scholarly journals The importance of intraspecific diversity on duckweed growth with and without salt stress

2021 ◽  
Author(s):  
Sofia Julia van Moorsel
Keyword(s):  
Salt Stress ◽  
Growth Rates ◽  
Lemna Minor ◽  
Freshwater Ecosystems ◽  
Intraspecific Diversity ◽  
Natural Community ◽  
Experimental Mesocosms ◽  
Freshwater Plants ◽  
Stressful Environments ◽  
Positive Effect

The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide. Freshwater plants, such as duckweed (Lemna minor), are potentially sensitive to novel stressful environments. To test if intraspecific diversity could increase resistance to stressful environments, I used seven L. minor populations and assessed their growth rates in the absence and presence of moderate salt stress across an intraspecific diversity gradient.I grew the populations (ecotypes) of L. minor over five months in 92 experimental mesocosms in a glasshouse either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes (23 unique compositions). The experiment was conducted in semi-natural conditions, including a natural community of algae and microbes. After assessing the duckweed growth rate in unperturbed conditions, the cultures were subjected to moderate salt stress (50mM NaCl) for several weeks. Population abundances were assessed weekly, both on the ecotype level and the whole-population level.Throughout the experiment, the ecotypes differed in their growth rates, the fastest growing at twice the rate of others. Whether the ecotypes grew in monoculture or in polyculture with other conspecifics further shaped the ecotype growth rates. Ecotype polycultures showed higher abundances towards the end of the experiment, indicating that over time, as the environment deteriorated, intraspecific diversity gained in importance. These findings show that intraspecific variation in growth rates can translate to a positive effect of intraspecific diversity on whole-population abundance. Exposure of L. minor to moderate salt levels did not significantly impact growth rates.

scholarly journals Ethylene reduces glucose sensitivity and reverses photosynthetic repression through optimization of glutathione production in salt-stressed wheat (Triticum aestivum L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zebus Sehar ◽  
Noushina Iqbal ◽  
M. Iqbal R. Khan ◽  
Asim Masood ◽  
Md. Tabish Rehman ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Salt Stress ◽  
Photosynthetic Activity ◽  
Reduced Glutathione ◽  
Buthionine Sulfoximine ◽  
Triticum Aestivum L ◽  
Sink Strength ◽  
Glucose Sensitivity ◽  
Photosynthetic Potential ◽  
Stressful Environments

AbstractEthylene plays a crucial role throughout the life cycle of plants under optimal and stressful environments. The present study reports the involvement of exogenously sourced ethylene (as ethephon; 2-chloroethyl phosphonic acid) in the protection of the photosynthetic activity from glucose (Glu) sensitivity through its influence on the antioxidant system for adaptation of wheat (Triticum aestivum L.) plants under salt stress. Ten-day-old plants were subjected to control and 100 mM NaCl and treated with 200 µl L−1 ethephon on foliage at 20 days after seed sowing individually or in combination with 6% Glu. Plants receiving ethylene exhibited higher growth and photosynthesis through reduced Glu sensitivity in the presence of salt stress. Moreover, ethylene-induced reduced glutathione (GSH) production resulted in increased psbA and psbB expression to protect PSII activity and photosynthesis under salt stress. The use of buthionine sulfoximine (BSO), GSH biosynthesis inhibitor, substantiated the involvement of ethylene-induced GSH in the reversal of Glu-mediated photosynthetic repression in salt-stressed plants. It was suggested that ethylene increased the utilization of Glu under salt stress through its influence on photosynthetic potential and sink strength and reduced the Glu-mediated repression of photosynthesis.

scholarly journals Species interactions in three Lemnaceae species growing along a gradient of zinc pollution

2021 ◽  
Author(s):  
Lorena Lanthemann ◽  
Sofia van Moorsel
Keyword(s):  
Growth Rates ◽  
Species Interactions ◽  
Metal Removal ◽  
Lemna Minor ◽  
Polluted Water ◽  
Future Research ◽  
Individual Species ◽  
High Tolerance ◽  
Species Mixture ◽  
The Individual

Duckweeds (Lemnaceae) are increasingly studied for their potential for phytoremediation of heavy-metal polluted water bodies. A prerequisite for metal removal, however, is the tolerance of the organism to the pollutant, e.g., the metal zinc (Zn). Duckweeds have been shown to differ in their tolerances to Zn, however, despite them most commonly co-occurring with other species, there is a lack of research concerning the effect of species interactions on Zn tolerance. Here we tested whether the presence of a second species influenced the growth rate of the three duckweed species Lemna minor, Lemna gibba, and Lemna turionifera. We used four different Zn concentrations in a replicated microcosm experiment under sterile conditions, either growing the species in isolation or in a 2-species mixture. The response to Zn differed between species, but all three species showed a high tolerance to Zn, with low levels of Zn even increasing the growth rates. The growth rates of the individual species were influenced by the identity of the competing species, but this was independent of the Zn concentration. Our results suggest that species interactions should be considered in future research with duckweeds and that several duckweed species have high tolerance to metal pollution, making them candidates for phytoremediation efforts.

The water flea Daphnia pulex (Cladocera, Daphniidae), a possible model organism to evaluate aspects of freshwater ecosystems

Crustaceana ◽  
2019 ◽  
Vol 92 (11-12) ◽  
pp. 1415-1426
Author(s):  
Juan-Alejandro Norambuena ◽  
Jorge Farías ◽  
Patricio De los Ríos
Keyword(s):  
Phylogenetic Trees ◽  
Daphnia Pulex ◽  
Model Organism ◽  
Freshwater Ecosystems ◽  
Intraspecific Diversity ◽  
Molecular Tools ◽  
Water Flea ◽  
Future Studies ◽  
Molecular Studies

Abstract Daphnia pulex is a freshwater planktonic crustacean, allegedly a cosmopolitan species, which is found in lentic ecosystems. The aim of this study was to conduct a literature review of D. pulex related to its life history and genetic variability, in order to mark a route for future studies. We noted that D. pulex is a model species on which ecological studies have been carried out, as well as molecular studies, in which its molecular diversity has been characterized and such in specimens from different environments: both pristine and under human influence. In particular those studies are highlighted, in which molecular tools have been used to construct phylogenetic trees for study intraspecific differences. Also, in some of these molecular studies, analyses of genetic, inter- and intraspecific diversity have been performed. In addition, analyses of protein expression in D. pulex and related species seem promising in evaluating the detailed role of this species.

scholarly journals Pretreatment with High-Dose Gamma Irradiation on Seeds Enhances the Tolerance of Sweet Osmanthus Seedlings to Salinity Stress

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 406 ◽  
Author(s):  
Xingmin Geng ◽  
Yuemiao Zhang ◽  
Lianggui Wang ◽  
Xiulian Yang
Keyword(s):  
Salt Stress ◽  
Gamma Irradiation ◽  
Salinity Stress ◽  
High Dose ◽  
Ros Scavenging ◽  
Osmanthus Fragrans ◽  
Seed Pretreatment ◽  
Flower Fragrance ◽  
Positive Effect ◽  
Different Doses

The landscape application of sweet osmanthus (Osmanthus fragrans) with flower fragrance and high ornamental value is severely limited by salinity stress. Gamma irradiation applied to seeds enhanced their tolerance to salinity stress as reported in other plants. In this study, O. fragrans ‘Huangchuang Jingui’ seeds were pretreated with different doses of gamma irradiation, and tolerance of the seedlings germinated from the irradiated seeds to salinity stress and the changes of reactive oxygen species (ROS) production and ROS scavenging systems induced by gamma irradiation were observed. The results showed that seed pretreatment with different doses of gamma irradiation enhanced the tolerance of sweet osmanthus seedlings to salinity stress, and the positive effect induced by gamma irradiation was more remarkable with the increase of radiation dose (50–150 Gy). The pretreatment with high-dose irradiation decreased O2− production under salinity stress and mitigated the oxidative damage marked by a lower malondialdehyde (MDA) level, which could be related to the significant increase of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in the seedlings germinated from the irradiated seeds compared to the corresponding control seedlings. In addition, the accumulation of proline in the irradiated seedlings may contribute to enhancing their tolerance to salt stress by the osmotic adjustment. The study demonstrated the importance of regulating plant ROS balance under salt stress and provided a potential approach to improve the tolerance of sweet osmanthus to salt stress.

scholarly journals Alleviation of Salt Stress by Plant Growth-Promoting Bacteria in Hydroponic Leaf Lettuce

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1523 ◽  
Author(s):  
Alessandra Moncada ◽  
Filippo Vetrano ◽  
Alessandro Miceli
Keyword(s):  
Salt Stress ◽  
Plant Growth ◽  
Leafy Vegetables ◽  
Mineral Nutrient ◽  
Plant Growth Promoting Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Leaf Lettuce ◽  
Positive Effect ◽  
Nutrient Solutions

Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L−1 of TNC BactorrS13 a commercial biostimulant containing 1.3 × 108 CFU g−1 of Bacillus spp.) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants.

Carcass additions increase juvenile salmonid growth, condition, and size in an interior Columbia River Basin tributary

2020 ◽  
Vol 77 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Matthew J. Kaylor ◽  
Seth M. White ◽  
Edwin R. Sedell ◽  
Dana R. Warren
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Life Histories ◽  
Freshwater Ecosystems ◽  
Steelhead Trout ◽  
Juvenile Salmonids ◽  
Early Fall ◽  
Juvenile Chinook ◽  
The Relationship

Numbers of anadromous fish returning to freshwater ecosystems have declined precipitously across much of western North America, reducing a potentially important resource subsidy for juvenile salmonids. We added carcasses to three sections of a Snake River tributary and assessed juvenile Chinook salmon (Oncorhynchus tshawytcha) and steelhead trout (Oncorhynchus mykiss) growth, body condition, size, and diet responses in summer and early fall. Juvenile salmonids consumed an abundance of eggs and carcass tissue, which increased energy rations. Within 3 weeks of carcass additions, juvenile Chinook and steelhead growth rates were 1.1–5 and 6–23 times greater in treatment reaches relative to control reaches, respectively. We used long-term tagging and detection data from this system to assess the relationship between juvenile Chinook size and emigration survival for two different juvenile life histories. The increased growth rates and body size in response to carcass additions, coupled with a positive relationship between body size and survival, suggest that juvenile salmonid rearing productivity and emigration survival may be limited by depressed returns of anadromous fishes in this system and potentially other tributaries of the Columbia Basin.

Effect of laser priming on canola yield and its components under salt stress

2012 ◽  
Vol 26 (1) ◽  
pp. 45-51 ◽  
Author(s):  
S. Mohammadi ◽  
F. Shekari ◽  
R. Fotovat ◽  
A. Darudi
Keyword(s):  
Salt Stress ◽  
Plant Height ◽  
Correlation Coefficients ◽  
Yield Increase ◽  
Effect On Yield ◽  
Lateral Branches ◽  
Pod Length ◽  
Positive Effect ◽  
Pod Number ◽  
Number Of Seeds

Effect of laser priming on canola yield and its components under salt stressThe effect of laser priming at different irradiation times on canola yield and its components under saline conditions were investigated. The results showed that laser priming had a positive effect on yield and its components and caused yield increase under saline conditions. Increase in salt levels had a negative and significant effect on seed yield, number of seeds per pod, number of pod per plant, pod length and plant height. The results showed that 45-min laser priming had the strongest effect on yield and yield components and reduced significantly the adverse effects of salinity. By contrast, laser radiation applied for 60 and 75 min, resulted in a dramatic decrease in yield and its components. Correlation coefficients between the attributes showed that canola yield had a positive and significant correlation with plant height, number of seeds, pod per main branch and lateral branches, length of pod and number of lateral branches. Effects of laser and salinity were significant on lateral branch pod length but not on main branch pods.

scholarly journals The Importance of Riparian Forest Cover to the Ecological Status of Agricultural Streams in a Nationwide Assessment

2021 ◽  
Author(s):  
Mikko Tolkkinen ◽  
Saku Vaarala ◽  
Jukka Aroviita
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Riparian Forest ◽  
Ecological Status ◽  
Freshwater Ecosystems ◽  
Agricultural Landscapes ◽  
Riparian Forests ◽  
Independent Effect ◽  
Medium Size ◽  
Positive Effect

AbstractForested riparian corridors are a key management solution for halting the global trend of declining ecological status of freshwater ecosystems. There is an increasing body of evidence related to the efficacy of these corridors at the local scale, but knowledge is inadequate concerning the effectiveness of riparian forests in terms of protecting streams from harmful impacts across larger scales. In this study, nationwide assessment results comprising more than 900 river water bodies in Finland were used to examine the importance of adjacent land use to river ecological status estimates. Random forest models and partial dependence functions were used to quantify the independent effect of adjacent land use on river ecological status after accounting for the effects of other factors. The proportion of adjacent forested land along a river had the strongest independent positive effect on ecological status for small to medium size rivers that were in agricultural landscapes. Ecological quality increased by almost one status class when the adjacent forest cover increased from 10 to 60%. In contrast, for large rivers, adjacent forested land did not show an independent positive effect on ecological status. This study has major implications for managing river basins to achieve the EU Water Framework Directive (WFD) goal of obtaining good ecological status of rivers. The results from the nationwide assessment demonstrate that forested riparian zones can have an independent positive effect on the ecological status of rivers, indicating the importance of riparian forests in mitigating the impacts of catchment-level stressors. Therefore, forested buffer zones should be more strongly considered as part of river basin management.

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