The Collection, Maintenance, and Environmental Importance, of the Genetic Resources of Wild Plants

1975 ◽  
Vol 2 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Peter A. Thompson
Keyword(s):  
Wild Species ◽  
Economic Value ◽  
Natural Populations ◽  
Wild Plants ◽  
Plant Resources ◽  
Economic Resource ◽  
Factors Affecting ◽  
Natural Systems ◽  
In The Wild ◽  
Major Factors

Plants are major factors conditioning an environment, and conservation of particular environments depends fundamentally on the maintenance of existing plant communities. In many parts of the world, the destruction of such communities is occurring so rapidly and so completely that entire natural systems are subject to, or threatened with, total destruction. In such cases artificial methods of conserving plant germplasm for ultimate regeneration, for supplementing natural populations, for study, or for use by Man as an economic resource, may be of great significance as one possible means of averting total loss. Under less extreme pressures, the availability of representative propagules of significant taxa or populations may be of crucial assistance as an aid to research directed towards a better understanding of factors affecting survival or competitive advantage in the wild, or as a means of providing stocks for assessment of the potential economic value of existing reserves of wild species.This paper discusses methods of recording, maintaining, and evaluating, collections of populations of wild species. Plant resources of this kind are extremely vulnerable when maintained under artificial conditions, and a very high proportion of collections are lost within a few years, remain unavailable for general use, or fail to be used owing to inadequate documentation. Conservation of plant germ-plasm as an international resource, in a usable form, depends on a wide acceptance and practice of greatly improved methods of documentation, and requires the creation of effective organizations for surveying, maintaining, and coordinating, plant resources on an international scale.

scholarly journals Epidemiological dynamics of viral infection in a marine picoeukaryote

2021 ◽  
Author(s):  
Luisa Listmann ◽  
Sarah Heath ◽  
Pedro F. Vale ◽  
C. Elisa Schaum ◽  
Sinead Collins
Keyword(s):  
Population Dynamics ◽  
Laboratory Experiments ◽  
Natural Populations ◽  
Epidemiological Models ◽  
Laboratory Findings ◽  
Serial Transfer ◽  
Natural Systems ◽  
Ostreococcus Tauri ◽  
In The Wild ◽  
Low Costs

AbstractOstreococcus tauri is a ubiquitous marine pico-eukaryote that is susceptible to lysis upon infection by its species specific Ostreococcus tauri viruses (OtVs). In natural populations of O. tauri, costs of resistance are usually invoked to explain the persistence or reappearance of susceptible individuals in resistant populations. Given the low costs of resistance measured in laboratory experiments with the O. tauri/OtV system to date, the question remains of why susceptible individuals persist in the wild at all. Epidemiological models of host and pathogen population dynamics are one useful approach to understand the conditions that can allow the coexistence of susceptible and resistant hosts. We used a SIR (Susceptible-Infected-Resistant) model to investigate epidemiological dynamics under different laboratory culturing regimes that are commonly used in the O.tauri/OtV system. When taking into account serial transfer (i.e. batchcycle lengths) and dilution rates as well as different resistance costs, our model predicts that no susceptible cells should be detected under any of the simulated conditions – this is consistent with laboratory findings. We thus considered an alternative model that is not used in laboratory experiments, but which incorporates one key process in natural populations: host populations are periodically re-seeded with new infective viruses. In this model, susceptible individuals re-occurred in the population, despite low costs of resistance. This suggests that periodic attack by new viruses, rather than (or in addition to) costs of resistance, may explain the high proportion of susceptible hosts in natural populations, and underlie the discrepancy between laboratory studies and observations of fresh isolates.ImportanceIn natural samples of Ostreococcus sp. and its associated viruses, susceptible hosts are common. However, in laboratory experiments, fully resistant host populations readily and irreversibly evolve. Laboratory experiments are powerful methods for studying process because they offer a stripped-down simplification of a complex system, but this simplification may be an oversimplification for some questions. For example, laboratory and field systems of marine microbes and their viruses differ in population sizes and dynamics, mixing or migration rates, and species diversity, all of which can dramatically alter process outcomes. We demonstrate the utility of using epidemiological models to explore experimental design and to understand mechanisms underlying host-virus population dynamics. We highlight that such models can be used to form strong, testable hypotheses about which key elements of natural systems need to be included in laboratory systems to make them simplified, rather than oversimplified, versions of the processes we use them to study.

ETUDE DE L'HEREDITE DE PHOSPHATASES ACIDES CHEZ LE DACTYLE (DACTYLIS GLOMERATA) DIPLOIDE ET TETRAPLOIDE

1981 ◽  
Vol 23 (3) ◽  
pp. 513-523 ◽  
Author(s):  
R. Lumaret
Keyword(s):  
Polymorphic Locus ◽  
Natural Populations ◽  
Dactylis Glomerata ◽  
Wild Plants ◽  
Starch Gel Electrophoresis ◽  
Ploidy Levels ◽  
Orchard Grass ◽  
In The Wild ◽  
Starch Gel ◽  
Dactylis Glomerata L

Starch gel electrophoresis of leaves of diploid and more particularly tetraploid orchard grass (Dactylis glomerata L.) from cultivars as well as natural populations disclosed several anodal stable bands with fast migration and phosphatasic activity. Six different phenotypes with one band, many others with three regular bands or six bands (only in the tetraploid individuals), were observed, showing the dimeric structure of the enzymes. Inheritance studies showed one polymorphic locus with six codominant alleles AcPH 11.00, AcPH 10.95, AcPH 10.90, AcPH 10.88, AcPH 11.02 and AcPH 11.04 with differences in enzymatic expression. AcPH 1.00 and AcPH 10.90 have been found in the two ploidy levels. Results from the tetraploid progenies involved tetravalents in meiosis for individuals originating from cultivars but bivalents in the wild plants. The two loci AcPH 1 and GOT 1 (this last one coding for a glutamate oxaloacetate transaminase) are not linked and seem to be located on different chromosomes.

Salt tolerance in the wild relatives of the cultivated tomato: Responses of Lycopersicon esculentum, L. peruvianum, and L. esculentum Minor to sodium chloride solution

1971 ◽  
Vol 22 (4) ◽  
pp. 631 ◽  
Author(s):  
M Tal
Keyword(s):  
Sodium Chloride ◽  
Lycopersicon Esculentum ◽  
Wild Species ◽  
Relative Water Content ◽  
Fruit Size ◽  
Dry Weight ◽  
Wild Plants ◽  
Relative Water ◽  
In The Wild ◽  
Leaf Succulence

The species used in this study were the cultivated tomato Lycopersicon esculentum, the wild species L. peruvianum, and plants originating from the wild species L, esculentum minor. The three plant types were compared in control and sodium chloride solutions for stability of fruit size, growth, dry weight, leaf relative water content and succulence, and chloride, sodium, and potassium contents. Fruit size decreased under salinity in the cultivated species but remained unchanged in the wild plants. It was also found that plant growth, shoot/root dry weight ratio, relative water content, and potassium concentration decreased under salinity in cultivated and wild plants. In all instances, except for potassium, the decrease was smaller in the wild plants. However, chloride and sodium concentrations and leaf succulence increased in all three plant types. Increases in chloride, sodium, and leaf succulence were greater in the wild plants. The differences in response to salinity between the cultivated and the wild plants and their significance are discussed.

scholarly journals Generalisation behaviour of predators toward warning signals displayed by harmful prey: answers from a videogame played by humans

2018 ◽  
Author(s):  
Mónica Arias ◽  
David Griffiths ◽  
Mathieu Joron ◽  
John Davey ◽  
Simon Martin ◽  
...  
Keyword(s):  
Video Game ◽  
Natural Populations ◽  
Computer Game ◽  
Warning Signals ◽  
Natural Systems ◽  
Natural Predator ◽  
In The Wild ◽  
Human Predation ◽  
Colour Patterns ◽  
Set Up

AbstractThe persistence of several warning signals in sympatry is a puzzling evolutionary question because selection favours convergence of colour patterns among toxic species. Such convergence is shaped by predators’ reaction to similar but not identical stimulus, i.e. generalisation behaviour. However, studying generalisation behaviour in complex natural communities of predators is challenging, and is thus generally limited to simple variations of prey colour patterns. Here, we used humans as surrogate predators to investigate generalisation behaviours on two prey communities with different level of warning signals complexity. Humans’ generalisation capacities were estimated using a computer game simulating a simple (4 morphs) and a complex (10 morphs) community of defended (associated with a penalty) and palatable butterflies. Colour patterns used in the game are actually observed in natural populations of the defended butterflies H. numata, and generalisation behaviour of natural predator’s communities on these colour patterns have previously been investigated in the wild, allowing direct comparison with human behaviour. We investigated human predation behaviour by recording attack rates on the different defended and palatable colour patterns, as well as player survival time (i.e. score). Phenotypic similarity among the different colour patterns was precisely quantified using a custom algorithm accounting for both colour and pattern variations (CPM method). By analysing attack behaviours of 491 game players, we found that learning was more efficient in the simple prey community. Additionally, profitable prey gained protection from sharing key visual features with unprofitable prey in both communities while learning, in accordance with natural predator behaviours. Moreover, other behaviours observed in natural predators, such as colour neophobia, were detected in humans and shaped morph vulnerability during the game. Similarities between our results in humans and the reaction of natural predator communities to the same colour patterns validate our video-game as a useful proxy to study predator behaviour. This experimental set-up can thus be compared to natural systems, enabling further investigations of generalisation on mimicry evolution.

Salt Tolerance in the Wild Relatives of the Cultivated Tomato: Responses of Lycopersicon esculentum, L. cheesmanii, L. peruvianum, Solanum pennellii and F1 Hybrids to High Salinity

1983 ◽  
Vol 10 (1) ◽  
pp. 109 ◽  
Author(s):  
M Tal ◽  
MC Shannon
Keyword(s):  
Wild Species ◽  
Elongation Rate ◽  
Wild Relatives ◽  
Wild Plants ◽  
F1 Hybrids ◽  
Cultivated Plants ◽  
Solanum Pennellii ◽  
High Accumulation ◽  
Relative Decrease ◽  
In The Wild

The performance of three wild relatives of the cultivated tomato (Lycopersicon cheesmanii, L. peruvianum and Solanum pennellii) and two tomato cultivars in control and saline media was compared. The parameters studied were elongation rate of the main stem, succulence, and accumulation of Na+, K+, and Cl- in the roots, stem, leaf, and shoot tip. The same parameters but in the leaf only were also studied comparatively in two of the wild species L. cheesmanii and S. pennellii, the same two cultivars, and F1 hybrids. Under control conditions, the elongation rate of the stem of the two cultivars was higher than that of the wild plants, but under salinity it was relatively lower. Among all species, S. pennellii was the most succulent in all its major parts under both control and saline conditions. The wild species, especially S. pennellii, showed high accumulation of Na+ in the leaf and top and a greater decrease in K+ content under salinity as compared with the cultivated plants. In all three species, Na+ probably substitutes for potassium in, at least, some of its physiological functions. Complete dominance of S. pennellii over the cultivated plants is indicated for the relative decrease of elongation rate and K+ level and for the increase of succulence under salinity. In contrast, L. cheesmanii seems to be completely dominant only for the relative decrease of K+ under salinity.

scholarly journals Relationship between Land Use Mix and Walking Choice in High-Density Cities: A Review of Walking in Seoul, South Korea

2021 ◽  
Vol 13 (2) ◽  
pp. 810
Author(s):  
Eun Yeong Seong ◽  
Nam Hwi Lee ◽  
Chang Gyu Choi
Keyword(s):  
Land Use ◽  
Neighborhood Environment ◽  
Single Family ◽  
Housing Type ◽  
General Belief ◽  
Factors Affecting ◽  
Land Use Mix ◽  
Family Housing ◽  
Mixed Land Use ◽  
Major Factors

This study confirmed the general belief of urban planners that mixed land use promotes walking in Seoul, a metropolis in East Asia, by analyzing the effect of mixed land use on the travel mode choice of housewives and unemployed people who make non-commuting trips on weekdays. Using binomial logistic regression of commuting data, it was found that the more mixed a neighborhood environment’s uses are, the more the pedestrians prefer to walk rather than drive. The nonlinear relationship between the land use mix index and the choice to walk was also confirmed. Although mixed land use in neighborhoods increased the probability of residents choosing walking over using cars, when the degree of complexity increased above a certain level, the opposite effect was observed. As the density of commercial areas increased, the probability of selecting walking increased. In addition to locational characteristics, income and housing type were also major factors affecting the choice to walk; i.e., when the residents’ neighborhood environment was controlled for higher income and living in an apartment rather than multi-family or single-family housing, they were more likely to choose driving over walking.

scholarly journals Is it possible to estimate the need for surgical management in patients with a tubo-ovarian abscess at admission? A retrospective long-term analysis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Murat Gözüküçük ◽  
Esra Gülen Yıldız
Keyword(s):  
Surgical Treatment ◽  
Antibiotic Therapy ◽  
Treatment Failure ◽  
Medical Treatment ◽  
Length Of Hospital Stay ◽  
Treatment Modalities ◽  
Laboratory Findings ◽  
Factors Affecting ◽  
Laboratory Infection ◽  
Major Factors

Abstract Background This study aimed to determine the possible prognostic factors correlated with the treatment modalities of tubo-ovarian abscesses (TOAs) and thus to assess whether the need for surgery was predictable at the time of initial admission. Materials and methods Between January 2012 and December 2019, patients who were hospitalized with a TOA in our clinic were retrospectively recruited. The age of the patients, clinical and sonographic presentation, pelvic inflammatory risk factors, antibiotic therapy, applied surgical treatment, laboratory infection parameters, and length of hospital stay were recorded. Results The records of 115 patients hospitalized with a prediagnosis of TOA were reviewed for the current study. After hospitalization, TOA was ruled out in 19 patients, and data regarding 96 patients was included for analysis. Twenty-eight (29.2%) patients underwent surgical treatment due to failed antibiotic therapy. Sixty-eight (70.8%) were successfully treated with parenteral antibiotics. Medical treatment failure and need for surgery were more common in patients with a large abscess (volume, > 40 cm3, or diameter, > 5 cm). The group treated by surgical intervention was statistically older than the patients receiving medical treatment (p < 0.05). Conclusions Although the treatment in TOA may vary according to clinical, sonographic, and laboratory findings; age of patients, the abscess size, and volume were seen as the major factors affecting medical treatment failure. Moreover, TOA treatment should be planned on a more individual basis.

scholarly journals Progress in Research on Carbon Nanotubes Reinforced Cementitious Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Qinghua Li ◽  
Jintao Liu ◽  
Shilang Xu
Keyword(s):  
Carbon Nanotubes ◽  
Large Scale ◽  
High Strength ◽  
Cementitious Composites ◽  
Scale Production ◽  
Multiwalled Carbon ◽  
Factors Affecting ◽  
Environment And Health ◽  
Research Activities ◽  
Major Factors

As one-dimensional (1D) nanofiber, carbon nanotubes (CNTs) have been widely used to improve the performance of nanocomposites due to their high strength, small dimensions, and remarkable physical properties. Progress in the field of CNTs presents a potential opportunity to enhance cementitious composites at the nanoscale. In this review, current research activities and key advances on multiwalled carbon nanotubes (MWCNTs) reinforced cementitious composites are summarized, including the effect of MWCNTs on modulus of elasticity, porosity, fracture, and mechanical and microstructure properties of cement-based composites. The issues about the improvement mechanisms, MWCNTs dispersion methods, and the major factors affecting the mechanical properties of composites are discussed. In addition, large-scale production methods of MWCNTs and the effects of CNTs on environment and health are also summarized.

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