Environmental and Experimental Botany, Jun 1, 2021
Abstract Microcystis is a genus of unicellular blue-green algae that is toxic and can be troubles... more Abstract Microcystis is a genus of unicellular blue-green algae that is toxic and can be troublesome in freshwater, especially where organic material is abundant. The aim of this work was to analyse photosystems photochemistry of Microcystis spp. colonies under salt stress by the use of comprehensive chlorophyll a fluorescence signals measurements (prompt, delayed and modulated 820 nm reflection- MR 820). The cyanobacteria samples were taken from a natural aquatic environment. Chlorophyll a fluorescence measurements were made on the aqueous suspension of these organisms. The following salt solutions were applied with 10 days intervals: 0.00 (control), 0.05, 0.10, 0.20, 0.40, 0.80, and 1.00 M. Data was collected three times (10, 20 and 30 days after treatment), prior to increasing the salt concentration in the solution. We found that the salt stress inhibited electron transfer from the reduced PQ pool to the photosystem I (PSI) reaction center (P700+) and the inhibition of reoxidation of the plastoquinone molecule tightly bound to photosystem II- PSII (QA-). An inhibition of quantum yields of photoinduced electron transport in PSII reaction center to QA together with a reduction of the fast phase of photoinduced kinetics of the MR signal was also noted under this stress. We recommend the combined analyses of the prompt and delayed chlorophyll fluorescence along with MR 820 to be used as a novel qualitative method for studying photosynthetic machinery reactions not only in higher plants, but also in cyanobacteria.
Chlorophyll a fluorescence (ChF) signal analysis has become a widely used and rapid, non-invasive... more Chlorophyll a fluorescence (ChF) signal analysis has become a widely used and rapid, non-invasive technique to study the photosynthetic process under stress conditions. It monitors plant responses to various environmental factors affecting plants under experimental and field conditions. Thus, it enables extensive research in ecology and benefits forestry, agriculture, horticulture, and arboriculture. Woody plants, especially trees, as organisms with a considerable life span, have a different life strategy than herbaceous plants and show more complex responses to stress. The range of changes in photosynthetic efficiency of trees depends on their age, ontogeny, species-specific characteristics, and acclimation ability. This review compiles the results of the most commonly used ChF techniques at the foliar scale. We describe the results of experimental studies to identify stress factors that affect photosynthetic efficiency and analyse the experience of assessing tree vigour in natural...
Perennial ryegrass is a grass species used to establish lawns in urban areas where pollution is a... more Perennial ryegrass is a grass species used to establish lawns in urban areas where pollution is a major environmental problems. Cadmium (Cd) and nickel (Ni) contribute significantly to these pollutants and may cause photosynthetic limitation. The main objective of this work was to perform a comprehensive analysis of photosynthetic efficiency of perennial ryegrass seedlings under Cd and Ni stress. Some of the main indices of photosynthetic efficiency (prompt and delayed chlorophyll-a fluorescence signals and modulated reflectance at 820 nm) were compared with growth parameters. Two cultivars were tested: 'Niga' and 'Nira'. A decrease in photosystem (PS) II and PSI activity was observed. This was due to an increase in nonradiative dissipation of the PSII antenna, a decrease in PSII antenna size, or a decrease in the number of photosynthetic complexes with fully closed PSII RCs. Efficiency of electron transport was decreased. The effect on the modulated reflectance sign...
Modern Tools and Techniques to Understand Microbes, 2017
The symbiotic relationship between plant and microbes is one of the most important types of symbi... more The symbiotic relationship between plant and microbes is one of the most important types of symbiosis among different living forms. Such kind of association helps both the host and the symbiont. Generally, bacteria and fungi are found in association with a variety of plants. It is believed that more than 80 % of plants from different families available on the earth surface have a symbiotic association with arbuscular mycorrhizal fungi. In this context, it is very important to understand the host–microbe interaction, which will elucidate the exact mechanisms involved in the symbiosis.
It is already known that there are many factors responsible for the successful grafting process i... more It is already known that there are many factors responsible for the successful grafting process in plants, including light intensity. However, the influence of the spectrum of light-emitting diodes (LEDs) on this process has almost never been tested. During the pre-grafting process tomato seedlings grew for 30 days under 100 μmol m-2 s-1 of mixed LEDs (red 70%+ blue 30%). During the post-grafting period, seedlings grew for 20 days under the same light intensity but the lightening source was either red LED, mixed LEDs (red 70% + blue 30%), blue LED or white fluorescent lamps. This was done to determine which light source(s) could better improve seedling quality and increase grafting success. Our results showed that application of red and blue light mixture (R7:B3) caused significant increase in total leaf area, dry weight (total, shoot and root), total chlorophyll/carotenoid ratio, soluble protein and sugar content. Moreover, this light treatment maintained better photosynthetic perf...
The effect of seven herbicides (U-46 Combi Fluid, Cruz, MR, Basagran Bromicide, Lumax, and Gramox... more The effect of seven herbicides (U-46 Combi Fluid, Cruz, MR, Basagran Bromicide, Lumax, and Gramoxone) on Xanthium strumarium plants was studied. Chlorophyll content and fluorescence, leaf temperature, and stomatal conductance were evaluated at 12 h, 36 h, 60 h, and 84 h after herbicides application. U46 Combi Fluid, Cruz, and MR did not have a significant effect on chlorophyll fluorescence induction curves as compared to the control treatment. However, Basagran, Bromicide, Lumax, and Gramoxone showed significant changes in the shape of polyphasic fluorescence transients (OJIP transients). Variations in chlorophyll content index, leaf temperature, and stomatal conductance parameters were dependent on the type of applied herbicide. Our study revealed that the specific impact of the applied herbicides on the photosynthetic efficiency of plants is related to their chemical groups and their mechanism of action.
Haberlea rhodopensis is a chlorophyll-retaining resurrection plant, which can survive desiccation... more Haberlea rhodopensis is a chlorophyll-retaining resurrection plant, which can survive desiccation to air dry state under both low light and sunny environments. Maintaining the integrity of the membrane during dehydration of resurrection plants is extremely important. In the present study, the diffusion model was improved and used for a first time to evaluate the changes in ion leakage through different cellular compartments upon desiccation of H. rhodopensis and to clarify the reasons for significant increase of electrolyte leakage from dry leaves. The applied diffusion approach allowed us to distinguish the performance of plants subjected to dehydration and subsequent rehydration under different light intensities. Well-hydrated (control) shade plants had lower and slower electrolyte leakage compared to control sun plants as revealed by lower values of phase amplitudes, lower rate constants and ion concentration. In well-hydrated and moderately dehydrated plants (50% relative water ...
The book begins with a detailed description of the characteristics of the photosynthetic apparatu... more The book begins with a detailed description of the characteristics of the photosynthetic apparatus and the processes that take place there, to then present the general principles of fluorescence. After that, it gives a description of the characteristics of direct and modulated fluorescence and a presentation of the shared and distinctive parameters of these two techniques. Then a brief presentation is made of other innovative approaches to the analysis of fluorescence (Chlorophyll Fluorescence Imaging - CFI, P700 absorbance, delayed fluorescence) and the relative tools. An important part of the book comprises a description of the possible applications of fluorescence techniques for the analysis of various types of stress (aridity, strong light radiations, UV, high and low temperatures, salinity, weedkillers, pollution, etc.) and, consequently, their possible use in agriculture, forestry and to protect the environment.
Environmental and Experimental Botany, Jun 1, 2021
Abstract Microcystis is a genus of unicellular blue-green algae that is toxic and can be troubles... more Abstract Microcystis is a genus of unicellular blue-green algae that is toxic and can be troublesome in freshwater, especially where organic material is abundant. The aim of this work was to analyse photosystems photochemistry of Microcystis spp. colonies under salt stress by the use of comprehensive chlorophyll a fluorescence signals measurements (prompt, delayed and modulated 820 nm reflection- MR 820). The cyanobacteria samples were taken from a natural aquatic environment. Chlorophyll a fluorescence measurements were made on the aqueous suspension of these organisms. The following salt solutions were applied with 10 days intervals: 0.00 (control), 0.05, 0.10, 0.20, 0.40, 0.80, and 1.00 M. Data was collected three times (10, 20 and 30 days after treatment), prior to increasing the salt concentration in the solution. We found that the salt stress inhibited electron transfer from the reduced PQ pool to the photosystem I (PSI) reaction center (P700+) and the inhibition of reoxidation of the plastoquinone molecule tightly bound to photosystem II- PSII (QA-). An inhibition of quantum yields of photoinduced electron transport in PSII reaction center to QA together with a reduction of the fast phase of photoinduced kinetics of the MR signal was also noted under this stress. We recommend the combined analyses of the prompt and delayed chlorophyll fluorescence along with MR 820 to be used as a novel qualitative method for studying photosynthetic machinery reactions not only in higher plants, but also in cyanobacteria.
Chlorophyll a fluorescence (ChF) signal analysis has become a widely used and rapid, non-invasive... more Chlorophyll a fluorescence (ChF) signal analysis has become a widely used and rapid, non-invasive technique to study the photosynthetic process under stress conditions. It monitors plant responses to various environmental factors affecting plants under experimental and field conditions. Thus, it enables extensive research in ecology and benefits forestry, agriculture, horticulture, and arboriculture. Woody plants, especially trees, as organisms with a considerable life span, have a different life strategy than herbaceous plants and show more complex responses to stress. The range of changes in photosynthetic efficiency of trees depends on their age, ontogeny, species-specific characteristics, and acclimation ability. This review compiles the results of the most commonly used ChF techniques at the foliar scale. We describe the results of experimental studies to identify stress factors that affect photosynthetic efficiency and analyse the experience of assessing tree vigour in natural...
Perennial ryegrass is a grass species used to establish lawns in urban areas where pollution is a... more Perennial ryegrass is a grass species used to establish lawns in urban areas where pollution is a major environmental problems. Cadmium (Cd) and nickel (Ni) contribute significantly to these pollutants and may cause photosynthetic limitation. The main objective of this work was to perform a comprehensive analysis of photosynthetic efficiency of perennial ryegrass seedlings under Cd and Ni stress. Some of the main indices of photosynthetic efficiency (prompt and delayed chlorophyll-a fluorescence signals and modulated reflectance at 820 nm) were compared with growth parameters. Two cultivars were tested: 'Niga' and 'Nira'. A decrease in photosystem (PS) II and PSI activity was observed. This was due to an increase in nonradiative dissipation of the PSII antenna, a decrease in PSII antenna size, or a decrease in the number of photosynthetic complexes with fully closed PSII RCs. Efficiency of electron transport was decreased. The effect on the modulated reflectance sign...
Modern Tools and Techniques to Understand Microbes, 2017
The symbiotic relationship between plant and microbes is one of the most important types of symbi... more The symbiotic relationship between plant and microbes is one of the most important types of symbiosis among different living forms. Such kind of association helps both the host and the symbiont. Generally, bacteria and fungi are found in association with a variety of plants. It is believed that more than 80 % of plants from different families available on the earth surface have a symbiotic association with arbuscular mycorrhizal fungi. In this context, it is very important to understand the host–microbe interaction, which will elucidate the exact mechanisms involved in the symbiosis.
It is already known that there are many factors responsible for the successful grafting process i... more It is already known that there are many factors responsible for the successful grafting process in plants, including light intensity. However, the influence of the spectrum of light-emitting diodes (LEDs) on this process has almost never been tested. During the pre-grafting process tomato seedlings grew for 30 days under 100 μmol m-2 s-1 of mixed LEDs (red 70%+ blue 30%). During the post-grafting period, seedlings grew for 20 days under the same light intensity but the lightening source was either red LED, mixed LEDs (red 70% + blue 30%), blue LED or white fluorescent lamps. This was done to determine which light source(s) could better improve seedling quality and increase grafting success. Our results showed that application of red and blue light mixture (R7:B3) caused significant increase in total leaf area, dry weight (total, shoot and root), total chlorophyll/carotenoid ratio, soluble protein and sugar content. Moreover, this light treatment maintained better photosynthetic perf...
The effect of seven herbicides (U-46 Combi Fluid, Cruz, MR, Basagran Bromicide, Lumax, and Gramox... more The effect of seven herbicides (U-46 Combi Fluid, Cruz, MR, Basagran Bromicide, Lumax, and Gramoxone) on Xanthium strumarium plants was studied. Chlorophyll content and fluorescence, leaf temperature, and stomatal conductance were evaluated at 12 h, 36 h, 60 h, and 84 h after herbicides application. U46 Combi Fluid, Cruz, and MR did not have a significant effect on chlorophyll fluorescence induction curves as compared to the control treatment. However, Basagran, Bromicide, Lumax, and Gramoxone showed significant changes in the shape of polyphasic fluorescence transients (OJIP transients). Variations in chlorophyll content index, leaf temperature, and stomatal conductance parameters were dependent on the type of applied herbicide. Our study revealed that the specific impact of the applied herbicides on the photosynthetic efficiency of plants is related to their chemical groups and their mechanism of action.
Haberlea rhodopensis is a chlorophyll-retaining resurrection plant, which can survive desiccation... more Haberlea rhodopensis is a chlorophyll-retaining resurrection plant, which can survive desiccation to air dry state under both low light and sunny environments. Maintaining the integrity of the membrane during dehydration of resurrection plants is extremely important. In the present study, the diffusion model was improved and used for a first time to evaluate the changes in ion leakage through different cellular compartments upon desiccation of H. rhodopensis and to clarify the reasons for significant increase of electrolyte leakage from dry leaves. The applied diffusion approach allowed us to distinguish the performance of plants subjected to dehydration and subsequent rehydration under different light intensities. Well-hydrated (control) shade plants had lower and slower electrolyte leakage compared to control sun plants as revealed by lower values of phase amplitudes, lower rate constants and ion concentration. In well-hydrated and moderately dehydrated plants (50% relative water ...
The book begins with a detailed description of the characteristics of the photosynthetic apparatu... more The book begins with a detailed description of the characteristics of the photosynthetic apparatus and the processes that take place there, to then present the general principles of fluorescence. After that, it gives a description of the characteristics of direct and modulated fluorescence and a presentation of the shared and distinctive parameters of these two techniques. Then a brief presentation is made of other innovative approaches to the analysis of fluorescence (Chlorophyll Fluorescence Imaging - CFI, P700 absorbance, delayed fluorescence) and the relative tools. An important part of the book comprises a description of the possible applications of fluorescence techniques for the analysis of various types of stress (aridity, strong light radiations, UV, high and low temperatures, salinity, weedkillers, pollution, etc.) and, consequently, their possible use in agriculture, forestry and to protect the environment.
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