scholarly journals Photosynthetic metabolism and antioxidant in Ormosia arborea are modulated by abscisic acid under water deficit?

2022 ◽  
Vol 82 ◽  
Author(s):  
S. S. Bastos ◽  
S. P. Q. Scalon ◽  
A. P. R. Souza ◽  
D. M. Dresch ◽  
F. S. Junglos ◽  
...  

Abstract The aim of this research was to evaluate the effect of abscisic acid (ABA) on gas exchange and the activity of antioxidant enzymes of Ormosia arborea (Vell.) Harms seedlings under water deficit and its influence on the recovery potential of the seedlings. The experiment was conducted using four treatments, being daily irrigation or water restriction without and with 10 μM ABA. Seedlings under water deficit + ABA showed greater adjustment to drought, and when re-irrigated, they restored photosynthetic metabolism and water potential. ABA minimizes the reduction in the photosynthetic metabolism and water potential of the leaf, however, it does not increase the antioxidant activity of the O. arborea seedlings under water deficit. These results suggest that this species exhibits plasticity, which enables it to survive also in environments subjected to temporary water deficit regardless of the supplementation of ABA. We suggest that other doses of ABA be researched to expand the beneficial effect of ABA on this species.

2019 ◽  
Vol 42 ◽  
pp. e42463
Author(s):  
Lorena Gabriela Almeida ◽  
Paulo César Magalhães ◽  
Décio Karam ◽  
Eder Marcos da Silva ◽  
Amauri Alves Alvarenga

The present research seeks to elucidate the feasibility of chitosan (CHT) in the induction of water deficit tolerance in different maize hybrids, contrasting tolerance to water restriction, tolerance and sensitivity. The maize plants were subjected to water deficit and foliar application of different chitosan doses (60, 100, 140, and 180 mg L-1) at the pre-flowering growth stage and evaluated during the stress period of fifteen days. To understand the induction behaviour of the tolerance to water restriction, biophysical parameters, such as water potential, relative water content and chlorophyll content, gas exchange, and biochemical assays, were quantified based on the activity of SOD, CAT, APX, and PAL antioxidant enzymes, lipid peroxidation activity and hydrogen peroxide content. Among the treatments, maize plants subjected to chitosan foliar application at a dose of 140 mg L-1 presented similar behavioural responses to plants under favourable irrigation conditions. Such positive responses are related to the high degree of activity of antioxidant enzymes, gas exchange and low levels of lipid peroxidation and hydrogen peroxide. The results support the potential use of CHT to increase tolerance to water stress.


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


2017 ◽  
Vol 45 (1) ◽  
pp. 238-244 ◽  
Author(s):  
Udson de Oliveira BARROS JUNIOR ◽  
Maria Antonia Machado BARBOSA ◽  
Michael Douglas Roque LIMA ◽  
Gélia Dinah Monteiro VIANA ◽  
Allan Klynger da Silva LOBATO

Low water supply frequently interferes on chlorophyll fluorescence and gas exchange. This study aimed to answer if a short-time of rehydration is efficient to re-establish chlorophyll fluorescence and gas exchange in cowpea plants. The experiment used four treatments (sensitive / water deficit, sensitive / control, tolerant / water deficit and tolerant / control). The sensitive and tolerant cultivars after water restriction had significant changes in gas exchange. On the third day, the stress caused lower for PN and gs in sensitive cultivar of 67% and 45%, respectively. After rehydration these parameters were not recovered significantly to two cultivars. In relation to chlorophyll fluorescence, water stress caused significant changes in all parameters evaluated of cultivars, being observed effects more intense on sensitive cultivar in the parameters Fv/Fm (38%) and Fo (69%). Rehydration did not promote recovery of the values of Fv/Fm and Fo to sensitive cultivar. Therefore, our study revealed that a short-time of rehydration is not effective to re-establish chlorophyll fluorescence and gas exchange in cowpea plants submitted to water deficit.


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.


2009 ◽  
Vol 45 (2) ◽  
pp. 189-198 ◽  
Author(s):  
F. P. GOMES ◽  
M. A. OLIVA ◽  
M. S. MIELKE ◽  
A-A. F. DE ALMEIDA ◽  
H. G. LEITE ◽  
...  

SUMMARYAbscisic acid (ABA) accumulation in leaves of drought-stressed coconut palms and its involvement with stomatal regulation of gas exchange during and after stress were investigated. Two Brazilian Green Dwarf coconut ecotypes from hot/humid and hot/dry environments were submitted to three consecutive drying/recovery cycles under greenhouse conditions. ABA accumulated in leaflets before significant changes in pre-dawn leaflet water potential (ΨPD) and did not recover completely in the two ecotypes after 8 days of rewatering. Stomatal conductance was influenced by ABA under mild drought and by ΨPD under severe drought. There were no significant differences between the ecotypes for most variables measured. However, the ecotype from a hot/dry environment showed higher water use efficiency after repeated cycles of water stress.


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.


2015 ◽  
Vol 33 (2) ◽  
pp. 164-173 ◽  
Author(s):  
Seyed Mehdi Jazayeri ◽  
Yurany Dayanna Rivera ◽  
Jhonatan Eduardo Camperos-Reyes ◽  
Hernán Mauricio Romero

Water supply is the main limiting factor that affects oil palm (Elaeis guineensis Jacq.) yield. This study aimed to evaluate the gas exchange and photosynthetic capacity, determine the physiological effects and assess the tolerance potential of oil palm genotypes under water-deficit conditions. The two oil palm commercial genotypes IRHO1001 and IRHO7010 were exposed to soil water potentials of -0.042 MPa (field capacity or well-watered) or -1.5 MPa (drought-stressed). The leaf water potential and gas exchange parameters, including photosynthesis, stomatal conductance, transpiration and water use efficiency (WUE), as well as the photosynthesis reduction rate were monitored at 4 and 8 weeks after treatment. The IRHO7010 genotype showed fewer photosynthesis changes and a smaller photosynthetic reduction under the prolonged water deficit conditions of 23% at 4 weeks after the treatment as compared to 53% at 8 weeks after treatment, but the IRHO1001 genotype showed 46% and 74% reduction at the two sampling times. 'IRHO7010' had a higher stomatal conductance and transpiration potential than 'IRHO1001' during the water shortage. The WUE and leaf water potential were not different between the genotypes during dehydration. The data suggested that 'IRHO7010' had a higher photosynthetic capacity during the drought stress and was more drought-tolerant than 'IRHO1001'.


2012 ◽  
Vol 58 (No. 11) ◽  
pp. 481-486 ◽  
Author(s):  
O.N. Silva ◽  
A.K.S. Lobato ◽  
F.W. Ávila ◽  
R.C.L. Costa ◽  
C.F. Oliveira Neto ◽  
...  

This study aims to explain the effects of silicon on chlorophyll and to measure gas exchange and carbohydrate levels in two Lycopersicon esculentum cultivars that are exposed to drought. The experimental design used in this study was a randomised combination of five different water and silicon conditions (control, water deficit + 0.00 μmol Si, water deficit + 0.25 μmol Si, water deficit + 1.00 μmol Si, and water deficit + 1.75 μmol Si) applied to the two cultivars (Super Marmante and Santa Cruz). Parameters measured were gas exchanges, chlorophylls, and total soluble carbohydrates. Silicon at concentrations of 0.25, 1.00, and 1.75 μmol induced a gradual increase in the total chlorophyll levels. A correlation analysis revealed a linear, positive interaction between the leaf water potential and the total chlorophyll (r = 0.71; P < 0.05). This study confirmed the hypothesis that silicon has a beneficial effect with regard to chlorophyll. Under water-deficient conditions, both cultivars showed an increase in chlorophyll a when treated with silicon in addition to changes in the total chlorophyll levels. These results were supported by the change in leaf water potential. In addition, a reduction of the effects of water restriction was also observed in the transpiration rate, the stomatal conductance and in the levels of total carbohydrates.


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