scholarly journals HydroShoot: a functional-structural plant model for simulating hydraulic structure, gas and energy exchange dynamics of complex plant canopies under water deficit - application to grapevine (Vitis vinifera L.)

2019 ◽  
Author(s):  
Rami Albasha ◽  
Christian Fournier ◽  
Christophe Pradal ◽  
Michael Chelle ◽  
Jorge Prieto ◽  
...  

This paper aims at presenting HydroShoot, a functional-structural plant model (FSPM) that is developed to simulate gas-exchange rates of complex plant canopies under water deficit conditions, by scaling up gas-exchange rates from the leaf to the canopy levels. The main hypothesis is that simulating both the hydraulic structure of the shoot together with the energy budget of individual leaves is the asset for successfully achieving this up-scaling task. HydroShoot was hence built as the ensemble of three interacting modules: hydraulic which calculates the distribution of xylem water potential across shoot hydraulic segments, energy which calculates the complete energy budget of individual leaves, and exchange which calculates net assimilation and transpiration rates of individual leaves. HydroShoot was coupled with irradiance interception and soil water balance models, and was evaluated on virtual and real grapevines having strongly contrasted canopies, under well-watered and water-deficit conditions. HydroShoot captured accurately the impact of canopy architecture and the varying soil water deficit conditions on plant-scale gas-exchange rates and leaf-scale temperature and water potential distributions. Both shoot hydraulic structure and leaf energy budget simulations were, as postulated, required to adequately scaling-up leaf to canopy gas-exchange rates. Notwithstanding, simulating the hydraulic structure of the shoot was found far more necessary to adequately performing this scaling task than simulating leaf energy balance. That is, the intra-canopy variability of leaf water potential was a better predictor of the reduction of whole plant gas-exchange rates under water deficit than the intra-canopy variability of leaf temperature. We conclude therefore that simulating the shoot hydraulic structure is a prerequisite if FSPM's are to be used to assess gas-exchange rates of complex plant canopies as those of grapevines. Finally HydroShoot is available through the OpenAlea platform (https://github.com/openalea/hydroshoot) as a set of reusable modules.

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
R Albasha ◽  
C Fournier ◽  
C Pradal ◽  
M Chelle ◽  
J A Prieto ◽  
...  

Abstract This paper presents HydroShoot, a leaf-based functional-structural plant model (FSPM) that simulates gas exchange rates of complex plant canopies under water deficit conditions. HydroShoot is built assuming that simulating both the hydraulic structure of the shoot together with the energy budget of individual leaves is the asset for successfully scaling-up leaf to canopy gas exchange rates. HydroShoot includes three interacting modules: hydraulic, which calculates the distribution of xylem water potential across shoot hydraulic segments; energy, which calculates the complete energy budget of individual leaves; and exchange, which calculates net carbon assimilation and transpiration rates of individual leaves. HydroShoot was evaluated on virtual and real grapevines having strongly contrasted canopies, under well-watered and water deficit conditions. It captured accurately the impact of canopy architecture and soil water status on plant-scale gas exchange rates and leaf-scale temperature and water potential. Both shoot hydraulic structure and leaf energy budget simulations were, as postulated, required to adequately scaling-up leaf to canopy gas exchange rates. Notwithstanding, simulating shoot hydraulic structure was found more necessary to adequately performing this scaling task than simulating leaf energy budget. That is, the intra-canopy variability of leaf water potential was a better predictor of the reduction of whole plant gas exchange rates under water deficit than the intra-canopy variability of leaf temperature. We conclude that simulating the shoot hydraulic structure is a prerequisite if FSPMs are to be used to assess gas exchange rates of complex plant canopies as those of grapevines. Finally, HydroShoot is available through the OpenAlea platform (https://github.com/openalea/hydroshoot) as a set of reusable modules.


2007 ◽  
Vol 29 (2) ◽  
pp. 355-358 ◽  
Author(s):  
José Moacir Pinheiro Lima Filho

The experiment was carried out at the Embrapa Semi-Árido, Petrolina-PE, Brazil, in order to study the physiological responses of umbu plants propagated by seeds and by stem cuttings under water stress conditions, based on leaf water potential and gas exchange measurements. Data were collected in one-year plants established in pots containing 30 kg of a sandy soil and submitted to twenty-day progressive soil water deficit. The evaluations were based on leaf water potential and gas exchange data collection using psychrometric chambers and a portable infra-red gas analyzer, respectively. Plants propagated by seeds maintained a significantly higher water potential, stomatal conductance, transpiration and photosynthesis under decreasing soil water availability. However, plants propagated by stem cuttings were unable to maintain a favorable internal water balance, reflecting negatively on stomatal conductance and leaf gas exchange. This fact is probably because umbu plants propagated by stem cuttings are not prone to formation of root tubers which are reservoirs for water and solutes. Thus, the establishing of umbu plants propagated by stem cuttings must be avoided in areas subjected to soil water deficit.


2021 ◽  
Vol 12 ◽  
Author(s):  
Fei Li ◽  
Dagang Guo ◽  
Xiaodong Gao ◽  
Xining Zhao

Elevated atmospheric CO2 concentrations ([eCO2]) and soil water deficits significantly influence gas exchange in plant leaves, affecting the carbon-water cycle in terrestrial ecosystems. However, it remains unclear how the soil water deficit modulates the plant CO2 fertilization effect, especially for gas exchange and leaf-level water use efficiency (WUE). Here, we synthesized a comprehensive dataset including 554 observations from 54 individual studies and quantified the responses for leaf gas exchange induced by e[CO2] under water deficit. Moreover, we investigated the contribution of plant net photosynthesis rate (Pn) and transpiration rates (Tr) toward WUE in water deficit conditions and e[CO2] using graphical vector analysis (GVA). In summary, e[CO2] significantly increased Pn and WUE by 11.9 and 29.3% under well-watered conditions, respectively, whereas the interaction of water deficit and e[CO2] slightly decreased Pn by 8.3%. Plants grown under light in an open environment were stimulated to a greater degree compared with plants grown under a lamp in a closed environment. Meanwhile, water deficit reduced Pn by 40.5 and 37.8%, while increasing WUE by 24.5 and 21.5% under ambient CO2 concentration (a[CO2]) and e[CO2], respectively. The e[CO2]-induced stimulation of WUE was attributed to the common effect of Pn and Tr, whereas a water deficit induced increase in WUE was linked to the decrease in Tr. These results suggested that water deficit lowered the stimulation of e[CO2] induced in plants. Therefore, fumigation conditions that closely mimic field conditions and multi-factorial experiments such as water availability are needed to predict the response of plants to future climate change.


Irriga ◽  
2018 ◽  
Vol 1 (01) ◽  
pp. 246
Author(s):  
Lígia Borges Marinho ◽  
José Antonio Frizzone ◽  
João Batista Tolentino Júnior ◽  
Janaina Paulino ◽  
Danilton Luiz Flumigan ◽  
...  

DINÂMICA DA ÁGUA NO SISTEMA SOLO-PLANTA NO CULTIVO DA PIMENTA TABASCO SOB DÉFICIT HÍDRICO1  LÍGIA BORGES MARINHO2; JOSÉ ANTONIO FRIZZONE3; JOÃO BATISTA TOLENTINO JÚNIOR4; JANAÍNA PAULINO5; DANILTON LUIZ FLUMIGNAN6 E DIEGO BORTOLOTI GÓES3    (1) Artigo extraído da tese do primeiro autor (2) Departamento Tecnologia e Ciências Sociais, Universidade do Estado da Bahia, av. Edgard Chastinet, São Geraldo, CEP 48905-680, Juazeiro, BA. Fone (74) 3611-7363. E-mail: [email protected](3) Departamento de Engenharia de Biossistemas/Escola Superior de Agricultura “Luiz de Queiroz” USP, Av. Pádua Dias, 11, CEP 13.418-900, Piracicaba/SP, E-mail(s): [email protected], [email protected]; (4) Campus Curitibanos, Universidade Federal de Santa Catarina, Curitibanos, SC. [email protected] (5) Universidade Federal de Mato Grosso UFMT, campus Sinop, Avenida Alexandre Ferronato Nº 1.200. Bairro: Setor Industrial. CEP: 78.550-000,  Sinop-MT, Email: [email protected] (6) Empresa Brasileira de Pesquisa Agropecuária, Agropecuária Oeste. Rodovia BR 163, km 253, Zona Rural, 79804970 - Dourados, MS,  Email: [email protected]  1 RESUMO  O objetivo da pesquisa foi acompanhar a variação da condição hídrica do solo e da planta de pimenta ‘Tabasco’ em função dos manejos de déficits hídricos impostos e determinar seu coeficiente de estresse hídrico. O experimento foi conduzido em ambiente protegido, no Departamento de Engenharia de Biossistemas da ESALQ - USP, Piracicaba-SP, de setembro de 2009 a julho de 2010. O delineamento experimental foi blocos casualizados, com quatro repetições, utilizando-se lâminas de irrigação a 100, 80, 60 e 40% da evapotranspiração da cultura diferenciadas a partir da fase vegetativa e da fase reprodutiva. O potencial da água na folha e no solo foi aferido com a câmara de pressão e tensiômetros, respectivamente. Houve variação do potencial mátrico, da extração de água no solo e do potencial de água na folha em função das lâminas e das épocas de diferenciação. Menores potenciais mátricos foram verificados quando o déficit de irrigação foi inicializado na fase vegetativa da pimenta. Os valores de coeficiente de estresse hídrico e o potencial de água na folha, ao alvorecer, indicaram que as pimenteiras estavam sob estresse moderado e severo, sendo a época reprodutiva da pimenta Tabasco a mais sensível à restrição hídrica.Palavras-chave: Capsicum frutencens L, tensiômetro, potencial da água no solo.                                                        MARINHO, L. B.; FRIZZONE, J. A.; TOLENTINO JÚNIOR, J. B.; PAULINO, J.; FLUMIGNAN, D. L.; GÓES, D. B.WATER DYNAMICS IN SOIL-PLANT SYSTEM IN THE CULTIVATION OF PEPPER TABASCO UNDER WATER DEFICIT  2 ABSTRACT The objective of the research was to determine the change in soil water condition and in Tabasco pepper plant according to the managements of water deficits. The experiment was conducted in a greenhouse at the Department of Biosystems Engineering of ESALQ - USP, Piracicaba-SP, from September 2009 to July 2010. The experimental design was randomized blocks with four replications, using irrigation depths to 100, 80, 60 and 40% of crop evapotranspiration in the vegetative phase and reproductive phase. The soil matric potential was measured by tensiometers installed at 0-20 and 20-40 cm depth. The most negative values of matric potential occurred in treatments submitted to the greater water deficit treatments that had higher water restriction imposed by the vegetative phase. For these, greater increase in water extraction in the deepest layer (40 cm) were also found.There were differences in matric potential of the soil, in ground water extraction and in leaf water potential in relation to the water depths and differentiation phases. The deficit irrigation that started in the vegetative phase led to greater reduction in soil matric potential due to the accumulated water deficit. The pepper plants have moderate to severe sensitivity to water deficit in the soil, with a higher sensitivity of the plants when water restriction is imposed during reproductive stages than when it is imposed during growing stages. Keywords : Capsicum frutencens, tensiometer; soil water potential


2019 ◽  
Vol 35 (1) ◽  
pp. 39-50
Author(s):  
H. C. Pringle, III ◽  
L. L. Falconer ◽  
D. K. Fisher ◽  
L. J. Krutz

Abstract. Irrigated acreage is expanding and groundwater supplies are decreasing in the Mississippi Delta. Efficient irrigation scheduling of soybean [ (L.) Merr] will aid in conservation efforts to sustain groundwater resources. The objective of this study was to develop irrigation initiation recommendations for soybean grown on Mississippi Delta soils. Field studies were conducted on a deep silty clay (SiC) in 2012, 2013, 2014, and 2015 and on a deep silty clay loam (SiCL) and deep silt loam (SiL) or loam (L) soil in 2013, 2014, and 2015. Irrigation was initiated multiple times during the growing season and soybean yield and net return were determined to evaluate the effectiveness of each initiation timing. Growth stage, soil water potential (SWP), and soil water deficit (SWD) were compared at these initiation timings to determine which parameter or combination of parameters consistently predicted the resulting greatest yields and net returns. Stress conditions that reduce yield can occur at any time from late vegetative stages to full seed on these deep soils. The wide range of trigger values found for SWP and SWD to increase yields in different years emphasizes the complexity of irrigation scheduling. Monitoring soil moisture by itself or use of a single trigger value is not sufficient to optimize irrigation scheduling to maximize soybean yield with the least amount of water every year on these soils. Monitoring one or more parameters (e.g., leaf water potential, canopy temperature, air temperature, humidity, solar radiation, and wind) is needed in conjunction with soil moisture to directly or indirectly quantify the abiotic stresses on the plant to better define when a yield reducing stress is occurring. Keywords: Irrigation initiation, Irrigation scheduling, Soil water deficit, Soil water potential, Soybean, Water conservation.


1988 ◽  
Vol 68 (4) ◽  
pp. 957-967 ◽  
Author(s):  
D. L. SMITH ◽  
M. DIJAK ◽  
D. J. HUME

White bean (Phaseolus vulgaris L.) is generally reported to fix less N than soybean (Glycine max Merrill [L.]). Recent work has shown that in soybean the onset of physiological responses that conserve plant and soil water occurs at greater water deficits than in some other legumes. Little is known about water use regulation in white bean. Research was conducted to compare the responses of these two species to water deficit, particularly its effects on N2 fixation, in both controlled environment and field conditions. In the growth room, plant water potential, leaf diffusive resistance, acetylene reduction and nodule mass per plant were measured for both species during progressive drought, and compared to watered controls. In the field, the leaf diffusive resistance of irrigated and unirrigated plants of both species was measured, as was the soil water potential in plots where these crops were grown. Under conditions of increasing water deficit white bean reacts to conserve plant and soil water sooner than soybean: closing its stomates earlier under drought conditions and maintaining higher plant water potentials. White bean acetylene reduction declined more rapidly over time and over plant water potential levels, but not over changes in leaf diffusive resistance, than that of soybean, as the droughting progressed. In the field, under drought conditions, white bean root nodules senesced, while soybean nodules did not, and white bean was observed to exhibit more parahelionasty than soybean. The onset of physiological responses that conserve plant and soil water occurred at lesser water deficits in white bean than soybean, and this was reflected in more extreme effects on N2 fixation by white bean.Key words: White bean, soybean, water deficit, acetylene reduction, nitrogen fixation, nodulation


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1143G-1143
Author(s):  
Sven E. Svenson ◽  
F. T. Davies

Pinus taeda L. seedlings inoculated with the ectomycorrhizal fungus, Pisolithus tinctorius, were grown in a glasshouse for eight months, and then subjected to rapidly developing cyclic water deficits, or to a single slowly developing water deficit. Water deficits developed at a rate of -0.16 MPa per day (predawn total water potential) for five cyclic water deficits, and at -0.04 MPa per day for the slow water deficit. In unstressed seedlings, carbon exchange rates (CER) did not differ between noninoculated and inoculated seedlings. During slow water deficit development, CER steadily declined. During rapid water deficit development, CER remained unchanged, then declined rapidly when water potentials fell below -1.3 MPa. Inoculated seedlings had higher CER when water potential was lower than -1.5 MPa.


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