scholarly journals Ecological assessment of the toxicity of nitrogen compounds for aquatic organisms using the Lemna minor L. Biotest

Author(s):  
V. P. Strokal ◽  
◽  
N. A. Makarenko ◽  
T. S. Chorna ◽  
A. V. Kovpak ◽  
...  

This research is motivated because of increasing eutrophication problems in water bodies. This happens as a result of excess nitrogen and phosphorus. Too many of these nutrients can cause algae to grow, leading to blooms. Harmful algal blooms consume dissolved oxygen in water. As a result, the oxygen level decreases, affecting the aquatic ecosystem. The stenobiont plant, which belongs to the group of the most sensitive bioassays, is the small duckweed Lemna minor L. This plant is sensitive to increasing levels of nutrients and blooms of algae. This research aimed to determine the level of water toxicity using the bioassay of duckweed (Lemna minor L.) to establish dangerous concentrations of nitrogen compounds (NO2-, NO3-, NH4+) (CA) for higher plants of aquatic ecosystems with subsequent risk forecast for Dnipro basin. The research was carried out in accordance with DSTU 32426-2013 “Testing of chemicals of environmental hazard. Lemna sp. Growth Inhibition. Test”. The number of effects associated with nitrogen compounds (NO2-, NO3-, NH4+) on plant growth and development during the testing period was detected. The number of green layers is the main variable that was investigated in the experiment. Changes in the morphological features of duckweed were also studied, in accordance with the standard, the toxicity of water was assessed by changes in leaf colour, manifestations of chlorosis, the transformation of whole plants into individuals, the appearance of young leaves. To estimate the number of effects associated with the nitrogen compounds toxicity, the half-maximal effect (EC50) was studied. It should be noted that studies of water toxicity on NO2- content using the Lemna minor L. test showed that even at the lowest concentration of 0.1 mgNO2-/L aquatic biota will be significantly affected by the toxicity with possible subsequent death. Summarizing the results of the research of the Lemna minor L reaction to the toxicity of water with different concentrations of NO3- came to the conclusion that even the lowest concentration (0.1 mgNO3-/L) will have a negative impact on their growth and development of the plant. Generally, 40.0 mgNO3-/L is considered “safe” for fish farming. However, this is not a case for aquatic vegetation, as shown by this result – such concentration will be toxic and cause death. If we take into account NH4+ salts, the reaction was even more progressive, the deterioration of the leaf layers of duckweed began to occur immediately from the first days of the research, and the number of damaged duckweed was 30% more on day 24 than in salts NO3-, NO2-. For algae of aquatic ecosystems the highest level of toxicity is shown by nitrogen compounds in the form of NO3-, the median concentration of EC50 (96 hours) is 7.7 mg/L. Therefore, the regulation of pollution of aquatic ecosystems by nitrogen compounds should be based primarily on the content of NO3-. To avoid the negative effects of compounds such as NH4+ and NO2- it is necessary to take into account their toxicity level: EC50 (96 hours) NH4+ – 250 mg/L, EC50 (96 hours) NO2- – 720 mg/L. From the above, the free-floating hydrophyte Lemna minor L. is a promising object of testing, as it easily absorbs all the elements and quickly shows the result. It is able to quickly accumulate harmful substances, because in the process of life, its leaves absorb absolutely all the elements that fall into the water.

2018 ◽  
Vol 45 ◽  
pp. 00056 ◽  
Author(s):  
Elena Neverova-Dziopak

Eutrophication is one of the consequences of the negative anthropogenic impact on aquatic ecosystems. It leads to the degradation of both sweet and marine ecosystems, constituting a kind of secondary pollution of waters, which disturbs all types of their use. Undertakings related to preventing the negative effects of eutrophication are mainly conducted towards reducing the loads of nutrients introduced into surface waters and controlling the entire conditions in aquatic ecosystems in order to limit the development of aquatic vegetation. The increasingly restrictive legal requirement regarding the content of nitrogen and phosphorus in wastewater discharged into recipients enforces the application of expensive treatment technologies, and the public is becoming more aware of the rising costs of water and wastewater fees. In addition, wastewater treatment is a factor which has a negative impact on air quality due to greenhouse gas emissions and generates other environmental problems. The challenge for facilities, however, is determining which treatment alternatives will best meet their needs, both technically and financially, and to choose the most sustainable path. The problem of establishing a reasonable level of nutrient removal from wastewater, justified from an ecological and economic point of view is discussed in the paper.


2014 ◽  
Vol 155 (26) ◽  
pp. 1011-1018 ◽  
Author(s):  
György Végvári ◽  
Edina Vidéki

Plants seem to be rather defenceless, they are unable to do motion, have no nervous system or immune system unlike animals. Besides this, plants do have hormones, though these substances are produced not in glands. In view of their complexity they lagged behind animals, however, plant organisms show large scale integration in their structure and function. In higher plants, such as in animals, the intercellular communication is fulfilled through chemical messengers. These specific compounds in plants are called phytohormones, or in a wide sense, bioregulators. Even a small quantity of these endogenous organic compounds are able to regulate the operation, growth and development of higher plants, and keep the connection between cells, tissues and synergy beween organs. Since they do not have nervous and immume systems, phytohormones play essential role in plants’ life. Orv. Hetil., 2014, 155(26), 1011–1018.


Author(s):  
Ekaterina Maksimova ◽  
Ekaterina Maksimova ◽  
Vladimir Zhigulsky ◽  
Vladimir Zhigulsky ◽  
Vladimir Shuisky ◽  
...  

The macrophyte thicket ecosystems of higher aquatic vegetation in the Neva Bay (NB) and Eastern Gulf of Finland (EGoF) perform many important roles, including acting as the habitats, nesting sites and migration sites for aquatic and semi-aquatic birds, creating the specific conditions necessary for the spawning and growth of many species of fish, and taking part in the self-purification of the aquatic ecosystems. Many anthropogenic disturbances, hydraulic works in particular, have a significant negative impact on these macrophyte thicket ecosystems. In recent years, the active growth of a new type of macrophyte thicket has been observed in the NB. This is due to the aftereffects of the construction of the Saint Petersburg Flood Prevention Facility Complex (FPFC). It is quite likely that the total macrophyte thicket area in these waters is currently increasing. In the future, it will be necessary to assess the environmental impacts of the hydraulic works on the macrophyte thicket of the NB and EGoF, taking into account the background processes of the spatiotemporal dynamics of the reed beds in the waters in question. To do this, it will be necessary to carry out a comprehensive study of these ecosystems and identify patterns in their spatial and temporal dynamics. The program of the study has been developed and is currently being implemented by Eco-Express-Service, a St. Petersburg eco-design company.


Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1687
Author(s):  
Richard E. Lizotte ◽  
Peter C. Smiley ◽  
Robert B. Gillespie ◽  
Scott S. Knight

Conservation agriculture practices (CAs) have been internationally promoted and used for decades to enhance soil health and mitigate soil loss. An additional benefit of CAs has been mitigation of agricultural runoff impacts on aquatic ecosystems. Countries across the globe have agricultural agencies that provide programs for farmers to implement a variety of CAs. Increasingly there is a need to demonstrate that CAs can provide ecological improvements in aquatic ecosystems. Growing global concerns of lost habitat, biodiversity, and ecosystem services, increased eutrophication and associated harmful algal blooms are expected to intensify with increasing global populations and changing climate. We conducted a literature review identifying 88 studies linking CAs to aquatic ecological responses since 2000. Most studies were conducted in North America (78%), primarily the United States (73%), within the framework of the USDA Conservation Effects Assessment Project. Identified studies most frequently documented macroinvertebrate (31%), fish (28%), and algal (20%) responses to riparian (29%), wetland (18%), or combinations (32%) of CAs and/or responses to eutrophication (27%) and pesticide contamination (23%). Notable research gaps include better understanding of biogeochemistry with CAs, quantitative links between varying CAs and ecological responses, and linkages of CAs with aquatic ecosystem structure and function.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1498
Author(s):  
Lucija Galić ◽  
Marija Špoljarević ◽  
Elizabeta Jakovac ◽  
Boris Ravnjak ◽  
Tihana Teklić ◽  
...  

Climate change poses a serious threat to agricultural production. Water deficit in agricultural soils is one of the consequences of climate change that has a negative impact on crop growth and yield. Selenium (Se) is known to be involved in plant defense against biotic and abiotic stress through metabolic, structural, and physiological activity in higher plants. The aim of this study was to investigate the physiological response of Se-biofortified soybean (Glycine max (L.) Merrill) seedlings under osmotic stress. For this research, we used biofortified soybean grain obtained after foliar Se biofortification in 2020. The experiment was conducted in a growth chamber with two cultivars (Lucija and Sonja) grown on filter paper in three replicates. The experiment was carried out with two watering treatments: distilled water (PEG-0) and 2.5% polyethylene glycol 6000 (PEG-2.5) on Se-biofortified seeds (Se) and nonbiofortified seeds (wSe). Contents of lipid peroxidation product (LP), free proline (PRO), total phenolic content (TP), ferric reducing antioxidant power (FRAP), and ascorbic acid (AA) were analyzed in 7-days-old seedlings. Significant differences were detected in the Se content of soybean grains between the two cultivars. A milder reaction to PEG-2.5 was observed in cultivar Lucija in both Se and wSe treatments, which might represent the mitigating effects of Se on osmotic stress in this cultivar. Contrarily, in cultivar Sonja, Se adversely affected all analyzed traits in the PEG-2.5 treatment. Ultimately, Se is a pro-oxidant in Sonja, whereas it represents an anti-oxidant in Lucija. In conclusion, different soybean cultivars show contrasting physiological reactions to both osmotic stress and Se. However, the activation of antioxidant pathways in Sonja can also be interpreted as added value in soybean seedlings as a functional food.


1989 ◽  
Vol 67 (2) ◽  
pp. 589-593 ◽  
Author(s):  
F. Buscot

In the upper Rhine forests, ascocarps of Morchella rotunda (Pers.) Boudier and Mitrophora semilibera (DC.) Lév. develop at the expense of preexisting subterranean mycelial structures (connective mycelium and mycelial muffs) associated with higher plants. Field data correlate the initial extent of springtime reheating of soil with ascocarp maturation and suggest that mycelial muffs may be storage and resistance structures formed as early as the summer preceding the spring fruiting. This suggests morels are biennial.


2018 ◽  
Vol 77 (2) ◽  
Author(s):  
Zengling Ma ◽  
Hengguo Yu ◽  
Ronald Thring ◽  
Chuanjun Dai ◽  
Anglv Shen ◽  
...  

Algal bloom has been a subject of much research, especially the occurrence of blue-green algae (cyanobacteria) blooms and their effects on aquatic ecosystems. However, the interaction between green algae blooms and zooplankton community was rarely investigated. In the present study, the effects exerted by Scenedesmus dimorphus (green alga) bloom on the community structure of zooplankton and the top-down control of the bloom process mediated by the zooplankton were evaluated using a series of laboratory cultures. The results showed that a dense S. dimorphus bloom could change the zooplankton community structure by decreasing its diversity indices, leading to the enrichment of a particular zooplankton species, Brachionus calyciflorus. In the presence of mixed species of zooplankton, the density of S. dimorphus in the culture was decreased as determined by a change in total chlorophyll a (Chl a) concentration, which was about 200 μg L-1 lower than that of the zooplankton-free culture. Furthermore, the number of species belonging to Cladocera, Copepoda and Rotifera all decreased, with all the cladocerans disappeared in the co-culture within 2 weeks of culturing, while the density of rotifers increased from 818 (±243) ind L-1 at the time of inoculation to 40733 (±2173) ind L-1 on the 14th day post-inoculation. Grazing of S. dimorphus by the rotifer B. calyciflorus neutralized its growth, and the gradual increase in B. calyciflorus density eventually led to the collapse of the bloom. Furthermore, grazing by B. calyciflorus also led to a decrease in the maximal photochemical efficiency (Fv/Fm) of photosystem II (PSII). The combined changes occurring in the zooplankton community structure during the process of S. dimorphus bloom and the negative effects of grazing on algal growth, morphology and photosynthetic activities confirmed the key role of zooplankton in the control of algal bloom. The results of the study therefore indicated that dense algal blooms caused by non-toxic algae could still remain a threat to aquatic ecosystems.


2018 ◽  
Vol 29 (2) ◽  
Author(s):  
N. O. Roshchyna

In this article, the current and former distribution of higher aquatic vegetation has been analyzed for floodplain lakes, arenas lakes and third terraces lakes in the valleys of large and medium North-Steppe Dnieper rivers. The article is devoted to the current state analysis of the higher aquatic vegetation at North-Steppe Dnieper lakes, its dynamics over a long-term period, as well as the determination of the nature and extent of anthropogenic-climatic changes in vegetation. Anthropogenic influence is a major threat to the development and functioning of most aquatic ecosystems. Since the twentieth century, it has been intensified by trends to long-term climate changes, which are also largely result of human activity. Increasing temperature of the winter season does not contribute to snow accumulation. Reduction of snow accumulation (frequent thaws during the winter), regulation of river flow (formation of a reservoirs cascade and ponds) and accumulation of melt water in artificial reservoirs led to the smoothing of the peak of the spring flood. Thus, the factor that provided spring washing of floodplain lakes, limited their overgrowing by air-water vegetation and their waterlogging disappeared. The anthropogenic factors that influence negatively include: intensification of agriculture, plowing of coastal areas, unreasonable land reclamation, overgrazing, development of transport and engineering infrastructure, urbanization, recreation, and chemical pollution. The presented data was obtained on the basis of processing our own research materials of 2009–2018 and literary and archival materials analysis (the herbarium of the Dnipropetrovs’k National University and the archive of the Research Institute of Biology). Natural Northern Steppe Dnieper lakes are located mainly in river valleys, so the study area was conventionally divided into sections: the large river valley (Dnieper) and the middle rivers valleys (Samara and Orel). Three ecological groups of macrophytes were reviewed and compared: hydatofites (submerged species), pleistophytes (species with floating leaves) and helophytes (air-water species). The vegetation of Dnieper floodplain lakes practically did not change for all three formation groups. The number of immersed plants communities within the floodplains of medium-sized rivers has decreased by three. The pleistophytes and helophytes associations decreased to fragments of associations. The lakes vegetation within the sandy Dnieper terrace practically did not change for all three formation groups. The submerged lakes plants associations within the sandy medium-sized rivers terraces have been reduced by two. As part of the lakes vegetation on the Dnipro saline terraces, fragments of associations of the two species are considered extinct. A new association of southern adventive species Ruppia maritima L. has appeared within the limits of the middle rivers saline terrace. Changes in higher aquatic vegetation are characteristic of all types of lakes. Changes occur in the direction of crowding out higher aquatic vegetation communities by airborne plant communities. The consequence of the anthropogenic-climatic transformation of aquatic ecosystems is increased mineralization, siltation, and, as a result, intensive overgrowing of lakes by aboriginal and adventive species with a wide ecological amplitude (replacement of sensitive to environmental changes species).


Author(s):  
Grigoriy Leonidovich Belov ◽  
Vladimir Nikolaevich Zeyruk ◽  
Vladimir Anatolyevich Barkov ◽  
Marina Konstantinovna Derevyagina ◽  
Svetlana Viktorovna Vasilieva

In field experiments in the conditions of sod-podzolic sandy loam soils of the Moscow region, protectants were tested. Before planting potatoes, tubers were treated with a new two-component insectofungicide AVG – 0190 (Idikum, SC, iprodion, 133 g/l + Imidacloprid, 100 g/l + diphenoconazole, 6.7 g/l)-1.0 – 1.5 l/t and a mixture of the fungicide Syncler, SC (75 g/l fludioxonyl) and the insecticide Tabu Super, SC (Imidacloprid, 400 g/l and fipronil, 100 g/l)-0.2-0.3 l/t. According to the results of three-year tests, it was found that the etching of potato tubers before planting does not have a negative impact on the germination and biometric indicators of growth and development of potatoes. Their use helped to reduce the development and spread of rhizoctoniosis and provided almost complete protection of potatoes from the first generation of the Colorado beetle – during the mass appearance of older larvae and during the beginning of the departure of larvae for pupation. Biological efficacy against Rhizoctonia amounted to 58.8-66,3%, the Colorado potato beetle – 93,7 95.5 per cent. The use of new potato tuber protectants allowed to increase the gross yield by 6.2-7.1 t / ha or 30.9-35.3% compared to the control. Treatment of seed tubers with protectants helped to obtain a crop free from rhizoctoniosis and increase the yield of standard healthy potatoes by 57.7


1991 ◽  
Vol 100 (2) ◽  
pp. 311-317
Author(s):  
RICHARD J. CYR

Microtubules (Mts) are found in four distinct arrays appearing sequentially in a cell-cycle-dependent fashion within the cells of higher plants. Additionally, the cortical Mts of non-cycling cells are spatially altered in a variety of differentiated states. Information regarding the molecular details underlying these Mt-reorientation events in plant cells is scarce. Moreover, it is unclear how cytoskeletal behavior integrates with the myriad of other cellular activities that are altered concomitantly in both differentiating and cycling cells. Data are presented herein to indicate that calcium, in the form of a Ca2+/calmodulin complex, can alter the behavior of Mts in lysed carrot protoplasts. Mechanistically, we show that Ca2+/calmodulin most likely interacts with Mts via associations with microtubule associated pro- teins (MAPS). These results are discussed with reference to how Ca2+ may alter the dynamic behavior of Mts during growth and development.


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