Oxygen stress in Salvinia natans: Interactive effects of oxygen availability and nitrogen source

The ability of Salvinia natans (L.) All. to tolerate growth in oxic, hypoxic and anoxic nutrient solutions when supplied with either NH₄⁺ or NO₃^? were studied in the laboratory to test the hypothesis that inorganic N-source affects the response of the plants to O₂ deprivation. The relative growth rate (RGR) was significantly reduced in the anoxic treatment, but in the hypoxic treatment RGR was only slightly affected. The NH₄⁺ fed plants generally had a higher shoot to root ratio than the NO₃^? fed plants, and highest in the anoxic treatment. Plants had more roots and larger leaves when supplied with NH₄⁺ as compared with NO₃^?, particularly in the oxic treatment, and root length was most affected by O₂ deprivation for NO₃^? fed plants. Cell walls in the endodermis, the bundle sheath and the cortex adjacent to endodermis developed thickened sclerenchymatous walls when deprived of O₂, and more so in plants supplied with NO₃^?. Plants lost chlorophylls, had lower rates of photosynthetic electron transport (ETR_max) and lower quantum yields (Fv/Fm ratios) when grown in anoxic solutions, and the negative effects were mildest for NO₃^? fed plants suggesting that NO₃^? may be used as an alternative e^?-acceptor in non-cyclic electron transport in the chloroplasts. Overall S. natans grew best on NH₄⁺, but it also grew well on NO₃^?, and the O₂ stress symptoms differed somewhat between NH₄⁺ fed and NO₃^? fed plants. However, because N-form itself significantly influenced morphology and cell metabolism, it was impossible to conclusively identify the role of N-form for the O₂ stress reactions. S. natans is not well-adapted to grow in O₂ deficient waters and will not tolerate completely anoxic conditions as will prevail in waters receiving high loadings of organic pollutants such as livestock wastewater.     

Changes in the Growth of Salvinia natans Induced by Cycles of Light and Darkness of widely Different Duration

The growth of Salvinia natans has been examined when clonalmaterial, maintained at a constant temperature (30 ^°C) receivesthe same amount of light energy per day but where the light-darkcycle of equal intervals varies in eight steps from 1 min to12 h. The area per leaf, the rate of leaf production, the netassimilation rate, and the relative growth-rate increase withthe lengthening of the cycle, but the leaf-area ratio is reduced.The magnitude of the changes differs between the criteria whilethe order of the response may be disparate between consecutiveintervals. In supporting experiments the same measurements weremade on plants subjected to a wide range of light intensitieswith a common photoperiod of 12 h. Here decreasing light intensityproduces similar trends to those recorded for increasing thelength of the cycle but the patterns of response may diverge.It was also established that the size of the stomatal pore isthe same in the light and in the dark. It is postulated thatvanations in the light-dark cycle may influence both the levelof photosynthetic activity and the pathways.     

Ecology of a simple plant-herbivore system. Biological control of Salvinia

The salvinia-herbivore system has been investigated in more detail than most, because of its relative simplicity due to the absence o f sexual and dormant stages in the plant's life cycle, the apparent genetic uniformity of the plant, the absence of water stress, the uniformity of the water surface habitat and the absence of herbivores outside the plant's native range. This review describes how biological control of salvinia was achieved and discusses ecological principles illustrated by salvinia and its herbivores.     

Hydrobiology and organic production in a marl lake of Kashmir Himalayan Valley

L. Naranbagh (alt. 1587 m) is a polymictic, shallow marl lake in the flood-plain valley of Kashmir, India. Macrofloral affinities resemble Potamogeton Type of Forsberg (1965) with alkaline waters, not rich in phosphorus. CaCO₃ precipitation coupled with decline in Ca²⁺ and alkalinity values are characteristic of the lake. Fluctuations in Mg²⁺, Na⁺, K⁺, and Cl^– were relatively conservative. The levels of PO _inf4 ^sup3– -P and NO _inf3 ^sup– -N indicate moderate fertility of the lake water.Persistence of a summer-autumn planktonic algal pulse is related to favourable irradiance, high water temperatures, and increased photosynthetic efficiency values. The most striking seasonality in photosynthetic rates (m^–2 h^–1) between winter minimum (3 mg C_assim) and summer maximum (75.4 mg C_assim) is determined by mainly climatic changes. Energy flow gave annual phytoplankton production of 51.95 × 10² KJ m^–2 for the ecosystem.The nutrient levels and productivity rates suggest mesotrophic status of L. Naranbagh in classic oligoeutrophic classification of lake types.     

Cytology of oil–body cells in Ricciocarpus natans

Oil–body cells in the liverwort Ricciocarpus natans are present as idioblasts and contain a single oil–body each. The limiting membrane of the oil–body has a tripartite dark–light–dark configuration. The layer facing the oil–body is thickest. Lipophilic globules are embedded in a matrix, which reacted positively for proteins, polysaccharides and lipids. The globules, which initially are minute, can coalesce to larger units, ultimately forming a single one. A peripheral layer was recognized by its different stainability. This layer was sometimes separated from the rest of the globule. Some seasonal variability was observed in the nature of the matrix and the amount of lipophilic material.
The origin of the oil–body from the central vacuole was traced from the meristematic zone. The resemblance between the oil–body membrane and the tonoplast is in accordance with this origin. Smooth endoplasmic reticulum is extensively developed and seems to contribute material to the developing oil–body.     

Structure and development of the air–pores in Ricciocarpus natans

The organization and development of air–pores in Ricciocarpus natans is presented here in detail for the first time. The study was done by light microscopy and electron microscopy.
The mature air–pore consists of three kinds of cells: 1) aperture cells, 2) intermediate cells, and 3) supporting cells. These cells limit a subporal cavity. The aperture cells and intermediate cells are small and flattened with degenerated cell contents. Towards the subporal cavity the cell walls are thickened. The supporting cells are similar to the usual epidermal cells.
The air–pores originate by the separation of epidermal cells adjacent to the growing point. The cells surrounding the opening divide unequally. They give rise to the supporting cells and mother cells that divide to yield the aperture cells and the intermediate cells. Part of the walls of these two kinds of cells become thickened, and their cell content disintegrates subsequently. These two circumstances cause their collapsed cell shape.     

Intensives Wachstum von Ricciocarpus natans (Lebermoos) in Durchlüftungskultur

Das Lebermoos Ricciocarpus natans wurde nichtaxenisch in Durchlüftungskulturen (etwa 2% CO₂ in Luft) im Lichtthermostaten angezogen und seine morphologischen Merkmale beschrieben. Als optimal für eine hohe Produktivität erwiesen sich bei der verwendeten Nährlösung 29 C, ein Licht-Dunkel-Wechsel von 14:10 Stunden und eine Beleuchtungsstärke von maximal 10000 Lux. Unter diesen Bedingungen ist das Wachstum bei relativ kleinen Schwankungen sehr gleichmäß. Die Verdopplungszeit für Masse und Individuen beträgt 48 Stunden. In eine 300 ml-Kulturröhre wurde 1 g Frischgewicht in 200 ml Nährlösung eingeimpft (Trockengewichtsanteil etwa 4 %). NH₄ (bei Konstanthalten des pH-Wertes) und NO₃ sind als Stickstoffquelle gleich gut geeignet. Bei Mangel an Stickstoff nimmt die Thallusgröße stark ab, die Ventralschuppen werden auffällig lang und violett gefärbt. Das Lebermoos eignet sich gut für eine standardisierte, effektive Laborkultur zum Zwecke physiologischer und biochemischer Untersuchungen.     

Ecology and production of invertebrates in a Canadian coldwater spring-springbrook system

Valley Spring is a hardwater rheocrene consisting of a single point issue and a springbrook some 60 m long. The fauna consists of > 60 taxa, with insects and mites predominating. During 1985–86, benthic densities varied both along the springbrook and at single stations over time (range 58 to 756 animals 900 cm⁻²). A clear longitudinal zonation of many of the major taxa occurred with the Diptera tending to be more abundant downstream, the Plecoptera and Acari more abundant upstream, and the Copepoda and Bivalvia most abundant in mid- and downstream sections. The Gastropoda and Trichoptera occurred throughout the system although, in the case of the latter, there were distributional differences at the species level (e.g. Diplectrona modesta downstream, Parapsyche apicalis and Lepidostoma vernale upstream). Life histories varied between major species and were grouped into: (A) those species in which there was a wide range of larval sizes for most of the year, with no easily discernible temporal succession of cohorts, e.g. L. vernale, P. apicalis, Sialis sp., Dixa sp., Metriocnemus sp., Trissopelopia sp., Micropsectra sp. and Mucronothrus nasalis (the generation time of species in this group ranged from < 1 year to > 2 years); and (B) those species in which there was a clear pattern of larval growth, with obvious temporal succession of cohorts, e.g. D. modesta, Nemoura trispinosa and Hyalella azteca (all of these species were univoltine). Differences between the “adaptive strategies” of these two life history types are discussed. Total secondary production in Valley Spring in 1985–86 was estimated to be 913.2 g wet wt yr⁻¹. Production upstream was more than twice that downstream (11.21 and 4.01 g wet wt m⁻² yr⁻¹, respectively). The three most abundant species of caddisfly together contributed > 30% of the total production, the stonefly N. trispinosa contributed > 17%, while the chironomids accounted for >16% of production at downstream stations but only 3% upstream.     

Salvinia auriculata in post-treatment of dairy industry wastewater

Abstract

The present study aimed to evaluate the aquatic macrophyte Savinia auriculata in post-treatment of wastewater from a dairy industry. The experiment was carried out in a greenhouse between February and March 2015. A batch system was used, each reactor was composed of polyethylene and had capacity of 250 liters of post-treated effluent. Every seven days, pH, turbidity, temperature, dissolved oxygen, chemical oxygen demand and series of solids (total, fixed and volatile) were determined in the wastewater. Besides that, the concentration of macro and micronutrients (P, N, K, Ca, Mg, Cu, Zn, Mn, and Fe) were determined in the wastewater and in plant tissue before and after the experiment. The results showed efficiency in the decrease of N, P, turbidity, pH, solids (ST, SF) and inefficiency in the reduction of volatile solids in the wastewater. The concentration of COD, Ca, Mn, Mg, and Fe increased at the end of the experiment. Due to the absorption of some nutrients such as N and P it is possible to conclude that Salvinia auriculata is a good option for the post-treatment of the wastewater from dairy industry. However, plant senescence promotes the elevation of some elements in the effluent because in this process, nutrients that were previously retained in the plant tissue are inserted into the wastewater again. Because of this it is necessary to remove plants of the reactor in the beginning of the process of senescence.     

Ecology, metabolite production, and substrate utilization in endophytic fungi.

Endophytic fungi are a taxonomically and ecologically heterogenous group of organisms, mainly belonging to the Ascomycotina and Deuteromycotina. The isolation methods affect the species composition of the endophyte assemblage in a given host. The number of endophyte taxa isolated from a host species is usually large; however, only few, normally host specific species or strains are dominant. Endophyte assemblages are specific at the host species level, but species composition and frequencies are significantly affected by site-specific conditions. Moreover, the relative importance and number of endophytic species vary among individuals within sites. In some cases, each individual could be considered a separate ecosystem. In general, however, 40 individuals with 30 to 40 sampling units per organ and individual should be enough to detect 80% of taxa present in a given host at one site. Endophytes usually produce the enzymes necessary for the colonization of plant tissues. Substrate utilization studies and isozyme analysis have demonstrated that most endophytes are able to utilize most plant cell components. The production of growth promoting factors and of metabolites useful in the pharmaceutical and agricultural industry is widespread among endophytic fungi. The usefulness of endophytes in agricultural and pharmaceutical research is briefly discussed.     

Phenolic and other constituents of fresh water fern Salvinia molesta

Two glycosides, 6'-O-(3,4-dihydroxy benzoyl)-beta-D-glucopyranosyl ester (1), and 4-O-beta-d-glucopyranoside-3-hydroxy methyl benzoate (2), along with five known compounds methyl benzoate (3), hypogallic acid (4), caffeic acid (5), paeoniflorin (6) and pikuroside (7) were isolated for the first time from a fresh water fern Salvinia molesta D.S. Mitch. These compounds showed a potent antioxidant radical scavenging activity in a non-physiological assay. Their structures were determined by NMR spectroscopic and CID mass spectrometry techniques.     

Epiphytic cyanobacterial strains in the roots of Salvinia auriculata and the effect of light and nutrients on the production of heterocyst,akinete and hormogonia

Aquatic Ecology - In epiphytic associations, cyanobacteria form the periphyton with phytoplanktonic algae and with aquatic macrophytes. In this study, we found homocytous and heterocytous...     

Maleic hydrazide induced changes in the physiology of Salvinia molesta mitch

Maleic hydrazide (MH) induced physiological changes in fronds of Salvinia molesta Mitch. in different durations of treatment up to 96 h. At 1000 and 5000 ppm, absorption of water, soluble proteins, reducing sugars and amylase activity were reduced; chlorophyll content and both protease and invertase activities were increased.     

Ecology, serology, and enterotoxin production of Vibrio cholerae in Chesapeake Bay.

A total of 65 isolates of Vibrio cholerae, serotypes other than O--1, have been recovered from water, sediment, and shellfish samples from the Chesapeake Bay. Isolations were not random, but followed a distinct pattern in which salinity appeared to be a controlling factor in V. cholerae distribution. Water salinity at stations yielding V. cholerae (13 out of 21 stations) was 4 to 17 0/00, whereas the salinity of water at stations from which V. cholerae organisms were not isolated was less than 4 or greater than 17 0/00. From results of statistical analyses, no correlation between incidence of fecal coliforms and V. cholerae could be detected, whereas incidence of Salmonella species, measured concurrently, was clearly correlated with fecal coliforms, with Salmonella isolated only in areas of high fecal coliform levels. A seasonal cycle could not be determined since strains of V. cholerae were detectable at low levels (ca. 1 to 10 cells/liter) throughout the year. Although none of the Chesapeake Bay isolates was agglutinable in V. cholerae O group 1 antiserum, the majority for Y-1 adrenal cells. Furthermore, rabbit ileal loop and mouse lethality tests were also positive for the Chesapeake Bay isolates, with average fluid accumulation in positive ileal loops ranging from 0.21 to 2.11 ml/cm. Serotypes of the strains of V. cholerae recovered from Chesapeake Bay were those of wide geographic distribution. It is concluded from the data assembled to date, that V. cholerae is an autochthonous estuarine bacterial species resident in Chesapeake Bay.