Chlorophyll A Fluorescence and Chlorophyll Content in Parmelia Quercina Thalli from a Polluted Region of Northern Castellon (Spain)

1996 ◽  
Vol 28 (1) ◽  
pp. 49-65 ◽  
Author(s):  
A. Calatayud ◽  
M. J. Sanz ◽  
E. Calvo ◽  
E. Barreno ◽  
S. del Valle-Tascon
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Electron Flow ◽  
Fluorescence Emission ◽  
Fluorescence Yield ◽  
Chlorophyll Fluorescence Parameters ◽  
Energy Capture ◽  
Pollution Concentrations ◽  
Made In

AbstractMeasurements of modulated chlorophyll a fluorescence emission and chlorophyll content were made in thalli of Parmelia quercina collected from northern Castellon(Spain). Althoug high air pollution concentrations have been measured in this area, the ratio of variable to maximal fluorescence is unaffected. Following dark-adaptation, the response to irradiance of chlorophyll fluorescence was examined. With respect to control samples, thalli collected in northern Castellon consistently showed differences in fluorescence quenching, the efficiency of excitation energy capture and quenching of basal fluorescence. However, the quantum ield of photochemistry and non-cyclic electron flow were not affected. The changes in chlorophyll fluorescence parameters were observed in the absence of both visual injuries and decrease in chlorophyll content. The results are discussed with regard to the possible role of environmental stress in chlorophyll fluorescence yield.

scholarly journals Electron and proton transport in wheat exposed to salt stress: is the increase of the thylakoid membrane proton conductivity responsible for decreasing the photosynthetic activity in sensitive genotypes?

2021 ◽  
Author(s):  
Ulkar Ibrahimova ◽  
Marek Zivcak ◽  
Kristina Gasparovic ◽  
Anshu Rastogi ◽  
Suleyman I. Allakhverdiev ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Proton Conductivity ◽  
Salinity Stress ◽  
Electron Flow ◽  
Soluble Sugars ◽  
Photosynthetic Apparatus ◽  
Photochemical Reactions ◽  
Chlorophyll Fluorescence Parameters

AbstractEffects of salinity caused by 150 mM NaCl on primary photochemical reactions and some physiological and biochemical parameters (K+/Na+ ratio, soluble sugars, proline, MDA) have been studied in five Triticum aestivum L. genotypes with contrasting salt tolerance. It was found that 150 mM NaCl significantly decreased the photosynthetic efficiency of two sensitive genotypes. The K+/Na+ ratio decreased in all genotypes exposed to salinity stress when compared with the control. Salinity stress also caused lipid peroxidation and accumulation of soluble sugars and proline. The amounts of soluble sugars and proline were higher in tolerant genotypes than sensitive ones, and lipid peroxidation was higher in sensitive genotypes. The noninvasive measurements of photosynthesis-related parameters indicated the genotype-dependent effects of salinity stress on the photosynthetic apparatus. The significant decrease of chlorophyll content (SPAD values) or adverse effects on photosynthetic functions at the PSII level (measured by the chlorophyll fluorescence parameters) were observed in the two sensitive genotypes only. Although the information obtained by different fast noninvasive techniques were consistent, the correlation analyses identified the highest correlation of the noninvasive records with MDA, K+/Na+ ratio, and free proline content. The lower correlation levels were found for chlorophyll content (SPAD) and Fv/Fm values derived from chlorophyll fluorescence. Performance index (PIabs) derived from fast fluorescence kinetics, and F735/F685 ratio correlated well with MDA and Na+ content. The most promising were the results of linear electron flow measured by MultispeQ sensor, in which we found a highly significant correlation with all parameters assessed. Moreover, the noninvasive simultaneous measurements of chlorophyll fluorescence and electrochromic band shift using this sensor indicated the apparent proton leakage at the thylakoid membranes resulting in a high proton conductivity (gH+), present in sensitive genotypes only. The possible consequences for the photosynthetic functions and the photoprotection are discussed.

scholarly journals Effects of Drought and Rehydration on the Physiological Responses of Artemisia halodendron

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 793
Author(s):  
Juanli Chen ◽  
Xueyong Zhao ◽  
Yaqiu Zhang ◽  
Yuqiang Li ◽  
Yongqing Luo ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Membrane Permeability ◽  
Chlorophyll Content ◽  
Physiological Responses ◽  
Severe Drought ◽  
Native Plant ◽  
Chlorophyll Fluorescence Parameters ◽  
Artemisia Halodendron ◽  
Effects Of Drought

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

scholarly journals Effects of arbuscular mycorrhizal inoculation on the growth, photosynthesis and antioxidant enzymatic activity of Euonymus maackii Rupr. under gradient water deficit levels

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259959
Author(s):  
Na Wu ◽  
Zhen Li ◽  
Sen Meng ◽  
Fei Wu
Keyword(s):  
Chlorophyll Content ◽  
Water Deficit ◽  
Antioxidant System ◽  
Biomass Accumulation ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Negative Influence ◽  
Positive Role ◽  
Chlorophyll Fluorescence Parameters

The role of arbuscular mycorrhizal (AM) fungus (Rhizophagus intraradices) in the amelioration of the water deficit-mediated negative influence on the growth, photosynthesis, and antioxidant system in Euonymus maackii Rupr. was examined. E. maackii seedlings were subjected to 5 water deficit levels, soil water contents of 20%, 40%, 60%, 80% and 100% field capacity (FC), and 2 inoculation treatments, with and without AM inoculation. The water deficit increasingly limited the seedling height, biomass accumulation in shoots and roots, chlorophyll content, gas exchange and chlorophyll fluorescence parameters with an increasing water deficit level. In addition, water deficit stimulated the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in both shoots and roots, except under 20% FC conditions. E. maackii seedlings under all water deficit conditions formed symbiosis well with AM fungi, which significantly ameliorated the drought-mediated negative effect, especially under 40% and 60% FC conditions. Under 40% to 80% FC conditions, AM formation improved seedling growth and photosynthesis by significantly enhancing the biomass accumulation, chlorophyll content and assimilation. Mycorrhizal seedlings showed better tolerance and less sensitivity to a water deficit, reflected in the lower SOD activities of shoots and roots and CAT activity of shoots under 40% and 60% FC conditions. Downregulation of the antioxidant system in mycorrhizal seedlings suggested better maintenance of redox homeostasis and protection of metabolism, including biomass accumulation and assimilation. All the results advocated the positive role of R. intraradices inoculation in E. maackii against a water deficit, especially under 40% FC, which suggested the distinct AM performance in drought tolerance and the potential role of the combination of E. maackii-AM fungi in ecological restoration in arid regions.

scholarly journals Gas exchange and chlorophyll fluorescence parameters in four maize genotypes influenced by first phase of salt stress

2019 ◽  
Vol 30 ◽  
pp. 26-32
Author(s):  
MN Uddin ◽  
MIU Hoque ◽  
S Monira ◽  
MAA Bari
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Net Photosynthesis ◽  
Pure Line ◽  
Photosynthesis Rate ◽  
Chlorophyll Fluorescence Parameters ◽  
Maize Genotypes ◽  
Fluorescence Characteristics

Responses in photosynthesis, transpiration, stomatal conductance, chlorophyll fluorescence characteristics and chlorophyll content of four maize (Zea mays L.) genotypes were examined under first phase of salt stress. In the experiment four maize genotypes viz. indigenous yellow pure line, indigenous yellow, hybrid, and indigenous white were tested in two levels of salinity (control: without NaCl application; salinity: 12 dS m-1 by applying NaCl). The experiment was laid out following completely randomized design (CRD) with four replications in the net house of Department of Crop Botany, Bangladesh Agricultural University, Mymensingh. Plants were harvested on day 21 after 7 d application of full salt stress (12 dS m-1). The reductions of shoot fresh masses under salinity were 70, 57, 55 and 61% in indigenous yellow pure line, indigenous yellow, hybrid, and indigenous white, respectively. Some core physiological parameters viz. net photosynthesis rate (Pn), transpiration rate (E), stomatal conductance (gs), and the chlorophyll content decreased in all the maize genotypes except indigenous white under first phase of salt stress. In contrast, the ratio of variable fluorescence to maximal fluorescence (Fv/Fm) of photosystem II significantly decreased only in indigenous yellow pure line under salinity stress. Thus the first phase of salt stress seemed to be deleterious on its response to shoot fresh mass production in all the tested four maize genotypes with the concomitant decrease in rate of photosynthesis, rate of transpiration, stomatal conductance and chlorophyll content in all genotypes except indigenous white. Progressive Agriculture, Vol. 30, Suppl. 1: 26-32, 2019

Adaptation of a Chlamydomonas mutant with reduced rate of photorespiration to different concentrations of CO2

2005 ◽  
Vol 83 (7) ◽  
pp. 834-841 ◽  
Author(s):  
Kensaku Suzuki ◽  
Hidenori Onodera
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlamydomonas Reinhardtii ◽  
Inorganic Carbon ◽  
Electron Flow ◽  
Effective Quantum Yield ◽  
Wild Type ◽  
Chlorophyll Fluorescence Parameters ◽  
Phosphoglycolate Phosphatase ◽  
Concentrating Mechanism ◽  
Type Strains

It has been widely accepted that Chlamydomonas reinhardtii cells utilize inorganic carbon very efficiently for photosynthesis by operating a CO2-concentrating mechanism (CCM) under conditions of limited CO2. To help define the mechanism, 7FR2N, one of the suppressor double mutants of phosphoglycolate phosphatase-deficient (pgp1) mutants that have a reduced photorespiration rate (RPR) was crossed with wild-type strains to generate the strain N21 as a single RPR mutant. The comparison of photosynthetic characteristics with wild-type strains after the cells adapted to different concentrations of CO2 revealed that photosynthetic affinity for inorganic carbon was higher than that in wild-type strains after adaptation to concentrations between 50 µL·L–1 CO2 and 5% CO2. Chlorophyll fluorescence parameters were also compared, and the biggest difference between N21 and the wild-type strains was observed in the photochemical quenching and effective quantum yield of photosystem II (ΔF/Fm′) at the CO2 compensation point. These values in N21 increased in a similar manner to the photosynthetic affinity for CO2, and increased significantly when the cells adapted to low-CO2 levels, whereas the values in the wild-type strains were apparently lower without any significant changes, regardless of the CO2 concentrations to which they were adapted. Although it was not clear if a nonphotochemical quenching parameter (NPQ) in N21 was higher than that in wild-type strains, NPQ increased coincidentally with the increase in photosynthetic affinity for inorganic carbon when the CO2 concentrations to which the strains were adapted decreased, in both the mutant and wild-type strain, suggesting that this form of NPQ reflects the operation of CCM in certain conditions. Possible candidates for the RPR mutation and the relationship between CCM and photosynthetic electron flow are discussed.Key words: Chlamydomonas reinhardtii, chlorophyll fluorescence, CO2-concentrating mechanism, low-CO2 responsive gene, phosphoglycolate phosphatase, photorespiration.

scholarly journals Effects of Arbuscular Mycorrhizal Inoculation on Growth, Photosynthesis and Antioxidant Enzymatic Activity of Euonymus Maackii Rupr. Under Gradient Water Deficit Levels

2020 ◽  
Author(s):  
Na Wu ◽  
Zhen Li ◽  
Sen Meng ◽  
Fei Wu
Keyword(s):  
Chlorophyll Content ◽  
Water Deficit ◽  
Antioxidant System ◽  
Biomass Accumulation ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Negative Influence ◽  
Positive Role ◽  
Chlorophyll Fluorescence Parameters

Abstract The role of arbuscular mycorrhizal (AM) fungus (Rhizophagus intraradices) in amelioration of water deficit mediated negative influence on growth, photosynthesis and antioxidant system in Euonymus maackii Rupr. was examined. E. maackii seedlings were subjected to 5 water deficit levels: soil water contents of 20 %, 40 %, 60 %, 80 % and 100 % field capacity (FC) respectively, and 2 inoculation treatment: with and without AM inoculation. Water deficit increasingly limited seedlings growth of height, biomass accumulation of shoot and root, chlorophyll content, gas exchange and chlorophyll fluorescence parameters along the increase of water deficit level. In addition, Water deficit stimulated the activities of antioxidant enzymatic activities, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of both shoot and root, except under 20 % FC condition. E. maackii seedlings under all water deficit conditions formed AM symbiosis well with AM fungi, which ameliorated the drought mediated negative effect significantly, especially under 40 % and 60 % FC conditions. Under 40 % to 80 % FC conditions, AM formation improved seedlings growth and photosynthesis by significantly enhancing biomass accumulation, chlorophyll content and assimilation. Mycorrhizal seedlings showed better tolerance and less sensitive to water deficit, reflected in lower SOD activities of shoot and root, and CAT activity of shoot under 40 % and 60 % FC conditions. Down-regulation of antioxidant system in mycorrhizal seedlings suggested better maintenance of redox homeostasis and protection of metabolism, including biomass accumulation and assimilation. All the results advocated the positive role of R. intraradices inoculation in E. maackii against water deficit, which suggested the potential role of AM fungi in ecological restoration in arid region.

scholarly journals Differential responses of ribulose-1,5-bisphosphate carboxylase/oxygenase activities of two Vigna unguiculata cultivars to salt stress

2005 ◽  
Vol 17 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Maria Erivalda Farias de Aragão ◽  
Marjorie Moreira Guedes ◽  
Maria de Lourdes Oliveira Otoch ◽  
Maria Izabel Florindo Guedes ◽  
Dirce Fernandes de Melo ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Vigna Unguiculata ◽  
Shoot Growth ◽  
Bisphosphate Carboxylase ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Root And Shoot Growth ◽  
Specific Activities

Vita 3 and Vita 5 are two Vigna unguiculata cultivars that differ in their capacities for survival in saline environments; Vita 3 is more tolerant and Vita 5 more sensitive. Both cultivars were submitted to salt stress with 0.1 M NaCl. After 8 days, root and shoot growth from both cultivars was reduced but reduction was more pronounced in Vita 5. Furthermore, leaf area was also reduced in this cultivar. Chlorophyll content and chlorophyll fluorescence parameters were not affected by salt stress, but the specific activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased in Vita 3 and increased in Vita 5. The use of immunological techniques also revealed that the Rubisco content from Vita 3 decreased while that of Vita 5 increased. The discussion of these results is aimed at reaching a better understanding of the differences between these cultivars in relation to salt stress.

scholarly journals Effects of NtSPS1 Overexpression on Solanesol Content, Plant Growth, Photosynthesis, and Metabolome of Nicotiana tabacum

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 518
Author(s):  
Ning Yan ◽  
Xiaolei Gai ◽  
Lin Xue ◽  
Yongmei Du ◽  
John Shi ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Nicotiana Tabacum ◽  
Plant Growth ◽  
Chlorophyll Content ◽  
Carbon Fixation ◽  
Leaf Growth ◽  
Pathway Enrichment Analysis ◽  
Photosynthetic Gas Exchange ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters

Nicotiana tabacum solanesyl diphosphate synthase 1 (NtSPS1) is the key enzyme in solanesol biosynthesis. However, changes in the solanesol content, plant growth, photosynthesis, and metabolome of tobacco plants after NtSPS1 overexpression (OE) have not been previously reported. In the present study, these parameters, as well as photosynthetic gas exchange, chlorophyll content, and chlorophyll fluorescence parameters, were compared between NtSPS1 OE and wild type (WT) lines of tobacco. As expected, NtSPS1 OE significantly increased solanesol content in tobacco leaves. Although NtSPS1 OE significantly increased leaf growth, photosynthesis, and chlorophyll content, the chlorophyll fluorescence parameters in the leaves of the NtSPS1 OE lines were only slightly higher than those in the WT leaves. Furthermore, NtSPS1 OE resulted in 64 differential metabolites, including 30 up-regulated and 34 down-regulated metabolites, between the OE and WT leaves. Pathway enrichment analysis of these differential metabolites identified differentially enriched pathways between the OE and WT leaves, e.g., carbon fixation in photosynthetic organisms. The maximum carboxylation rate of RuBisCO and the maximum rate of RuBP regeneration were also elevated in the NtSPS1 OE line. To our knowledge, this is the first study to confirm the role of NtSPS1 in solanesol biosynthesis and its possible functional mechanisms in tobacco.

Sun-Induced chlorophyll Fluorescence full spectrum retrieval and analysis of long-term time series

2020 ◽  
Author(s):  
Ilaria Cesana ◽  
Sergio Cogliati ◽  
Marco Celesti ◽  
Tommaso Julitta ◽  
Roberto Colombo
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll Content ◽  
Canopy Structure ◽  
Fluorescence Emission ◽  
Simulated Data ◽  
Terrestrial Ecosystems ◽  
Retrieval Algorithm ◽  
Satellite Mission ◽  
Biophysical Parameters ◽  
Full Spectrum

<p>Remote sensing of Sun-Induced chlorophyll Fluorescence (SIF) represents a growing and promising area of research in support of the upcoming ESA’s FLEX (FLuorescence EXplorer) satellite mission. For this reason, the link between SIF and photosynthetic activity has been widely explored in the recent years, as tool to characterize and monitoring terrestrial ecosystems functioning.</p><p> </p><p>The SIF detection is challenging because this faint signal (which represents only few percent of the total radiance) is over imposed on the light reflected from the Earth’s surface. Decoupling these two contributions is not trivial and dedicated algorithms are needed. For this reason, a novel SIF retrieval algorithm, named SpecFit, has been developed in order to retrieve the entire SIF spectrum in the entire wavelength interval in which chlorophyll fluorescence emission occurs (670-768 nm). This novel approach is able to disentangle SIF and reflectance contributions from the total radiance spectrum emerging from the top of canopy. Nevertheless, the further interpretation of the SIF spectrum in relation to plant photosynthesis is complicated by the fact that the SIF signal is strongly influenced by several biophysical parameters, such as canopy structure and chlorophyll content that affect the leaves/canopy radiation transfer and therefore the overall remote sensed signal. </p><p>The proposed work aims to verify first the SpecFit algorithm robustness on both simulated and field data and, second to investigate the potential of novel fluorescence indexes defined from the SIF full spectrum.   </p><p> </p><p>The algorithm accuracy has been tested on a set of simulated data, obtained by coupling MODTRAN (atmosphere) and SCOPE (canopy) radiative transfer models. Scatterplots between forward simulations and retrieved SIF showed R<sup>2 </sup>close to 0.98 considering all the evaluated metrics, namely: maximum of the peaks in the red and far-red and SIF spectrum integral.</p><p>The temporal series acquired during the ESA’s ATMOFlex and FLEXSense campaigns organised in an agricultural area in Braccagni (Tuscany, Italy) were, instead, used to test the algorithm on experimental measures acquired with FLOX spectrometers, from February to August on different crops (forage, alfalfa and corn). For the first time, SIF spectra observed on different vegetation species at different growing stages are presented in this work and their consistency with SIF values estimated by the more consolidated and widely used Spectral Fitting retrieval Method (SFM) are presented. The relationship found shows a linear regression slopes close to 1, intercepts approximately equal to 0 and R<sup>2 </sup>higher than 0.92 are all evidences of the SpecFit accuracy.  </p><p> </p><p>The final step consists in analysing the temporal evolution of novel fluorescence indexes derived from the SIF spectrum. Specifically, SpecFit SIF evaluated at 760 nm and 687 nm and normalized by the retrieved spectrum integral (SIF<sub>SpecFit</sub>/SIF<sub>INT</sub>) were compared to the index SIF<sub>760</sub>/SIF<sub>687</sub>, the latter is a proxy of the chlorophyll content. SIF<sub>760</sub>/SIF<sub>687</sub> and SIF<sub>760</sub>/SIF<sub>INT</sub> increase linearly during the growing season due to re-absorption processes that affect both the indexes. Conversely, an inverse relationship is found between SIF<sub>760</sub>/SIF<sub>687</sub>and SIF<sub>687</sub>/SIF<sub>INT </sub>because the contribute in the visible red wavelengths to the integral become weaker at increasing biomass content. </p>

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