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Results for “salinity stress”

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At least 19 recordsLinked to original sources

PubMed2003

Uptake of an endocytic marker by rice cells: variations related to osmotic and saline stress.

Saline and osmotic stress are the main abiotic factors limiting the productivity of rice and other crop plants. Although both coincide in generating water deficit and affect many aspects of plant growth and development similarly, some effects of salinity are distinctively related to the ionic component of salt stress. At the cellular level, dessication tolerance is largely dependent on the cell's ability for osmotic adjustment. Here, we have studied the effects of saline and osmotic stress on endocytosis by rice cells, to investigate the common and distinctive effects of saline-generated stress and osmotically generated stress, and the possible involvement of endocytosis in tolerance mechanisms. For this purpose, we have used rice cell lines with different levels of tolerance and biotinylated bovine serum albumin (bBSA) as an endocytic marker, which in our previous experiments has been shown to enter rice cells by a process with the characteristics of receptor-mediated endocytosis. Our results indicate that the pattern of uptake is common to both types of stress. Thus, when rice cells were subjected to saline or osmotic stress there was an initial dose-dependent inhibition of uptake. However, after more extended stress periods, there was an activation of uptake in the stressed cells. This late activation appears mainly related to the inhibition of growth commonly caused by the different stress agents used in this study. When using cell lines with different degrees of tolerance, the level of uptake activation varied as a function of the type of stress. Thus, under osmotic stress, a higher stress tolerance was directly related to a higher bBSA uptake, while the opposite occurred under saline stress. The possible role of endocytosis in the cellular responses to osmotic and saline stress is discussed.

Biological Transport↗

PubMed2005

Enhanced antioxidant enzymes are associated with reduced hydrogen peroxide in barley roots under saline stress.

Antioxidant enzymes are related to the resistance to various abiotic stresses including salinity. Barley is relatively tolerant to saline stress among crop plants, but little information is available on barley antioxidant enzymes under salinity stress. We investigated temporal and spatial responses of activities and isoform profiles of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), non-specific peroxidase (POX), and glutathione reductase (GR) to saline stress in barley seedlings treated with 200 mM NaCl for 0, 1, 2, 5 days, respectively. In the control plant, hydrogen peroxide content was about 2-fold higher in the root than in the shoot. Under saline stress, hydrogen peroxide content was decreased drastically by 70% at 2 d after NaCl treatment (DAT) in the root. In the leaf, however, the content was remained unchanged by 2 DAT and increased about 14 % at 5 DAT. In general, the activities of antioxidant enzymes were increased in the root and shoot under saline stress. But the increase was more significant and consistent in the root. The activities of SOD, CAT, APX, POX, and GR were increased significantly in the root within 1 DAT, and various elevated levels were maintained by 5 DAT. Among the antioxidant enzymes, CAT activity was increased the most drastically. The significant increase in the activities of SOD, CAT, APX, POX, and GR in the NaCl-stressed barley root was highly correlated with the increased expression of the constitutive isoforms as well as the induced ones. The hydrogen peroxide content in the root.

Antioxidants↗

PubMed1997

Expression of arginine decarboxylase in seedlings of indica rice (Oryza sativa L.) cultivars as affected by salinity stress.

The effect of salinity stress on the activity of arginine decarboxylase (ADC, EC 4.1.1.19), the first enzyme in biosynthesis of polyamines (PA) from arginine, as well as its transcript level has been compared in salt-sensitive (M-1-48) and salt-tolerant (Pokkali) rice cultivars. Treatment of 72 h grown seedlings either with increasing concentrations of NaCl or with 150 mM NaCl for different time periods, showed a gradual increase of activity in Pokkali. In M-1-48 an immediate increase followed by sharp decrease was observed on prolonged treatment beyond 6 h or above 150 mM NaCl. To generate a DNA probe for ADC, the polymerase chain reaction was used with oat genomic DNA and sequence-specific primers. A region of oat genomic DNA containing a coding sequence for 166 amino acids of the C-terminal part of the ADC enzyme was amplified and called OAD1. Southern analysis of EcoRI- or BamHI-cut genomic DNAs from different cultivars of rice with OAD1 as the probe revealed strong hybridization with one DNA fragment of rice and restriction fragment length polymorphism (RFLP) was noticed. Northern analysis of total RNA of rice with OAD1 as the probe revealed hybridization with a transcript of similar size to the ADC transcript in oat. While in Pokkali, at least a 20-fold accumulation of OAD1 homologous transcript was detected after treatment with 200 mM NaCl, only a seven-fold increase in transcript level was found in M-1-48 after 150 mM NaCl treatment. Results suggest that in the salt-tolerant rice cultivar Pokkali, ADC enzyme activity increases and its transcript also accumulates during the prolonged salinity stress, this mechanism is absent in the salt-sensitive rice cultivar M-1-48 where a prolonged period of salinity stress down-regulates both ADC activity and its transcript level.

Carboxy-Lyases↗

PubMed2000

The transcriptional response of yeast to saline stress.

Adaptation to changes in extracellular salinity is a critical event for cell survival. Genome-wide DNA chip analysis has been used to analyze the transcriptional response of yeast cells to saline stress. About 7% of the genes encoded in the yeast genome are induced more than 5-fold after a mild and brief saline shock (0.4 m NaCl, 10 min). Interestingly, most responsive genes showed a very transient expression pattern, as mRNA levels dramatically declined after 20 min in the presence of stress. A quite similar set of genes increased expression in cells subjected to higher saline concentrations (0.8 m NaCl), although in this case the response was delayed. Therefore, our data show that cells respond to saline stress by inducing the expression of a very large number of genes and suggest that stress adaptation requires regulation of many cellular aspects. The transcriptional induction of most genes that are strongly responsive to salt stress was highly or fully dependent on the presence of the stress-activated mitogen-activated protein kinase Hog1, indicating that the Hog1-mediated signaling pathway plays a key role in global gene regulation under saline stress conditions.

Gene Expression Regulation, Fungal↗

PubMed2002

Effects of salinity stress on photosystem II function in cyanobacterial Spirulina platensis cells.

The changes in PSII photochemistry in Spirulina platensis cells exposed to salinity stress (0-0.8 M NaCl) for 12 h were studied. Salinity stress induced a decrease in oxygen evolution activity, which correlated with the decrease in the quantum yield of PSII electron transport (PhiPSII). Phycocyanin content decreased significantly while chlorophyll content remained unchanged in salt-stressed cells. Salinity stress induced an increase in non-photochemical quenching (qN) and a decrease in photochemical quenching (qP). Analyses of the polyphasic fluorescence transients (OJIP) showed that with the increase in salt concentration, the fluorescence yield at the phases J, I and P declined sharply and the transient almost levelled off at salt concentration of 0.8 M NaCl. The effects of DCMU on the polyphasic rise of fluorescence transients decreased significantly. Salinity stress resulted in a decrease in the efficiency of electron transfer from QA- to QB. The slope at the origin of the relative variable fluorescence curves (dV/dto) and the relative variable fluorescence at phase J (VJ) increased in the absence of DCMU, but decreased in the presence of DCMU. The shape of the relative variable fluorescence transients in salt-stressed cells was comparable to that of the control cells incubated with DCMU. The results in this study suggest that salt stress inhibited the electron transport at both donor and acceptor sides of PSII, resulted in damage to phycobilisome and shifted the distribution of excitation energy in favour of PSI.

Journal Article↗

PubMed2002

Can the nitrogenous composition of xylem sap be used to assess salinity stress in Casuarina glauca?

It is predicted that dryland salinity will affect up to 17 Mha of the Australian landscape by 2050, and therefore, monitoring the health of tree plantings and remnant native vegetation in saline areas is increasingly important. Casuarina glauca Sieber ex Spreng. has considerable salinity tolerance and is commonly planted in areas with a shallow, saline water table. To evaluate the potential of using the nitrogenous composition of xylem sap to assess salinity stress in C. glauca, the responses of trees grown with various soil salinities in a greenhouse were compared with those of trees growing in field plots with different water table depths and groundwater salinities. In the greenhouse, increasing soil salinity led to increased allocation of nitrogen (N) to proline and arginine in both stem and root xylem sap, with coincident decreases in citrulline and asparagine. Although the field plots were ranked as increasingly saline-based on ground water salinity and depth-only the allocation of N to citrulline differed significantly between the field plots. Within each plot, temporal variation in the composition of the xylem sap was related to rainfall, rainfall infiltration and soil salinity. Periods of low rainfall and infiltration and higher soil salinity corresponded with increased allocation of N to proline and arginine in the xylem sap. The allocation of N to citrulline and asparagine increased following rainfall events where rain was calculated to have infiltrated sufficiently to decrease soil salinity. The relationship between nitrogenous composition of the xylem sap of C. glauca and soil salinity indicates that the analysis of xylem sap is an effective method for assessing changes in salinity stress in trees at a particular site over time. However, the composition of the xylem sap proved less useful as a comparative index of salinity stress in trees growing at different sites.

Arginine↗

PubMed2006

Genome-wide transcriptional analysis of salinity stressed japonica and indica rice genotypes during panicle initiation stage.

Rice yield is most sensitive to salinity stress imposed during the panicle initiation (PI) stage. In this study, we have focused on physiological and transcriptional responses of four rice genotypes exposed to salinity stress during PI. The genotypes selected included a pair of indicas (IR63731 and IR29) and a pair of japonica (Agami and M103) rice subspecies with contrasting salt tolerance. Physiological characterization showed that tolerant genotypes maintained a much lower shoot Na+ concentration relative to sensitive genotypes under salinity stress. Global gene expression analysis revealed a strikingly large number of genes which are induced by salinity stress in sensitive genotypes, IR29 and M103 relative to tolerant lines. We found 19 probe sets to be commonly induced in all four genotypes. We found several salinity modulated, ion homeostasis related genes from our analysis. We also studied the expression of SKC1, a cation transporter reported by others as a major source of variation in salt tolerance in rice. The transcript abundance of SKC1 did not change in response to salinity stress at PI stage in the shoot tissue of all four genotypes. However, we found the transcript abundance of SKC1 to be significantly higher in tolerant japonica Agami relative to sensitive japonica M103 under control and stressed conditions during PI stage.

DNA Primers↗

PubMed2006

Regulation of osmotic stress transcription factor 1 (Ostf1) in tilapia (Oreochromis mossambicus) gill epithelium during salinity stress.

Mechanisms of induction of osmotic stress transcription factor 1 (Ostf1) were analyzed in gill epithelium of tilapia exposed to salinity stress. Experiments with primary cultures of gill epithelial cells revealed that hyperosmotic Ostf1 induction was independent of systemic factors. In addition, the synthetic glucocorticoid receptor agonist dexamethasone did not affect Ostf1 levels, arguing against cortisol being the signal for Ostf1 induction during hyperosmotic stress. Exposure of primary gill cell cultures to a hyperosmotic agent that is cell permeable and non-hypertonic (glycerol) did not trigger Ostf1 induction. However, when gill cells were exposed to hypertonicity (either in the form of NaCl or other forms) Ostf1 was rapidly and significantly induced. Analysis of hnRNA and mRNA levels revealed that Ostf1 upregulation in gill cells of intact fish and primary cultures of gill epithelial cells was mediated by transient mRNA stabilization. In addition to the initial transient mRNA stabilization a subsequent transcriptional induction of Ostf1 was observed. In cultured gill cells increase in Ostf1 mRNA synthesis was stable and very potent, whereas in gill cells of intact fish this increase was transient. This observation suggests positive feedback by Ostf1 or one of its targets and negative feedback by systemic factors on Ostf1 transcription. We conclude that Ostf1 induction in gill epithelial cells of tilapia exposed to salinity stress (1) is independent of cortisol or other systemic factors; (2) depends on hypertonicity as the signal; and (3) is based on transient mRNA stabilization. Moreover, our data on primary cell cultures show that systemic signals are necessary to prevent sustained transcriptional induction of Ostf1 during hyperosmotic stress, indicating feedback regulation and a high degree of complexity of osmosensing and signaling networks in euryhaline fishes.

Animals↗

PubMed2005

Transgenic tobacco plants overexpressing glyoxalase enzymes resist an increase in methylglyoxal and maintain higher reduced glutathione levels under salinity stress.

The mechanism behind enhanced salt tolerance conferred by the overexpression of glyoxalase pathway enzymes was studied in transgenic vis-à-vis wild-type (WT) plants. We have recently documented that salinity stress induces higher level accumulation of methylglyoxal (MG), a potent cytotoxin and primary substrate for glyoxalase pathway, in various plant species [Yadav, S.K., Singla-Pareek, S.L., Ray, M., Reddy, M.K. and Sopory, S.K. (2005) MG levels in plants under salinity stress are dependent on glyoxalase I and glutathione. Biochem. Biophys. Res. Commun. 337, 61-67]. The transgenic tobacco plants overexpressing glyoxalase pathway enzymes, resist an increase in the level of MG that increased to over 70% in WT plants under salinity stress. These plants showed enhanced basal activity of various glutathione related antioxidative enzymes that increased further upon salinity stress. These plants suffered minimal salinity stress induced oxidative damage measured in terms of the lipid peroxidation. The reduced glutathione (GSH) content was high in these transgenic plants and also maintained a higher reduced to oxidized glutathione (GSH:GSSG) ratio under salinity. Manipulation of glutathione ratio by exogenous application of GSSG retarded the growth of non-transgenic plants whereas transgenic plants sustained their growth. These results suggest that resisting an increase in MG together with maintaining higher reduced glutathione levels can be efficiently achieved by the overexpression of glyoxalase pathway enzymes towards developing salinity stress tolerant plants.

Antioxidants↗

PubMed2001

Increase in the Culturable Cell Number of Escherichia coli during Recovery from Saline Stress: Possible Implication for Resuscitation from the VBNC State.

The change in colony-forming units (CFUs) in saline-stressed Escherichia coli cultures was examined. Exposure of E. coli cells to high saline stress decreased the number of CFUs significantly. When the culture was relieved from the stressful condition, the number of CFUs returned within 2 hr to the same level as before the stress. This recovery in the number of CFUs seemed to be independent of DNA synthesis and cell division, because the same phenomenon was also observed in the presence of nalidixic acid. However, the total cell number enumerated by microscopy was the same before and after relief from saline stress. This phenomenon was considered to be the result of the resuscitation of cells that had been in the VBNC state during saline stress. Our method, in which we examined CFU recovery in the presence of a DNA synthesis inhibitor, might be useful for further VBNC study.

Journal Article↗

PubMed2005

Mycorrhizal symbiosis and response of sorghum plants to combined drought and salinity stresses.

Arbuscular mycorrhizal (AM) symbiosis can confer increased host resistance to drought stress, although the effect is unpredictable. Since AM symbiosis also frequently increases host resistance to salinity stress, and since drought and salinity stress are often linked in drying soils, we speculated that the AM influence on plant drought response may be partially the result of AM influence on salinity stress. We tested the hypothesis that AM-induced effects on drought responses would be more pronounced when plants of comparable size are exposed to drought in salinized soils. In two greenhouse experiments, several water relations characteristics were measured in sorghum plants colonized by Glomus intraradices (Gi), Gigaspora margarita (Gm) or a mixture of AM species, during a sustained drought following exposure to salinity treatments (NaCl stress, osmotic stress via concentrated macronutrients, or soil leaching). The presence of excess salt in soils widened the difference in drought responses between AM and nonAM plants in just two instances. Days required for plants to reach stomatal closure were similar for Gi and nonAM plants exposed to drought alone, but with exposure to combined NaCl and drought stress, stomates of Gi plants remained open 17-22% longer than in nonAM plants. Promotion of stomatal conductance by Gm occurred with exposure to NaCl/drought stress but not with drought alone or with soil leaching before drought. In other instances, however, the addition of salt tended to nullify an AM-induced change in drought response. Our findings confirm that AM fungi can alter host response to drought but do not lend much support to the idea that AM-induced salt resistance might help explain why AM plants can be more resilient to drought stress than their nonAM counterparts.

Biomass↗

PubMedDate not supplied

Interaction of flooding and salinity stress on baldcypress (Taxodium distichum).

Coastal wetlands of the southeastern United States are threatened by increases in flooding and salinity as a result of both natural processes and man-induced hydrologic alterations. Furthermore, global climate change scenarios suggest that, as a consequence of rising sea levels, much larger areas of coastal wetlands may be affected by flooding and salinity in the next 50 to 100 years. In this paper, we review studies designed to improve our ability to predict and ameliorate the impacts of increased flooding and salinity stress on baldcypress (Taxodium distichum (L.) Rich.), which is a dominant species of many coastal forested wetlands. Specifically, we review studies on species-level responses to flooding and salinity stress, alone and in combination, we summarize two studies on intraspecific variation in response to flooding and salinity stress, we analyze the physiological mechanisms thought to be responsible for the interaction between flooding and salinity stress, and we discuss the implications for coastal wetland loss and the prospects for developing salt-tolerant lines of baldcypress.

Journal Article↗

PubMed2006

Expression analysis of barley (Hordeum vulgare L.) during salinity stress.

Barley (Hordeum vulgare L.) is a salt-tolerant crop species with considerable economic importance in salinity-affected arid and semiarid regions of the world. In this work, barley cultivar Morex was used for transcriptional profiling during salinity stress using a microarray containing approximately 22,750 probe sets. The experiment was designed to target the early responses of genes to a salinity stress at seedling stage. We found a comparable number of probe sets up-regulated and down-regulated in response to salinity. The differentially expressed genes were broadly characterized using gene ontology and through expression-based hierarchical clustering to identify interesting features in the data. A prominent feature of the response to salinity was the induction of genes involved in jasmonic acid biosynthesis and genes known to respond to jasmonic acid treatment. A large number of abiotic stress (heat, drought, and low temperature) related genes were also found to be responsive to salinity stress. Our results also indicate osmoprotection to be an early response of barley under salinity stress. Additionally, we compared the results of our studies with two other reports characterizing gene expression of barley under salinity stress and found very few genes in common.

Cyclopentanes↗

PubMed1989

Salinity-stress-induced proteins in two nitrogen-fixing Anabaena strains differentially tolerant to salt.

Salinity altered the protein synthesis patterns in two cyanobacterial strains: Anabaena torulosa, a salt-tolerant brackish water strain, and Anabaena sp. strain L-31, a salt-sensitive freshwater strain. The cyanobacterial response to salinity was very rapid, varied with time, and was found to be correlated with the external salt (NaCl) concentration during stress. Salinity induced three prominent types of modification. First, the synthesis of several proteins was inhibited, especially in the salt-sensitive strain; second, the synthesis of certain proteins was significantly enhanced; and third, synthesis of a specific set of proteins was induced de novo by salinity stress. Proteins which were selectively synthesized or induced de novo during salt stress, tentatively called the salt-stress proteins, were confined to an isoelectric pI range of 5.8 to 7.5 and were distributed in a molecular mass range of 12 to 155 kilodaltons. These salt-stress proteins were unique to each Anabaena strain, and their expression was apparently regulated coordinately during exposure to salt stress. In Anabaena sp. strain L-31, most of the salt-stress-induced proteins were transient in nature and were located mainly in the cytoplasm. In A. torulosa, salt-stress-induced proteins were evenly distributed in the membrane and cytoplasmic fractions and were persistent, being synthesized at high rates throughout the period of salinity stress. These initial studies reveal that salinity-induced modification of protein synthesis, as has been demonstrated in higher plant species, also occurs in cyanobacteria and that at least some of the proteins preferentially synthesized during salt stress may be important to cyanobacterial osmotic adaptation.

Cell Membrane↗

PubMed2026

Low-salinity stress alters growth, histology, physiology, and transcriptomic profiles of the gills and antennal glands in Macrobrachium rosenbergii.

Salinity is a major abiotic constraint in freshwater aquaculture of the giant freshwater prawn Macrobrachium rosenbergii, yet the coordinated roles of the gills and antennal glands, the two primary osmoregulatory organs in decapod crustaceans, under low-salinity stress remain poorly characterized. Here, we integrated histological, physiological, and transcriptomic analyses to characterize the adaptive responses of M. rosenbergii to acute (96 h) and chronic (8 weeks) exposure to salinity 5. Chronic low-salinity stress significantly impaired growth performance and decreased the survival rate. Acute stress induced thinning of the gill filaments, partial disorganization of pillar cells, and dilation of the intermicrovillar space in the antennal glands, whereas chronic stress caused gill vacuolization, cuticle thinning, and adaptive folding of antennal gland microvilli. In parallel, acute exposure significantly decreased hemolymph sodium and potassium ion concentrations but increased magnesium ion concentration, whereas chronic exposure increased hemolymph sodium and potassium ion concentrations, upregulated gill Na+/K+-ATPase activity, and enhanced hepatopancreatic antioxidant capacity. Transcriptomic analyses revealed distinct tissue-specific responses. Under acute stress, the gills preferentially activated pathways associated with cytoskeletal remodeling, motor proteins, and tight junctions, whereas chronic acclimation shifted the transcriptional response toward the renin-angiotensin system and glutathione metabolism. In the antennal glands, acute stress rapidly activated the renin secretion pathway, whereas chronic exposure promoted membrane remodeling by enriching pathways related to lipid and glycan metabolism. These findings reveal tissue-specific functional differentiation and synergistic coordination between the gills and antennal glands that underpin M. rosenbergii's adaptive response to low-salinity stress.

Animals↗

PubMed2002

Inhibition of biosynthesis and activity of nitrogenase in Azospirillum brasilense Sp7 under salinity stress.

Azospirillum brasilense is a microaerophilic, plant growth-promoting bacterium, whose nitrogenase activity has been shown to be sensitive to salinity stress. Growth of A. brasilense in semi-solid medium showed that diazotrophic growth in N-free medium was relatively less sensitive to high NaCl concentrations (200-400 mM) than that in presence of NH4+. Increase in salinity stress to diazotrophic A. brasilense in the semi-solid medium led to the migration of the pellicle to deeper anaerobic zones. Assays of acetylene reduction and nifH- lacZ and nifA- lacZ fusions indicated that salinity stress inhibited nitrogenase biosynthesis more strongly than nitrogenase activity. Under salt stress, the amount of dinitrogenase reductase inactivated by ADP-ribosylation was strongly reduced, indicating that the dinitrogenase reductase ADP ribosyl transferase (DRAT) activity was also inhibited by increased NaCl concentrations. Movement of the pellicle to the anaerobic zone and inhibition of DRAT might be adaptive responses of A. brasilense to salinity stress under diazotrophic conditions. Supplementation of glycine betaine, which alleviates salt stress, partially reversed both responses.

Anaerobiosis↗

PubMed2002

Protective role of exogenous polyamines on salinity-stressed rice (Oryza sativa) plants.

Salt-tolerant Pokkali rice plants accumulate higher polyamines (PAs) such as spermidine (Spd) and spermine (Spm) in response to salinity stress, while the sensitive cultivarM-1-48 is unable to maintain high titres of these PAs under similar conditions. The effects of the triamine Spd and the tetramine Spm on physiological and biochemical changes in 12-day-old rice seedlings were investigated during salinity stress to determine whether they could protect the sensitive plants from stress effects. At physiological concentrations Spd and Spm significantly prevented the leakage of electrolytes and amino acids from roots and shoots induced by salinity stress. To different degrees they also prevented chlorophyll loss, inhibition of photochemical reactions of photosynthesis as well as downregulation of chloroplast-encoded genes like psbA, psbB, psbE and rbcL, indicating a positive correlation between salt tolerance and accumulation of higher PAs in rice. The inhibitory effect of salinity stress and its reversal by exogenous PAs were more pronounced in the salt-sensitiveM-1-48 plants than in the tolerant Pokkali plants.

Journal Article↗

PubMed2000

Combined effects of pentachlorophenol and salinity stress on phagocytic and chemotactic function in two species of abalone.

The effect of pentachlorophenol (PCP) combined with salinity stress on specific aspects of cellular immunity was examined in two species of abalone. Chemotactic and phagocytic ability (percent phagocytosis, %P; and phagocytic index, PI), as well as gross morphological characteristics, of hemocytes withdrawn from red (Haliotis rufescens) and black abalone (H. cracherodii) after in vivo exposure to 25, 35, or 45 per thousand seawater salinity plus 1.2 mg/l PCP were determined. Abalone exposures of 3.5 and 6.5 h, respectively, were based on species-specific metabolic endpoints (MEPs) derived from previous NMR data. Hemocyte chemotaxis was found to be augmented by low salinity in red but not black abalone, while high salinity seemed to reduce chemotactic ability in both species. PCP did not potentiate the effects demonstrated by salinity variations alone in red abalone, although chemotaxis was further compromised in black abalone exposed to high salinity stress combined with PCP. Although chemotactic ability was similar among both species, both %P and PI was greater among black abalone. Low salinity may offset the effects of PCP in red but not black abalone. Whereas red abalone demonstrated a reduction in phagocytic ability upon exposure to high salinity alone, black abalone appeared more resilient to high salinity stress alone. Furthermore, while the effect of high salinity plus PCP is subadditive among red abalone, high salinity seems to potentiate the effect of PCP on black abalone. Finally, hemocytes exposed to acute salinity variations plus PCP showed varying morphological characteristics when compared to controls. Over 30% of hemocytes of high salinity plus PCP exposed abalone remained rounded and generally unattached to glass slides with only a few pseudopod extensions. Hemocyte preparations incubated in rhodamine-conjugated phalloidin were observed with fluorescence microscopy and reveal an altered actin filament pattern. Overall, black abalone demonstrate greater phagocytic ability than red abalone both in the presence and absence of PCP. Furthermore, increases in salinity are accompanied with reduced phagocytic ability with red abalone demonstrating particular sensitivity to salinity variations. While PCP inhibits ATP synthesis, salinity variations may impose an additional stress on intertidal animals exposed to transient or seasonal environmental changes.

Journal Article↗