Terms Of Chlorophyll Research Articles

Biohydrogen production of a halophytic cyanobacteria Phormidium keutzingium and activated sludge co-culture using different carbon substrates and saline concentrations

Hydrogen (H2) production using a biological pathway such as anaerobic digestion suffers limitations in the survival of microorganisms. Usually, microalgae are used as feedstock but the acidic pH of digestate ruptures the cell wall of microalgae resulting in dead cellular debris. Whereas some cyanobacteria (blue-green microalgae) are very resilient and tolerant to stressful environments such as hypersaline conditions. Therefore, in this study, a microbial consortium (co-culture) of cyanobacteria Phormidium keutzingianum and activated sludge bacteria (ASB) was established to generate H2 production from waste resources. Different co-culturing ratios 2:1, 1:1, and 1:2 v/v (P. keutzingianum: ASB) were analyzed for H2 production with glucose, sorbitol, and mannitol as carbon substrates. In addition, the effect of different concentrations (0, 10, and 20 g/L) of salt (NaCl) on H2 production was also tested. Results indicated that the amount of cumulative H2 produced changed significantly by varying the carbon substrates. Glucose-supplemented co-culture produced the lowest amount of H2 at 278 mL/L as compared to 980 and 562 mL H2/L in sorbitol and mannitol-supplemented co-cultures, respectively. The addition of NaCl negatively affected H2 production by increasing the salinity level from 0 to 20 g/L, and the cumulative H2 reduced from 980 to 176.8 mL/L and 562 to 333 mL/L in sorbitol and mannitol-supplemented co-culture, respectively. Sorbitol showed cyanobacterial growth in terms of chlorophyll from 600 to 1200 μg/L and optical density from 1 to 12 at λ 620 nm. Total organic carbon (TOC) in sorbitol supplemented co-cultures also increased to the peak 5.7, 6.7, and 7.7 g/L in 2:1, 1:2, and 1:1 v/v ratios, respectively, indicating anaerobic growth. Hence, this study signifies that sorbitol appeared to be the significant carbon substrate that helped cyanobacteria grow under anaerobic conditions resulting in higher H2 production. Moreover, cyanobacteria are more tolerant to stressful environments such as hypersaline and acidic conditions compared to microalgae.

Variety-strain interaction specificity of <i>Bacillus subtilis</i> with salt-stressed <i>Phaseolus vulgaris</i> L. plants

The effectiveness of crop inoculation using growth-stimulating bacteria can depend on the plant variety and environmental conditions. The reactions of three-week-old plants of the Ufimskaya and Zolotistaya green bean varieties to inoculation with strains 26D and 10-4 in normal conditions and under stress (1% NaCl 48 h) were analysed. Although the Zolotistaya variety formed less biomass and leaf area, it surpassed the Ufimskaya variety in terms of chlorophyll and root water content, as well as reacting to stress by reducing the content of photosynthetic pigments and root water content. Inoculation contributed to the preservation of these indicators at the level of non–stressed plants: the positive effect of strain 26D was expressed in the effect on the composition of pigments, while that of strain 10-4 was expressed in the hydration of roots. Under stress, the Ufinskaya variety improved the water status of the roots, on which inoculation had a weak or negative effect; however, the decrease in the level of synthetic pigments under stress was compensated by inoculation with both strains. According to the biomass of three-week-old plants, the Zolotistaya variety was shown to respond positively to inoculation with both strains both normally and under stress, while the Ufimskaya variety tended to react negatively to inoculation with strain 26D; under stress, the effect of inoculation with both strains was positive. Compared with the stress-induced control, the malondialdehyde content in the roots of inoculated plants of both varieties decreased in comparison with that of the uninoculated control both in normal conditions and under stress. The revealed differences in plant reactions to inoculation serve as a basis for further analysis of the effectiveness of variety-strain combinations of symbiotic partners.

Effect of Cultivars, Apical Pinching and Copper Nano-Fertilizer on 1-Characteristics of Vegetative Growth of Broad Bean (Vicia faba L.)

Research was conducted at the vegetable field of the University of Mosul’s Department of Horticulture and Landscape Engineering (in the College of Agriculture and Forestry) (2021). The experiment included a study of three factors, the first of which was the use of three different bean sprout cultivars (Spanish, American, and Dutch), the second of which was the condition of apical pinching (apical pinching and without pinching), and the third of which was the use of copper Nano-fertilizer at three different concentrations (zero, one, and 1.5 gm L-1) (2 x 3 x 3). Field research was conducted utilizing a factorial experiment with split-plots in R.C.B.D. Varieties were planted in the main plots, and the correlation between pinching and copper Nano-fertilizer concentrations was observed in the sub-plots. The Duncan multiple range test was used to compare the means of the groups, and a significance threshold of 5% was used for the study. Here’s a rundown of the A- The significant effect of the plants of the three cultivars varied in the characteristics of the vegetative growth, as the plants of the Spanish and American cultivars were significantly superior in plant height and percentage of dry matter, while the plants of the Dutch and Spanish cultivars excelled in the number of branches, while no significant differences were observed between the cultivars in terms of chlorophyll and leaf area. B- The treatment of apical pinching excelled in terms of the number of branches and leaf area compared to the treatment of not pinching. C- The use of copper Nano-fertilizer in two concentrations resulted in significant effects on all vegetative growth traits compared to comparison plants. D- Most of the effects of the binary and triple interaction of the studied factors were consistent with the single effect of each factor for most of the previous characteristics.

Effects of Cd and Zn Treatments on Leaf Chemıcal Compounds of Japanese barberry (Berberis thunbergii), Boxwood (Buxus sempervirens var. rotundifolia), and Gold tassel (Euonymus japonica var. aurea) Species

In the present study, the effects of cadmium (25 μM and 50 μM) and zinc (200 μM and 400 μM) treatments on some bioactive compounds and mineral levels in leaves of japanese barberry, boxwood, and gold tassel genotypes were investigated. Given the results, it was determined that photosynthetic pigments were stimulated by 200 μM Zn and 400 μM Zn. Boxwood was found to be tolerant to the treatments in terms of chlorophyll and carotenoid. In contrast, japanese barberry was found to be tolerant in terms of chlorophyll b and total chlorophyll. The amount of anthocyanin was higher in the leaves of gold tassel, and boxwood and the total phenolic was higher level in gold tassel and japanese barberry in all treatments. Proline and nitrate levels were generally high in the treated groups of three plants, as well as RWC in japanese barberry and boxwood. Given the element results, japanese barberry had a higher accumulation capacity for P, S, Mn, Cl, Cd, Fe, Al, Si, Cu, Ba, Zn, Ti, and Cr, boxwood for K, Mn, Cl, Cd, Zn, Fe, Al, Si, and Cr, and Gold tassel for K, P, S, Mn, Cl, and Cd. As a result, boxwood showed a higher tolerance to 400 μM Zn, japanese barberry plant to 200 μM Zn, and 50 μM Cd. It can be said that boxwood and japanese barberry plants can be used in afforestation projects in urban parks, gardens, and roadside, as well as in areas with high soil pollution, to reduce the pollution damage.

ПЛАНКТОННЫЕ И БЕНТОСНЫЕ СООБЩЕСТВА ЮГО-ВОСТОЧНОЙ ЧАСТИ БАЛТИЙСКОГО МОРЯ В ЛЕТНИЙ ПЕРИОД 2018–2019 гг.

During the expeditions in July 2018 and 2019 data were obtained on the state of summer plankton and benthos over the entire Russian water area in the southeastern part of the Baltic Sea. The highest abundance of phytoplankton (in terms of chlorophyll “a”) is typical for the coastal region, where it reaches the eutrophic state, and decreases in the seaward zone to the mesotrophic state. Brackish water conditions determined a rather small number of species of zooplankton (36 taxa) and zoobenthos (40 taxa), including invading species (4 in zooplankton and 6 in benthos). Copepoda dominated in zooplankton in the deep-water zone, while the proportion of Cladocera and Rotifera increased in the coastal zone. The abundance and biomass of zooplankton corresponded to the maximum level observed in recent years in the SouthEastern Baltic. Zooplankton was more abundant from the coast to depths of 40 m, as a result, the best feeding conditions for planktophagous fish extended at this area. In benthos, Polychaeta and Bivalvia dominated in abundance, and Bivalvia dominated in biomass. The hydrological conditions in the Russian zone determine the development of zoobenthos in two regions separated by the Gdansk depression, which is characterized by benthic “desert” conditions. The largest region extends from the coast to depths of 70–80 m, and the second – in the deep northwestern part and is confined to the Gdansk-Gotland Sill. High abundance and biomass of zoobenthos are characteristic of the Gdansk basin down to depths of 60 m, where favorable conditions are formed for benthophage fish. The species composition and abundance of zoobenthos on the Gdansk-Gotland Sill much lower and is determined by the presence of North Sea waters inflows, in particular, in 2019 there was an increase in the abundance and distribution of benthos as a result of the inflow of North Sea waters.

Scutellaria orientalis subsp. virens ve Scutellaria salviifolia üzerinde Anatomik, Mikromorfolojik, Karyolojik ve Biyokimyasal bir çalışma

In this study, the anatomical and micromorphological structure, karyological characteristics and biochemical content of Scutellaria orientalis subsp. virens and endemic Scutellaria salviifolia, whose distributions areas overlap, were compared. Some anatomical and micromorphological differences were observed on the taxa; scleranchymatic pericycle layer on the stem, stomata density, distribution of trichomes, as well as the main vascular bundle and general shape of the petiole. The chromosome numbers of both taxa were determined as 2n = 22. However, there was a difference between chromosome length range and total chromosome length. The chromosome numbers and chromosome morphologies of these species have been defined for the first time in this paper. Differences in biochemical content were observed between species. Chlorophyll a (Chl a), total chlorophyll (Total Chl), total carbohydrate and malondialdehyde (MDA) contents were determined higher in leaf and stem samples of S. orientalis subsp. virens than S. salviifolia. There was no significant difference between the two taxa in terms of chlorophyll b (Chl b) content. Carotenoid (Car) content was detected higher in leaves samples of S. orientalis subsp. virens, but no significant difference was found between stems samples. Also, the effect of taxa on biochemical contents in relation to the habitat they live in is given in this study.

Formation and Characterization of Fucus virsoides J. Agardh Pigment–Polyethylene Glycol Microparticles Produced Using PGSS Process

The particles from the gas-saturated solutions (PGSS) process was employed to micronize brown algae pigments separated by different extraction techniques. The particle formation of pigments with a coating material, polyethylene glycol (PEG), was carried out by the PGSS process using supercritical CO2. Environmental scanning electron microscopy (ESEM) and Fourier-transform infrared spectroscopy (FTIR) were performed to characterize the produced particles, while encapsulation efficiency was determined using spectrophotometric methods. The physical properties of obtained microparticles were also determined. The PGSS process enabled a high encapsulation yield in the range from 61.60 to 73.73%, and high encapsulation efficiency in terms of chlorophyll a, chlorophyll b, and carotenoid content. The release of CO2 during the PGSS process gave the microparticles their characteristic open and porous form, and enhanced the solubility and flow properties at the same time.

A Novel Bacillus safensis-Based Formulation along with Mycorrhiza Inoculation for Controlling Alternaria alternata and Simultaneously Improving Growth, Nutrient Uptake, and Steviol Glycosides in Stevia rebaudiana under Field Conditions.

The excess use of chemicals by farmers in the agroecosystems degrades soil quality, disturbs soil ecology, and increases soil salinity and health hazards in humans. Stevia rebaudiana is an important medicinal and aromatic crop whose leaves contain steviol glycosides (SGs). The Bacillus safensis NAIMCC-B-02323 strain STJP from the rhizosphere of S. rebaudiana producing salicylic acid (16.80 µg/mL), chitinase (75.58 U/mL), β-1,3-glucanase (220.36 U/mL), and cellulase (170 U/mL) was taken as a plant growth-promoting rhizobacteria (PGPR). The cell-free supernatant (CFS) from strain STJP showed significant biocontrol activity against Alternaria alternata (80%), suggesting the protective role of extracellular metabolite(s) against phytopathogens. Paneer whey-based bioformulation (P-WBF) was developed to exploit B. safensis STJP to enhance the growth, nutrient uptake, soil properties, stevioside content, and SGs biosynthesis in S. rebaudiana under an A. alternata-infested field. The combined treatment of P-WBF and mycorrhiza (Glomus fasciculatum ABTEC) significantly enhanced plant growth parameters after 90 days, in comparison with control. The symbiotic action (P-WBF and mycorrhiza) displayed much better results in terms of chlorophyll a and b (improved by 132.85% and 39.80%, respectively), protein (by 278.75%), flavonoid (by 86.99%), carbohydrate (by 103.84%), antioxidant (by 75.11%), and stevioside (by 120.62%) contents in plants as compared to the untreated set. Further, the augmentation of potassium (by 132.39%), phosphorous (by 94.22%), and zinc (by 111.11%) uptake in plant tissues and soil was also observed by the application of P-WBF and mycorrhiza. The expression of UGT74G1 and UGT85C2 genes related to SG biosynthesis was upregulated (2.7- and 3.2-fold, respectively) in plants treated with P-WBF and mycorrhiza as further confirmed by the accumulation of SGs. The results suggest that the application of P-WBF and mycorrhiza not only provides an ecofriendly and sustainable solution to improve stevioside content in S. rebaudiana by a nutrient-linked mechanism but also paves the way to enhanced production of stevioside.

Newly isolated native microalgal strains producing polyhydroxybutyrate and energy storage precursors simultaneously: Targeting microalgal biorefinery

With escalating urbanization and ever-increasing population, plastic pollution has become the problem of hour. Owing to its deep roots in our daily life, it is imperative to find an alternative. Sustainable production of poly hydroxy butyrate (PHB) can be our way out from this soup of plastic pollution. Microalgae, being photoautotrophs, helps in bioremediation and can metabolize the waste products into biodiesel, bioethanol, protein, and also bioplastics in the form of PHB. The present study reports the accumulation of PHB in Coelastrella sp., Ettlia texensis and Pecatinodesmus sp. isolated from nearby regions of Indore under nutrient stress and mixotrophic conditions. The individual effect of nutrients was studied, and concluded that under mixotrophic cultivation, Coelastrella sp. can accumulate up to 151.8 ± 12.1 μg/mg dry cell weight (DCW) of PHB under N1.5P0.04Ga10 supplementation in 72 h of cultivation. A two-stage cultivation strategy enabled the accumulation of high PHB content in microalgae without compromising the microalgal growth, which was noted in terms of chlorophyll and biomass accumulation. Principle component analysis (PCA) revealed close relation between biomass and poly hydroxybutyrate (PHB) accumulation with organic carbon presence having a great impact. These results pave the way for sustainable PHA/PHB production using three microalgal species.

Evaluation of Proline, Chlorophyll, and Carotenoid Contents of Two Globe Artichokes [Cynara cardunculus var. scolymus (L.) Fiori] Leaves Based on the Growing Season

Globe artichoke [Cynara cardunculus var. scolymus (L.) Fiori], a member of the Asteraceae family, has been known since ancient times. Edible parts of this valuable vegetable are rich in antioxidants and polyphenols as well as possessing healing properties against certain diseases. When the life cycle of plants is taken into consideration, the processes which are highly affected by environmental conditions are photosynthesis and cell growth. Chlorophyll level is known as a good indicator of the photosynthesis of plants. Carotenoids, one of the important functions of which protects chlorophyll from photo-oxidation, can prevent the destruction of chlorophyll. Therefore, chlorophyll and carotenoids play an important role in photosynthesis and the protection of photosynthetic pathways against harmful free radicals. The proline concentration present in various plants is increased in many different stress conditions, such as cold, temperature, salinity, drought, UV, and heavy metals, thus, providing better tolerance to stress conditions. The aim of the present study was to comparatively evaluate the proline, chlorophyll (a and b), and carotenoid contents of the young and mature leaves of two OP cultivars (Bayrampaşa and Sakız) based on different growing seasons. Obtained results demonstrated that there were differences between two OP artichoke cultivars based on the growing season and young and mature leaves with regards to proline, chlorophyll (a and b), and carotenoid contents. Findings revealed that proline and chlorophyll b levels in autumn were quite promising, while in terms of chlorophyll a and carotenoid levels winter was prominent. Regarding the young and mature leaves, high proline and chlorophyll a levels were found to be dominant in young leaves. On the other hand, chlorophyll b and carotenoid were more accumulated in mature leaves. Turkey has several other globe artichoke cultivars and the findings of the present study may play a supportive role in determining proline, chlorophyll (a and b), and carotenoid contents for combating several environmental stress factors.

Weed Control, Growth, Nodulation, Quality and Storability of Peas as Affected by Pre- and Postemergence Herbicides

Weeds represent a major constraint for successful pea cultivation, resulting in loss of green pea yield and quality. Two field experiments were carried out during the winter seasons of 2018/2019 and 2019/2020. The objectives of the current study were to evaluate the efficacy of pendimethalin, butralin, fluazifop butyl, bentazon, and hoeing on weed control, and their impact on pea growth, nodule formation, yield, quality, and storability. The results indicated that hoeing and fluazifop butyl were the most effective treatments for weed control in terms of the lowest values of total weed dry weight. The bentazon and fluazifop butyl herbicides didn’t affect active nodules number, plant height, plant weight, root length, or number of leaves and branches. Additionally, bentazon and hoeing resulted in the highest total yield per plant and protein content. Butralin and pendimetalin achieved the lowest yield, and butralin also resulted in the lowest plant height and weight. Bentazon-treated peas had the highest chemical compositions in terms of chlorophyll, carotenoids, total sugar, and vitamin C contents in pea pods at harvest and during cold storage at 4 °C and 95 RH for 45 days. No detectable residues of the four herbicides under study were detected in green pods, suggesting that pods can be safely consumed at the time of harvesting. It can be concluded that nodules formation in pea was not affected significantly by the application of the tested herbicides, except pendimethalin and butralin. Furthermore, bentazon had a positive impact on nodules formation and pods quality and could be used effectively for controlling the broadleaf weeds, and it was simultaneously a selective and safe herbicide in pea cultivation.

Size-fractionated surface phytoplankton in the Kara and Laptev Seas: environmental control and spatial variability

Climate-induced variability of phytoplankton size structure influences primary productivity, marine food web dynamics, biosedimentation and exchange of CO2between the atmosphere and ocean. Investigation of phytoplankton size structure in the Arctic Ocean is important due to rapid changes in its ecosystems related to increasing temperature and declining sea ice cover. We estimated the contribution of surface micro-, nano- and picophytoplankton to the total carbon biomass, chlorophyllaconcentration and primary production in the Kara and Laptev Seas and investigated the relationships of these phytoplankton size groups with environmental factors which determine their spatial variability. Additionally, we compared chlorophyll specific carbon fixation rate, specific growth rate and carbon to chlorophyll ratios among different phytoplankton size groups. The investigation was carried out from August to September 2018. Generally, picophytoplankton was dominant in terms of chlorophyllaand primary production in the whole study area. The spatial variability of phytoplankton size classes was influenced by river discharge and relied mainly on water temperature, salinity and dissolved silicon concentration. Microphytoplankton prevailed across the river runoff region under conditions of low salinity and relatively high water temperature, while picophytoplankton was predominant under conditions of high salinity and low water temperature. Our study is the first to characterize size-fractionated phytoplankton abundance in the Kara and Laptev Seas, and provides a baseline for future assessment of the response of Kara and Laptev Sea ecosystems to climate-induced processes using phytoplankton size structure.

Implications of Nutrient Enrichment and Related Environmental Impacts in the Pearl River Estuary, China: Characterizing the Seasonal Influence of Riverine Input

The Pearl River estuary is an ecologically dynamic region located in southern China that experiences strong gradients in its biogeochemical properties. This study examined the seasonality of nutrient dynamics, identified related environmental responses, and evaluated how river discharge regulated nutrient sink and source. The field investigation showed significant differences of dissolved nutrients with seasons and three zones of the estuary regarding the estuarine characteristics. Spatially, nutrients exhibited a clear decreasing trend along the salinity gradient; temporally, their levels were obviously higher in summer than other seasons. The aquatic environment was overall eutrophic, as a result of increased fluxes of nitrogen and silicate. This estuary was thus highly sensitive to nutrient enrichment and related pollution of eutrophication. River discharge, oceanic current, and atmospheric deposition distinctly influenced the nutrient status. These factors accordingly may influence phytoplankton that are of importance in coastal ecosystems. Phytoplankton (in terms of chlorophyll) was potentially phosphate limited, which then more frequently resulted in nutrient pollution and blooms. Additionally, the nutrient sources were implied according to the cause–effect chains between nutrients, hydrology, and chlorophyll, identified by the PCA-generated quantification. Nitrogen was constrained by marine-riverine waters and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea, while a different source of terrestrial emission from coastal cities contributed to phosphate greatly.

Investigations on thermal degradation of phytochemicals from lavender extract

The importance of lavender as a source of essential oils has been well recognized. This study reports the phytochemical profile of lavender extract in terms of chlorophylls, total carotenoids, polyphenols and flavonoids, related to antioxidant activity. The extract displayed a high polyphenolic and flavonoids content, with an antioxidant activity of 2.28±0.18 mMol Trolox/g D.W. The fractional conversion and first order kinetic models were found suitable for predicting the changes that occur in the selected phytochemicals. Kinetic and thermodynamic parameters were calculated confirming the irreversible degradation of phytochemicals. Both the temperature and duration of heating significantly impacted the content in bioactive compounds.

Impact of anthropogenic forcing on the environmental controls of phytoplankton dynamics between 1974 and 2017 in the Pearl River estuary, China

Abstract How phytoplankton responded spatiotemporally to the co-occurrence of multiple variables is of central importance for ecosystem management. In this study, extensive investigations in the Pearl River estuary (PRE), southern China, between 1974 and 2017 revealed a strong anthropogenic effect on the environmental drivers of phytoplankton dynamics (in terms of chlorophyll a). The empirical cause-and-effect chain summarized as human activity → hydrology → nutrient → chlorophyll may constitute fundamental quantitative tools for predicting effects of coastal eutrophication. Change in subaqueous topography induced by human stress resulted in shoal-trough instability, which unexpectedly shifted nutrient dynamics across the entire regions. Over time, dissolved inorganic nitrogen (DIN) and phosphorus (PO4) increased, as did the molar N/P ratio (DIN/PO4), indicating that phytoplankton growth was potentially phosphate-limited in most PRE. The adsorption of phosphorus by sediment particles was stronger than that of nitrogen. The quantification of phytoplankton drivers demonstrated the importance of river-tide dynamics, which incorporated the interplay between environmental variables. Particularly, the influence of riverine input varied over time and site, affecting hydrological control variables and nutrient limitations. Our structural equation modelling results (p

Phytocomplex Characterization and Biological Evaluation of Powdered Fruits and Leaves from Elaeagnus angustifolia.

Fully ripe fruits and mature leaves of Elaeagnus angustifolia were harvested and analyzed by means of analytical and biological tests to better comprehend the chemical composition and therapeutic/nutraceutical potential of this plant. Fruits and leaves were dried and the obtained powders were analyzed to study their color character and (via headspace gas chromatography) describe the chemical profile. Subsequently, they were submitted to a chloroform–methanol extraction, to a hydroalcoholic extraction procedure assisted or not by microwaves, and to an extraction with supercritical CO2, assisted or not by ethanol as the co-solvent, to detect the polyphenolic and the volatile content. The resulting extracts were evaluated in terms of chlorophyll and carotenoid content, polyphenolic content, volatile fraction, total phenolic content, total flavonoid content, antioxidant activity, radical scavenging activity, and enzymatic inhibition activity. The results confirmed the correlation between the chemical composition and the high antioxidant potential of leaf extracts compared to the fruit extracts in terms of the phenolic and pigment content. A promising effect against tyrosinase emerged for all the extracts, suggesting a therapeutic/nutraceutical use for this plant. Conversely, the volatile content from both natural matrices was similar.

Influence of Electromagnetic Stimulation of Seeds on the Photosynthetic Indicators in Medicago sativa L. Leaves at Various Stages of Development

The paper explores the impact of electromagnetic stimulation of Ulstar alfalfa seeds on fresh mass yield, the quantum efficiency of the plants’ photochemical reactions, and the content of photosynthetic pigments in leaves. Before sowing, seeds were subjected to electromagnetic stimulation in the following configurations: control (C), no stimulation; stimulation with He–Ne laser light with the wavelength of 632.8 nm, surface power density of 3 mW·cm−2 and exposition time of 1 min (L1) or 5 min (L5); stimulation with alternating magnetic field with the induction of 30 mT and exposition time of 1 min (F1) or 5 min (F5). It was established that the variability of alfalfa yields at the onset of anthesis was dependent on weather conditions as well as, above all, on the electromagnetic stimulation employed. At the same time, the values of fresh mass yield of alfalfa and photosynthetic efficiency were higher in the first year of cultivation (2014) compared to the last year (2016). In terms of photosynthetic efficiency, the best results were observed for L1 and F5, respectively: 0.801 and 0.800. The significantly highest values in terms of chlorophyll a and b and carotenoid content were observed in 2014 at the onset of budding in the combination involving alternating magnetic field stimulation (F5), and were, respectively, 30%, 28% and 73% relative to the control.

Filtration rates of the manila clam, Ruditapes philippinarum, in tidal flats with different hydrographic regimes.

The manila clam Ruditapes philippinarum is widely distributed in the sandy mud sediments of tidal flats and plays a role in seawater purification by filtering suspended organic matter. This study was designed to evaluate differences in seawater purification based on the filtration rate of the manila clam in terms of particulate organic matter (POM) between two tidal flats with different hydrographic regimes. In situ experiments were carried out at Geunso and Sihwa tidal flats, along the west coast of Korea. The amount of POM removed from the water column by the feeding activity of the clam was measured in the field using a closed circulation chamber. The filtration rate of clams for POM at Sihwa tidal flat (2.86 for POC, 2.29 for PON and 5.46 L h-1 gDW-1 for Chl a) was higher than that at Geunso tidal flat (0.61 for POC, 0.89 for PON and 2.54 L h-1 gDW-1 for Chl a) which resulted from differences in the hydrographic regime, including tide characteristics, current speed and submergence time, and food quantity and quality. The current speed was much greater at Geunso tidal flat than at Sihwa tidal flat, but the submergence time by tide was longer at the latter site than the former, resulting in different feeding times for clams. The food quantity in terms of chlorophyll a was higher at Sihwa tidal flat than at Geunso tidal flat, and the food quality based on the C/N ratio of POM was better at the former site than the latter, with values of 12.8 and 15.6, respectively. These findings suggest that hydrographic regime could be important in understanding in situ filtration rates of R. philippinarum.

Age-Related Changes of Some Chemical Components in the Leaves of Oriental Beech (Fagus orientalis Lipsky.)

Background and Purpose: This study presents the analysis of photosynthetic pigments, proline, total soluble protein, total amino acids, glucose, sucrose, total soluble sugars, total amount of phenolic compounds and flavonoids, malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentration in the leaf samples collected from oriental beech trees, which are naturally spread in Kastamonu Province, Turkey, with differing ages, enzyme activities of ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD). Material and Methods: The research was carried out on oriental beech trees (Fagus orientalis L.) of different ages located at 1300 m high elevation in Ahlat Village of Kastamonu Province, Turkey. Oriental beech trees of different ages (≥25, ≥50, ≥100, ≥200 and ≥600 years-old) constituted the material of this study. In leaf samples taken from trees of different ages, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoid), proline, total soluble protein, total amino acid, glucose, sucrose, total soluble sugars, the amount of total phenolic compounds and flavonoids, MDA, H2O2 concentration, enzyme activities of APX, CAT and SOD, as well as the relationship between the total content of C, N and H elements and the tree ages were studied. Results: As a result of the research conducted, significant differences were determined in terms of chlorophyll, total phenolic compound, flavonoid, glucose, amounts of sucrose, nitrogenous compounds, proline, total soluble protein, MDA, H 2O2 concentrations, and the activities of APX, CAT and SOD in the leaves of oriental beech trees with differing ages. The highest content of chlorophyll a was found to be in the youngest age group of ≥25 years. Total chlorophyll is low in young trees and high in middle-aged, old and very old trees. According to the results obtained, it was concluded that the MDA and H2O2 concentrations in the trees did not vary depending on the age of trees only, but also on the genotype, environmental conditions and metabolic activities. It was concluded that the fact that the total chlorophyll, phenolic compounds and sucrose content in oriental beech trees are high and that MDA content is low could have an influence on the long life of ≥600 years-old oriental beech trees. Conclusions: The activity of photosynthesis is related to leaf characteristics more than the age of trees.

Ecological–Microbiological Studies of Lake Beloe in Winter and Spring with the Use of Innovation Test-Systems

Chlorophyll a concentration, the total abundance of bacteria, the number of bacterial cells with active metabolism, and the abundance of saprotrophic bacteria were studied in the surface and bottom water layers of Lake Beloe in winter and spring 2015–2016. The abundance of sanitary-indicator microorganisms was determined for the first time with the use of Petrifilm test-systems (3MTM Petrifilm™). In most cases, Lake Beloe water in spring and winter was found to correspond to eutrophic level (in terms of chlorophyll a concentration in water) and polysaprobic status (in terms of microbiological indices). By its sanitary-microbiological characteristics, the lake is clear—the values of the total microbial count, determined with the use of test-systems 3M™ Petrifilm™ Aqua (AQHC), were <1000 CFU/mL, and the abundance of coliform bacteria, determined with the use of test-systems 3M™ Petrifilm™ Aqua (AQСC), varied from 20 to 135 CFU/100 mL. Coliform bacteria were mostly found in the bottom water layer. It was shown that, in the organization of ecological–microbiological studies, special attention is to be paid to the bottom horizons of water bodies.