State Of Photosynthetic Apparatus Research Articles

The influence of powdery mildew (Sawadaea bicornis (Wallr.) Miyabe) on chlorophyll fluorescence in Norway maple (Acer platanoides L.) seedlings

The article presents the results of research on impact of Sawadaea bicornis (Wallr.) Miyabe on the state of photosynthetic apparatus in Acer platanoides L. seedlings using a technique of chlorophyll fluorescence induction (ChlF) measurement, which at the present time can be implemented through the use of biosensors. The research was conducted in September 2022 in the territory of the Botanical Garden of Oles Honchar Dnipro National University. To diagnose a violation of the native chlorophyll photosynthesis in fresh leaves of A. platanoides, a portable fluorometer “Floratest” was used (selected spectral range for fluorescence intensity measurement was 670–800 nm). The research was carried out on fresh leaves of Norway maple seedlings both not unaffected and affected with powdery mildew. Analysis of the data obtained indicates a high sensitivity of the parameters of chlorophyll fluorescence induction to damage by the disease regardless of environmental conditions of local growth of A. platanoides seedlings. The high informativeness of induction changes in chlorophyll fluorescence in the structural organization of chloroplasts in Norway maple leaves determined by the parameters Fo, Fm, Fv, Fv/Fо, Fv/Fm, (Fm–Fst)/Fst, (Fp–Fо)/Fv was revealed. This study demonstrated the effectiveness of using the studied chlorophyll fluorescence parameters to detect severe stress in Norway maple seedlings caused by powdery mildew exposure when the fungus affects more than 50% of the leaf blade area. It is further necessary to conduct dynamic studies throughout the growing season to determine the effectiveness of using these parameters to detect mild stress in the early stages of infection. Therefore, our research showed that the method of induction of chlorophyll fluorescence using the “Floratest” device allows you to quickly determine the general condition of the plant by evaluating photosynthesis, which is the main life process. Analysis of chlorophyll fluorescence parameters is a powerful and effective tool for determining the effect of a parasitic fungus on a plant.

Effect of Cameraria ohridella feeding on Aesculus hippocastanum photosynthesis

The complex of invasive species of phytophagous insects that can adapt to novel living conditions is constantly increasing. The ecological effect of their vital activity in the new environment is almost impossible to predict. As a result, invasions undesirable in the economic sense are often observed. The horse -chestnut leaf miner (Cameraria ohridella Deschka & Dimič, 1986, Gracillariidae) is one of these problematic invader species in the introduced range of the horse chestnut (Aesculus hippocastanum (Linnaeus, 1753), Sapindaceae). We studied the effect of C. ohridella on the state of the photosynthetic apparatus in Ae. hippocastanum leaves. Photosynthesis is the one of the processes most vulnerable to stress factors, so information about the state of photosynthetic apparatus in a plant under the influence of phytophage feeding obtained with fluorescence analysis can be significant. The feeding effect of C. ohridella caterpillars on the functional state and activity of Ae. hippocastanum photosynthetic apparatus was studied. We studied critical parameters of chlorophyll fluorescence induction reflecting the effect of a single C. ohridella generation (feeding the caterpillar for the five stages of this species’ development) on the functional links of the photosystem II in Ae. hippocastanum leaves. The data obtained show a decrease in PS II quantum efficiency (inhibition of photosynthetic activity) in the leaves from different parts of the crown; it suggests the destructive effect of C. ohridella caterpillar feeding on Ae. hippocastanum photosynthetic apparatus. Values of all key parameters of chlorophyll fluorescence indication evidence inhibition of photophysical and photochemical processes of photosynthesis and impaired coherence of Calvin cycle reactions. Study of the feeding effect of C. ohridella caterpillars on the efficiency of the main enzyme in the Calvin cycle (which closely correlates with the coefficient of fluorescence induction that characterizes the efficiency of dark photosynthetic processes) showed a significant decrease in its activity in the leaves of both the illuminated and shaded parts of the crown. Our study has shown that the method of chlorophyll fluorescence induction allows one to determine the general state of a plant in an express regime by evaluating the main process of plant life as photosynthesis. Analysis of chlorophyll fluorescence parameters is a powerful and effective tool for determining the effect of phytophages on the plant body. The obtained data allow us to apply the method of analyzing chlorophyll fluorescence induction in practice to establish the physiological state of tree flora in forests and garden farms.

Дiя 2-(2-оксипiролiдин-1-iл)ацетамiду на рiст i функцiональний стан фотосинтетичного апарату Chlamydomonas reinhardtii

Дiя 2-(2-оксипiролiдин-1-iл)ацетамiду на рiст i функцiональний стан фотосинтетичного апарату Chlamydomonas reinhardtii

Effect of immunity inductors on the structural and functional state of photosynthetic apparatus and oxidative status of cucumber plants (cucumis sativus l.) Infected by Fusarium oxysporum

The effect of inductors of the immune response of β-aminobutyric acid (BABA), β-1.3-glucan (GK), salicylic acid (SA) and their mixture on the structural and functional state of photosynthetic apparatus and the oxidative status of cucumber plants under infection by fungal pathogen Fusarium oxysporum was studied. It was found that the disorganizing effect of the pathogenic fungus Fusarium oxusporum in cucumber plants caused the suppression of the synthesis of photosynthetic pigments and the functional activity of the photosystem 2 in chloroplast membranes, as well as in changing the character of the redistribution of absorbed light energy, leading to a decrease in the photochemical energy conversion (qP) and enhancing non-photochemical quenching (qN) of chlorophyll. In this conditions intensification of lipid peroxidation processes was observed. The use of immunomodulators such as BABA, GK and SA promotes the improvement of the adaptive properties of the photosynthetic apparatus, and the reduction of oxidative processes activity in infected cucumber leaves, which indicates the protective role of these substances against the fusarious wilt caused by Fusarium oxysporum.

Estimation of the Prospects of Using Model Species of Wood Plants for the Overcoming the "City Heat Island" by Parameters of the Functional State of Photosynthetic Apparatus

Estimation of the Prospects of Using Model Species of Wood Plants for the Overcoming the "City Heat Island" by Parameters of the Functional State of Photosynthetic Apparatus

On-line laser sensor of the natural water pollution based on the photosynthetic organisms as fluorescent bioindicators

The possibility of using photosynthetic organisms as a fluorescent sensor of the presence of toxicants in natural waters is presented. It is based on high sensitivity of molecular photophysical parameters of chlorophyll a obtained by the method of nonlinear laser fluorimetry to the physiological state of photosynthetic apparatus. Laboratory study of the dependence of photophysical parameters of microalgae Chlorella pyrenoidosa on the presence of herbicides and heavy metal ions was performed for experimental validation of the proposed approach.

Delayed Chlorophyll Fluorescence as a Monitor for Physiological State of Photosynthetic Apparatus

ABSTRACTIntact plants emit light quanta called delayed fluorescence (DF). DF is result of radiative deactivation of secondary excited chlorophyll molecules in Photosystem II (PS II) antennae complexes. The excitations are produced by backward electron- transfer reactions both in the donor and acceptor sides of PS II. The poly-exponential dark decay of DF in a time interval of tens of nanoseconds to tens of seconds reflects the kinetics of different forward and backward reactions of the photosynthetic electron transfer. The current work reviews the mechanisms of the DF light quanta generation and the methodical approaches that allow us to obtain quantitative information about the photosynthetic machinery state using the DF signal from native objects. We examine an approach for the simultaneous record of DF and prompt chlorophyll fluorescence during the transition of the photosynthetic machinery from dark-adapted to light-adapted state. A new device (Senior PEA) built by Hansatech (King's Lynn, UK) allows us to measure simultaneously the induction transients of prompt chlorophyll fluorescence, DF decaying in a time range 10 μs—240 ms, and the changes in transmission at 820 nm. The comparative analysis of the three types of signals and the application of a model-based description of the processes and reactions that determine the dynamics of the signals during the light-induced transitions (dynamic models and JIP-test) allow us to obtain, from a single few-seconds-long measurement, quantitative information for: a) energetic fluxes and efficiencies at different steps of energy transformation; b) rate constants of electron transfer in and between the two photosystems; c) energization of the thylakoid membrane. This illustrates that DF in combination with other optical and luminescent measurements is a highly informative method for investigation of the physiological state of the photosynthetic apparatus of plants in vivo and in situ, and is an indispensable tool for the purposes of the biophysical phenomics.

Virus impact upon bean plant photosynthesising tissue lipid composition

Study of bean plants infected by tabacco mosaic virus and potato X virus was performed. Virus infection of bean plants induced the injury of structural state of photosynthetic apparatus, viz., the a/b chlorophyll ratio decreased and the main photosynthetic membrane lipid monogalactosyl diacylglycerol degradation took place with parallel accumulation of intermediate compound suggested to perform a signal function. Phospholipid and free sterol content increase pointed out on the changes of the membrane fluidity and permeability. Accumulation of sulphoquinovosyl diacylglycerol in infected plants evidences the probability of latter to play important roles in adaptive reactions of photosynthetic apparatus.