Phomopsis subordinaria and associated stalk disease in natural populations of Plantago lanceolate

1987 ◽  
Vol 65 (11) ◽  
pp. 2318-2325 ◽  
Author(s):  
Marianne P. de Nooij ◽  
Huub A. van der Aa
Keyword(s):  
Natural Selection ◽  
Plant Species ◽  
Plant Tissue ◽  
Plantago Lanceolata ◽  
Natural Populations ◽  
Taxonomic Position ◽  
Selection For ◽  
Viable Seeds

Natural populations of Plantago lanceolata L. can be infected by the fungus Phomopsis subordinaria (Desm.) Trav., which causes a stalk disease. Inoculation experiments revealed that the fungus needs a wound to enter the plant tissue. Symptoms of the disease in the field and from inoculation experiments in the greenhouse are described and the taxonomic position of the fungus is discussed. The pathogen could not be isolated from other plant species in heavily infected Pl. lanceolata populations and can be regarded as specialized on Pl. lanceolata. Other species of the genus Plantago differed considerably in their susceptibility to the disease. Comparison of Pl. lanceolata genotypes indicated that there is variation in susceptibility among host genotypes. Because the disease may reduce the production of viable seeds, the possibility of natural selection for resistance in the host is considered.

GENIC DIVERSITY OF NATURAL POPULATIONS OF A CLONE- FORMING TREE POPULUS TREMULOIDES

1982 ◽  
Vol 24 (5) ◽  
pp. 611-616 ◽  
Author(s):  
William M. Cheliak ◽  
Bruce P. Dancik
Keyword(s):  
Plant Species ◽  
Populus Tremuloides ◽  
Animal Species ◽  
Woody Plant ◽  
Neutral Theory ◽  
Natural Populations ◽  
Trembling Aspen ◽  
Insufficient Time ◽  
Selection For ◽  
Genic Diversity

Effects of asexual reproduction as a primary reproductive strategy on population structure and levels of variability were investigated electrophoretically in natural populations of a woody plant species, trembling aspen (Populus tremuloides Michx.), from Alberta. As expected, levels of genic diversity, 42%, and proportion of polymorphic loci, 92%, averaged over all clones are considerably greater than those reported for comparable samples of sexually reproducing plant and animal species. These measures of genic variability of a primarily asexual plant species are similar to those reported for asexual species of insects, fish and bacteria. In addition, each of the 222 clones was electrophoretically unique. Since neutral theory would predict each individual clone to be heterozygous for a unique mutation at each gene locus at equilibrium, these results can be interpreted in a number of ways: (i) insufficient time to reach equilibrium, (ii) inability of electrophoresis to detect all variation at a locus, (iii) periodic establishment of sexually derived propagules in the population, and (iv) selection for similar genotypes at each location or against mutations at particular gene loci. Re-invasion of Pleistocene-glaciated areas by trembling aspen likely was by sexual means, with subsequent reproduction being primarily asexual.

Specific features of long-term domestication of australian crayfish Cherax quadricarinatus in conditions of the western part of Russian Federation

2018 ◽  
Vol 194 ◽  
pp. 188-192
Author(s):  
D. I. Shokasheva
Keyword(s):  
Natural Selection ◽  
Russian Federation ◽  
Natural Populations ◽  
Cherax Quadricarinatus ◽  
Local Environments ◽  
Local Species ◽  
Adaptive Ability

Natural populations of crayfish are in depression in Russia and local species are not cultivated. In this situation, experimental cultivation of allochtonous australian crayfish Cherax quadricarinatus is conducted. This species is distinguished by high reproductive abilities and good consumer properties. It has domesticated in Russia spontaneously and produced 9–10 generations in Astrakhan Region. Certain natural selection in the process of domestication provides adaptive ability of this species to local environments and its capabil­ity to reproduce a viable progeny, so there is no doubts in good prospects of its cultivation in industrial conditions.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

scholarly journals Polygenic and single gene responses to selection for resistance to diazinon in Lucilia cuprina.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 613-620 ◽  
Author(s):  
J A McKenzie ◽  
A G Parker ◽  
J L Yen
Keyword(s):  
Resistant Strain ◽  
Single Gene ◽  
Natural Populations ◽  
Susceptible Strain ◽  
Selection Line ◽  
Base Population ◽  
Gene Response ◽  
Biochemical Profiles ◽  
Resistant Strains ◽  
Selection For

Abstract Following mutagenesis with ethyl methanesulfonate, selection in a susceptible strain with a concentration of the insecticide diazinon (0.0004%, w/v) above that required to kill 100% of the susceptible strain, the LC100 of that strain, resulted in a single gene response. The resultant four mutant resistant strains have equivalent physiological, genetical and biochemical profiles to a diazinon-resistant strain derived from a natural population and homozygous for the Rop-1 allele. Modification of the microsomal esterase E3 is responsible for resistance in each case. The Rop-1 locus maps approximately 4.4 map units proximal to bu on chromosome IV. Selection within the susceptible distribution, at a concentration of diazinon [0.0001% (w/v)] less than the LC100, resulted in a similar phenotypic response irrespective of whether the base population had been mutagenized. The responses were polygenically based, unique to each selection line and independent of Rop-1. The relevance of the results to selection for insecticide resistance in laboratory and natural populations is discussed.

scholarly journals Phytoremediation Potential of Native Herbaceous Plant Species Growing on a Paradigmatic Brownfield Site

2021 ◽  
Vol 232 (7) ◽  
Author(s):  
N. Matanzas ◽  
E. Afif ◽  
T. E. Díaz ◽  
J. R. Gallego
Keyword(s):  
Plant Species ◽  
Contaminated Soils ◽  
Native Species ◽  
Low Cost ◽  
Plantago Lanceolata ◽  
Herbaceous Plant ◽  
Plant Interactions ◽  
Aerial Parts ◽  
Medicago Lupulina ◽  
Icp Ms

AbstractPhytomanagement techniques using native species allow the recovery of contaminated soils at low cost and circumvent the ecological risks associated with the use of non-native species. In this context, a paradigmatic brownfield megasite highly contaminated by As and Pb was sampled in order to analyze soil–plant interactions and identify plant species with phytoremediation potential. A survey was first carried out in a 20-ha area to obtain an inventory of species growing spontaneously throughout the site. We then performed another survey in the most polluted sub-area (1 ha) within the site. Pseudototal concentrations of contaminants in the soil, aerial parts of the plants, and roots were measured by ICP-MS. A detailed habitat classification was done, and a specific index of coverage was applied by means of a 1-year quadrat study in various sampling stations. Results converged in the selection of six herbaceous species (Dysphania botrys, Lotus corniculatus, Lotus hispidus, Plantago lanceolata, Trifolium repens, Medicago lupulina). All of these plants are fast-growing, thereby making them suitable for use in phytostabilization strategies. Furthermore, they are all easy to grow and propagate and are generally self-sustaining. All six plants showed accumulation factors below 1, thus revealing them as pseudomethallophytes and excluders. However, L. hispidus and M. lupulina showed translocation capacity and are considered worthy of further study.

scholarly journals Terrestrial Morphotypes of Aquatic Plants Display Improved Seed Germination to Deal with Dry or Low-Rainfall Periods

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 741
Author(s):  
Rocío Fernández-Zamudio ◽  
Pablo García-Murillo ◽  
Carmen Díaz-Paniagua
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Aquatic Plants ◽  
Aquatic Plant ◽  
Population Persistence ◽  
Temporary Ponds ◽  
Percent Germination ◽  
Plant Assemblages ◽  
Viable Seeds

In temporary ponds, seed germination largely determines how well aquatic plant assemblages recover after dry periods. Some aquatic plants have terrestrial morphotypes that can produce seeds even in dry years. Here, we performed an experiment to compare germination patterns for seeds produced by aquatic and terrestrial morphotypes of Ranunculus peltatus subsp. saniculifolius over the course of five inundation events. During the first inundation event, percent germination was higher for terrestrial morphotype seeds (36.1%) than for aquatic morphotype seeds (6.1%). Seed germination peaked for both groups during the second inundation event (terrestrial morphotype: 47%; aquatic morphotype: 34%). Even after all five events, some viable seeds had not yet germinated (terrestrial morphotype: 0.6%; aquatic morphotype: 5%). We also compared germination patterns for the two morphotypes in Callitriche brutia: the percent germination was higher for terrestrial morphotype seeds (79.5%) than for aquatic morphotype seeds (41.9%). Both aquatic plant species use two complementary strategies to ensure population persistence despite the unpredictable conditions of temporary ponds. First, plants can produce seeds with different dormancy periods that germinate during different inundation periods. Second, plants can produce terrestrial morphotypes, which generate more seeds during dry periods, allowing for re-establishment when conditions are once again favorable.

The relationship between facial whorl direction and sidedness in ridden horses

2006 ◽  
Vol 35 ◽  
pp. 247-250
Author(s):  
H. Randle ◽  
E. Elworthy
Keyword(s):  
Natural Selection ◽  
Artificial Selection ◽  
Competitive Ability ◽  
Close Association ◽  
Human Behaviour ◽  
Physical Ability ◽  
Facial Hair ◽  
Selection For ◽  
The Relationship ◽  
The Brain

The influence of Natural Selection on the evolution of the horse (Equus callabus) is minimal due to its close association with humans. Instead Artificial Selection is commonly imposed through selection for features such as a ‘breed standard’ or competitive ability. It has long been considered to be useful if indicators of characteristics such as physical ability could be identified. Kidd (1902) suggested that the hair coverings of animals were closely related to their lifestyle, whether they were active or passive. In 1973 Smith and Gong concluded that hair whorl (trichloglyph) pattern and human behaviour is linked since hair patterning is determined at the same time as the brain develops in the foetus. More recently Grandin et al. (1995), Randle (1998) and Lanier et al. (2001) linked features of facial hair whorls to behaviour and production in cattle. Hair whorl features have also been related to temperament in equines (Randle et al., 2003).

Laboratory comparison of the relative success of Biomphalaria glabrata stocks which are susceptible and insusceptible to infection with Schistosoma mansoni

Parasitology ◽  
1983 ◽  
Vol 86 (2) ◽  
pp. 335-344 ◽  
Author(s):  
D. J. Minchella ◽  
P. T. Loverde
Keyword(s):  
Life Cycle ◽  
Natural Selection ◽  
Reproductive Success ◽  
Natural Populations ◽  
Biomphalaria Glabrata ◽  
Selective Advantage ◽  
Controlled Conditions ◽  
Plausible Answer ◽  
Major Objection ◽  
Transmit Disease

SUMMARYA method of interrupting the life-cycle of the human blood fluke Schistosoma by increasing the proportion of genetically insusceptible intermediate host snails in natural populations was first proposed nearly 25 years ago. The method assumes that insusceptible snails will be at a selective advantage over susceptible snails when the schistosome parasite is present, and therefore natural selection will act to increase the proportion of alleles for insusceptibility. A major objection to the proposed technique is ‘If insusceptible snails are at a selective advantage, then why are they not predominant in natural populations that transmit disease?’ One explanation of this paradox is that insusceptibility may be associated with a disadvantageous character or a physiological defect. This study tests this hypothesis by measuring the relative reproductive success of susceptible and insusceptible snails under controlled conditions. Results indicate that insusceptible (unsuitable) snails are negatively affected in the presence of either susceptible snails or schistosome parasites. Furthermore, in the presence of both susceptible snails and schistosome parasites, insusceptible snails are selectively disadvantaged compared to susceptible snails. These results obtained under laboratory-controlled conditions suggest a plausible answer as to why insusceptible snails are not predominant in natural populations that transmit disease.

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