This study introduces an evaluation methodology tailored for bioreactors, with the aim of assessing the stress experienced by algae due to harmful contaminants released from antifouling (AF) paints. We present an online monitoring system equipped with an ultra-sensitive sensor that conducts non-invasive measurements of algal culture's optical density and physiological stage through chlorophyll fluorescence signals. By coupling the ultra-sensitive sensor with flash-induced chlorophyll fluorescence, we examined the dynamic fluorescence changes in the green microalga Chlamydomonas reinhardtii when exposed to biocides. Over a 24-h observation period, increasing concentrations of biocides led to a decrease in photosynthetic activity. Notably, a substantial reduction in the maximum quantum yield of primary photochemistry (FV/FM) was observed within the first hour of exposure. Subsequently, we detected a partial recovery in FV/FM; however, this recovery remained 50% lower than that of the controls. Integrating the advanced submersible sensor with fluorescence decay kinetics offered a comprehensive perspective on the dynamic alterations in algal cells under the exposure to biocides released from antifouling coatings. The analysis of fluorescence relaxation kinetics revealed a significant shortening of the fast and middle phases, along with an increase in the duration of the slow phase, for the coating with the highest levels of biocides. Combining automated culturing and measuring methods, this approach has demonstrated its effectiveness as an ultrasensitive and non-invasive tool for monitoring the physiology of photosynthetic cultures. This is particularly valuable in the context of studying microalgae and their early responses to various environmental conditions, as well as the potential to develop an AF system with minimal harm to the environment.
- Klíčová slova
- Antifouling coatings, Bioreactor, Chlorophyll fluorescence spectroscopy, Microalgae, Toxicity, Ultrasensitive sensor,
- MeSH
- bioreaktory * MeSH
- chemické látky znečišťující vodu analýza MeSH
- Chlamydomonas reinhardtii * účinky léků metabolismus MeSH
- chlorofyl metabolismus MeSH
- dezinficiencia farmakologie MeSH
- fluorescence MeSH
- fotosyntéza účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chemické látky znečišťující vodu MeSH
- chlorofyl MeSH
- dezinficiencia MeSH
The model plant Arabidopsis thaliana was exposed to combined stress factors, i.e., titanium dioxide nanoparticles (TiNPs) and high light. The concentrations of TiNPs used for irrigation were 250, 500, and 1000 μg/mL. This study shows that TiNPs alter the morphology and nanomechanical properties of chloroplasts in A. thaliana, which leads to a decrease in membrane elasticity. We found that TiNPs contributed to a delay in the thermal response of A. thaliana under dynamic light conditions, as revealed by non-invasive thermal imaging. The thermal time constants of TiNP-treated plants under excessive light are determined, showing a shortening in comparison to control plants. The results indicate that TiNPs may contribute to an alleviation of temperature stress experienced by plants under exposure to high light. In this research, we observed a decline in photosystem II photochemical efficiency accompanied by an increase in energy dissipation upon exposure to TiNPs. Interestingly, concentrations exceeding 250 µg/mL TiNPs appeared to mitigate the effects of high light, as shown by reduced differences in the values of specific OJIP parameters (FV/FM, ABS/RC, DI0/RC, and Pi_Abs) before and after light exposure.
- Klíčová slova
- Arabidopsis, High light, Joint stress factors, Light-induced thermal kinetics, Photosynthetic efficiency, Titanium dioxide nanoparticles,
- MeSH
- Arabidopsis * metabolismus MeSH
- chlorofyl metabolismus MeSH
- chloroplasty MeSH
- fotosyntéza fyziologie MeSH
- fotosystém II (proteinový komplex) metabolismus MeSH
- nanočástice * MeSH
- světlo MeSH
- titan metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chlorofyl MeSH
- fotosystém II (proteinový komplex) MeSH
- titan MeSH
- titanium dioxide MeSH Prohlížeč
A non-destructive thermal imaging method was used to study the stomatal response of salt-treated Arabidopsis thaliana plants to excessive light. The plants were exposed to different levels of salt concentrations (0, 75, 150, and 220 mM NaCl). Time-dependent thermograms showed the changes in the temperature distribution over the lamina and provided new insights into the acute light-induced temporary response of Arabidopsis under short-term salinity. The initial response of plants, which was associated with stomatal aperture, revealed an exponential growth in temperature kinetics. Using a single-exponential function, we estimated the time constants of thermal courses of plants exposed to acute high light. The saline-induced impairment in stomatal movement caused the reduced stomatal conductance and transpiration rate. Limited transpiration of NaCl-treated plants resulted in an increased rosette temperature and decreased thermal time constants as compared to the controls. The net CO2 assimilation rate decreased for plants exposed to 220 mM NaCl; in the case of 75 mM NaCl treatment, an increase was observed. A significant decline in the maximal quantum yield of photosystem II under excessive light was noticeable for the control and NaCl-treated plants. This study provides evidence that thermal imaging as a highly sensitive technique may be useful for analyzing the stomatal aperture and movement under dynamic environmental conditions.
- Klíčová slova
- evapotranspiration, excessive light, infrared thermal imaging, light-induced temperature kinetics, photosystem II efficiency, salinity, stomatal conductance,
- MeSH
- Arabidopsis účinky léků fyziologie účinky záření MeSH
- chlorid sodný aplikace a dávkování MeSH
- fotosystém II (proteinový komplex) účinky léků metabolismus účinky záření MeSH
- fyziologický stres MeSH
- kinetika MeSH
- osmotický tlak MeSH
- průduchy rostlin účinky léků fyziologie účinky záření MeSH
- salinita MeSH
- světlo MeSH
- termografie metody MeSH
- transpirace rostlin účinky léků fyziologie účinky záření MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chlorid sodný MeSH
- fotosystém II (proteinový komplex) MeSH
- MeSH
- antioxidancia terapeutické užití MeSH
- kardiovaskulární nemoci prevence a kontrola MeSH
- polyfenoly terapeutické užití MeSH
- rostliny chemie MeSH
- Publikační typ
- úvodníky MeSH
- Názvy látek
- antioxidancia MeSH
- polyfenoly MeSH
- MeSH
- antioxidancia chemie terapeutické užití MeSH
- kardiovaskulární nemoci prevence a kontrola MeSH
- oxidační stres MeSH
- peroxidace lipidů MeSH
- reaktivní formy kyslíku chemie metabolismus MeSH
- rostliny chemie metabolismus MeSH
- Publikační typ
- úvodní články MeSH
- úvodníky MeSH
- Názvy látek
- antioxidancia MeSH
- reaktivní formy kyslíku MeSH
In the present study, singlet oxygen (¹O₂) scavenging activity of tocopherol and plastochromanol was examined in tocopherol cyclase-deficient mutant (vte1) of Arabidopsis thaliana lacking both tocopherol and plastochromanol. It is demonstrated here that suppression of tocopherol and plastochromanol synthesis in chloroplasts isolated from vte1 Arabidopsis plants enhanced ¹O₂ formation under high light illumination as monitored by electron paramagnetic resonance spin-trapping spectroscopy. The exposure of vte1 Arabidopsis plants to high light resulted in the formation of secondary lipid peroxidation product malondialdehyde as determined by high-pressure liquid chromatography. Furthermore, it is shown here that the imaging of ultra-weak photon emission known to reflect oxidation of lipids was unambiguously higher in vte1 Arabidopsis plants. Our results indicate that tocopherol and plastochromanol act as efficient ¹O₂ scavengers and protect effectively lipids against photooxidative damage in Arabidopsis plants.
- Klíčová slova
- EPR spin-trapping, chloroplast,
- MeSH
- Arabidopsis genetika metabolismus účinky záření MeSH
- chloroplasty metabolismus MeSH
- intramolekulární transferasy genetika MeSH
- listy rostlin genetika metabolismus účinky záření MeSH
- oxidační stres * MeSH
- scavengery volných radikálů metabolismus MeSH
- singletový kyslík metabolismus MeSH
- spin trapping MeSH
- tokoferoly metabolismus MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- intramolekulární transferasy MeSH
- scavengery volných radikálů MeSH
- singletový kyslík MeSH
- tocopherol cyclase MeSH Prohlížeč
- tokoferoly MeSH
