Pennate Research Articles

Integration of physiologically relevant photosynthetic energy flows into whole genome models of light-driven metabolism.

Characterizing photosynthetic productivity is necessary to understand the ecological contributions and biotechnology potential of plants, algae, and cyanobacteria. Light capture efficiency and photophysiology have long been characterized by measurements of chlorophyll fluorescence dynamics. However, these investigations typically do not consider the metabolic network downstream of light harvesting. By contrast, genome-scale metabolic models capture species-specific metabolic capabilities but have yet to incorporate the rapid regulation of the light harvesting apparatus. Here, we combine chlorophyll fluorescence parameters defining photosynthetic and non-photosynthetic yield of absorbed light energy with a metabolic model of the pennate diatom Phaeodactylum tricornutum. This integration increases the model predictive accuracy regarding growth rate, intracellular oxygen production and consumption, and metabolic pathway usage. Through the quantification of excess electron transport, we uncover the sequential activation of non-radiative energy dissipation processes, cross-compartment electron shuttling, and non-photochemical quenching as the rapid photoacclimation strategy in P. tricornutum. Interestingly, the photon absorption thresholds that trigger the transition between these mechanisms were consistent at low and high incident photon fluxes. We use this understanding to explore engineering strategies for rerouting cellular resources and excess light energy towards bioproducts in silico. Overall, we present a methodology for incorporating a common, informative data type into computational models of light-driven metabolism and show its utilization within the design-build-test-learn cycle for engineering of photosynthetic organisms.

Effect of the substrate surface and nutrient adsorption and elution on the growth of benthic diatom Nitzschia palea

Benthic diatoms are beneficial organisms whose activity supports ecosystems and improves water quality. The pennate diatom Nitzschia palea is an important diatom species, as it has a potential to control cyanobacterial blooms. Several studies have attempted to restore lakes by using artificially produced substrates that remove nutrients or harmful substances. Although substrates provide attachment sites, they may adversely affect the growth of diatoms by removing nutrients. In this study, we investigated a suitable substrate for N. palea growth. Substrates such as glass beads, activated carbon, and oyster shells, which can be used for lake water or ecosystem restoration, were selected. The most suitable substrate was determined from the perspective of nutrient adsorption, elution, and availability of adhesion sites. N. palea was cultivated with substrates until the stationary growth phase was attained, and N. palea growth and the change in nutrient content of the medium were investigated. Silicate eluted from small glass beads considerably increased the maximum cell yield of N. palea (7.03 × 106 cells mL−1). Activated carbon absorbed nitrate from the medium and decreased the specific growth rate of N. palea from 0.47 d−1 (without substrate) to 0.24 d−1 while providing attachment sites and increasing the maximum cell yield compared to the control (1.49 × 106 and 1.01 × 106 cells mL−1 under activated carbon and control treatments, respectively). Oyster shells absorbed phosphate and did not increase the maximum cell yield. Our results suggest that submerged substrates that absorb nutrients may negatively affect the growth of attached diatoms. Therefore, when using the substrates for lake water restoration, attention must be paid to the growth of attached diatoms.

Spatial variation in diatom abundance and composition in Biwase Bay and Hamanaka Bay (Eastern Hokkaido, Japan), with reference to environmental features.

This study aims to examine the spatial variation of diatom abundance and composition along the nearshore areas of Biwase Bay and Hamanaka Bay, eastern Hokkaido. Terrestrial input via Kiritappu Wetland is expected to affect variation and composition differently depending on the position of the two bays. We conducted an oceanographic survey in June 2014 to measure seawater temperature, salinity, colored dissolved organic matter (CDOM) absorption, nutrient concentrations, and total and size-fractionated chlorophyll (Chl) a concentration at 11 stations of the shallowest (<5 m) parts of the bays. These were grouped into four areas (Areas 1 and 2 in Biwase Bay, and Areas 3 and 4 in Hamanaka Bay) based on the distance of the location from the wetland outlet (nearest in Area 1 to the farthest in Area 4). Diatoms are the major primary producers in the water column. Therefore, we also determined genus level cell abundance and diversity of diatoms to compare similarity among areas. Sea surface temperature was the lowest at Area 4, whereas sea surface salinity was the lowest at Area 1. The contribution of CDOM absorption, an indicator of wetland-influenced river discharge, and silica concentration was highest at Area 1. Total amount of nitrite and nitrate concentrations was the highest at Area 4. Total amount of Chl a concentration was also lowest in Area 1. Our size-fractionated Chl a results revealed that while the size composition of phytoplankton varied among areas, micro-sized (>10 µm) phytoplankton were predominant in Area 4. Finally, diatom composition at the genus level differed greatly among areas. Pennate diatoms were predominant in Areas 1 and 2, but centric diatoms dominated in Areas 3 and 4. Our results suggested great spatial variability in oceanographic conditions among areas, with less influence of wetland and more influence of Coastal Oyashio Water based on distance from the wetland outlet. Diatom composition showed geographical division between Biwase and Hamanaka Bays.

Effects of temperature, irradiance, and pH on the growth and biochemical composition of Haslea ostrearia batch-cultured in an airlift plan-photobioreactor.

Haslea ostrearia is a pennate diatom that produces marennine, a water-soluble blue pigment responsible for the greening phenomenon and the increase of organoleptic quality of oysters. Apart from the oyster industry, there is a growing interest in the mass cultivation of this diatom due to the biological activities of marennine. To gain knowledge about the feasibility to upscale production of this diatom, in particular, in the context of global warming, the effects of different temperatures (20, 25, and 30°C), irradiances (100, 200, and 300μmol photons m-2s-1), and pH (7.0, 8.0, and 9.0) on growth and biochemical composition were studied in H. ostrearia cultured in an airlift plan-photobioreactor. The maximum growth rate of H. ostrearia (0.9 ± 0.0day-1) was obtained at 20°C, 200μmol photons m-2s-1, and pH 7.0, referred to as control conditions. The highest concentration in Chla (2.5 ± 0.1µg 10-6 cells) and total fatty acids (71.6 ± 1.4mgg-1 of dry weight, DW) was observed at 20°C, 300μmol photons m-2s-1, and pH 7.0. The highest concentration of carotenoids (1.4 ± 0.1µg 10-6 cells), Chlc (1.3 ± 0.1µg 10-6 cells), and extracellular marennine (33.1 ± 0.2µg 10-6 cells) was observed at 30°C, 200μmol photons m-2s-1, and pH 7.0, and a higher protein content (309.7 ± 24.5mgg-1 of DW) at 25°C, 200μmol photons m-2s-1, and pH 7.0. The biomass of H. ostrearia was enriched with C14:0 fatty acid at 30°C, 200μmol photons m-2s-1, and pH 7.0, and with C16:0 and C16:1n - 7 fatty acids at control conditions. However, DHA C22:6n - 3 (ω-3), C22:0, and C20:0 were only observed at 300µmol photons m-2s-1, 20°C, and pH 7.0. A high abundance of essential polyunsaturated fatty acids C22:1n - 9 (ω-9) + C20:5n - 3 (EPA) was observed at 100µmol photons m-2s-1, 20°C, and pH 7.0. It is thus possible to anticipate and tune the production of specific metabolites through the control of growth conditions of the benthic diatom H. ostrearia. KEY POINTS: • Validation of H. ostrearia culture in a new photobioreactor in batch mode • Biochemical composition variation of H. ostrearia in function of growth conditions • Growth inhibition and unbalanced metabolites induced by the treatment conditions.

Complete Genome Sequence of Vibrio maritimus BH16, a Siderophore-Producing Mutualistic Bacterium Isolated from Diatom Skeletonema costatum.

Complete Genome Sequence of Vibrio maritimus BH16, a Siderophore-Producing Mutualistic Bacterium Isolated from Diatom Skeletonema costatum.

Ice algae in current water-ice environmental condition of the Arctic Ocean

In the Arctic Ocean (AO) of today, there are noticeable changes in the composition and structure of biological communities inhabiting the water-ice environment. Over the past two decades, a decrease in the number of species of the sea ice flora and fauna has been noted in the central regions of the AO due to the changing physical environment of their habitat. In view of the current climatic instability in the AO, it is important to monitor and evaluate their composition, structure and dynamics of development. It is also important to preserve the methods of processing the materials collected in order to compare the state of the water-ice biota on similar spatial and temporal scales of the basin. In the present study, centric and pennate diatoms dominating in ice floristic communities were selected as indicators of changes. The aim of the work is to analyze the physical state of the water-ice environment and the species composition of ice diatoms based on the materials of the expeditions within the NABOS program at the Research Vessel (R/V) “Akademik Treshnikov” in the Arctic Basin in 2018 and 2021. The field work included observations of the state of the sea-ice cover in the area of the expeditions, the selection of ice cores to assess the salt composition and species composition of the algae, as well as CTD-sounding of the under ice — water layer. The analysis of the materials collected showed significant differences in the species composition and abundance of algae between the seasons, which indicates the formation of independent floristic communities in the current conditions of unstable physical environment in the central regions of the AO, which confirms the previously obtained results in the period 2007–2015. The materials under discussion were obtained in a short period of time and in limited spaces in the zones of production of annual ice in the waters of the shelf seas and zones of removal to the central regions of the AO. At the same time, short-term observations provide “instant” information about the qualitative and quantitative state of sea-ice biological communities. In order to obtain reliable estimates, long-term observations are needed, which may be organized in the near future based on new logistical approaches to the study of the marine Arctic.

Araphid pennate diatoms of Ngor (Dakar, Senegal)

Araphid pennate diatoms of Ngor (Dakar, Senegal)

Araphid pennate diatoms of Ngor (Dakar, Senegal)

The present study provides the first list of marine araphid pennate diatoms from Ngor (Senegal). A total of 18 taxa belonging to 9 genera, 9 families, and 8 orders of Fragilariophyceae Class were described and identified by light microscopy in Ngor’s waters between July 2009 and November 2011. All these taxa are new for the microflora of Ngor.

Effects of the Source–Sink Relationship on Walnut Nut Quality at the Scale of the Fruit–Bearing Branch

Fruit quality is known to be regulated by the balance between leaf number/area and fruit number, but less is known about the effects of fruit–bearing branch agronomic traits, particularly for walnuts (Juglans regia L.). We assessed nut quality, physiological and biochemical indexes of leaves, and microstructure of leaves and fruit stalks at various leaf–to–fruit ratios to gain insight into the relationships between branch agronomic traits and nut quality, to identify those traits that made a better contribution to nut quality and to find out the range of the leaf–to–fruit ratio and the object of fruit to be removed for thinning. We found that the top fruit on the fruit stalk had a higher longitudinal diameter and kernel weight than the bottom at the low leaf–to–fruit level, and branches with more pinnate compound leaves had a better capacity for carbohydrate assimilation and transportation to produce better quality fruits. Specifically, with the increasing leaf number, the branch diameter, total leaf area, net photosynthetic rate, chlorophyll content, fruit weight, fruit diameters, and kernel protein content also increased. Moreover, at the microscopic level, the fruit stalk vascular bundle, leaf thickness, palisade mesophyll thickness, and ratios of palisade mesophyll to spongy mesophyll thickness in the leaf also showed the same trend. Therefore, when the ratio of leaf area to the fruit number was less than 181.5 square centimeters per fruit on the branches, reducing the fruit number could improve the size and the crude fat content of fruits. While the ratio was more than 247.8 square centimeters per fruit, the fruit number had no significant effect on fruit quality, but increasing leaf area and branch diameter could improve the fruit size and yield.

Effects of Hydrogen Peroxide Products on Basil, Lettuce, and Algae in an Ebb and Flow Hydroponic System

Hydrogen peroxide has been used as a sanitation agent for many years. Recently, hydrogen peroxide products have been used to remove algae from irrigation lines and sanitize hydroponic systems between uses. However, hydrogen peroxide can have phytotoxic effects on plants at high concentrations. The goal of this research was to determine if hydrogen peroxide treatments affected plant and algae growth in the ebb and flow hydroponic systems. The research was conducted at the Department of Horticulture and Landscape Architecture greenhouses in Stillwater, OK. Two cultivars of lettuce, ‘Green Forest’ and ‘Tropicana’, and two cultivars of basil, ‘Aroma II’ and ‘Genovese’, were transplanted into the ebb and flow hydroponic systems, and three different hydrogen peroxide products, PERpose Plus, ZeroTol, and 3% hydrogen peroxide, were applied at different rates and combinations in two experiments. Shoot fresh weight in lettuce was found to be significantly greater in control and 3% hydrogen peroxide treatments for both cultivars; however, in ‘Tropicana’ those treatments were not different from any other treatment. Greater amounts of PERpose Plus and ZeroTol, such as 60 mL, restricted plant growth in lettuce, whereas only cultivar differences for SPAD and plant width were reported for basil. Algae growth was not significantly controlled by any treatment in this research based on algae counts, weights, or spectrometer readings. However, algae species quantification did show that Microspora tumidula was found in the greatest concentrations in control, with a 96.0%, 99.2%, 94.0%, and 97.9% reduction in the 15 mL ZeroTol, 60 mL ZeroTol, 15 mL PERpose Plus, and 3% hydrogen peroxide treatments, respectively. Other algae genera identified included Scenedesmus, Chlamydomonas, Gloeocystis, Tetraspora, Leptolyngbya, Pennate diatoms, and Centric diatoms.

The Differential Responses of Coastal Diatoms to Ocean Acidification and Warming: A Comparison Between Thalassiosira sp. and Nitzschia closterium f.minutissima.

Marine diatoms are one of the marine phytoplankton functional groups, with high species diversity, playing important roles in the marine food web and carbon sequestration. In order to evaluate the species-specific responses of coastal diatoms to the combined effects of future ocean acidification (OA) and warming on the coastal diatoms, we conducted a semi-continuous incubation on the large centric diatom Thalassiosira sp. (~30 μm) and small pennate diatom Nitzschia closterium f.minutissima (~15 μm). A full factorial combination of two temperature levels (15 and 20°C) and pCO2 (400 and 1,000 ppm) was examined. The results suggest that changes in temperature played a more important role in regulating the physiology of Thalassiosira sp. and N. closterium f.minutissima than CO2. For Thalassiosira sp., elevated temperature significantly reduced the cellular particulate organic carbon (POC), particulate organic nitrogen (PON), particulate organic phosphate (POP), biogenic silica (BSi), chlorophyll a (Chl a), and protein contents, and the C:N ratio. CO2 only had significant effects on the growth rate and the protein content. However, for the smaller pennate diatom N. closterium f.minutissima, the growth rate, POC production rate, and the C:P ratio significantly increased with an elevated temperature, whereas the cellular POP and BSi contents significantly decreased. CO2 had significant effects on the POC production rate, cellular BSi, POC, and PON contents, the C:P, Si:C, N:P, and Si:P ratios, and sinking rate. The interaction between OA and warming showed mostly antagonistic effects on the physiology of both species. Overall, by comparison between the two species, CO2 played a more significant role in regulating the growth rate and sinking rate of the large centric diatom Thalassiosira sp., whereas had more significant effects on the elemental compositions of the smaller pennate diatom N. closterium f.minutissima. These results suggest differential sensitivities of different diatom species with different sizes and morphology to the changes in CO2/temperature regimes and their interactions.

Luxury iron uptake and storage in pennate diatoms from the equatorial Pacific Ocean

Iron is a key micronutrient for ocean phytoplankton, and the availability of iron controls primary production and community composition in large regions of the ocean. Pennate diatoms, a phytoplankton group that responds to iron additions in low-iron areas, can have highly variable iron contents, and some groups such as Pseudo-nitzschia, are known to use ferritin to store iron for later use. We quantified and mapped the intracellular accumulation of iron by a natural population of Pseudo-nitzschia from the Fe-limited equatorial Pacific Ocean. A total of 48 h after iron addition, nearly half of the accumulated iron was localized in storage bodies adjacent to chloroplasts believed to represent ferritin. Over the subsequent 48h, stored iron was distributed to the rest of the cell through subsequent growth and division, partially supporting the iron contents of the daughter cells. This study provides the first quantitative view into the cellular trafficking of iron in a globally relevant phytoplankton group and demonstrates the unique capabilities of synchrotron-based element imaging approaches.

Flow cytometry and 5-ethynyl-2'-deoxyuridine (EdU) labeling to detect the cell cycle dynamics of Phaeodactylum tricornutum under light.

Cell cycle studies in plants and algae are highly dependent on reliable methods for detecting cellular DNA replication. With its short growth cycle and ease of genetic transformation, Phaeodactylum tricornutum is an important model organism for the study of pennate diatoms. Here we explored two different methods to detect the cell cycle of P. tricornutum, one using SYBR-green I to via flow cytometry, and the other using EdU labeling to observe cell cycle changes under fluorescence microscopy. Both EdU labeling fluorescence microscopy and SYBR-green I staining flow cytometry accurately indicated that the cells of P. tricornutum enter the G2/M phase after 12 h of light exposure. The results indicate that SYBR Green I was an adequate detection method for nuclear DNA quantitation in cells of P. tricornutum using a flow cytometer and without RNase A treatment. In addition, EdU can be applied to P. tricornutum to reliably detect cell proliferation. Besides, Mg-ProtoIX was able to reverse the cell cycle division inhibition of P. tricornutum and allow the nuclear DNA replication to proceed normally. Taken together, the photoperiodic division time point was clearly identified, which sheds light on the regulation of cell division mechanism in P. tricornutum.

Early leaf development in Euterpe oleracea Mart. (Arecaceae, Arecoideae): Leaflets, pinnae or segments?1

Euterpe oleracea presents long leaves with divisions in the blade frequently referred to as leaflets or pinnae, as if they were compound. The purpose of this article is to present the first leaf ontogeny study for this species. Buds of dissected E. oleracea were classified according to their size and morphology and examined under scanning electron and light microscopy. The youngest leaf primordia are conical. The first foldings in the leaf blade appear in primordia ca. 0.8 mm in length and already have procambium. When young leaves reach 1.5 mm long, these plications separate from one another. Segments change their orientation throughout leaf development. Leaf blade in E. oleracea is initially entire (nonplicate), becoming plicate at a later stage, and plications separate from each other as a final step. This developmental process has some similarities with what is observed in other palm species. According to early stages of the leaf ontogeny, these plants have simple pinnatisect and not compound pinnate leaves. The use of terminology such as “leaflets” or “pinnae” is incongruent with simple leaves, and we recommend that adult leaf blade subdivisions of Arecaceae should be called “leaf segments” instead. This work contributed to the understanding of histological changes during palm leaf development, being a contemporary report on both histological and micromorphological study on palm leaf ontogeny.

Characterization of the manufacturing process simplicia Syzygium aromaticum as raw material for wound healing drug preparations

Characterization is the first step before standardization. Standardization of a drug substance is a requirement to achieve parameters that will ensure constant quality in a preparation. The main compounds contained in clove leaves have analgesic and antibacterial properties to accelerate wound healing. This study aims to characterize the process of making clove leaf simplicia and Simplicia (Syzygium aromaticum) originating from Lemukutan Island, Bengkayang Regency, West Kalimantan as raw material for wound healing drug preparations. Clove leaf Simplicia was characterized biologically including habitat and morphology, physically including organoleptic, microscopic, moisture content, ash content, and acid insoluble ash content, and chemically, namely phytochemical screening. Making clove leaf Simplicia consists of harvesting, wet sorting, washing, drying, dry sorting, packaging, and storage. The yield of clove leaf Simplicia was obtained as much as 70.90%. The results of the characterization of clove leaves showed that the clove tree grows in the highlands, with a tropical climate, with a temperature range of 25 C-32 C. Clove leaves are oval in shape, tapered tip, pinnate leaf bone, leaf length is approximately 9-12 cm and width 4 cm-4.5 cm. The moisture content, ash content, and insoluble ash content of the clove leaf Simplicia powder were 9.21%, 3.05%, and 0.69%, respectively. The outcomes of the phytochemical screening of clove leaf Simplicia powder have beensuperbfor holding flavonoids, saponins, triterpenoids, and tannins.

Genus-specific and Habitat-dependent Plant Ingestion in West African Sabre-toothed Frogs (Anura, Odontobatrachidae: Odontobatrachus)

Although frogs are predominately opportunistic carnivores, numerous studies report large amounts of plant material in anuran stomachs, citing accidental ingestion as the likely cause. Herein, we present evidence suggesting deliberate plant uptake in the Sabre-toothed Frog (Odontobatrachus ziama) and propose that this trait is specific to the entire family Odontobatrachidae. We performed stomach-flushing on 814 frogs, resulting in 665 dietary samples comprising all 5 Odontobatrachus species and two similar-sized, syntopic frogs, Astylosternus occidentalis and Conraua alleni. We collected dietary samples across the entire range of Odontobatrachus, in both wet and dry season. Additionally, we collected stomach contents of an O. ziama population during a 12-d capture–mark–recapture study in three different river habitats and compared the consumed and available plant material. We found that all Odontobatrachus spp. ingested the pinnate leaf of the riparian tree Parkia bicolor. These leaves were the most abundant food items in the stomachs of three out of the five Odontobatrachus species. Although mean proportional uptake of the leaflets did not differ seasonally, the maximum amount of leaflets was greater during the dry season, coinciding with peak leaflet availability. We found up to 100 single leaflets in stomachs of Odontobatrachus arndti, but syntopic Astylosternus and Conraua had ingested considerably smaller quantities of Parkia leaflets. Lastly, we found a greater prevalence of Parkia leaflets in females, with significant variation in leaflet uptake between stream microhabitats that could not be explained by the availability of the plant material. Consequently, we analyzed the dietary items for co-occurrences of plant material and preyed-upon animals that would support the hypothesis of an accidental uptake. However, we could not find biologically meaningful co-occurrences. Based on the combined results of stomach-flushing, availability of food items, absence of meaningful co-occurrences of plant with animal matter and feeding experiment, we concluded that leaflets were likely swallowed deliberately, but not eaten for energy demands. The reason for the deliberate ingestion of plant material across the genus Odontobatrachus so far remains unresolved. Key words: Astylosternus occidentalis; Conraua alleni; Frog diet; Guinea; Herbivory; Parkia bicolor; Stomach-flushing

Winter microalgal communities of the southern Sea of Okhotsk: A comparison of sea ice, coastal, and basinal seawater

The Sea of Okhotsk is a marginal sea of the western North Pacific Ocean and a key region for the seawater circulation of the North Pacific. In winter, a large amount of sea ice forms over the northern shelf and off the eastern Sakhalin coast. The sea ice is transported to the southern part of the sea by the fresh and cold East Sakhalin Current (ESC). Microalgae are the main players in the primary production of the sea ice ecosystems. We investigated the winter microalgal communities of the sea ice ecosystem in the southern Sea of Okhotsk, including the communities living in sea ice and seawater using microscopy and DNA barcoding. The results showed that diatoms were the major component in the microalgal communities. Sea ice algal communities were dominated by Thalassiosira spp., Porosira glacialis, and Fragilariopsis cylindrus, while other typical sea ice pennate diatoms were rarely found. The seawater stations were separated into two groups by hydrological conditions: coastal stations strongly affected by ESC; basinal stations influenced by the deep mixing and the basinal gyre. Small-sized diatoms and naked nanoflagellates were more abundant at the ESC-influenced stations that had higher concentrations of dissolved Fe (DFe) and ammonia (NH4). In particular, spores of Chaetoceros dominated the ESC-influenced seawater. Representative algal taxa specific to the basinal stations, including the diatom Shionodiscus spp., the haptophyte Coccolithus pelagicus, and the dinoflagellate Prorocentrum minimum, were either typical for the basinal gyres or the remnants of the autumn algal blooms. The results suggested that the winter phytoplanktonic communities of the southern Sea of Okhotsk were dependent almost entirely on whether they were within the influence of the ESC. Ice algae were far more abundant than phytoplankton, indicating their major role in the seeding of the spring bloom.

Luxury iron uptake and storage in pennate diatoms from the equatorial Pacific Ocean

Luxury iron uptake and storage in pennate diatoms from the equatorial Pacific Ocean

Anatomical and morphological characteristics of the authenticity of &lt;i&gt;Astragalus zingeri&lt;/i&gt; Korsh. herb

Aim to analyse the morphological and anatomical structure of the herb Astragalus zingeri, identifying the diagnostic signs of plant raw material.&#x0D; Material and methods. The object of the study was plant raw materials the herb Astragalus zingeri Korsh., harvested in July, 2020, in the Saratov region, Tatishchevsky district, nearby the Kurdyum station, during the mass flowering period. The State Pharmacopoeia XIV standard was used for macro and microscopic analysis.&#x0D; Results. The macroscopic features of the raw material are: pronounced ribbing of the stem, a small number of pairs of leaflets (46) of an unpaired pinnate leaf, as well as the size of the leaf plate, more pronounced trichomes on the bottom-side of the leaf, shortened, capitate, dense racemes with a pale purple corolla and a long flag. The characteristic microdiagnostic distinguishing features include: sinuous walls of leaf epidermal cells with numerous anomocytic stomata; slightly sinuous walls of the cells of the calyx epidermis; trichomes of the outer side of the calyx with T-shaped hairs with characteristic outgrowths of the cuticle.&#x0D; Conclusion. The revealed macro- and microscopic diagnostic features of the herb Astragalus zingeri make it possible to identify the plant raw material and distinguish it from similar species.

Blue light irradiation increases the relative abundance of the diatom Nitzschia palea in co-culture with cyanobacterium Microcystis aeruginosa.

Lake eutrophication is associated with cyanobacterial blooms. The pennate diatom Nitzschia palea (N. palea) inhibits the growth of the cyanobacterium Microcystis aeruginosa (M. aeruginosa); therefore, increasing the relative abundance of N. palea may contribute to the inhibition of Microcystis blooms. Several studies have demonstrated that blue light irradiation promotes diatom growth and inhibits cyanobacterial growth. In this study, we evaluated the effects of blue light irradiation on N. palea and M. aeruginosa abundance. Monocultures and co-cultures of N. palea and M. aeruginosa were exposed to blue light and fluorescent light at 32 μmol photons m-2s-1. The relative abundance of N. palea under fluorescent light decreased gradually, whereas the abundance under blue light was relatively higher (approximately 74% and 98% under fluorescent light and blue light, respectively, at the end of the experiment). The inhibition efficiency of blue light on the growth rate of M. aeruginosa was related to the light intensity. The optimal light intensity was considered 20 μmol photons m-2s-1 based on the inhibition efficiency of 100%. Blue light irradiation can be used to increase the abundance of N. palea to control Microcystis blooms. PRACTITIONER POINTS: The effects of blue light irradiation on N. palea abundance was discussed. Monocultures and co-cultures of N. palea and M. aeruginosa were exposed to blue light and to fluorescent light. The relative abundance of N. palea increased upon irradiation with blue light in co-culture with M. aeruginosa.