Inter- and intra-population variation in seedling performance of Rio Grande cottonwood under low and high salinity

2004 ◽  
Vol 34 (7) ◽  
pp. 1458-1466 ◽  
Author(s):  
D L Rowland ◽  
A A Sher ◽  
D L Marshall

The Rio Grande watershed ecosystem has been increasingly threatened since the construction of dams and severe channelization in the past century. Rio Grande cottonwood (Populus deltoides var. wislizenii (S. Wats.) Eckenw.) has been suffering stress and high mortality rates with decreased water availability and increased salinity levels. Genetic variation in salt tolerance has been documented in adult cottonwoods, and we hypothesized that these traits might be heritable. This potential heritable genetic variation in seedling offspring might be advantageous in reforestation efforts along the Rio Grande. We screened four New Mexican Rio Grande populations for seedling genotypes that might be salt tolerant and correlated seedling performance under both high- and low-salt treatments with the physiological performance of their open-pollinated family. For all populations, we found significant stunting effects of high salinity on mean leaf size, plant height, total plant mass, root mass, and shoot mass, with no effects on chlorophyll content (as measured by a Minolta SPAD-502 meter) or root/shoot ratio. Although there were no significant differences between the four populations, there were highly significant differences between open-pollinated families within each site. In addition, at one site (San Antonio), genetically based open-pollinated family physiology, as measured in a common garden, was significantly correlated with seedling performance, especially under low-salt conditions. This indicates these traits are heritable, and adult salt tolerance may convey an advantage in offspring establishment under high-salt conditions.

2001 ◽  
Vol 31 (5) ◽  
pp. 845-853 ◽  
Author(s):  
Diane L Rowland

A common garden was established using 120 genotypes of Populus deltoides var. wislizenii (S. Wats.) Eckenwalder from four New Mexico populations (Abiquiu, Corrales, Bernardo, and San Antonio) to examine physiological and morphological differentiation within and among populations. All populations were located within the same watershed along the Rio Grande and one of its tributaries, the Rio Chama. In the common garden, I measured physiological and morphological variation during the 1996 and 1997 growing seasons to determine the extent of inter- and intra-population variation in these traits. In addition, because the sex of each source tree from the field was known, I was able to determine if these same traits varied among male, female, and nonreproductive trees. Small but significant differences within and among populations occurred for photosynthesis, transpiration, and stomatal conductance in both years. Leaf morphological traits also differed within and among populations, including leaf size, chlorophyll content, and specific leaf mass. Stomatal conductance differed significantly between female and nonreproductive trees in both years. This study demonstrated the existence of genetic variation in ecophysiological and morphological traits within and among cottonwood populations and among cottonwoods of differing reproductive status within a single watershed.


Author(s):  
Michelle L. Davis ◽  
Carl Barker ◽  
Ian Powell ◽  
Keith Porter ◽  
Paul Ashton

Abstract The Marsh Fritillary butterfly (Euphydryas aurinia) is a Eurasian species which has suffered significant reductions in occurrence and abundance over the past century, particularly across the western side of its range, due to agricultural intensification and habitat loss. This loss has been particularly severe in the UK with extensive localised extinctions. Following sympathetic management, reintroduction was undertaken at four Cumbria (northern UK) sites in 2007 with stock from a captive admixture population descended from Cumbrian and Scottish founders. Annual population monitoring of the reintroductions was undertaken. Nine years post-reintroduction, the level of population genetic variation was assessed using microsatellites. Variation in historical Cumbrian samples was determined using museum samples and Scottish samples from current populations were assayed to characterise natural population variation. Half of the Scottish sites also served as indicators of the alleles present in the founder populations. The genetic contribution of the founder populations allied to population size data allowed patterns of genetic variation to be modelled. Alleles from Cumbrian and Scottish founders are present in the reintroduced populations. The four sites have levels of variation akin to natural populations and exhibit differentiation as predicted by statistical modelling and comparable with natural populations. This suggests that reintroduction following captive breeding can produce self-sustaining populations with natural levels of genetic diversity. These populations appear to be undergoing the same evolutionary dynamics with bottlenecks and drift as natural populations. Implications for insect conservation Reintroduction of captive bred individuals is a viable strategy for producing populations with natural levels of genetic diversity and evolutionary dynamics. Hybridisation of populations on the brink of extinction with those thriving can preserve some of the genetic distinctiveness of the declining population.


2018 ◽  
Vol 19 (8) ◽  
pp. 2433 ◽  
Author(s):  
Mohamed El-Esawi ◽  
Abdullah Al-Ghamdi ◽  
Hayssam Ali ◽  
Aisha Alayafi ◽  
Jacques Witczak ◽  
...  

Pisum sativum L. (field pea) is a crop of a high nutritional value and seed oil content. The characterization of pea germplasm is important to improve yield and quality. This study aimed at using fatty acid profiling and amplified fragment length polymorphism (AFLP) markers to evaluate the variation and relationships of 25 accessions of French pea. It also aimed to conduct a marker-trait associations analysis using the crude oil content as the target trait for this analysis, and to investigate whether 5-aminolevulinic acid (ALA) could enhance salt tolerance in the pea germplasm. The percentage of crude oil of the 25 pea genotypes varied from 2.6 to 3.5%, with a mean of 3.04%. Major fatty acids in all of the accessions were linoleic acid. Moreover, the 12 AFLP markers used were polymorphic. The cluster analysis based on fatty acids data or AFLP data divided the 25 pea germplasm into two main clusters. The gene diversity of the AFLP markers varied from 0.21 to 0.58, with a mean of 0.41. Polymorphic information content (PIC) of pea germplasm varied from 0.184 to 0.416 with a mean of 0.321, and their expected heterozygosity (He) varied from 0.212 to 0.477 with a mean of 0.362. The AFLP results revealed that the Nain Ordinaire cultivar has the highest level of genetic variability, whereas Elatius 3 has the lowest level. Three AFLP markers (E-AAC/M-CAA, E-AAC/M-CAC, and E-ACA/M-CAG) were significantly associated with the crude oil content trait. The response of the Nain Ordinaire and Elatius 3 cultivars to high salinity stress was studied. High salinity (150 mM NaCl) slightly reduced the photosynthetic pigments contents in Nain Ordinaire leaves at a non-significant level, however, the pigments contents in the Elatius 3 leaves were significantly reduced by high salinity. Antioxidant enzymes (APX—ascorbate peroxidase; CAT—catalase; and POD—peroxidase) activities were significantly induced in the Nain Ordinaire cultivar, but non-significantly induced in Elatius 3 by high salinity. Priming the salt-stressed Nain Ordinaire and Elatius 3 plants with ALA significantly enhanced the pigments biosynthesis, antioxidant enzymes activities, and stress-related genes expression, as compared to the plants stressed with salt alone. In conclusion, this study is amongst the first investigations that conducted marker-trait associations in pea, and revealed a sort of correlation between the diversity level and salt tolerance.


Fine Focus ◽  
2017 ◽  
Vol 3 (2) ◽  
pp. 101-110
Author(s):  
Maedgen Q. Lindsey ◽  
Jennifer R. Huddleston

The goals of this study were to isolate microorganisms from oil well-produced water, identify the microorganisms, and test the microorganisms’ salt tolerance. Saltwater collected from two well locations producing from different zones in Jones County, Texas, was spread onto Mannitol Salt Agar (MSA). Isolates showed a 16S rDNA gene sequence identity of 99% with Idiomarina baltica and Marinobacter persicus. Salt tolerance assays indicated an optimal growth concentration of 10-12.5% NaCl for the Idiomarina isolate and a decrease in growth beyond 5% NaCl for the Marinobacter isolate. In conclusion, organisms that are phylogenetically similar to marine microorganisms are present in oil well environments, and have variable salt tolerances, which may prove useful in microbialmediated hydrocarbon bioremediation of high salinity environments.


2019 ◽  
Vol 159 (3) ◽  
pp. 151-161 ◽  
Author(s):  
Ricardo Micolino ◽  
Maykon P. Cristiano ◽  
Danon C. Cardoso

Trachymyrmex is one of the most species-rich genera within fungus-farming ants and presents intraspecific cytogenetic polymorphisms as well as possible cryptic species. This ant genus is currently paraphyletic. Therefore, to unravel systematic and taxonomic misunderstandings, it is necessary to incorporate new information. We aimed to cytogenetically and genetically examine Trachymyrmex holmgreni populations from southern and northern Brazil to identify intraspecific chromosomal variations that support incipient speciation and reveal the species' position in a molecular phylogeny. Our cytogenetic approach did not show population variation in the mapping of both 18S rDNA and the TTAGG(6) motif, presenting instead a pattern characteristic of correlated species. However, the clustered pattern of the microsatellite GA(15) showed significant differences among populations: a well-defined block in each homologue, distinctly irregular signs between homologues, and blocks in 2 pairs of homologues. Our phylogenetic reconstruction yielded unexpected results, grouping representatives of 3 former morphological groups into 1 clade, namely T. urichii, T. papulatus, and T. holmgreni. Previously, it was suggested that northern and southern populations of T. holmgreni may be undergoing incipient speciation, but we can only indicate that the southernmost population differs prominently from the others in its distribution pattern of the microsatellite GA(15). Our study also supports the uniformity of karyotypes and repetitive DNA from both telomeric sequences and ribosomal DNA in Trachymyrmex studied here. In addition, we clarify some phylogenetic uncertainties within the genus and suggest further relevant systematic changes. Finally, additional studies utilizing other probes and additional populations may allow the detection of hidden genetic variation.


1998 ◽  
Vol 4 (S2) ◽  
pp. 1174-1175
Author(s):  
A.D. Barnabas ◽  
R. Jagels ◽  
W.J. Przybylowicz ◽  
J. Mesjasz-Przybylowicz

Ruppia maritima L. is a submerged halophyte which occurs frequently in estuaries where sodium chloride is the dominant salt. Unlike terrestrial halophytes, R. maritima does not possess any specialised salt-secreting structures such as salt glands. Knowledge of salt tolerance mechanisms in this plant is important to our understanding of its biology. In a previous study it was shown that leaf epidermal cells of R. maritima, which possess transfer cell characteristics, are implicated in salt regulation. In the present investigation, the effect of calcium (Ca) on salt tolerance of leaf epidermal cells was studied since Ca has been found to be an important factor in resistance to salt stress in terrestrial plants.Plants were grown in artificial seawater of high salinity (33%) and at two different Ca concentrations : 400 ppm (high Ca) and 100 ppm (low Ca).


2020 ◽  
Vol 13 (2) ◽  
pp. 59-67
Author(s):  
Ryan A. Thum ◽  
Gregory M. Chorak ◽  
Raymond M. Newman ◽  
Jasmine A. Eltawely ◽  
Jo Latimore ◽  
...  

AbstractPopulation genetic studies of within- and among-population genetic variability are still lacking for managed submerged aquatic plant species, and such studies could provide important information for managers. For example, the extent of within-population genetic variation may influence the potential for managed populations to locally adapt to environmental conditions and control tactics. Similarly, among-population variation may influence whether specific control tactics work equally effectively in different locations. In the case of invasive Eurasian watermilfoil (Myriophyllum spicatum L.), including interspecific hybrids with native northern watermilfoil (Myriophyllum sibiricum Kom.), managers recognize that there is genetic variation for growth and herbicide response. However, it is unclear how much overall genetic variation there is, and how it is structured within and among populations. Here, we studied patterns of within- and among-lake genetic variation in 41 lakes in Michigan and 62 lakes in Minnesota using microsatellite markers. We found that within-lake genetic diversity was generally low, and among-lake genetic diversity was relatively high. However, some lakes were genetically diverse, and some genotypes were shared across multiple lakes. For genetically diverse lakes, managers should explicitly recognize the potential for genotypes to differ in control response and should account for this in monitoring and efficacy evaluation and using pretreatment herbicide screens to predict efficacy. Similarly, managers should consider differences in genetic composition among lakes as a source of variation in the growth and herbicide response of lakes with similar control tactics. Finally, laboratory or field information on control efficacy from one lake may be applied to other lakes where genotypes are shared among lakes.


2008 ◽  
Vol 43 (No. 1) ◽  
pp. 7-15 ◽  
Author(s):  
P. Múdry ◽  
J. Kraic

Evaluation of genetic variation was performed within 62 local maize populations originating from Slovakia and Czech Republic. In total 48 alleles at 22 analyzed isoenzyme loci with an average of 2.2 alleles per locus were revealed. The percentage of polymorphic loci ranged from 14% to 59% and the frequencies of detected alleles varied from null to four per locus. No polymorphism was detected at the loci <i>Dia2</i>, <i>Got3</i>, <i>Mdh4</i>, <i>Mmm</i>, and <i>Pgm1</i>. The highest number of alleles (four) was detected at loci <i>Acp1</i>, <i>Cat3</i>, <i>Pgm2</i>. No new alleles were identified, nevertheless the frequency of seven alleles was only about 1%. The expected heterozygosity ranged from null to 0.492 with an average of 0.197. The revealed isoenzyme polymorphism confirmed that all analyzed populations were heterogeneous and as many as 17 of them were completely heterogeneous. None of the analyzed populations was identical in the frequency of alleles at all 22 analyzed loci.


2020 ◽  
Vol 3 (1) ◽  
pp. 14-29
Author(s):  
Guo-Dong Han ◽  
Yun-Wei Dong

Climate-driven adaptive genetic variation is one of the most important ways for organisms to tolerate environmental change and succeed in altered environments. To understand rapid climate-driven evolution, and how this evolution might shift biogeographic distributions in response to global change, we measured the adaptive genetic variation to the local environment of a marine invasive species Mytilus galloprovincialis. The genetic structure of eight populations from the Mediterranean Sea, northeastern Atlantic, northeastern Pacific, and northwestern Pacific were determined using genome-wide screens for single nucleotide polymorphisms. The relationships of genetic variation to environmental (seawater and air) temperature were analyzed using redundancy analysis and BayeScEnv analysis to evaluate the impacts of temperature on the genetic divergences among these eight populations. We found that the genetic compositions were significantly different among populations and the adaptive genetic variation was associated with temperature variables. Further, we identified some genetic markers exhibiting signatures of divergent selection in association with environmental features that can be used in the future to closely monitor adaptive variation in this species. Our results suggest that divergent climatic factors have driven adaptive genetic variation in M. galloprovincialis over the past century. The rapid evolutionary adaptation has played a pivotal role in enabling this species to invade a wide range of thermal habitats successfully. Species like M. galloprovincialis that possess high levels of genetic variation may not only be especially capable of invading new habitats with different environmental conditions, but also poised to cope rapidly and successfully with rising global temperatures.


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 287 ◽  
Author(s):  
Ibrahim Al-Ashkar ◽  
Ali Alderfasi ◽  
Walid Ben Romdhane ◽  
Mahmoud F. Seleiman ◽  
Rania A. El-Said ◽  
...  

Salinity is a major obstacle to wheat production worldwide. Salt-affected soils could be used by improving salt-tolerant genotypes depending upon the genetic variation and salt stress response of adapted and donor wheat germplasm. We used a comprehensive set of morpho-physiological and biochemical parameters and simple sequence repeat (SSR) marker technique with multivariate analysis to accurately demonstrate the phenotypic and genetic variation of 18 wheat genotypes under salinity stress. All genotypes were evaluated without NaCl as a control and with 150 mM NaCl, until the onset of symptoms of death in the sensitive plant (after 43 days of salinity treatment). The results showed that the relative change of the genetic variation was high for all parameters, heritability (>60%), and genetic gain (>20%). Stepwise regression analysis, noting the importance of the root dry matter, relative turgidity, and their respective contributions to the shoot dry matter, indicated their relevance in improving and evaluating the salt-tolerant genotypes of breeding programs. The relative change of the genotypes in terms of the relative turgidity and shoot dry matter during salt stress was verified using clustering methods. For cluster analysis, the genotypes were classified into three groups: tolerant, intermediate, and sensitive, representing five, six, and seven genotypes, respectively. The morphological and genetic distances were significantly correlated based on the Mantel test. Of the 23 SSR markers that showed polymorphism, 17 were associated with almost all examined parameters. Therefore, based on the observed molecular marker-phenotypic trait association, the markers were highly useful in detecting tolerant and sensitive genotypes. Thus, it considers a helpful tool for salt tolerance through marker-assisted selection.


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