Effect of salinity on photosynthesis and mannitol synthesis in the green flagellate Platymonas suecica

1976 ◽  
Vol 54 (15) ◽  
pp. 1735-1741 ◽  
Author(s):  
Johan A. Hellebust
Keyword(s):  
High Salinity ◽  
Photosynthetic Capacity ◽  
Osmotic Shock ◽  
Linear Increase ◽  
Salinity Range ◽  
Content Increase ◽  
Lower Growth ◽  
Soluble Cell ◽  
Green Flagellate ◽  
Mannitol Concentration

Platymonas suecica, a brackish-water green flagellate belonging to the Prasinophyceae, grows almost at the same rate over a salinity range of 20–200% normal seawater, and at lower growth rates at salinities as high as 300% or as low as 10% seawater. Both cell size and carbon content increase significantly at salinities above 200% seawater, and there is a linear increase in intracellular mannitol concentration with increasing salinites from 50 to 300% seawater. This relationship between salinity and mannitol content indicates that mannitol is probably involved in osmoregulation in this alga. Photosynthesis is relatively little affected when cells adapted to low salinities are transferred to high salinities, while high-salinity-adapted cells suffer a temporary loss of much of their photosynthetic capacity when transferred to low salinities. It appears that this temporary loss of photosynthetic capacity in response to osmotic shock is due to a non-specific release of soluble cell constituents, including mannitol and amino acids, followed by regain of normal permeability properties and readjustment of cellular composition to the new osmotic environment.

scholarly journals Osmoadaptation Strategy of the Most Halophilic Fungus, Wallemia ichthyophaga, Growing Optimally at Salinities above 15% NaCl

2013 ◽  
Vol 80 (1) ◽  
pp. 247-256 ◽  
Author(s):  
Janja Zajc ◽  
Tina Kogej ◽  
Erwin A. Galinski ◽  
José Ramos ◽  
Nina Gunde-Cimerman
Keyword(s):  
Biomass Production ◽  
Osmotic Shock ◽  
Model Organism ◽  
Salinity Range ◽  
Growth Media ◽  
Optimal Salinity ◽  
Content Type ◽  
Batch Cultures ◽  
Specific Growth Rates ◽  
Optimum Salinity

ABSTRACTWallemia ichthyophagais a fungus from the ancient basidiomycetous genusWallemia(Wallemiales, Wallemiomycetes) that grows only at salinities between 10% (wt/vol) NaCl and saturated NaCl solution. This obligate halophily is unique among fungi. The main goal of this study was to determine the optimal salinity range for growth of the halophilicW. ichthyophagaand to unravel its osmoadaptation strategy. Our results showed that growth on solid growth media was extremely slow and resulted in small colonies. On the other hand, in the liquid batch cultures, the specific growth rates ofW. ichthyophagawere higher, and the biomass production increased with increasing salinities. The optimum salinity range for growth ofW. ichthyophagawas between 15 and 20% (wt/vol) NaCl. At 10% NaCl, the biomass production and the growth rate were by far the lowest among all tested salinities. Furthermore, the cell wall content in the dry biomass was extremely high at salinities above 10%. Our results also showed that glycerol was the major osmotically regulated solute, since its accumulation increased with salinity and was diminished by hypo-osmotic shock. Besides glycerol, smaller amounts of arabitol and trace amounts of mannitol were also detected. In addition,W. ichthyophagamaintained relatively small intracellular amounts of potassium and sodium at constant salinities, but during hyperosmotic shock, the amounts of both cations increased significantly. Given our results and the recent availability of the genome sequence,W. ichthyophagashould become well established as a novel model organism for studies of halophily in eukaryotes.

scholarly journals Analysis Methods for Characterizing Salinity Variability from Multivariate Time Series Applied to the Apalachicola Bay Estuary

2012 ◽  
Vol 29 (4) ◽  
pp. 613-628 ◽  
Author(s):  
Steven L. Morey ◽  
Dmitry S. Dukhovskoy
Keyword(s):  
Time Series ◽  
Time Scales ◽  
River Discharge ◽  
River Flow ◽  
High Salinity ◽  
Multivariate Time Series ◽  
Salinity Range ◽  
Apalachicola Bay ◽  
Analysis Methods ◽  
Salinity Variability

Abstract Statistical analysis methods are developed to quantify the impacts of multiple forcing variables on the hydrographic variability within an estuary instrumented with an enduring observational system. The methods are applied to characterize the salinity variability within Apalachicola Bay, a shallow multiple-inlet estuary along the northeastern Gulf of Mexico coast. The 13-yr multivariate time series collected by the National Estuary Research Reserve at three locations within the bay are analyzed to determine how the estuary responds to variations in external forcing mechanisms, such as freshwater discharge, precipitation, tides, and local winds at multiple time scales. The analysis methods are used to characterize the estuarine variability under differing flow regimes of the Apalachicola River, a managed waterway, with particular focus on extreme events and scales of variability that are critical to local ecosystems. Multivariate statistical models are applied that describe the salinity response to winds from multiple directions, river flow, and precipitation at daily, weekly, and monthly time scales to understand the response of the estuary under different climate regimes. Results show that the salinity is particularly sensitive to river discharge and wind magnitude and direction, with local precipitation being largely unimportant. Applying statistical analyses with conditional sampling quantifies how the likelihoods of high-salinity and long-duration high-salinity events, conditions of critical importance to estuarine organisms, change given the state of the river flow. Intraday salinity range is shown to be negatively correlated with the salinity, and correlated with river discharge rate.

Sorbitol and proline as intracellular osmotic solutes in the green alga Stichococcus bacillaris

1978 ◽  
Vol 56 (6) ◽  
pp. 676-679 ◽  
Author(s):  
Lewis M. Brown ◽  
Johan A. Hellebust
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
High Salinity ◽  
Single Amino Acid ◽  
Salinity Range ◽  
Wide Range ◽  
Osmotic Solutes ◽  
Steady State Levels ◽  
Total Amino Acids ◽  
Stichococcus Bacillaris

A freshwater isolate of Stichococcus bacillaris Naeg. (strain UTEX 314) was evaluated for its ability to grow, photosynthesize, and osmoregulate over a wide range of salinity. The growth and photosynthetic measurements indicate that it is a euryhaline organism. Studies of the soluble organic metabolite pools showed that the steady-state levels of two solutes varied with salinity; sorbitol (a polyol) and proline (an amino acid). Intracellular proline levels increased from 0.002 to 0.28 M over the salinity range of 0 to40%c whereas the sorbitol level increased from 0.10 to 0.52 M. The level of total amino acids (excepting proline) remained relatively constant. No single amino acid of this group exceeded an intracellular concentration of 0.04 M. The changes in the concentrations of these solutes accounted for at least 75% of the required increase in intracellular osmolality in cells following adaptation to high salinity media. Sorbitol and proline are very soluble, nontoxic, and are efficient osmotic solutes. These properties make them ideal solutes for osmoregulation.

scholarly journals Discrepancy in photosynthetic responses of the red alga Pyropia yezoensis to dehydration stresses under exposure to desiccation, high salinity, and high mannitol concentration

2021 ◽  
Author(s):  
Guoying Du ◽  
Xiaojiao Li ◽  
Junhao Wang ◽  
Shuai Che ◽  
Xuefeng Zhong ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
High Salinity ◽  
Pyropia Yezoensis ◽  
Photochemical Quenching ◽  
Northwestern Pacific ◽  
Heterogeneous Effects ◽  
Relative Electron ◽  
Photosynthetic Responses ◽  
Photosynthetic Activities ◽  
Mannitol Concentration

AbstractMacroalgae that inhabit intertidal zones are exposed to the air for several hours during low tide and must endure desiccation and high variations in temperature, light intensity, and salinity. Pyropia yezoensis (Rhodophyta, Bangiales), a typical intertidal red macroalga that is commercially cultivated in the northwestern Pacific Ocean, was investigated under different dehydration stresses of desiccation, high salinity, and high mannitol concentration. Using chlorophyll fluorescence imaging, photosynthetic activities of P. yezoensis thalli were analyzed using six parameters derived from quenching curves and rapid light curves. A distinct discrepancy was revealed in photosynthetic responses to different dehydration stresses. Dehydration caused by exposure to air resulted in rapid decreases in photosynthetic activities, which were always lower than two other stresses at the same water loss (WL) level. High salinity only reduced photosynthesis significantly at its maximum WL of 40% but maintained a relatively stable maximum quantum yield of photosystem II (PSII) (Fv/Fm). High mannitol concentration induced maximum WL of 20% for a longer time (60 min) than the other two treatments and caused no adverse influences on the six parameters at different WL except for a significant decrease in non-photochemical quenching (NPQ) at 20% WL. Illustrated by chlorophyll fluorescence images, severe spatial heterogeneities were induced by desiccation with lower values in the upper parts than the middle or basal parts of the thalli. The NPQ and rETRmax (maximum relative electron transport rate) demonstrated clear distinctions for evaluating photosynthetic responses, indicating their sensitivity and applicability. The findings of this study indicated that the natural dehydration of exposure to air results in stronger and more heterogeneous effects than those of high salinity or high mannitol concentration.

scholarly journals Studies on Physiological Response to Salt Stress of Eelgrass (Zostera marina L.)

2015 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Jia Yu
Keyword(s):  
Plasma Membrane ◽  
Zostera Marina ◽  
Physiological Response ◽  
Large Scale ◽  
High Salinity ◽  
Physiological Activity ◽  
External Environment ◽  
Proline Content ◽  
Salinity Range ◽  
High Permeability

<p>In lab conditions, study on physiological response of eelgrass in different salinities (0, 10, 20, 30, 40, 50, 60). Take permeability of plasma membrane, proline content and chlorophyll content as parameters. The results show, (1) High salinity leads to high permeability of plasma membrane making intracellular material spreads to external environment which cannot maintain the normal physiological activity, (2) with the increasing of salinity, proline is accumulated in eelgrass in a large scale, which has an toxic action on eelgrass, (3) with the increasing of salinity, the content of chlorophyll descends. Comprehensive the above results, (1) the suitable salinity range for eelgrass living is 10-30, (2) the most suitable salinity for eelgrass living is about 20, (3) when the salinity is greater than 40, eelgrass cannot grow normally, (4) when the salinity is greater than 60, the plasma membrane is seriously damaged and it has a high permeability, the cells of eelgrass cannot maintain the basic physiological activity.</p>

Effect of naphthalene and aqueous crude oil extracts on the green flagellate Chlamydomonas angulosa. II. Photosynthesis and the uptake and release of naphthalene

1975 ◽  
Vol 53 (2) ◽  
pp. 118-126 ◽  
Author(s):  
C. Soto ◽  
J. A. Hellebust ◽  
T. C. Hutchinson
Keyword(s):  
Crude Oil ◽  
Photosynthetic Capacity ◽  
Open Systems ◽  
Complete Loss ◽  
Original Medium ◽  
Rate Of Recovery ◽  
Green Flagellate ◽  
Saturated Media ◽  
Closed Systems ◽  
Actual Loss

Comparisons have been made of the effects of crude oil extracts and naphthalene on the photosynthesis of the alga Chlamydomonas angulosa. The addition of the hydrocarbon naphthalene to C. angulosa cultures causes an immediate and almost complete loss of photosynthetic capacity. When cells that have been incubated in closed systems containing naphthalene-saturated media are transferred to open systems which allow loss by volatilization of naphthalene, the rate of recovery of photosynthesis is inversely proportional to the length of incubation in the closed system with naphthalene. Incubation of cells in open systems with media containing aqueous crude oil extracts has no significant effect on their photosynthetic capacity as compared with that of cells incubated in control media. However, the photosynthetic capacity is decreased when cells are incubated in closed systems with media containing aqueous crude oil extracts. This is followed by a gradual recovery with time of incubation after treatment in the closed systems.Experiments using labelled naphthalene indicate that C. angulosa cells accumulate naphthalene from the medium in closed systems for up to 7 days. When such cells are transferred to fresh media not containing naphthalene, there is an almost immediate loss of the aromatic hydrocarbon from the cells. However, when cells are retained in their original medium after opening the culture system to allow naphthalene to escape, the decrease in naphthalene content per cell appears dependent upon resumption of cell division and occurs in a stepwise manner, which suggests cell retention rather than an actual loss of naphthalene to the medium.

Pullout Tests Study on Performance of Interface between Geogrid and Soil

2012 ◽  
Vol 446-449 ◽  
pp. 1661-1665
Author(s):  
Jian Cheng Sun ◽  
Zi Jia ◽  
Cheng Zhi Xiao
Keyword(s):  
Water Content ◽  
Frictional Coefficient ◽  
Linear Increase ◽  
Reinforced Soil ◽  
Content Increase ◽  
Normal Stresses ◽  
Geosynthetic Reinforced Soil ◽  
Pullout Tests ◽  
Water Content Increase ◽  
Water Contents

The interface interaction between geogrid and soil is one of key issues on stability of geosynthetic-reinforced soil structures. Comparative analysis of properties of geogrid-clay interface under the different kinds of geogrid, different normal stresses, speeds of pullout and water contents of clay are conducted by medium-sized pullout tests. The tests results showed that ultimate pullout force of geogrid, interfacial cohesion and frictional coefficient are significantly affected by various water contents of clay. Ultimate pullout forces of geogrid tending to remarkably difference when subject to different normal stresses at lower water contents, and frictional coefficient of interface decrease with the increase of water content, interfacial cohesion has a tendency to increase followed by decreasing with increase of water contents. Moreover, the curves of load and displacement possess three piecewise consisting of linear increase, non-linear increase and ultimate pullout, and as water content increase interval nonlinear changing stage is not conspicuous.

scholarly journals The Importance of Non-diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (Chenopodium quinoa Willd.) Subjected to Salinity Conditions

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 927
Author(s):  
José Delatorre-Herrera ◽  
Karina B. Ruiz ◽  
Manuel Pinto
Keyword(s):  
Salt Stress ◽  
High Salinity ◽  
Photosynthetic Capacity ◽  
Chenopodium Quinoa ◽  
Co2 Assimilation ◽  
Stress Conditions ◽  
Saline Stress ◽  
Salt Treatment ◽  
Broad Distribution ◽  
Bisphosphate Carboxylase

The broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotypes, Amarilla (salt-tolerant, salares ecotype) and Hueque (salt-sensitive, coastal ecotype). Our results show that saline stress induced a significant decrease in the K+/Na+ ratio in roots and an increase in glycine betaine in leaves, particularly in the sensitive genotype (Hueque). Measurement of the photosynthesis-related parameters showed that maximum CO2 assimilation (Amax) in control plants was comparable between genotypes (ca. 9–10 μmol CO2 m−2 s−1). However, salt treatment produced different responses, with Amax values decreasing by 65.1% in the sensitive ecotype and 37.7% in the tolerant one. Although both genotypes maintained mesophyll conductance when stomatal restrictions were removed, the biochemical components of Amarilla were impaired to a lesser extent under salt stress conditions: for example, the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; Vcmax) was not as affected in Amarilla, revealing that this enzyme has a higher affinity for its substrate in this genotype and, thus, a better carboxylation efficiency. The present results show that the higher salinity tolerance of Amarilla was also due to its ability to control non-diffusional components, indicating its superior photosynthetic capacity compared to Hueque, particularly under salt stress conditions.

scholarly journals Living in the intertidal: desiccation and shading reduce seagrass growth, but high salinity or population of origin have no additional effect

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5234 ◽  
Author(s):  
Wouter Suykerbuyk ◽  
Laura L. Govers ◽  
W.G. van Oven ◽  
Kris Giesen ◽  
Wim B.J.T. Giesen ◽  
...  
Keyword(s):  
High Salinity ◽  
Antagonistic Effect ◽  
Interactive Effects ◽  
Salinity Range ◽  
Emergence Time ◽  
Local Conditions ◽  
Salinity Regime ◽  
Upper Limit ◽  
Negative Effect ◽  
General Response

The limiting effects of stressors like desiccation, light and salinity on seagrass growth and distribution are well-studied. However, little is known about their interactive effects, and whether such effects might differ among populations that are adapted to different local conditions. In two laboratory experiments we tested (a) if growth and development of intertidal, temperate Zostera noltii is affected by emergence time (experiment 1 and 2), and (b) how this is affected by an additional, second stressor, namely shading (experiment 1) or high salinity (25, 30 and 35, experiment 2). In addition, we tested (c) whether the effects of emergence time and salinity varied between three different European seagrass populations (Saint-Jacut/France, Oosterschelde/The Netherlands, and Sylt/Germany), which are likely adapted to different salinity levels (experiment 2). In both experiments, emergence of 8 h per tidal cycle (of 12 h) had a negative effect on seagrass relative growth rate (RGR), and aboveground biomass. Emergence furthermore reduced either rhizome length (experiment 1) or belowground biomass (experiment 2). Shading (experiment 1) resulted in lower RGR and a two-fold higher aboveground/belowground ratio. We found no interactive effects of emergence and shading stress. Salinity (experiment 2) did not affect seagrass growth or morphology of any of the three populations. The three tested populations differed greatly in morphology but showed no differential response to emergence or salinity level (experiment 2). Our results indicate that emergence time and shading show an additive negative effect (no synergistic or antagonistic effect), making the plants still vulnerable to such combination, a combination that may occur as a consequence of self-shading during emergence or resulting from algal cover. Emergence time likely determines the upper limit of Z. noltii and such shading will likely lower the upper limit. Shading resulted in higher aboveground/belowground ratios as is a general response in seagrass. Z. noltii of different populations originating from salinity 30 and 35 seem tolerant to variations in salinity within the tested range. Our results indicate that the three tested populations show morphotypic rather than ecotypic variation, at least regarding the salinity and emergence, as there were no interactive effects with origin. For restoration, this implies that the salinity regime of the donor and receptor site of Z. noltii is of no concern within the salinity range 25–35.

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