil palms as well as a first estimate of oil palm water use across a gradient of plantation age. It sheds first light on some of the hydrological consequences of the continuing expansion of oil palm plantations.

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