Vegetative survival,akinete and zoosporangium formation and germination in some selected algae as affected by nutrients,pH, metals,and pesticides

Lack of nitrogen, phosphorus, or all nutrients, extremes of pH (<4, >11), presence of ‘heavy’ metals (Co, Cu, Zn, Hg, Pb; 0.5–10 ppm) or pesticides (carbofuran, 2,4-D, dithane, phorate, or bavistin; 1–50 ppm) decreased to various extent or completely inhibited the survival of vegetative cells in all studied algae. The formation of akinetes, thier viability and germination inAnabaena iyengarii, Westiellopsis prolifica, Nostochopsis lobatus andPithophora oedogonia and the formation of zoosporangia, their viability, and the germination of zoospores inCladophora glomerata andRhizoclonium hieroglyphicum was affected. The formation of viable akinetes or zoosporangia was shown to be directly linked with vegetative cell survival and growth; it could not be induced by any chemical stress imposed.     

Viability of dried vegetative trichomes, formation of akinetes and heterocysts and akinete germination in some blue-green algae under water stress

Almost all dried vegetative trichomes ofAnabaena iyengarii, Westiellopsis prolifica andNostochopsis lobatus died within 1 h, while those ofOscillatoria acuminata retained viability to some extent for 1 d under similar storage conditions. The viability of dried vegetative trichomes ofO. acuminata decreased about equally on storage at 20 degrees C in the light or in the dark, but dropped rapidly at 12 and 0 degrees C in the dark. Vegetative trichomes ofA. iyengarii, N. lobatus andW. prolifica were more sensitive to frost than those ofO. acuminata, and this correlated with their low resistance to desiccation because both types of exposure involved osmotic stress. Both dried and wet akinetes ofA. iyengarii, W. prolifica andN. lobatus were about equally viable when stored at 20 degrees C in the light or the dark or at 12 and 0 degrees C in the dark, but their germination ability decreased on storage at 0 degrees C. The water stress imposed on growing vegetative trichomes either in high-agar media or in NaCl-supplemented liquid media reduced the survival ofO. acuminata trichomes, decreased or totally suppressed akinete and heterocyst formation and akinete germination inA. iyengarii, W. prolifica andN. lobatus. The sensitivity decreased in the sequenceA. iyengarii 相似文献   

Effects of UV-light andγ-rays on the survival,akinete formation and akinete germination inStigeoclonium pascheri

The damage produced by UV light to any of the three different stages of the life cycle of the parent generation of the green algaS. pascheri, i.e. akinetes, germinating akinetes and vegetative cells remained up to the stage of germination of akinetes of the first generation and no deleterious effect was reported thereafter. Lower doses of γ-rays (25–75 Gy) increased the percentage germination of akinetes and germinating akinetes of parent generation. The percentage germination of akinetes, germinating akinetes, survival of colonies originated from vegetative cells and sporulation of cells of the parent generation decreased with increasing doses from 100 to 300 Gy. The γ-induced effect to any of the three different stages was not transferred to the subsequent stage of algal generation.     

Catalase activity in thermal blue-green algae in relation to temperature

Biologia Plantarum - The author has studied the relation of the catalase activity in thermal blue-green algae to temperature. Experimental data were taken from the first phase of the reaction, so...     

Viability of dried vegetative cells or filaments,survivability and/or reproduction under water and light stress,and following heat and UV exposure in some blue-green and green algae

Vegetative cells in dried, mucilagenous mass of Gloeocapsa aeruginosa and Aphanothece nidulans, reticulum of Hydrodictyon reticulatum, mucilagenous mass of Chroococcus minor, and filaments of Oedogonium sp. and Scytonema hofmanni died within 1/2, 1/2, 1/2, 1, 3 and 6 h, respectively, while dried vegetative filaments of Phormidium foveolarum retained under similar storage conditions viability for 4 d. P. foveolarum tolerated 1 mol/L NaCl. The resistance to desiccation in P. foveolarum exhibited similar dependence as that to heat or UV light. The water stress imposed on growing algae either on high-agar solid media or in NaCl-containing liquid media reduced at various levels or altogether inhibited the survival of vegetative parts in all, the cell division in C. minor, G. aeruginosa and A. nidulans, formation of heterocyst and false branch in S. hofmanni, oogonium in Oedogonium sp., and daughter net in H. reticulatum. Heat or UV shock of any level also produced similar effects as that by water stress. P. foveolarum tolerated low light level of 10 and 2 mumol m-2 s-1 and no light longer than the rest of other algae studied. Tolerance of microalgal forms to water, heat or UV stress depends primarily upon cell-wall characteristics or cell-sap osmotic properties rather than their habitats, morphology and prokaryotic or eukaryotic nature.     

The influence of daylength,light intensity and temperature on the growth rates of planktonic blue-green algae

The in vitro growth rates under continuous light of the four dominant blue-green algae in Lough Neagh, Anabaena flos-aquae Bréb., Aphanizomenon flos-aquae Ralfs fa. gracile Lemm., Oscillatoria agardhii Gom. and Oscillatoria redekei van Goor were slower than in situ rates from Lough Neagh that had been corrected for hours of light received by the algae. However, by culturing on a 6: 18 light-dark cycle in vitro growth rates were obtained that were similar to the in situ rates. Under continuous light small species showed the fastest growth with Oscillatoria redekei the dominant species. However, this pattern was almost completely reversed under the light-dark cycle with Oscillatoria redekei only exhibiting the fastest growth rate under low light conditions. This observation showed agreement with Lough Neagh field data which showed that Oscillatoria redekei reached its maximum crop in April while the other three species were dominant during the summer months. Compared to the generally assumed high thermal tendency of blue-green algae the temperature maxima of the four species were low. No growth was observed at 35°C for any species while Anabaena flos-aquae was severely inhibited at 25°C.     

Growth rate of four freshwater algae in relation to light and temperature

Four algae of freshwater phytoplankton were studied in monospecific culture: Chlorella vulgaris, Fragilaria crotonensis, Staurastrum pingue and Synechocystis minima. Experiments were performed to determine the growth rate over a wide range of light intensities (5–800 µE m^–2 s^–1, 15/9 light/dark photoperiod) and temperatures (10–35 °C). The results provide a set of parameters (particularly the maximal growth rate associated to optimal conditions of light and temperature) for a three-equation model used to described the growth rate response of a non-nutrient-limited culture.     

The influence of light quality on akinete formation and germination in the toxic cyanobacterium Anabaena circinalis

Physiological control of akinete formation and subsequent germination is likely to be important in understanding and predicting how natural populations of cyanobacteria respond to their environment. While previous research has indicated nutrient limitation may be important in akinete formation new results presented here indicate that in the toxic and bloom-forming species Anabaena circinalis there was a profound effect of spectral quality. Under 40 μmol photons m^?2 s^?1 photosynthetically active irradiance (PAR) of predominately red irradiance akinete production was maximal at 2.1 × 10^?4 akinetes vegetative cell^?1 d^?1, some 3000 times greater than the 6.5 × 10^?8 akinetes vegetative cell^?1 d^?1 observed under equivalent PAR but predominately blue light. For cells grown under a range of predominantly red, white and green irradiance even short exposures to blue light reduced akinete formation rates by a factor of ten relative to controls, indicating that exposure to blue light inhibits akinete formation. Germination of akinetes was not influenced by the irradiance under which akinetes were formed: 88 ± 4.1% (mean ± 1 S.D.) of akinetes germinated with no evidence of an effect on germination success due to their production under predominately red, white or green irradiance (germination of akinetes produced under blue light was not tested). Spectral quality had a significant impact on both vegetative cell and germling growth rates. The results indicate a significant reduction in the cellular differentiation of A. circinalis vegetative cells into akinetes that is mediated by blue light. In an ecological context the production of akinetes will be greater in environments with less blue light; potentially including those with slower flow, more stratification, less vertical mixing and more turbidity. The resulting spatial pattern of akinete production is likely to influence the location of akinetes in sediments and the development of subsequent blooms from excysting germlings.     

Vegetative characteristics of three low-lying Florida coastal rivers in relation to flow, light, salinity and nutrients

The Chassahowitzka, Homosassa and Crystal rivers along the central Gulf coast of Florida were studied from 1998 to 2000 to identify factors controlling the abundance and distribution of submersed aquatic vegetation (SAV). Each of these three low-lying coastal rivers are spring-fed and exhibit low to moderate absolute flow rates (flows in either direction because of tidal influences, 0.06–0.46ms^–1) with only 14 of the stations sampled for SAV having flow rates in excess of 0.25ms^–1. At those stations where flow rates exceeded 0.25ms–1, the substrate was generally comprised of exposed limestone outcroppings and did not provide a favorable habitat for either submersed macrophytes or macroalgae. The remaining sampling stations, where flow rates were less than 0.25ms–1, had suitable substrates (e.g. mud, mud/sand, and sand) for the colonization and subsequent growth of SAV. Light availability and salinity were determined to be major factors affecting the distribution and abundance of SAV. Sampling stations, where the percent of incident light at the surface reaching the substrate was less than 10, had little or no SAV biomass. Low SAV biomass was also linked to sites where annual average salinities exceeded 3.5. Nutrient loads and nutrient concentrations accounted for little variance in SAV biomass after accounting for flow and related substrate type, light and salinity. These latter factors control the distribution and abundance of SAV in these three Florida coastal rivers.     

Effects of light intensity and nutrients (N and P) on growth,toxin concentration,heterocyte formation and akinete germination of Nodularia spumigena (Cyanobacteria)

Hydrobiologia - Harmful effects of the toxic cyanobacterium Nodularia spumigena were observed in experimental marine shrimp production ponds in Brazil. Strains of this cyanobacterial species were...     

Ferredoxin from Aphanothece halophitica, a unicellular blue-green alga: close relationship to ferredoxins from filamentous blue-green algae and phylogenetic implications

The amino acid sequence of a ferredoxin from a unicellular blue-green alga, Aphanothece halophitica, was established by the conventional methods. Total number of residues was 98 lacking only tryptophan. A most probable phylogenetic tree was constructed for 19 algal ferredoxins on the basis of an amino acid difference matrix made from the sequence comparison. A. halophitica has been classified as a unicellular blue-green alga in the same genus to which Aphanothece sacrum belongs, but the tree indicates A. halophitica ferredoxin to be very close to those of the members of filamentous blue-green algae. The tree divides prokaryotic and eukaryotic algal ferredoxins into several groups, suggesting that the ferredoxin phylogenetic tree reflects the evolutionary trails of various algae, which is also reflected in the structural characteristics, particularly in the presence of gaps. Other notable features are presented in considering algal taxonomy.     

The ultrastructure of Spirulina platensis in relation to temperature and light intensity

The ultrastructure of Spirulina platensis, a cyanobacterium with a helical morphology, has been studied in relation to temperature and light intensity. An increase in temperature gives rise to a more tightly coiled trichome, an increase in sheath material formation and a decrease in cyanophycin (above 17°C) and polyglucan (above 20°C) granule concentration. An increase in light intensity leads to an increase in gas vesicle concentration while the phycobilisome content decreases. Furthermore, cylindrical bodies have been observed with a somewhat different ultrastructure from those found in other species of cyanobacteria. The occurrence, size and ultrastructure of polyhedral bodies, photosynthetic lamellae, mesosomes, lipid deposits and an unknown kidney-shaped inclusion in relation to temperature and light intensity are described.     

Flash kinetics and light intensity dependence of oxygen evolution in the blue-green alga Anacystis nidulans

Patterns of oxygen evolution in flashing light for the blue-green alga Anacystis nidulans are compared with those for broken spinach chloroplasts and whole cells of the green alga Chlorella pyrenoidosa. The oscillations of oxygen yield with flash number that occur in both Anacystis and Chlorella, display a greater degree of damping than do those of isolated spinach chloroplasts. The increase in damping results from a two- to threefold increase in the fraction (α) of reaction centers “missed” by a flash. The increase in α cannot be explained by non-saturating flash intensities or by the dark reduction of the oxidized intermediates formed by the flash. Anaerobic conditions markedly increase α in Anacystis and Chlorella but have no effect on α in broken spinach chloroplasts. The results signify that the mechanism of charge separation and water oxidation involved in all three organisms is the same, but that the pool of secondary electron acceptors between Photosystem II and Photosystem I is more reduced in the dark, in the algal cells, than in the isolated spinach chloroplasts.Oxygen evolution in flashing light for Anacystis and Chlorella show light saturation curves for the oxygen yield of the third flash (Y₃) that differ markedly from those of the steady-state flashes (Y_s). In experiments in which all flashes are uniformly attenuated, Y₃ requires nearly twice as much light as Y_s to reach half-saturation. Under these conditions Y₃ has a sigmoidal dependence on intensity, while that of Y_s is hyperbolic. These differences depend on the number of flashes attenuated. When any one of the first three flashes is attenuated, the variation of Y₃ with intensity resembles that of Y_s. When two of the first three flashes are attenuated, Y₃ is intermediate in shape between the two extremes. A quantitative interpretation of these results based on the model of Kok et al. (Kok, B., Forbush, B. and McGloin, M. (1970) Photochem. Photobiol. 11, 457–475, and Forbush, B., Kok, B. and McGloin, M. P. (1971) Photochem. Photobiol. 14, 307–321) fits the experimental data.     

Phenolic compounds and antioxidant properties in the snow alga Chlamydomonas nivalis after exposure to UV light

The snow alga Chlamydomonas nivalis was collected from the Sierra Nevada, California, USA, and examined for its ability to produce phenolic compounds, free proline, and provide antioxidant protection factor in response to UV-A and UV-C light. Exposure of C. nivalis cells to UV-A light (365nm) for 5 days resulted in a 5–12% increase in total phenolics, where as exposure to UV-C light (254 nm) resulted in a 12–24% increase in phenolics after 7 days of exposure. Free proline was not affected by UV-A, but increased markedly after UV-C exposure. A three-fold increase in free proline occurred within two days after exposure to UV-C, but then dropped as cells became bleached. Antioxidant protection factor (PF) increased after treatment of cells with UV-A and remained constant throughout UV-C exposure. Spectral analysis of algal extracts revealed a decrease in absorption in the 215–225 nm region, short-term (2day) stimulation of pigment at 280 nm, and an increase in carotenoids (473 nm), after exposure to UV-A. Snow alga exposed to UV-C light had a different spectrum from that of UV-A exposed cells, i.e. an enhancement of three major peaks at 220, 260, and 280 nm, and loss of absorption in the carotenoid region.We report that UV light exposure, especially in the UV-C range, can stimulate phenolic-antioxidant production in aplanospores of C. nivalis effecting biochemical pathways related to proline metabolism. This revised version was published online in August 2006 with corrections to the Cover Date.     

Feulgen stain stability in relation to three mounting media and exposure to light

Fading of Feulgen-stained rat liver nuclei was studied with sections mounted in Eukitt, Clearmount, and Permount, each under conditions of light and dark storage. Repeated microdensitometric measurements were made on selected nuclei over a 160 day post-staining period. In all three media the stain faded significantly when exposed to daily laboratory lighting, but faded least in Eukitt. Slides stored in darkness faded less than those exposed to light but, again, Eukitt-mounted preparations showed the least fading. Eukitt's low refractive index, however, imparts a high refractility to the cytoplasm which may be undesirable for scanning microdensitometry, and its apparently long stabilizing period may be disadvantageous if care is not taken to measure slides at comparable times during the period following mounting.     

Effect of pH, light intensity and population on the toxicity of the pesticide carbofuran to the blue-green alga Nostoc muscorum.

The effect of pH, light intensity and population on the toxicity of the pesticide furadan (containing 3% carbofuran as the active ingredient) was studied on the nitrogen fixing blue-green alga Nostoc muscorum. It was observed that all these factors had effects on the toxicity of the pesticide. The blue-green alga grew better in the pH range of 7.5-10, whereas the acidic pH of 5-6 retarded growth. The pesticide was more toxic to alga in the medium of pH 5-6, whereas reduction in toxicity was noticed in alkaline pH of 7.5-10. The alga grew slowly in a light intensity of 1,500 lux in comparison to a light intensity of 3,000 lux, and no growth occurred in the dark. The toxicity of the pesticide gradually decreased with increasing light intensity. The toxic effect of the pesticide was increased when the initial population level was low, and increasing the initial population reduced the toxicity.     

Formation of biomass,total protein,chlorophylls, lipids and fatty acids in green and blue-green algae during one growth phase.

Batch cultures (8–32 l.) of Chlorella vulgaris and Scenedesmus obliquus and of Anacystis nidulans and Microcystis aeruginosa were grown in media containing 0.001 % KNO₃ and at several stages in growth sampled for biomass, total protein, chlorophylls, lipids and fatty acids. With increasing time and decreasing nitrogen concentrations, the biomass of all of the algae increased, whereas the total protein and chlorophyll content dropped. Green and blue-green algae, however, behaved differently in their lipid metabolism. In the green algae the total lipid and fatty acid content as well as the composition of these compounds changed considerably during one growth phase and was dependent on the nitrogen concentration in the media at any given day of growth. More specifically, during the initial stages of growth the green algae produced larger amounts of polar lipids and polyunsaturated C₁₆ and C₁₈ fatty acids. Towards the end of growth, however, these patterns changed in that the main lipids of the green algae were neutral with mainly saturated fatty acids (mostly 18:1 and 16:0). Such changes did not occur in the blue-green algae. These differences between prokaryotic and eukaryotic algae can possibly be explained by the ‘endosymbiont theory’.     

Growth responses and root porosity of rice in relation to temperature,light intensity and aeration

Summary Experiments were conducted under which rice plants were grown under three energy input levels (temperature and light) and two solution-oxygen concentrations. The rice variety was Colusa. Increasing the energy input increased total top growth. There was no significant effect of solution-oxygen concentration on top growth. The highest number of tillers developed under medium energy input followed by high energy input and the least under low energy input. There was a trend towards more tiller production under low oxygen conditions as compared to high oxygen. Decreasing the oxygen supply increased the dry weight production of roots under the two higher energy input levels, but had no significant effect under the low energy input. The highest amount of root growth occurred under high and medium energy input and least under lower energy input. Increasing the energy input increased the percent root porosity, but the oxygen level had no significant effect on root porosity. None of the treatments had a significant effect on nitrogen concentration in the tops. The amount of water necessary per unit dry matter production had a trend towards increase with increased energy input level and also significantly higher under low oxygen as compared to high oxygen conditions. Contribution of the Department of Soils and Plant Nutrition, University of California, Riverside. Supported in part by NSF Grant No. GB-5733X1.