Chlorophyll Fluorescence Induction Parameters 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 antigibberellins on morphogenesis, photosynthetic apparatus, productivity and their residual content in tomato fruits

The application of growth and development regulators on crops in order to optimize their production process is one of the leading tasks of modern plant physiology. Retardants – gibberellin inhibitors are widely used for this purpose. We investigated the effect of foliar treatment with EW-250, ССС-750 and 2-СEPA on morphogenesis, leaf apparatus, content of photosynthetic pigments, indices of chlorophyll fluorescence induction, CO2 gas exchange, and residual amounts of drugs in the fruits of tomato (Lycopersicon esculentum Mill.) Bobcat hybrid. The field experiment was laid on plots with an area of 33 m2. The treatment of the plants was carried out at the budding stage. Morphometric indices were determined at the stages of flowering and fruit formation. The chlorophylls content was determined in the raw material by the spectrophotometric method. Indices of photosystem II (PSII) photochemical activity were determined according to the parameters of chlorophyll fluorescence induction after a half-hour exposure of plants in the dark using a portable single-beam fluorimeter "Floratest". The determination of the residual content of retardants in the fruits was carried out on a Shimadzu GC gas chromatograph with a mass spectrometric detector – GCMS- QP2020 EI. All gibberellin inhibitors reduced linear plant size. The number of leaves on the plants decreased under 2-CEPA treatment, and increased after the application of EW-250. Treatment with 2-CEPA decreased, EW-250 significantly increased, and CCC-750 practically did not change the leaves’ fresh and dry weight. Leaf area and leaf index decreased under 2-CEPA treatment, but practically did not change when EW-250 and ССС-750 were applied. All antigibberellin drugs increased the leaf specific leaf weight and thickened the leaf lamina due to the growth of chlorenchyma cells. At the same time, growth inhibitors increased the volume of columnar parenchyma cells and practically did not change the size of spongy parenchyma cells. Retardants increased the chlorophylls content in leaves, while the ethylene producer 2-CEPA did not change this index. The plants’ chlorophyll index after treatment with drugs increased significantly. The whole plant dry weight increased under EW-250 treatment, decreased after 2-CEPA application, and did not change under CCC-750. It was established that the photosynthetic rate increased under the EW-250 treatment, both in the flowering stage and in the stage of fruit formation, while when using 2-CEPA and CCC-750, it occurred only at the stage of fruit formation. The most significant positive changes of PSII photochemical activity indices were observed under the use of EW-250. Under the action of the drug, the maximum and actual quantum efficiency of PSII increased, the linear electron transport accelerated, and the fraction of reaction centers that did not transfer electrons from the primary acceptor QA to QB decreased, at the same time the chlorophyll fluorescence decay coefficient significantly increased, which indicates an increase in the CO2 assimilation intensity. Retardants increased the proportion of the fruit in the whole plant dry weight. All growth regulators increased net photosynthetic efficiency. A significant increase in fruit yield occurred under EW-250 treatment. When using CCC-750, the index tended to increase, while under the influence of 2-CEPA the yield decreased. The residual amounts of EW-250 and CCC-750 in the fruits did not exceed the maximum permissible concentrations.

Phytochrome-Dependent Regulation of Melon Resistance to Fusarium Wilt

The effect of pre-sowing seed treatment with light in the red spectral region on the resistance of melon plants (Cucumis melo) of the cultivar Kichkintoy to Fusarium wilt damage caused by Fusarium oxysporum f. sp. melonis was investigated. The directly-opposite effects of red and far red light on the degree of plant damage by the pathogen, which was determined by the special symptoms of the disease on the leaves and stems of plants, were revealed. When alternating seed treatment with red and far red light, the final effect was determined by the type of irradiation that acted last. The results of photobiological testing made it possible to establish the participation of the phytochrome system in the control of the resistance of melon plants of the cv. Kichkintoy to Fusarium wilt. It is shown that there is a high positive correlation between the parameters of chlorophyll fluorescence induction of leaves reflecting the functional activity of the photosynthetic apparatus and the degree of damage to plants grown from non-irradiated seeds and seeds irradiated with red light. The results of the conducted studies establish the possibility of effective regulation of the resistance of the melon cv. Kichkintoy to the defeat of F. oxysporum f. sp. melonis through photoactivation of the phytochrome system of seeds before sowing.

Physiological and biochemical parameters of drought tolerance of some genotypes of garden roses

To identify drought resistance of the studied genotypes of garden roses during the period of maximum probability of drought on the Southern Coast of the Crimea, the water regime, proline concentration, enzyme activity and chlorophyll fluorescence induction parameters under controlled dehydration were studied. Analysis of water regime parameters showed that under conditions of water stress, the best water-holding and recovery capabilities were shown by leaves of cv. ‘Borisfen’ and R. hugonis species. Species R. indica, R. bracteata, R. rouletti, R. foetida showed instability of water regime under conditions imitating dry weather. Studies of changes in biochemical parameters revealed that under relatively mild wilting conditions after removal of stress, metabolic processes are restored in R. hugonis, R. bracteata, R. indica and cv. ‘Borisfen’. Wilting under conditions imitating dry weather does not cause irreversible metabolic disturbances in R. hugonis, R. bracteata, and cv. ‘Borisfen’. Under different wilting conditions, cv. ‘Borisfen’and R. foetida species had relatively stable functioning of FS II. Simulation of dry weather led to irreversible disturbances in the oxygen-releasing complex and thylakoid destruction in R. gallica during the stressor, and in R. indica and R. bracteata species - after recovery of water availability. The highest drought tolerance is in in cv. ‘Borisfen’and R. hugonis sprcies.

ASSESSMENT OF THE COMPLEX INFLUENCE OF BIOPREPARATIONS ON THE PROCESS OF CHLOROPHYLL FLUORESCENCE INDUCTION IN POTATO LEAVES BY ORGANIC CULTIVATION TECHNOLOGY

Organic farming is gaining increasing popularity due to growing demand for environmentally friendly organic produce. However, to cultivate high and sustainable yields of organic products, it is important to use biological preparations. Biological preparations have different mechanisms of action aimed at improving nutrient availability and absorption, enhancing physiological processes, stimulating plant growth and development, as well as protecting crops from diseases and pests. To optimize the cultivation technology and select the right combination of biological preparations, research is necessary to demonstrate the impact of these preparations on plants at different stages of development. The aim of this study was to determine the comprehensive effect of biological preparations with different functionalities depending on the methods of application on the induction of chlorophyll fluorescence in potato leaves under organic cultivation technology. The research was conducted at the Volyn State Agricultural Research Station of the National Academy of Agrarian Sciences of Ukraine. In a two-factor study, the effects of the EcoStern destructor at a dose of 1.2 liters/hectare and the biological preparations Mikohelp, Agat, Regoplant, Fitohelp, and Stimp were investigated. Measurements of chlorophyll fluorescence induction parameters were carried out using the portable fluorometer "Flora-test," which provides express diagnostics of the plant's condition at early stages of its development. The comprehensive application of the biodestructor with biological preparations resulted in the improvement of photosynthetic processes. An increase in the parameters Fmax, Fv, Fv/Fmax, (Fmax - Fst)/Fst relative to the control was established. The best results in terms of photosynthesis productivity (Fv/Fmax) were observed with the application of the biodestructor EcoStern (1.2 liters/hectare) in combination with the application of Mikohelp in the soil at 2.0 liters/hectare and foliar application of Fitohelp at 1.0 liter/hectare.

The role of photosynthetic activity in the regulation of flg22-induced local and systemic defence reaction in tomato

Flagellin (flg22) induces rapid and long-lasting defence responses. It may also affect the photosynthetic activity depending on several internal and external factors, such as the phytohormone ethylene or the day/night time. Based on the results, flg22 treatment, neither in the light phase nor in the evening, caused any significant change in chlorophyll fluorescence induction parameters in the leaves of wild-type and ethylene-receptor mutant Never ripe tomato plants measured the next morning. However, flg22 in the light phase decreased the effective quantum yield and the photochemical quenching both locally and systemically in guard cells. In parallel, the production of reactive oxygen species and nitric oxide increased, which contributed to the stomatal closure and a decrease in CO2 assimilation the next day. A decrease in sugar content and elevated hexokinase activity measured after flg22 exposure can also contribute to local defence responses in intact tomato plants.

The effect of moisture deficiency on the photosynthesis of evergreen shrubs of the genus Cotoneaster L

The paper presents data on the features of the water regime (water deficit, water-retaining forces, and total hydration of leaf tissues) in four evergreen species of the genus Cotoneaster , as well as the effect of the growing water stress on the course of primary photosynthesis processes. It was found that during the periods of maximum impact of dry factors of the summer season on the Southern Coast of the Crimea, the species Cotoneaster salicifolius and Cotoneaster graucophyllus var. serotinus show signs of increased drought resistance, which is manifested in the ability to economically consume moisture by leaf tissues during wilting, and subsequently restore the normal turgescence of leaf tissues. These species maintained minimal levels of water deficit in the leaves, and the sublethal level was 12% water loss. The genotypes Cotoneaster × watereri 'Cornubia' and Cotoneaster franchetii showed relatively weak water retention capacity combined with low leaf repair capability. Water loss of more than 8-10% was already critical, after which the number of intact leaf blade tissues was unsatisfactory (less than 60%). It was found that the parameters of chlorophyll fluorescence induction (CPI) are most sensitive to lack of moisture and they are features of fast phase. Water deficiency within 10% leads to irreversible disturbances in the photosynthetic apparatus in Cotoneaster franchetii , which was expressed in a decrease in the ratio of variable and base fluorescence below the norm of vitality and the absence of pronounced peaks on the CPI curve. In the species Cotoneaster salicifolius and Cotoneaster graucophyllus var. serotinus , an increase in the level of water deficiency was accompanied by a decrease in the efficiency of the light phase of photosynthesis and an increase in the number of unrecoverable Q a in the reaction centers of PS2. However, these changes were reversible. It is concluded that the species Cotoneaster salicifolius and Cotoneaster graucophyllus var. serotinus are relatively resistant to lack of moisture and are characterized by a high level of water-retaining forces and stable operation of the photosynthetic apparatus. Controlled wilting in combination with the CPI method can be used for quick diagnostics of the drought resistance of Cotoneaster species.

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.

Some special features of the water regime and the photosynthetic apparatus activity in Feijoa sellowiana (O. Berg) O. Berg plants under the water stress

When assessing the drought tolerance of Feijoa sellowiana cultivars and forms, the total water content in leaf tissues and their waterretaining and regenerative capacity were determined, and the parameters of chlorophyll fluorescence induction were measured at different water content in leaves. Current-year leaves were characterized by a higher sensitivity to drought. According to the complex of water regime parameters and characteristics of the chlorophyll fluorescence induction (CFI), it was found that the cultivar Aromatnaya Fantazia and the form 3/1 are characterized by a relatively high drought tolerance. It has been demonstrated that the common method for assessing plant tolerance by the index of their water-retaining forces, in relation to Feijoa sellowiana genotypes, does not allow determining the critical level of water deficit. It has been found that in the cultivars and forms with low water stress tolerance, with the water loss of 20-25% from the leaf tissues complete hydration, irreversible irregularities in the PS II structures occurred. The most sensitive to the lack of water in the leaves were such parameters as variable fluorescence, rate constants of the photochemical and non-photochemical deactivation of the excitation, as well as the processes of Qa reduction in the reaction centers of PS II.

Impact of negative temperatures on the state of the photosynthetic apparatus of evergreen species of <i>Osmanthus</i> Lour. genus

The results of studies of photosynthetic processes in annual leaves of two species of the genus Osmanthus - Osmanthus x fortunei and O. fragrans in the cold period on the Southern coast of the Crimea and under the controlled action of negative temperatures are presented. It is shown that the main parameters of chlorophyll fluorescence induction (CFI) in annual leaves of O. x fortunei was relatively more stable during the winter months compared to O. fragrans . The effect of temperature -8,0°C for 8 hours on the leaves of the species in O. fragrans caused a decrease in the fluorescence decay coefficient to the lower limit of the norm of vitality and a significant increase in the processes of thermal dissociation of light energy. It is established that the temperature is -10°C is critical for the leaves of O. fragrans , which indicates its lower frost resistance. Changes in the state of PSII depend on both the duration and intensity of low-temperature exposure. It was found that for the more resistant species of O. x fortunei a relatively long-term effect of -10,0°C and a short one of -8,0°C temperature have a similar effect on the state of the photosynthetic apparatus, which is probably due to the activation of protective mechanisms.

Physiological and biochemical parameters of apricot cultivars under drought conditions on the Southern Coast of the Crimea

In order to determine special features of the photosynthetic apparatus activity and the content of thread compounds in various apricot cultivars during the period of maximum drought probability on the Southern Coast of the Crimea, we studied the concentration of proline, phenolic compounds and chlorophylls, as well as the parameters of chlorophyll fluorescence induction (CFI) in some apricot cultivars ( Prunus armeniaca Lam.), characterized by various degree of drought tolerance (‘Alupkinsky’, ‘Krymskiy Amur’) are weakly resistant; Khurmai cultivar is characterized by labile resistance, and the cultivars Kazachok, Professor Smykov, Nagycorosi Orias are drought tolerant cultivars). It has been found out that drought-resistant cultivars are characterized by a relatively low content of proline in their leaves. It is supposed that this amino acid is involved in the protective reactions of apricot plants under water stress. The results of the photosynthetic apparatus studies in the presented cultivars demonstrated that in leaves, water loss less than 20% caused reversible changes in the parameters of CFI. An increase in the water deficit up to 25-30% caused the destruction of PS2 in weakly drought-resistant cultivars. The most stable photosynthetic apparatus activity was noticed in the cultivar Nagycorosi Orias. Deviations in photosynthesis processes were most pronounced during the period of water restoration in leaves.

Physiological and biochemical parameters of Ficus species and cultivars under dehydration conditions on the Southern coast of the Crimea

The results of the studies of proline content, peroxidase, catalase, polyphenol oxidase activity and chlorophyll fluorescence induction (ChFI) parameters in leaves of Ficus species and cultivars under controlled dehydration conditions are presented. It was shown that the ChFI parameters, the most sensitive to the lack of water availability, are the characteristics of the chlorophyll fluorescence fast phase. Proline content, peroxidase and polyphenol oxidase activity can be used to addition diagnose of drought resistance of the plants of the genus Ficus. The cultivars Sabrutsiya Rozovaya, Sary Stambulskij and the species F. palmata are relatively drought tolerant.

Assessment of the impact of horse-chestnut leaf miner (Cameraria ohridella Deschka & Dimič, 1986) on photosynthesis of common horse chestnut (Aesculus hippocastanum Linnaeus, 1753)

The article presents the results of studies on Cameraria ohridella Deschka & Dimič, 1986 feeding on the state of the photosynthetic apparatus in Aesculus hippocastanum Linnaeus, 1753. The studies were carried out in June 2019 (during the life of C. ohridella first generation) on the territory of the Botanical Garden of the Oles Honchar Dnipro National University. Photosynthesis is one of the processes most susceptible to stress factors; important information on state of the photosynthetic apparatus in plants under influence of various abiotic and biotic factors can be obtained by fluorescence analysis. Chlorophyll fluorescence is an indicator that allow to investigate a behavior of photochemical reactions related to system II (PSII) in living objects as an indicator the most sensitive to effect of environmental factors. One of the effective methods for plant state monitoring is a technique on chlorophyll fluorescence induction (CFI) measurement, which at the present stage can be introduced due to the use of biosensors. The objective of our study was to establish characteristics of C. ohridella vital activity on the photosynthesis process in A. hippocastanum trees using CFI evaluation technique. To diagnose photosynthesis violation of native chlorophyll in a living leaf of A. hippocastanum, we used a portable fluorometer “Floratest” (spectral range for measuring fluorescence intensity 670 to 770 nm) developed by V. M. Glushkov Institute of Cybernetics of National Academy of Sciences of Ukraine. The studies were conducted using alive A. hippocastanum leaves not damaged by C. ohridella and, accordingly, the damaged ones. Analysis of the data obtained showed that the worm feeding affects all CFI parameters (initial CFI value (non-damaged leaf: 582 relative units, damaged: 264); “plateau” CFI value (1460 to 722); maximum CFI (1890 to 940) and stationary CFI value after light adaptation of the leaf (1530 to 746)). Our studies have shown that CFI technique using “Floratest” apparatus allow express determining the general condition of the plant by assessing the main process of vital activity, namely photosynthesis. Analysis of chlorophyll fluorescence parameters is a powerful and effective tool for determining the phytophage effect on the plant.

Physiological and Biochemical Aspects of Frost Resistance in Оlea europaea L.

The results of studies on the frost resistance of Olea europaea L. varieties and its subspecies O. europaea subsp. cuspidata (Wall. and G. Don) Cif. under the conditions of the Southern Coast of Crimea (SCC), as well as the influence of temperature close to the absolute minimum value (–15°С) on the state of the photosynthetic apparatus, catalase activity, polyphenol oxidase, and the content of proline and phenolic compounds, are shown. It was established that a relatively high frost resistance is characteristic of the Nikitskaya variety under the conditions of the SCC. Varieties Ascoliano, Coregiolo, and Razzo turned out to be slightly frost-resistant. Minimum resistance was detected in the subspecies O. europaea subsp. cuspidata. The temperature of –15°C led to irreversible disruptions in the photosynthetic apparatus of weak varieties Razzo, Coregiolo and O. europaea subsp. cuspidata, which manifested in a significant decrease in photosynthetic activity immediately after the end of low-temperature exposure (by 80.19, 50.0, and 89.78%, respectively) as well as a fluorescence decay coefficient below the vital norm. After 24 h, a slowdown in the decrease in the parameters of chlorophyll fluorescence induction (CFI) was noted in the Ascoliano and Nikitskaya varieties. It was revealed that negative temperatures contribute to a decrease in the activity of catalase in weakly resistant O. europaea genotypes (by 40–60% on average) in contrast to the frost-resistant variety Nikitskaya, in which the activity of this enzyme remained almost unchanged. The change in polyphenol oxidase activity was multidirectional. In the Razzo and Coregiolo varieties, an increase in polyphenol oxidase activity was noted (19 and 24%, respectively). A decrease (by 8 and 37%, respectively) was noted in the subspecies O. europaea subsp. cuspidata and Nikitskaya variety. It was shown that, under the influence of negative temperatures, representatives of O. europaea decrease proline concentration in leaf tissues (by 17–55%). The most significant changes were detected in the variety Coregiolo (by 45.09%). The total content of phenolic compounds decreased in all weakly frost-resistant varieties and O. europaea subsp. cuspidata by 7–42% and remained unchanged in the frost-resistant variety Nikitskaya. It has been established that negative temperatures cause irreversible changes in the photosynthetic apparatus in weakly resistant representatives of O. europaea. The correlation of the degree of frost resistance of the studied genotypes with the activity of catalase and with the content of proline and phenolic compounds in leaf tissues was revealed.

Physiological and biochemical parameters of apricot varieties characterized by various drought resistance

The aim of the presented work was to identify the peculiarities of the photosynthetic apparatus, the activity of redox enzymes and proline content in apricot varieties with different drought tolerance. Four apricot varieties such as Kazachok, Nagycorosi Orias, Khurmai and Krymsky Amur were used as objects of the studies. To determine the effect of drought on the state of the photosynthetic apparatus, a series of experiments was carried out to analyze chlorophyll fluorescence induction (ChFI) parameters, peroxidase and polyphenol oxidase activity and proline content in apricot leaves. It was found out that in summer 2018, when the amount of precipitation exceeded the climatic norm, during the period of the maximum drought probability, catalase activity decreased, polyphenol oxidase activity increased or was unchanged and the proline content did not change significantly. Extremely arid conditions in summer 2019 resulted in peroxidase and polyphenol oxidase activation and a decrease in the proline concentration in all the studied apricot varieties. However, the drought tolerant variety Nagycorosi Orias was characterized by the most stable indexes of peroxidase activity during the entire experiment. A decrease in the leaf tissue hydration was the reason for the increase in the base fluorescence and the decrease in the correlation index of the rate constants of photochemical and nonphotochemical deactivation of excitation in PS 2. In the drought tolerant varieties Nagycorosi Orias and Kazachok changes in the ChFI parameters were reversible. It has been demonstrated that disturbances during primary photosynthetic processes were most pronounced during the restoration of turgidity. It was revealed that the most sensitive parameters of ChFI in apricot are the characteristics of the fast phase. A decrease in reparative abilities in the midsummer was probably associated with age-related changes in leaves and fruit load.

Chlorophyll fluorescence for classification of tomato fruits by their maturity stage

Classification of tomato fruit and control of post-harvest maturation based on the stage of maturity at harvesting, are necessary to ensure the highest possible quality and marketability of the final ripe product. A method of sorting tomatoes to assess the degree of their maturation based on the control of their chlorophyll fluorescence induction is proposed. Tomatoes (Black baron) at five different stages of maturity were used. Variance analysis (ANOVA) was performed and the Duncan’s mean values were compared at a significance level of p ≤0.05. In addition, the correlation between the chlorophyll fluorescence induction parameters and the maturity of the same fruit was carried out using the statistical software SPSS 20.0. The general pattern of fluorescence induction analysis was revealed; as the fruit matures, the value of both maximum fluorescence induction (Fm) and the coefficient of specific photosynthetic activity of tomatoes (Kf) decreases. Both Fm and Kf exhibited a statistically significant difference (p ≤0.05) between stages of maturity. A very strong negative correlation between slow chlorophyll fluorescence induction parameters (Fm and Kf) and maturity were observed. Moreover, there is a strong positive correlation between Fm and Kf. In conclusion, the slow induction of chlorophyll fluorescence is a good indicator of the degree of maturity of tomato fruits and the proposed method had better reflected the actual ripening process of fruit per maturity stage.

BRIEF COMMUNICATIONEstimation of changes in the activity of photosynthetic apparatus of plant leaves based on half-time of fluorescence intensity decrease

The range of variations in parameter τ0.5 - half-time of fluorescence intensity decrease during the slow phase of chlorophyll fluorescence induction (CFI) - has been studied during ontogeny of leaves of monocotyledonous and dicotyledonous plants in plant communities of different structures. Plants were grown hydroponically on expanded clay aggregate in growth chambers, under PPFD of 400 μmol(photon) m-2 s-1, under controlled conditions. Analysis of the literature data and results of experimental observations of τ0.5 behavior compared to other CFI parameters, nonphotochemical quenching coefficient, qN, in particular, leads to the conclusion that parameter τ0.5 can be effectively used for indirect estimation of variations in the activity of photosynthetic apparatus during ontogeny of plant leaves. Dramatic global climate change is a factor that increases the importance of stress tolerance of plants, on the one hand, and urges researchers to develop methods for monitoring the state of the plants, on the other. All stressors, whatever part of the plant they may affect, eventually, directly or indirectly, influence photosynthesis, which is primarily related to the activity of photosynthetic apparatus (PSA) at the leaf level. In recent years, the method of chlorophyll fluorescence induction (CFI) based on the Kautsky effect has become a widespread method for ecological monitoring of plant communities (Lichtenthaler et al. 2005, LazĂĄr 2015, Kalaji et al. 2017). Sometimes, when plants are subjected to external stresses, it is essential to determine quickly the functional state of the leaf PSA and estimate reversibility (or extent) of changes in PSA activity. A common approach is to use a set of characteristics based on measurements of amplitude parameters of the plant leaf CFI curve (Roháček 2002).

Експресний метод діагностики грибних захворювань соняшника (Helianthus annuus L.)

This work is devoted to development of early diagnosis methods of fungal diseases in agricultural plants, which will increase effectiveness of protective measures against them. For today, there are many diagnosis methods of diseases and identifying fungal pathogens. These diagnosis methods of diseases allow the identification of fungal pathogens only after the beginning of development the pathological process. In such cases it is not able to protect the plants in time. Found that in the early stages of the disease, which is still impossible to identify visually, the first changes, are happening in the processes of photosynthesis and can be fixed. Chlorophyll fluorescence is the only indicator that allows studying the photochemical reactions in live objects that are connected with work of photosystem II (FS2) of Streptophyta plants. However, these methods will not allow identified of fungal diseases in agricultural plants. The aim of study is developing an express method for early sunflower fungal diseases diagnosis by modifying the methods for recording induction of chlorophyll fluorescence and fluorescence microscopy. Research objects were sunflower Helianthus annuus L. With the aim of identifying the state of photosynthetic apparatus are evaluated changes in the functioning of photosynthetic processes in sunflower leaves Helianthus annuus L. The investigation was conducted on fluorescent photoinduced indicators basis. Definition of fungal disease and assessment of its impact as a stress factor, they were conducted by comparison informative indicators of chlorophyll fluorescence induction of experimental plants. We investigated the interconnection between the changes of chlorophyll fluorescence induction parameters and the presence of fungal diseases in plants that didn`t have visual damage to viruses and diseases. In the process of performance work were conducted the expert research of chlorophyll fluorescence. The results of the study were monitored by light microscopy. In the process of performance work, we found that all investigated plants were characterized by a uniform emission of red fluorescence intensity. Absence of differences in the intensity of fluorescence doesn`t make it possible to determine the presence of fungal infection. With the aim of detecting hidden fungal infection. We have developed method of temperature influence on the plant leaves during the research. As a result, of the influence of temperatures on the leaves of individual plants were recorded flashes of yellow-green fluorescence. In these plants the fungal disease was detected visually by light microscopy in 12-18 days later and it was identified as Phomopsis helianthi M. The proposed modification of the method of photoinduction fluorescence in combination with the luminescent microscopy method have allowed to detect the presence of hidden fungal infection in annual sunflower at the earliest stages of its development. Perspective of the further development of this method for the purpose of early diagnosis of the presence of hidden infection in various agricultural plants. Keywords: annual sunflower, fungal diseases, diagnosis, fluorescence induction of chlorophyll, Phomopsis helianthi M.

Функціональна діагностика адаптивності інтродукованих видів роду сніжноягідник (Symphoricarpos duhamel) в умовах Києва

The important condition of the environmental improvement is mobilization and wide introduction of introduced trees and shrubs, which have already had successful preliminary investigation in the botanical gardens and dendrological parks and have shown characteristics of high ornamentality. The snowberries are such perspective but not so widespread plants now, which have very high decorativeness and attractiveness during almost the whole vegetative period, which is especially important when creating urban landscape compositions. Observations on the development of snowberries in the street landscapes ofKievhave shown quite high resistance of plants to the megapolis conditions, which made us to conduct the study of their functional state in the places with the most intensive traffic. The purpose of the study was to determine the functional state and photosynthetic potential of plants of the genus snowberry ( Symphoricarpos Duhamel) different species in the megapolis conditions. Seasonal inductive changes of chlorophyll fluorescence parameters of leaves of 9 species of the genus snowberry ( Symphoricarpos Duhamel): S. albus (L.) S.F.Blake, S. × chenaultii Rehder, S. × doorenbosii Krűssm., S. hesperius G.N.Jones, S. mollis Nutt., S. occidentalis Hook., S. orbiculatus Moench, S. oreophilus A.Gray, S. rivularis Suksd. are studied. For the assessment of the functional state of green plants a method based on the study of correlation of changes of intensity of chlorophyll fluorescence induction (CFI) with photosynthetic reactions in chloroplasts of leaves was used. To measure parameters of fluorescence and its inductive changes in the field conditions we used a portable device – a fluorometer Floratest (developed by the Engineering Center of V. M. Glushkov Institute of Cybernetics of National Academy of Sciences ofUkraine). The study of seasonal changes in the parameters of CFI of the leaves has revealed very small seasonal variability of the parameters of CFI in the leaves of snowberries: on average, the intensity of fluorescence at the maximum F p 1 and F p 2 decreased by 4,0 and 1,5 %, and the coefficient К 1 by 3,4 %, indicating on the high stability of electron transport processes near the reaction centers of photosystem II (FSII). The analysis of normalized inductive changes of fluorescence intensity in the time range of the slow decline of fluorescence showed slight decrease in the intensity of dark photochemical processes: К 2 ( Rfd ) ratio decreased only by 6,0 %. Thus, by means of the comprehensive analysis of functional indicators we found the high stability of photosynthetic processes in snowberry leaves, which allow the plants to maintain their ornamental features for the long periods of time. The analysis of the content of metal pollutants in the different parts of common snowberry plants ( S. albus ) was carried out using an atomic absorption spectroscopy method. Preparation of the bioprobes was carried out by such method as ozonation in a muffle furnace, followed by extraction in nitric acid. Determination of the content of metals in the prepared filtrates was carried out with the use of flame atomization (in the case of determination of large quantities) on the «C115-M1» spectrophotometer and electrothermal atomization (in the case of determination of trace quantities) on the «Saturn-3» spectrophotometer with the complex «Graphite-2». The comparative analysis of the accumulation of metal pollutants and the parameters of CFI of S. albus leaves in the park zone and near the transport line at Sevastopolska square has established the negative influence of the complex of factors on the activity of reaction centers and the effectiveness of dark photochemical processes. So, according to the «coefficient of plateau» K pL , which controls the number of inactive reactive centers of FSII, their growth is determined by 50–60%. Also, within the limits of 30–50%, the reduction of the Rfd parameter is registered, indicating a decrease in the activity of dark photochemical processes, that is the Calvin cycle. At the same time, the effectiveness of the light phase of photosynthesis in the leaves of S. albus on the experimental plots of Sevastopolska square in relation to similar indices obtained for plants of the park zone of the Institute of Horticulture of the National Academy of Sciences of Ukraine, does not change significantly, within 4,0–6,5%. The latest information obtained indicates that there is significant stability of the light phase of photosynthesis in the relation to the dark photochemical processes in snowberry plants and their high adaptive potential in the conditions of the urban environment. The results of the research allow us to recommend previously tested in Kyiv city conditions introduced snowberry species for the further usage in the plantations in the megacity conditions, and in particular in the places with the high level of contamination.

Some Peculiarities of Chlorophyll Fluorescence Induction in Leaves of Acer Platanoides L. Cultivars under Conditions of Kyiv City

Наведено порівняльну оцінку функціонального стану пігментного комплексу листкового апарату поширених в озелененні міста Києва рослин культиварів Acer platanoides L. За аналізом змін індукції флуоресценції хлорофілу листків визначено вплив умов місця зростання з різним ступенем антропогенного навантаження та генотипової специфічності рослин досліджуваних культиварів на окремі показники та коефіцієнти, що характеризують перебіг світлових фаз фотосинтезу та ефективність фотохімічних процесів для темнових фаз упродовж літніх місяців. За результатами аналізу отриманих даних виявлено залежність показників індукції флуоресценції хлорофілу від рівня антропогенного навантаження на рослини виду A. platanoides та всіх досліджених культиварів, за винятком A. p. 'Schwedleri', що свідчить про їхню толерантність до міських умов та дає підстави стверджувати про доцільність ширшого використання цих рослин у складних умовах міського середовища.