chlorophyll-a and sodium-carbonate

Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the algaecides compared, SCP can selectively mitigate risks associated with noxious cyanobacterial growths (e.g. M. aeruginosa), with an enhanced margin of safety for non-target species (e.g. P. promelas).

Topics: Amphipoda; Animals; Aquatic Organisms; Carbonates; Chlorophyll; Chlorophyll A; Chlorophyta; Cyprinidae; Fresh Water; Herbicides; Hydrogen Peroxide; Lethal Dose 50; Microcystis

The osmotic potential and effects of plasmolysis on photosynthetic oxygen evolution and chlorophyll fluorescence were studied in two Arctic Zygnema sp. (strain B, strain G) and two Antarctic Zygnema sp. (strain E, strain D). Antarctic strain D was newly characterized by rbcL sequence analysis in the present study. The two Antarctic strains, D and E, are most closely related and may represent different isolates of the same species, in contrast, strain B and G are separate lineages. Incipient plasmolysis in the cells was determined by light microscopy after incubating cells in sorbitol solutions ranging between 200 mM and 1000 mM sorbitol for 3, 6 and 24h. In Zygnema strain B and G incipient plasmolysis occurred at ~600 mM sorbitol solution (720 mOsmol kg(-1), ψ=-1.67 MPa) and in strains D and E at ~300 mM (318 mOsmol kg(-1), ψ=-0.8 MPa) sorbitol solution. Hechtian strands were visualized in all plasmolysed cells, which is particularly interesting, as these cells lack pores or plasmodesmata. Ultrastructural changes upon osmotic stress were a retraction of the condensed cytoplasm from the cell walls, damages to chloroplast and mitochondrial membranes, increasing numbers of plastoglobules in the chloroplasts and membrane enclosed particles in the extraplasmatic space. Maximum photosynthetic rates (P(max)) in light saturated range were between 145.5 μmol O(2) h(-1)mg(-1)Chl a in Zygnema G and 752.9 μmol O(2) h(-1)mg(-1)Chl a in Zygnema E. After incubation in 800 mM sorbitol for 3h P(max) decreased to the following percentage of the initial values: B: 16.3%, D: 16.8%, E: 26.1% and G: 35.0%. Osmotic stress (800 mM sorbitol) decreased maximum photochemical quantum yield of photosystem II (F(v)/F(m)) when compared to controls. Maximum values of relative electron transport rates of photosystem II (rETR(max)) decreased after incubation in 400 mM sorbitol in Zygnema D and E, while they decreased in Zygnema B and G only after incubation in 800 mM sorbitol. The kinetics of the rETR curves were similar for the Arctic strains Zygnema B and G, but distinct from the Antarctic strains Zygnema D and E, which were similar when compared with each other. This suggests that the investigated Arctic Zygnema sp. strains might be better adapted to tolerate osmotic water stress than the investigated strains from the Antarctic.

Topics: Antarctic Regions; Arctic Regions; Carbonates; Chlorophyll; Chloroplasts; Electron Transport; Microscopy, Electron, Transmission; Osmosis; Osmotic Pressure; Oxygen; Photosynthesis; Photosystem II Protein Complex; Ribulose-Bisphosphate Carboxylase; Sorbitol; Zygnematales

Endophyte infected and uninfected seedlings of rice (Oryza sativa L.) were subjected to five different levels of Na(2)CO(3) for 2 weeks. Under both Na(2)CO(3) stress as well as no stress, endophyte-infected plants were higher for above-ground dry weight and shoot length, but lower for root length compared to non-infected controls, and there was no significant difference for below-ground dry weight. Chlorophylls and carotenoid contents, net photosynetic rate, transpiration rate, catalase and peroxidase activities increased, but malondialdehyde content declined in the infected plants compared to non-infected controls under Na(2)CO(3) stress. Compared to non-infected controls, water use efficiency, stomatal conductance, chlorophyll fluorescence parameters (F(v)/F(m), F(v)/F(o)) and superoxide dismutase activity in infected plants increased under high concentrations of Na(2)CO(3) while there was no significant difference under low concentrations of Na(2)CO(3). Endophyte infection was concluded to be beneficial to the growth and antioxidative mechanisms in Oryza sativa under Na(2)CO(3) stress.

Topics: Carbonates; Catalase; Chlorophyll; Malondialdehyde; Oryza; Photosynthesis; Seedlings; Soil Pollutants

Experiments were conducted to study the effects of different sodium salts viz., sodium chloride (NaCl), sodium sulphate (Na(2)SO(4)) and sodium carbonate (Na(2)CO(3)) on growth, dry matter production, mineral contents, biochemical constituent and enzyme activities of sunflower (Helianthus annuus L.). The germinating sunflower seeds were treated with 10, 20 and 50mM NaCl and Na(2)SO(4) and 5, 10 and 15 mM Na(2)CO(3). The seedling growth, minerals, chlorophyll content and biochemicals like protein and free amino acid contents with enzyme activities like ATPase and protease were analysed on 8 DAS. The seedlings were separated into root, stem, leaf and cotyledon on 8 DAS. All the treatments decreased the germination percentage; shoot length, root length, leaf area and dry weight, chlorophyll and protein contents significantly. Potassium, sodium and free amino acid contents; activities of ATPase and protease were increased when compared to control. This effect was very high in the Na(2)CO(3) treated seedlings this was followed by Na(2)SO(4) and NaCl treated seedlings. From the results of this investigation, it is clear that, the sunflower seedlings were affected significantly in the Na(2)CO(3) treatments, and followed by Na(2)SO(4) and NaCl treatments.

Topics: Adenosine Triphosphatases; Carbonates; Carboxypeptidase B; Chlorophyll; Helianthus; Potassium; Sodium; Sodium Chloride; Sulfates

The comparative study of physiological reaction to salt, alkali and mixed salt stresses in two ecotypes of grey-green and yellow-green of Leymus chinensis were made. At the stage of seedling, the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers were determined in planting containers with sands in two ecotypes by stress of salt, alkali and mixed salt of different concentrations. The results of quantitative analysis showed that the relationships between the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers and concentration of salt, alkali and mixed salt could expressed as linear equation, which were significant or obviously significant. There were capabilities of salt-alkali resistance in the physiological characteristics of two populations, but the capabilities of salt-alkali resistance were stronger in grey-green ecotype than in yellow-green ecotype. The differentiation of the content of chlorophyll, the leakage rate of electrolyte of leaves, free proline and Na/K of tillers were significant or obviously significant in two ecotypes under three kinds of salt stress. Physiological characteristics of salt-alkali resistance were significantly different in two ecotypes. The study provided physiological evidence for making sure that the main ecological factor was salt-alkali. It resulted in adaptive differentiation in Leymus chinensis ecotypes.

Topics: Carbonates; Cell Membrane Permeability; Chlorophyll; Ecology; Hydrogen-Ion Concentration; Plant Leaves; Poaceae; Proline; Sodium Chloride

Two groups of Aneurolepidium chinense seedlings were stressed by 300 mmol.L-1 NaCl and 100 mmol.L-1 Na2CO3, respectively and the effect of ABA, Ca2+ and H3PO4 on relaxing their stress was studied. The results show that external Ca2+, ABA and H3PO4 could obviously mitigat the inhibitory effect of NaCl and NaCO3 on seedling growth. In the treatment of Na2CO3, praying it on leaves had a better effect than root-irrigating, while in the treatment of NaCl, there was no significant difference. The effect of Ca(NO3)2 was much better than that of CaCl2, and of mingling CaCl2 and ABA had a much better effect than CaCl2 or ABA alone.

Topics: Abscisic Acid; Calcium; Carbonates; Chlorophyll; Citric Acid; Drug Interactions; Phosphoric Acids; Poaceae; Potassium; Proline; Sodium