Comparative physiological responses to increasing ambient salinity levels in Procambarus clarkii (Girard) and Orconectes lancifer (Hagen)

2011 ◽  
Vol 18 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Christopher Green ◽  
Katherine Gautreaux ◽  
Rosa Perez Perez
Keyword(s):  
Procambarus Clarkii ◽  
Physiological Responses ◽  
Salinity Levels ◽  
Ambient Salinity

scholarly journals Covid-19 Pandemic in relation to levels of Pollution with PM2.5 and Ambient Salinity – An Environmental Wake-up Call

2020 ◽  
Author(s):  
Yves Muscat Baron
Keyword(s):  
Particulate Matter ◽  
Environmental Factors ◽  
Chloride Ion ◽  
Small Island ◽  
Great Loss ◽  
Loss Of Life ◽  
Coastal Cities ◽  
High Incidence ◽  
Salinity Levels ◽  
Ambient Salinity

ABSTRACTINTRODUCTIONCovid-19 infection continues to be a source of great loss of life and global suffering, necessitating national lockdowns. There are however some countries and cities which appear to have contained the pandemic. Common to these countries are environmental factors including the levels of particulate matter (PM2.5) and ambient salinity.METHODPM2.5 and ambient salinity were assessed in a number of cities, differentially affected by Covid-19 infection. The cities chosen to be assessed were divided into two groups. The first group included cities having significantly high rates of Covid-19 infection, while the second group consisted of coastal cities or small island countries, all of which have low rates of Covid-19 infection. Minimum and maximum levels of PM2.5 were obtained from the Air Quality Index, one month before and one month after statutory lockdown. Salinity levels were obtained from a study that assessed chloride ion wet deposition, a surrogate for ambient salinity.RESULTSOne month prior to the statutory national lock-down or mandatory restrictions, there appear to be high levels of particulate matter, PM2.5 (min-max 67.4 - 118.7 AQI), in countries which had a high incidence of Covid-19 infection compared to lower levels in countries that have contained the infection (min-max 45.6 - 79.8) (p<0.046). One month after national restrictions there still appeared to be higher levels of particulate matter, PM2.5 (min-max 51 - 90.5 AQI), in countries which had a high incidence of Covid-19 infection compared to countries that have contained the infection (min-max 42.7 - 69.5 AQI) but this was not statistically significant.There seemed to be an inverse relationship between Covid-19 infection and ambient salinity levels. Countries that were spared high Covid-19 infection rates, besides their geographical isolation, also have higher ambient salinity levels (124 - 617mgCl/m2/TAG) compared to salinity levels noted in countries with high Covid-19 rates of infection (28.4 - 162. mgCl/m2/TAG) (p<0.003).CONCLUSIONHigh levels of PM2.5 in the presence of low ambient salinity may increase the risk of Covid-19 infection in the population. Addressing these two environmental factors may attenuate the severity of the pandemic.

scholarly journals Physiological responses of watercress to brackish waters and different nutrient solution circulation times

2020 ◽  
Vol 41 (6) ◽  
pp. 2555-2570
Author(s):  
Camila Alves de Souza ◽  
◽  
Alexsandro Oliveira da Silva ◽  
Claudivan Feitosa de Lacerda ◽  
Ênio Farias de França e Silva ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Nutrient Solution ◽  
Brackish Water ◽  
Root Length ◽  
Agricultural Development ◽  
Block Design ◽  
Physiological Responses ◽  
Stem Diameter ◽  
Randomized Block Design ◽  
Salinity Levels

Water scarcity and the use of brackish water are the main challenges for agricultural development. In view of this, the present study proposes to examine physiological responses of the broadleaf-cress crop in an NFT hydroponics system according to the use of brackish water and nutrient solution circulation times. The treatments were distributed in a randomized block design with five water salinity levels (ECw: 0.6, 1.6, 2.6, 3.6 and 4.6 dS m-1) and two nutrient solution circulation times (T1 = 10 min and T2 = 15 min), totaling 10 treatments with four replicates, which resulted in 40 experimental plots. The following variables were analyzed: net photosynthetic rate, stomatal conductance, transpiration, leaf proline content, shoot moisture content, stem diameter and root length. The maximum observed photosynthetic rates were 20.9 mmol m-2 s-1 (T1) and 20.0 mmol m-2 s-1 (T2). Maximum stomatal conductance was 0.44 mol m-2 s-1, which decreased by 63.4% at the highest salinity level. The increasing ECw levels in both growing cycles evaluated reduced gas exchanges, stem diameter and root length. The nutrient solution circulation time of 15 min provided the most satisfactory results for the analyzed variables.

Physiological responses of eight maize varieties to salinity under the field and greenhouse conditions

2019 ◽  
Vol 48 (3) ◽  
pp. 489-495
Author(s):  
Molazem Davar ◽  
Elshad M Qurbanov
Keyword(s):  
Chlorophyll A ◽  
Zea Mays L ◽  
Physiological Responses ◽  
Maximum Amount ◽  
Proline Content ◽  
Chlorophyll B ◽  
Saline Condition ◽  
Maize Varieties ◽  
Significant Difference ◽  
Salinity Levels

An experiment was conducted in two fields (normal and saline) to study the effect of salinity on eight varieties of maize (Zea mays L.) for three years. Another experiment was carried out in three salinity levels, zero (control), 50 and 100 mM NaCl in greenhouse at the factorial design in a year. During the experiment characters such as chlorophyll a, chlorophyll b and proline content were measured. Comparison of means in different soil of salinity showed that, there were significant differences in genotypes in most traits. Maximum amount of chlorophyll a was observed in S.C704 in control condition and there was no significant difference from B73. In field condition maximum and minimum amount of proline were observed in S.C704 in saline condition and K3615/1 in normal condition, respectively. In greenhouse, maximum amount of chlorophyll a was observed in K3615/1 variety.

Growth and development of potatoes under salinity and water deficit

1995 ◽  
Vol 46 (7) ◽  
pp. 1477 ◽  
Author(s):  
B Heuer ◽  
A Nadler
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Harvest Index ◽  
Dry Matter ◽  
Physiological Responses ◽  
Stem Number ◽  
Fresh Weight ◽  
Leaf Elongation ◽  
Water Plant ◽  
Salinity Levels

The agronomic and physiological responses of potato to salinity and to water deficits were determined. The experiment consisted of five treatments: three salinity levels and two restricted amounts of water. Plant height, leaf area and fresh weight accumulation were significantly affected by the salinity and moisture treatments. Stem number, leaf elongation and the content of dry-matter in leaves, stems and tubers were hardly affected. Harvest index, an important agronomic trait, was markedly improved by the different treatments.

scholarly journals Coexistence of Two Invasive Species, Procambarus clarkii and Aphanomyces astaci, in Brackish Waters of a Mediterranean Coastal Lagoon

2021 ◽  
Vol 8 ◽  
Author(s):  
Laura Martín-Torrijos ◽  
Angel Jose Correa-Villalona ◽  
Antonio Pradillo ◽  
Javier Diéguez-Uribeondo
Keyword(s):  
Invasive Species ◽  
Coastal Lagoon ◽  
Procambarus Clarkii ◽  
Freshwater Ecosystems ◽  
Freshwater Crayfish ◽  
Brackish Waters ◽  
Aphanomyces Astaci ◽  
Salinity Levels ◽  
Native Crayfish ◽  
Mediterranean Coastal Lagoon

Procambarus clarkii is a worldwide freshwater invasive crustacean from North America and was first introduced into Europe the 1970s. Along with P. clarkii, another invasive alien species was also spreading: Aphanomyces astaci. This pathogen is listed among the 100 World’s worst invasive species and involved in the European native crayfish decline. Although both species live in freshwater ecosystems, P. clarkii can withstand brackish waters and inhabit estuarine habitats. However, the presence of A. astaci associated to North American crayfishes has never been described in brackish waters. In this study, we have investigated the presence of A. astaci in a P. clarkii population of a Mediterranean coastal lagoon in the Albufera Natural Park, Valencia, Spain introduced in 1976. Our study confirmed the presence of this pathogen, and suggests that A. astaci has been spreading for more than four decades in the mentioned estuarine environment. Mitochondrial ribosomal rnnS and rnnL indicated that the isolated pathogen belongs to d1-haplotype (i.e., D-haplogroup) typically hosted by P. clarkii. The presence of this pathogen in a brackish environment may suggest a better adaptation than other A. astaci strains to adverse conditions, such as high salinity levels. This is a matter of concern for the conservation of European native freshwater crayfish and highlights once more the risk of introducing invasive alien crustaceans.

scholarly journals Investigation of physiological responses of Procambarus clarkii and some enzyme activities to selected heavy metals

2019 ◽  
Vol 4 (1) ◽  
pp. 023-027
Author(s):  
Elkhidir Noreldaim ◽  
AB Hussein ◽  
Abbas A ◽  
Hussein N
Keyword(s):  
Heavy Metals ◽  
Enzyme Activities ◽  
Procambarus Clarkii ◽  
Physiological Responses

Physiological responses of Enhalus acoroides to osmotic stress

2018 ◽  
Vol 61 (3) ◽  
pp. 257-267 ◽  
Author(s):  
Pimpanit Kongrueang ◽  
Pimchanok Buapet ◽  
Peerapat Roongsattham
Keyword(s):  
Chlorophyll Content ◽  
Physiological Responses ◽  
Total Chlorophyll ◽  
Ionic Homeostasis ◽  
Short Term ◽  
Photosynthetic System ◽  
Total Chlorophyll Content ◽  
Enhalus Acoroides ◽  
Highly Sensitive ◽  
Salinity Levels

Abstract This study aims to examine photophysiological and osmotic responses in seedlings of the seagrass Enhalus acoroides after exposure to different salinity levels. Seagrass seedlings were grown for 20 days in control (salinity 30), hyposaline (salinity 10 and 20) and hypersaline (salinity 40 and 50) conditions. The present study showed that both hypo- and hypersaline conditions affected the photophysiology of E. acoroides seedlings, reducing the maximum quantum yield of photosystem II (Fv/Fm) and total chlorophyll content. The photosynthetic system appeared to be more sensitive to hyposaline than to hypersaline conditions as shown by immediate declines in Fv/Fm and total chlorophyll content. Hyposaline conditions increased the water content in roots. The increase in tissue Na+ content induced by hypersalinity did not affect photosynthetic integrity and was more pronounced in leaves than in roots. It is concluded that the ionic homeostasis of E. acoroides seedlings is less affected by short-term hypersalinity than by hyposalinity. The K+/Na+ ratios in leaves with hypersalinity decreased by 20 days after treatment. Additionally, the photosynthetic efficiency (Fv/Fm and total chlorophyll content) is highly sensitive to salinity shifts and can be used as a marker for short-term acclimation to salinity stress in this seagrass species.

The Lateral Giant Fiber to Motor Giant Fiber Synapse in Crayfish

1972 ◽  
Vol 30 ◽  
pp. 170-171
Author(s):  
Charles A. Stirling
Keyword(s):  
Synaptic Vesicles ◽  
Procambarus Clarkii ◽  
Synaptic Contact ◽  
Giant Fiber ◽  
Synaptic Junctions

The lateral giant (LG) to motor giant (MoG) synapses in crayfish (Procambarus clarkii) abdominal ganglia are the classic electrotonic synapses. They have previously been described as having synaptic vesicles and as having them on both the pre- and postsynaptic sides of symmetrical synaptic junctions. This positioning of vesicles would make these very atypical synapses, but in the present work on the crayfish Astacus pallipes the motor giant has never been found to contain any type of vesicle at its synapses with the lateral giant fiber.The lateral to motor giant fiber synapses all occur on short branches off the main giant fibers. Closely associated with these giant fiber synapses are two small presynaptic nerves which make synaptic contact with both of the giant fibers and with their small branches.

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