scholarly journals Leaf Gas Exchange and Chlorophyll a Fluorescence in Wheat Plants Supplied with Silicon and Infected with Pyricularia oryzae

2014 ◽  
Vol 104 (2) ◽  
pp. 143-149 ◽  
Author(s):  
Carlos Eduardo Aucique Perez ◽  
Fabrício Ávila Rodrigues ◽  
Wiler Ribas Moreira ◽  
Fábio Murilo DaMatta
Keyword(s):  
Gas Exchange ◽  
Chlorophyll A ◽  
Electron Transport Rate ◽  
Leaf Gas Exchange ◽  
Chlorophyll Concentration ◽  
Pyricularia Oryzae ◽  
Gas Exchange Parameters ◽  
Photosynthetic Gas Exchange ◽  
Exchange Performance ◽  
Exchange Parameters

This study investigated the effect of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal CO2 concentration [Ci], and transpiration rate [E]) and chlorophyll fluorescence a parameters (maximum quantum quenching [Fv/Fm and Fv′/Fm′], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]) in wheat plants grown in a nutrient solution containing 0 mM (–Si) or 2 mM (+Si) Si and noninoculated or inoculated with Pyricularia oryzae. Blast severity decreased due to higher foliar Si concentration. For the inoculated +Si plants, A, gs, and E were significantly higher in contrast to the inoculated –Si plants. For the inoculated +Si plants, significant differences of Fv/Fm between the –Si and +Si plants occurred at 48, 96, and 120 h after inoculation (hai) and at 72, 96, and 120 hai for Fv′/Fm′. The Fv/Fm and Fv′/Fm′, in addition to total chlorophyll concentration (a + b) and the chlorophyll a/b ratio, significantly decreased in the –Si plants compared with the +Si plants. Significant differences between the –Si and +Si inoculated plants occurred for qP, NPQ, and ETR. The supply of Si contributed to decrease blast severity in addition to improving gas exchange performance and causing less dysfunction at the photochemical level.

scholarly journals Alterations in Gas Exchange and Oxidative Metabolism in Rice Leaves Infected by Pyricularia oryzae are Attenuated by Silicon

2015 ◽  
Vol 105 (6) ◽  
pp. 738-747 ◽  
Author(s):  
Gisele Pereira Domiciano ◽  
Isaías Severino Cacique ◽  
Cecília Chagas Freitas ◽  
Marta Cristina Corsi Filippi ◽  
Fábio Murilo DaMatta ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Photochemical Efficiency ◽  
Pyricularia Oryzae ◽  
Gas Exchange Parameters ◽  
Photosynthetic Gas Exchange ◽  
Exchange Performance ◽  
Rice Leaves ◽  
Maximum Photochemical Efficiency ◽  
Important Disease ◽  
Exchange Parameters

Rice blast, caused by Pyricularia oryzae, is the most important disease in rice worldwide. This study investigated the effects of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal-to-ambient CO2 concentration ratio [Ci/Ca], and transpiration rate [E]); chlorophyll fluorescence a (Chla) parameters (maximum photochemical efficiency of photosystem II [Fv/Fm], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]); concentrations of pigments, malondialdehyde (MDA), and hydrogen peroxide (H2O2); and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and lypoxigenase (LOX) in rice leaves. Rice plants were grown in a nutrient solution containing 0 or 2 mM Si (−Si or +Si, respectively) with and without P. oryzae inoculation. Blast severity decreased with higher foliar Si concentration. The values of A, gs and E were generally higher for the +Si plants in comparison with the −Si plants upon P. oryzae infection. The Fv/Fm, qp, NPQ, and ETR were greater for the +Si plants relative to the −Si plants at 108 and 132 h after inoculation (hai). The values for qp and ETR were significantly higher for the –Si plants in comparison with the +Si plants at 36 hai, and the NPQ was significantly higher for the –Si plants in comparison with the +Si plants at 0 and 36 hai. The concentrations of Chla, Chlb, Chla+b, and carotenoids were significantly greater in the +Si plants relative to the –Si plants. For the –Si plants, the MDA and H2O2 concentrations were significantly higher than those in the +Si plants. The LOX activity was significantly higher in the +Si plants than in the –Si plants. The SOD and GR activities were significantly higher for the –Si plants than in the +Si plants. The CAT and APX activities were significantly higher in the +Si plants than in the –Si plants. The supply of Si contributed to a decrease in blast severity, improved the gas exchange performance, and caused less dysfunction at the photochemical level.

scholarly journals Growth and Photosynthetic Response of Two Persimmon Rootstocks (Diospyros kaki and D. virginiana) under Different Salinity Levels

2014 ◽  
Vol 42 (2) ◽  
pp. 386-391 ◽  
Author(s):  
Meral INCESU ◽  
Berken CIMEN ◽  
Turgut YESILOGLU ◽  
Bilge YILMAZ
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Chlorophyll Concentration ◽  
Dry Mass ◽  
Diospyros Kaki ◽  
Gas Exchange Parameters ◽  
Leaf Chlorophyll ◽  
Salinity Levels ◽  
Leaf Chlorophyll Concentration ◽  
Exchange Parameters

Salinity continues to be a major factor in reduced crop productivity and profit in many arid and semiarid regions. Seedlings of Diospyros kaki Thunb. and D. virginiana L. are commonly used as rootstock in persimmon cultivation. In this study we have evaluated the effects of different salinity levels on photosynthetic capacity and plant development of D. kaki and D. virginiana. Salinity was provided by adding 50 mM, 75 mM and 100 mM NaCl to nutrient solution. In order to determine the effects of different salinity levels on plant growth, leaf number, plant height, shoot and root dry mass were recorded. Besides leaf Na, Cl, K and Ca concentrations were determined. Also leaf chlorophyll concentration, chlorophyll fluorescence (Fv’/Fm’) and leaf gas exchange parameters including leaf net photosynthetic rate (PN), stomatal conductance (gS), leaf transpiration rate (E), and CO2 substomatal concentration (Ci) were investigated. Significant decrease of leaf number, shoot length and plant dry mass by increasing salinity levels was observed in both rootstocks. D. virginiana was less affected in terms of plant growth under salinity stress. Leaf chlorophyll concentration reduction was higher in the leaves of D. kaki in comparison to D. virginiana in 100 mM NaCl treatment. By increasing salinity levels PN, gS and E markedly decreased in both rootstocks and D. kaki was more affected from salinity in terms of leaf gas exchange parameters. In addition there was no significant difference but slight decreases were recorded in leaf chlorophyll fluorescences of both rootstocks.

scholarly journals Leaf 13C and 15N composition shedding light on easing drought stress through partial K substitution by Na in eucalyptus species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nikolas Souza Mateus ◽  
Antonio Leite Florentino ◽  
Jessica Bezerra Oliveira ◽  
Elcio Ferreira Santos ◽  
Salete Aparecida Gaziola ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Chlorophyll Concentration ◽  
Dry Mass ◽  
Eucalyptus Species ◽  
Gas Exchange Parameters ◽  
Lower Growth ◽  
Mda Content ◽  
Exchange Parameters

AbstractThis work aimed to investigate the partial K-replacement by Na supply to alleviate drought-induced stress in Eucalyptus species. Plant growth, leaf gas exchange parameters, water relations, oxidative stress (H2O2 and MDA content), chlorophyll concentration, carbon (C) and nitrogen (N) isotopic leaf composition (δ13C and δ15N) were analyzed. Drought tolerant E. urophylla and E. camaldulensis showed positive responses to the partial K substitution by Na, with similar dry mass yields, stomatal density and total stomatal pore area relative to the well K-supplied plants under both water conditions, suggesting that 50% of the K requirements is pressing for physiological functions that is poorly substituted by Na. Furthermore, E. urophylla and E. camaldulensis up-regulated leaf gas exchanges, leading to enhanced long-term water use efficiency (WUEL). Moreover, the partial K substitution by Na had no effects on plants H2O2, MDA, δ13C and δ15N, confirming that Na, to a certain extent, can effectively replace K in plants metabolism. Otherwise, the drought-sensitive E. saligna species was negatively affected by partial K replacement by Na, decreasing plants dry mass, even with up-regulated leaf gas exchange parameters. The exclusive Na-supplied plants showed K-deficient symptoms and lower growth, WUEL, and δ13C, besides higher Na accumulation, δ15N, H2O2 and MDA content.

scholarly journals Leaf Gas Exchange and Chlorophyll a Fluorescence in Maize Leaves Infected with Stenocarpella macrospora

2015 ◽  
Vol 105 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Maria Bianney Bermúdez-Cardona ◽  
João Américo Wordell Filho ◽  
Fabrício Ávila Rodrigues
Keyword(s):  
Gas Exchange ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Leaf Gas Exchange ◽  
Photochemical Quenching ◽  
Efficiency Coefficient ◽  
Gas Exchange Parameters ◽  
Photosynthetic Gas Exchange ◽  
Chl A ◽  
Fluorescence Maximum

This study investigated the effect of macrospora leaf spot (MLS), caused by Stenocarpella macrospora, on photosynthetic gas exchange parameters and chlorophyll a fluorescence parameters determined in leaves of plants from two maize cultivars (‘ECVSCS155’ and ‘HIB 32R48H’) susceptible and highly susceptible, respectively, to S. macrospora. MLS severity was significantly lower in the leaves of plants from ECVSCS155 relative to the leaves of plants from HIB 32R48H. In both cultivars, net CO2 assimilation rate, stomatal conductance, and transpiration rate significantly decreased, while the internal to ambient CO2 concentration ratio increased in inoculated plants relative to noninoculated plants. The initial fluorescence and nonphotochemical quenching significantly increased in inoculated plants of ECVSCS155 and HIB 32R48H, respectively, relative to noninoculated plants. The maximum fluorescence, maximum PSII quantum efficiency, coefficient for photochemical quenching, and electron transport rate significantly decreased in inoculated plants relative to noninoculated plants. For both cultivars, concentrations of total chlorophyll (Chl) (a + b) and carotenoids and the Chl a/b ratio significantly decreased in inoculated plants relative to noninoculated plants. In conclusion, the results from the present study demonstrate, for the first time, that photosynthesis in the leaves of maize plants is dramatically affected during the infection process of S. macrospora, and impacts are primarily associated with limitations of a diffusive and biochemical nature.

scholarly journals The effect of the application of the biological control agent EM1 on gas exchange parameters and productivity of Pisum sativum L. infected with Fusarium oxysporum Schlecht.

2012 ◽  
Vol 63 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Adam Okorski ◽  
Jacek Olszewski ◽  
Katarzyna Głowacka ◽  
Sylwia Okorska ◽  
Agnieszka Pszczółkowska
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Fusarium Wilt ◽  
Chemical Control ◽  
Foliar Application ◽  
Biological Control Agent ◽  
Leaf Gas Exchange ◽  
Growth Conditions ◽  
Gas Exchange Parameters ◽  
Exchange Parameters

A pot experiment on different methods of EM 1 application was conducted in the period 2002-2004. The study was carried out under controlled growth conditions. The experimental factor was the method of EM1 application. Before application, the biological preparation EM1 was propagated as recommended by the manufacturer (Greenland). The health status of the aboveground parts of 'Ramrod' pea plants was estimated at the flowering stage. The assessment of pea leaf gas exchange parameters (An, E, Gs, and Ci) was made using a LI-Cor 6400 Portable Photosynthesis System. Soil application of EM1 combined with chemical control contributed to inhibiting Fusarium wilt of pea. Foliar application of EM1 combined with chemical control increased all gas exchange rates of pea leaves. Fusarium wilt of pea insignificantly decreased all gas exchange rates of pea leaves and the number of seeds per pod. The best method of EM1 application was soil treatment combined with chemical control, which increased all yield-related morphometric parameters of pea.

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