scholarly journals PHYSIOLOGICAL RESPONSES OF Eucalyptus camaldulensis (Dehnh.) TO SIMULATED GLYPHOSATE DRIFT

2021 ◽  
Vol 6 (1) ◽  
pp. 46
Author(s):  
Diego Ariel Meloni ◽  
Carlos Alberto Martínez
Keyword(s):  
Oxidative Stress ◽  
Physiological Responses ◽  
Stomatal Closure ◽  
Photosynthetic Apparatus ◽  
Eucalyptus Camaldulensis ◽  
Photochemical Quenching ◽  
Rubisco Activity ◽  
Photosynthetic Assimilation ◽  
Eucalyptus Camaldulensis Dehnh ◽  
Glyphosate Drift

Weed control with glyphosate produces damages in plantations of Eucalyptus camaldulensis, although the involved physiological mechanisms have not been completely elucidated. This work aimed at assessing the physiological responses of E. camaldulensis to simulated glyphosate drift. Greenhouse trials were performed with four-month-old E. camaldulensis clone117 seedlings. The herbicide drift was simulated applying doses of 0; 43,2; 86,4; 172,8 and 345,6 g a.e. ha−1 glyphosate. Twenty-three days after the application, we measured gas exchange and chlorophyll a fluorescence. We also quantified Rubisco activity and indicator variables of oxidative stress. Glyphosate decreased carbon photosynthetic assimilation, increased non-photochemical quenching, induced stomatal closure, and increased photoinhibition. It also decreased Rubisco activity and increased photorespiration. The herbicide produced oxidative stress, and increased the activities in the enzymes catalase, ascorbate peroxidase, and superoxide dismutase, involved in the detoxification of reactive oxygen species. We concluded that glyphosate´s deleterious effects on the assimilation of CO2 in E. camaldulensis are due to stomatal and non-stomatal effects. The decrease in Rubisco activity, the increase in photorespiration, and photoinhibition stand out among non-stomatal effects. The increase in the activity of the antioxidant system is insufficient to compensate for the production of H2O2 in photorespiration, which damages the photosynthetic apparatus.

Morphological and Physiological Comparisons of Clonal Lines of Eucalyptus camaldulensis. I. Responses to Drought and Waterlogging

1996 ◽  
Vol 23 (4) ◽  
pp. 497 ◽  
Author(s):  
RCC Farrell ◽  
DT Bell ◽  
K Akilan ◽  
JK Marshall
Keyword(s):  
Leaf Area ◽  
Physiological Responses ◽  
Eucalyptus Camaldulensis ◽  
Specific Weight ◽  
Root Weight ◽  
Total Leaf Area ◽  
Agricultural Catchments ◽  
Number Of Leaves ◽  
Clonal Lines ◽  
Eucalyptus Camaldulensis Dehnh

Morphological and physiological responses to drought and waterlogging of six clonal lines of Eucalyptus camaldulensis Dehnh., originally from five geographically separated locations, were compared under controlled glasshouse conditions. The clones differed significantly in their ability to produce leaf and root tissue during stress periods. Clones which produced the greatest numbers of leaves (Dongara, WA clone M76 and Silverton, NSW clone M79) had leaves of low specific weight, while clones which produced fewer leaves (Erudina, SA clone M66 and Murray Bridge, SA clone M86) had leaves of relatively high specific weight. Clonal lines that produced the greatest leaf area also produced the greatest root weight. Comparisons of water use produced fewer differences, although clone M76, which produced the greatest number of leaves and the greatest total leaf area, also used the most water in both the drought and waterlogging trials. Stomatal conductance, net gas exchange and leaf nutrient allocation did not differ greatly among the clonal lines. An ability to produce and maintain transpiration surface appears the most valuable physiological attribute of plants selected to dewater damaged agricultural catchments currently being subjected to increasing periods of waterlogging due to excessive clearing of native woodlands.

How does a C3 epiphytic tank bromeliad respond to drought?

2019 ◽  
Vol 192 (4) ◽  
pp. 855-867
Author(s):  
Bruno Nobuya Katayama Gobara ◽  
Frederico Rocha Rodrigues Alves ◽  
Filipe Christian Pikart ◽  
Ana Zangirolame Gonçalves ◽  
Deborah Yara Alves Cursino Dos Santos ◽  
...  
Keyword(s):  
Stomatal Closure ◽  
Photosynthetic Apparatus ◽  
Co2 Exchange ◽  
Thermal Dissipation ◽  
C3 Plants ◽  
Photochemical Quenching ◽  
Leaf Water Content ◽  
Hydrophilic Antioxidants ◽  
Air Channels ◽  
Epiphytic Bromeliads

Abstract Intermittent water availability characterizes the canopy habitat, but few studies have focused on how C3 epiphytic bromeliads deal with drought. In this context, we investigated how water deficits affect the photosynthetic responses of the epiphytic bromeliad Vriesea gigantea regarding its physiological and anatomical traits that can minimize the effects of stomatal closure. In a controlled experiment in which bromeliads were submitted to 21 days of drought, we demonstrated a reduction in the leaf water content followed by strong reductions in net CO2 exchange and the efficiency of the photochemical system. However, there were increases in the yield of non-photochemical quenching and the activities of hydrophilic antioxidants. We observed substomatal chambers connected with air channels reaching the chlorophyllous parenchyma. Our findings indicate that the low net CO2 exchange and the energy imbalance possibly increased the cyclic transport of electrons and activated the thermal dissipation of energy to avoid damage to the photosynthetic apparatus. Additionally, the aeration channels may passively store CO2 to facilitate its re-assimilation. Because most epiphytic bromeliads are C3 plants and drought is frequent in the canopy, we speculate that some attributes of V. gigantea may occur in other C3 species, favouring their radiation in the epiphytic environment.

scholarly journals Hydrogen peroxide, superoxide, lipid peroxidation and membrane damage in leaves of the tree Prosopis nigra (Fabaceae) under simulated glyphosate drift

2021 ◽  
Vol 13 (1) ◽  
pp. e3170
Author(s):  
Diego Ariel Meloni ◽  
Graciela Inés Bolzón
Keyword(s):  
Oxidative Stress ◽  
Electron Transport Rate ◽  
Stomatal Closure ◽  
Membrane Damage ◽  
Fluorescence Emission ◽  
Modulated Fluorescence ◽  
Glyphosate Drift ◽  
The Impact ◽  
And Oxidative Stress ◽  
Herbicide Glyphosate

Introduction: The tree Prosopis nigra is native to the Western Chaco phytogeographic region, affected by the application of glyphosate in the surrounding crops. Objective: To determine the impact of simulated glyphosate drift on growth, photosynthesis and oxidative stress in P. nigra seedlings. Methods: We simulated drift in seedlings at doses of 0, 200, 400 and 800 g a.e. ha-1 of glyphosate. We also measured gas exchange and modulated fluorescence emission of chlorophyll a. Results: Glyphosate reduced biomass, photosynthetic rate, and stomatal conductance. Doses of 400 and 800 g a.e. ha-1 glyphosate produced photoinhibition. The electron transport rate was sensitive to glyphosate, and it decreased at all doses of the herbicide. Glyphosate generated oxidative stress, and produced damage to membranes, because of the accumulation of H2O2 and O2.. Conclusions: Glyphosate reduces growth and photosynthesis in these seedlings. The inhibition of photosynthesis is due to stomatal closure, and alterations in the photochemical stage, associated with oxidative stress. 

scholarly journals ECOPHYSIOLOGICAL ANALYSIS OF Eucalyptus camaldulensis (DEHNH) SUBMITTED TO ATTACK FROM Thaumastocoris peregrinus (CARPINTERO & DELLAPE)

2018 ◽  
Vol 42 (1) ◽  
Author(s):  
Kamilla Emmanuelle Carvalho de Almeida ◽  
Junia Grazielle Soares da Silva ◽  
Inaê Mariê de Araujo Silva ◽  
Alisson Lucrecio da Costa ◽  
Marcelo Luiz de Laia
Keyword(s):  
Photosynthetic Apparatus ◽  
Eucalyptus Camaldulensis ◽  
Experimental Period ◽  
Mixed Linear Model ◽  
Leaf Chlorophyll ◽  
Bronze Bug ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Eucalyptus Camaldulensis Dehnh ◽  
Insect Attack

ABSTRACT Works correlating the effect of a bronze bug attack on ecophysiological aspects of eucalyptus can be used in selection programs for resistant genetic materials. The objective of this study was to evaluate the injuries caused by Thaumastocoris peregrinus (Carpintero & Dellape) through the ecophysiological analysis of Eucalyptus camaldulensis (Dehnh). The experiment was conducted in a completely randomized design, with two groups of plants, infested and non-infested, kept in a room at 25 ± 2 °C, relative humidity 60 ± 2% and a photoperiod of 12 hours. For 26 days, every 48 hours, the chlorophyll a fluorescence, using the electron transport rate (ETR) and the potential quantum efficiency (Fv/Fm), was measured, in addition to the leaf chlorophyll content of the plants. The variables observed were analyzed in relation to treatments and times using a mixed linear model, with plants and leaves being random effects. Plants protected from insect attack showed better results over the experimental period. However, the attack from the bronze bug negatively affected all the ecophysiological variables evaluated in E. camaldulensis, indicating a possible compromise of the photosynthetic apparatus of the plants.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

ALTURA E SOBREVIVÊNCIA DE Eucalyptus camaldulensis Dehnh EM DIFERENTES ESPAÇAMENTOS AOS 14 MESES APÓS PLANTIO EM CAMPO EM ALVORADA DO GURGUÉIA –PIAUÍ

2018 ◽  
Author(s):  
Silva Raynara Ferreira da ◽  
Sousa Moema Barbosa de ◽  
Silva Aluísio Costa ◽  
Marinho Eduardo Silva ◽  
Dias Bruna Anair Souto
Keyword(s):  
Eucalyptus Camaldulensis ◽  
Eucalyptus Camaldulensis Dehnh

scholarly journals Effect of Lead and Copper on Photosynthetic Apparatus in Citrus (Citrus aurantium L.) Plants. The Role of Antioxidants in Oxidative Damage as a Response to Heavy Metal Stress

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 155
Author(s):  
Anastasia Giannakoula ◽  
Ioannis Therios ◽  
Christos Chatzissavvidis
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Heavy Metal ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Membrane Integrity ◽  
Photosynthetic Apparatus ◽  
Heavy Metal Stress ◽  
Photosynthetic Parameters ◽  
Citrus Aurantium

Photosynthetic changes and antioxidant activity to oxidative stress were evaluated in sour orange (Citrus aurantium L.) leaves subjected to lead (Pb), copper (Cu) and also Pb + Cu toxicity treatments, in order to elucidate the mechanisms involved in heavy metal tolerance. The simultaneous effect of Pb− and Cu on growth, concentration of malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophylls, flavonoids, carotenoids, phenolics, chlorophyll fluorescence and photosynthetic parameters were examined in leaves of Citrus aurantium L. plants. Exogenous application of Pb and Cu resulted in an increase in leaf H2O2 and lipid peroxidation (MDA). Toxicity symptoms of both Pb and Cu treated plants were stunted growth and decreased pigments concentration. Furthermore, photosynthetic activity of treated plants exhibited a significant decline. The inhibition of growth in Pb and Cu-treated plants was accompanied by oxidative stress, as indicated by the enhanced lipid peroxidation and the high H2O2 concentration. Furthermore, antioxidants in citrus plants after exposure to high Pb and Cu concentrations were significantly increased compared to control and low Pb and Cu treatments. In conclusion, this study indicates that Pb and Cu promote lipid peroxidation, disrupt membrane integrity, reduces growth and photosynthesis and inhibit mineral nutrition. Considering the potential for adverse human health effects associated with high concentrations of Pb and Cu contained in edible parts of citrus plants the study signals that it is important to conduct further research into the accessibility and uptake of the tested heavy metals in the soil and whether they pose risks to humans.

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