scholarly journals Half-Sib Lines of Pedunculate Oak (Quercus robur L.) Respond Differently to Drought Through Biometrical, Anatomical and Physiological Traits

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 153 ◽  
Author(s):  
Erna Vastag ◽  
Claudia Cocozza ◽  
Saša Orlović ◽  
Lazar Kesić ◽  
Milena Kresoja ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quenching ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Quercus Robur ◽  
Light Energy ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Drought Tolerant ◽  
Selection Of

Quercus robur L. is one of the most valued tree species of deciduous temperate forests. However, in the last decade, serious oak declines and loss of adaptation plasticity have been reported throughout Europe as a consequence of drought. Therefore, the aim of the present study was to define the adaptation potential of five Q. robur half-sib lines from the UNESCO Biosphere Reserve Mura-Drava-Danube to drought, using physiological, anatomical and biometrical traits. Half-sib lines that exhibited drought tolerance had particular suites of trait expression regarding biometrical traits (seedling height, root length, root to shoot ratio of dry mass and specific leaf area), leaf stomatal traits (stomatal density per mm2, stomata guard cell length and width, stomatal aperture length and width) and leaf structural traits (adaxial epidermis thickness, palisade parenchyma thickness, spongy parenchyma thickness, lamina thickness). All of the observed parameters of chlorophyll a fluorescence were shown to be good indicators of short-term and severe drought. For the selection of drought-tolerant half-sib lines, all studied chlorophyll a fluorescence parameters associated with the heat dissipation of light energy (coefficient of non-photochemical quenching, quantum yield of regulated energy dissipation, Stern-Volmer type non-photochemical fluorescence quenching) and one parameter related to photochemical dissipation of light energy (effective quantum yield (efficiency) of PS II photochemistry) were proven to be suitable. On the other hand, the coefficient of photochemical quenching, coefficient of photochemical fluorescence quenching assuming interconnected photosystem II antennae and electron transport rate were not suitable for distinguishing the different responses of the studied half-sib lines under drought. The importance of results of the present study is in the selection of drought-tolerant Q. robur half-sib lines for future reforestation programs, particularly in protected areas with sensitive forest management and restricted activities for mitigation of the adverse effects of climate changes.

scholarly journals Photosynthetic Potential and Productivity of Common Beans under Herbicide Effect

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
G.R. LIMA ◽  
D.C. MACEDO ◽  
R.L.N. BARROS ◽  
A.F.L. MACHADO ◽  
C. PIMENTEL
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Common Bean ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Environmental Influence ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Herbicide Application ◽  
Fluorescence Parameters

ABSTRACT: The objective of this study was to evaluate the effects of the application of contact herbicides recommended for common bean crops, as for chlorophyll a fluorescence parameters, leaf soluble proteins content (LSPC) and productivity. The experiment was conducted on the field with five treatments, which were the application of the following herbicides: bentazon (720 g ha-1), fluazifop-p-butil (187.5 g ha-1), fomesafen (250 g ha-1) fluazifop-p-butil + fomesafen (187.5 + 250 g ha-1), and a manually weeded control treatment without herbicide application, in a randomized block design with four replications. Bentazon was the only herbicide causing significant reductions, but only until the first day after herbicide application (DAA), on the following chlorophyll a fluorescence parameters: maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (ϕPSII), photochemical quenching (qP); it also induced an increase in non-photochemical quenching (NPQ). Fv/Fm was the best parameter to indicate herbicide effect on the photosynthetic apparatus of plants in the field. Chlorophyll a fluorescence parameters obtained in light-adapted leaves underwent a high environmental influence, especially deriving from the variation in the photosynthetic photon flow density (PPFD) during measurements; they are not recommended to evaluate the effects of herbicides on the field. None of the applied herbicides evaluated caused reductions in grain yield; therefore, they are recommended for common bean crops.

scholarly journals Seasonality and Small Spatial-Scale Variation of Chlorophyll a Fluorescence in Bryophyte Syntrichia ruralis [Hedw.] in Semi-Arid Sandy Grassland, Hungary

Plants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 92 ◽  
Author(s):  
Ruchika ◽  
Zsolt Csintalan ◽  
Evelin Ramóna Péli
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quenching ◽  
Spatial Scale ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Small Spatial Scale ◽  
Variation Trend ◽  
Fluorescence Parameters ◽  
Semi Arid ◽  
Sandy Grassland

Bryophytes face challenges due to global climate change which is leading to in-depth research in monitoring and studying their photosynthetic activity. The aim of this preliminary experiment was to study the seasonal variation trend in the chlorophyll a fluorescence parameters, Fv/Fm (ratio of variable to maximum fluorescence), photochemical fluorescence quenching (qP), photochemical quantum yield of photosystem II (ΦPS II), fluorescence quenching (qN), and non-photochemical quenching (NPQ), in the moss cushions of Syntrichia ruralis [Hedw.] collected from semi-arid sandy dunes for two slopes i.e., north-east (NE) and south-west (SW) direction. Our results showed a seasonal and small-spatial scale variation trend in all chlorophyll fluorescence parameters. These variations are due to different seasonal conditions referring to different degrees of environmental stress. ΦPS II and qP values were maximum in winter and in spring seasons while Fv/Fm, NPQ and qN were maximum in summer. Based on the different exposition of dunes, the SW slope showed increased values of the effective quantum yield of PS II and qP in comparison to the NE slope due to the optimal microclimate conditions for their expansion. These results may refer to the future changing in diversification and coverage of the Syntrichia species in semi-arid sandy grassland due to more effective metabolism in the beneficial microclimatic conditions.

scholarly journals Comparative stomatal conductance and chlorophyll a fluorescence in leaves vs. fruits of the cerrado legume tree, Dalbergia miscolobium

2004 ◽  
Vol 16 (2) ◽  
pp. 89-93 ◽  
Author(s):  
José Pires de Lemos Filho ◽  
Rosy Mary dos Santos Isaias
Keyword(s):  
Water Vapor ◽  
Stomatal Conductance ◽  
Quantum Yield ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Rate ◽  
Early Morning ◽  
Effective Quantum Yield ◽  
Quantum Yield Of Psii ◽  
Chronic Photoinhibition

The aim of this study was to compare water vapor conductance and chlorophyll a fluorescence between leaflets and fruits of Dalbergia miscolobium, the Jacaranda tree. The frequency of stomata on the leaflets was 20 times higher than that observed on the fruits, and this was related with the lower conductance of the fruits in comparison with the leaflets. The potential quantum yield of PSII (Fv /Fmax) was significantly lower in fruits than in leaflets. The Fv /Fmax values for leaflets increased to over 0.8 during the afternoon, indicating the occurrence of dynamic photoinhibition. In contrast, Fv /Fmax values for fruits remained low even at early morning, indicating the occurrence of chronic photoinhibition. The maximum values of effective quantum yield (deltaF/F'm), and of the apparent electron transport rate (ETRmax) were higher in leaflets than in fruits. It was concluded that, like other green tissues, the pericarp of D. miscolobium was photosynthetically active, and therefore can contribute to the maintenance of the fruits and/or to the development of the seeds.

scholarly journals Comparisons of Chlorophyll Fluorescence and Physiological Characteristics of Wheat Seedlings Influenced by Iso-Osmotic Stresses from Polyethylene Glycol and Sodium Chloride

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 325
Author(s):  
Chiu-Yueh Lan ◽  
Kuan-Hung Lin ◽  
Chun-Liang Chen ◽  
Wen-Dar Huang ◽  
Chang-Chang Chen
Keyword(s):  
Chlorophyll Fluorescence ◽  
Polyethylene Glycol ◽  
Sodium Chloride ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Wheat Seedlings ◽  
Level 3 ◽  
Level 2

Wheat (Triticum aestivum) cultivar Taichung SEL.2 (TCS2) is a salt-tolerance variety, but the mechanism involved remains unclear. This study aims to distinguish between the non-ionic osmotic and salt-mediated physiological effects on TCS2. Osmotic agents polyethylene glycol (PEG) and sodium chloride (NaCl) were applied at three iso-osmotic levels, level 1 containing 24% (w/v) PEG and 200 mM NaCl, level 2 containing 26.5% (w/v) PEG and 250 mM NaCl), and level 3 containing 29% (w/v) PEG and 300 mM NaCl, respectively. According to the investigation of chlorophyll fluorescence in the better NaCl-treated seedlings, maximal quantum yield of photosystem II (PSII) (Fv/Fm) and significant higher effective quantum yield of PSII (ΦPSII) at level 3 were observed. Meanwhile, the non-photochemical quenching of PSII (NPQ) and the quantum yield of regulated energy dissipation of PSII [Y(NPQ)] were significantly higher in the NaCl-treated seedlings, and the quantum yield of non-regulated energy dissipation of PSII [Y(NO)] in the NaCl-treated seedlings was lower than the PEG-treated ones at level 2 and level 3. Furthermore, the less extensive degradation of photosynthetic pigments, the better ascorbate peroxidase (APX) activity and the less accumulation of malondialdehyde (MDA) were also observed in NaCl-treated seedlings. In the morphological traits, shoot elongation in NaCl-treated seedlings was also preserved. These results suggest that TCS2 is more resistant to NaCl-induced osmotic stress than to the PEG-induced stress. This study contributes to plant breeder interest in drought- and/or salt-tolerant wheat varieties.

scholarly journals Effect of Drought Stress on Chlorophyll Fluorescence Parameters, Phytochemical Contents, and Antioxidant Activities in Lettuce Seedlings

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 238
Author(s):  
Yu Kyeong Shin ◽  
Shiva Ram Bhandari ◽  
Jung Su Jo ◽  
Jae Woo Song ◽  
Jun Gu Lee
Keyword(s):  
Ascorbic Acid ◽  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Quantum Yield ◽  
Antioxidant Activities ◽  
Growth Parameters ◽  
Photochemical Quenching ◽  
Total Phenol Content ◽  
Effective Quantum Yield ◽  
Chlorophyll Fluorescence Parameters

This study monitored changes in chlorophyll fluorescence (CF), growth parameters, soil moisture content, phytochemical content (proline, ascorbic acid, chlorophyll, total phenol content (TPC), and total flavonoid content (TFC)), and antioxidant activities in 12-day-old lettuce (Lactuca sativa L.) seedlings grown under drought stress (no irrigation) and control (well irrigated) treatments in controlled conditions for eight days. Measurements occurred at two-day intervals. Among ten CF parameters studied, effective quantum yield of photochemical energy conversion in PSII (Y(PSII)), coefficient of photochemical quenching (qP), and coefficient of photochemical quenching of variable fluorescence based on the lake model of PSII (qL) significantly decreased in drought-stressed seedlings from day 6 of treatment compared to control. In contrast, maximum quantum yield (Fv/Fm), ratio of fluorescence (Rfd), and quantum yield of non-regulated energy dissipation in PSII (Y(NO)) were significantly affected only at the end. All growth parameters decreased in drought-stressed seedlings compared to control. Proline started increasing from day 4 and showed ~660-fold elevation on day 8 compared to control. Chlorophyll, ascorbic acid, TPC, TFC, and antioxidant activities decreased in drought-stressed seedlings. Results showed major changes in all parameters in seedlings under prolonged drought stress. These findings clarify effects of drought stress in lettuce seedlings during progressive drought exposure and will be useful in the seedling industry.

scholarly journals PYRACLOSTROBIN PRESERVES PHOTOSYNTHESIS IN ARABICA COFFEE PLANTS SUBJECTED TO WATER DEFICIT

2020 ◽  
Vol 28 ◽  
pp. 109-119
Author(s):  
Anelisa Figueiredo Peloso ◽  
Sandro Dan Tatagiba ◽  
Francisco José Teixeira Amaral ◽  
Paulo César Cavatte ◽  
José Eduardo Macedo Pezzopane
Keyword(s):  
Quantum Yield ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Photosynthetic Performance ◽  
Effective Quantum Yield ◽  
Fluorescence Maximum ◽  
Common Strategy ◽  
Coffee Plants

The objective of this study was to investigate the effect of pyraclostrobin on the photosynthetic performance of rabica coffee plants subjected or not to a water deficit, using the parameter of gas exchange (net CO2 assimilation, stomatal conductance, transpiration rate, and internal CO2 concentration and nocturnal respiration), chlorophyll fluorescence a parameters (minimum fluorescence, maximum fluorescence, maximum quantum yield of photosystem II, effective quantum yield of PSII, quantum yield of regulated energy dissipation and quantum yield dissipation non-regulated) as well as the concentrations of chloroplast pigments. In the plants maintained without water deficit, pyraclostrobin did not cause any alteration on the parameters of chlorophyll a fluorescence; however, it contributed to an increase in the level of chlorophyll a + b, CO2 assimilation and CO2 influx for the carboxylation sites of the stroma. Decreases in nocturnal respiration in plants treated with pyraclostrobin, submitted or not to water deficit seems to be a common strategy in reducing energy waste in the maintenance metabolism. Under water deficit, pyraclostrobin contributed to increase the photochemical yield, enabling plants to effectively prevent the capture, use and dissipation of light energy.

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