Genetic analysis of morphological variability in three Plantago species with different mating systems

Summary Morphological variability in three Plantago species possessing different mating systems — P. Major, P. coronopus, and P. lanceolata — was analyzed. From each species several populations were analyzed. In comparing the species, it appeared that both the inbreeding P. major and the outbreeding P. lanceolata showed a high degree of morphological differentiation between populations. It was hypothesized that the absence of population differentiation for the species with a mixed mating system, P. coronopus, was caused by high adaptive plasticity. Plasticity is probably the predominant mechanism by which this species copes with different environments. There were considerable differences between populations within each species for their levels of variability and their heritabilities. It appeared that besides the influence of the mating system, selection may diminish morphological variability in the case of strong directional selection, especially in P. major and P. lanceolata.Grassland Species Research Group Publication No. 135     

Population and species variation of minisatellite DNA in Plantago

Three Plantago species were surveyed for within- and between-population variation at DNA sequences detected with the M13 minisatellite probe. The levels and patterns of variation detected by this probe correspond to those expected from the mating systems of the species. The highly-selfing species P. major has a relatively low variability of minisatellite sequences within populations and considerable differentiation between populations. The outcrossing species P. lanceolata exhibits higher minisatellite variability within populations and moderate differentiation between populations. P. coronopus, with a mixed mating system, has levels of variation intermediate between P. major and P. lanceolata. The levels of variation within and between populations corresponds, in general, to the levels of allozyme variation determined in an earlier study. Mating system and population structure appear to have a major influence on M13-detected fragment variation.     

Genetic variability in Plantago species in relation to their ecology

Summary Populations of the three Plantago species P. major, P. lanceolata and P. coronopus were scored for allozyme variability. They showed normal variability levels compared with other, similar plant species. Differentiation among populations appeared to be rather low in comparison with other species, probably due to a considerable amount of long distance seed transport. In order to be able to make an analysis of small-scale gene flow, all (sub)populations were critically checked for the existence of population structure equilibrium. The allozyme variation was tested for neutrality by testing homogeneity of F values among loci: between populations (Lewontin-Krakauer test) and within populations. No systematic deviations from the prediction of the neutral theory could be established. From the population structure analyses, little gene flow in the species P. major (with high selfing levels) and P. coronopus could be concluded, whereas P. lanceolata showed relatively high levels of gene flow. The degree of homozygosity in the latter species was too high to explain with the available data. In P. coronopus, on the other hand, an unusually high number of heterozygotes were observed.Grassland Species Research Group Publication No. 73     

Chloroplast DNA variation within and among five Plantago species

Chloroplast DNA variation was studied within and among five Plantago species. We determined polymorphism by surveying 86% of the chloroplast genome using 9 or 11 restriction enzymes for intra or interspecific variation, respectively. All five species were polymorphic for both site and length mutations. The outcrossing P. lanceolata has six chloroplast haplotypes of which some were found in the Netherlands as well as in the United States. The highly selfing P. major had five haplotypes and Dutch and United States populations were differentiated from each other in cpDNA. Plantago species are highly differentiated from each other. Of 252 restriction-sites, 52% were variable among species. Most of this variation was localized in part of the large single copy region. We derived a molecular phylogeny of the five species from restriction-site variability using PAUP 3.0. P. coronopus and P. maritima form a group as do P. major and P. media. P. lanceolata is more distantly related to the other four species. In a consensus tree both P. major haplotypes and both P. media haplotypes were connected to one node.     

Lipid Composition of the Roots of Plantago Species: Response to Alteration of the Level of Mineral Nutrition and Ecological Significance

In a study of the adaptation of Plantago species to their specific environment the lipid composition of the roots of several species: Plantago major L. ssp. major, Plantago major L. ssp. pleiosperma Pilger, Plantago lanceolata L., Plantago media L., Plantago maritima L., Plantago coronopus L. was studied as well as the effect of the nutritional regime. Upon exposure to low-salt conditions Plantago major L. ssp. major L. and Plantago maritima L. maintained the level of free sterols in the roots, despite a depressed level of total sterols, and the root lipids were more saturated than under high-salt conditions. Both factors may reduce nutrient leakage from the roots to the low-salt condition. Upon exposure to low-salt conditions, all Plantago species showed a decreased level of galactolipid (exception: Plantago coronopus) and a decreased level of sitosterol (exception: Plantago maritima); the latter being compensated by an elevated level of cholesterol + tocopherol in Plantago major ssp. pleiosperma, Plantago lanceolata and Plantago media. Plantago coronopus was the only species which under low-salt conditions showed an increased level of free sterols, among which cholesterol was the most important; thus indicating a high degree of regulation of membrane permeability under alternating nutritional conditions. The level of sulfolipid was kept constant in all Plantago species, with the highest level observed in Plantago maritima. The role which various lipids may play in maintenance of membrane integrity under alternating nutritional conditions is discussed.     

Genetic systems of six species ofPlantago (Plantaginaceae)

Investigation of the genetic system of six species ofPlantago has revealed striking differences in their breeding and meiotic systems.Plantago patagonica is an inbreeder on account of preanthesis cleistogamy, whereasP. lanceolata is an obligate outbreeder, as it is self-incompatible.Plantago drummondii, P. lagopus, P. ovata, andP. major show mixed mating but in varying proportions. In terms of their energy budgets, outbreeding species invest more in floral advertisement and male function, while inbreeders invest more in female function. The contribution of the meiotic system to genetic variability, as revealed through recombination index, is more important in the inbreeding species.     

Nitrate production in the rhizosphere of Plantago species

Summary The production of nitrate in an old established dune grassland soil and its uptake by plants was studied by comparing amounts of mineral nitrogen and numbers of nitrifying bacteria in the rhizosphere on the one hand, and on the other accumulated nitrate and levels of nitrate reductase (NaR) of individual plants of three Plantago species,i. e., P. major, P. lanceolata andP. coronopus. For these three Plantago species andP. media basal levels of NaR in the absence of nitrate were determined in plants grown in culture solutions. The basal NaR levels ofP. major andP. media (species occurring on nutrient-rich soils) were significantly higher than those ofP. lanceolata andP. coronopus (species found on nutrient-poor soils). NaR activity increased in the presence of nitrate and was suppressed by ammonium.From the numbers of nitrifying bacteria in the rhizosphere and NaR activity in the leaves it was concluded that nitrate was produced in the root environments of the three Plantago species and that the compound was taken up by the plants. NaR activities and numbers of nitrifying bacteria were higher for individuals ofP. major than for those ofP. lanceolata andP. coronopus. No correlation was found between the ammonium levels and the numbers of nitrifying bacteria in the soil, and no indications of inhibition of nitrifying bacteria in the rhizosphere were obtained. For individuals ofP. lanceolata a correlation was found between the numbers of nitrifying bacteria in the soil and NaR activity in the leaves. The results are discussed in relation to the ecological habitats of the three species.Grassland Species Research Group Publication No.38.     

Ca2+ and Mg2+-Stimulated ATPases from Roots of Plantago lanceolata, Plantago media and Plantago coronopus: Response to Alterations of the Level of Mineral Nutrition and Ecological Significance

Growth of Plantago lanceolata L., P. media L. and P. coronopus L. was followed at two levels of mineral nutrition (low-salt and high-salt). In addition the response of transfer of plants from low-salt conditions to high-salt conditions and vice versa was studied. Growth of these Plantago species was not much affected by the nutritional level. P. coronopus showed the least dependence on the level of mineral nutrition. The Ca²⁺- and Mg²⁺-stimulated ATPase activity of microsomal preparations of the roots of Plantago was also studied. A pH optimum at pH 6.5 was observed in all species, together with a relatively high ATPase activation by Mg²⁺ in P. lanceolata, by Ca²⁺ in P. media, and by both ions in P. coronopus. The specific activity of the ATPases was highest in preparations from low-salt roots. The three species all occur in relatively nutrient-poor habitats, but they are at the same time particularly adapted to circumneutral soils (P. lanceolata), to Ca²⁺-rich soils (P. media) and to alternating levels of mineral nutrition (P. coronopus). The properties of the ATPases (K_m, V_max, protein content) and the growth are discussed in relation to these ecological properties of the species.     

Comparison of Plantago Species from Nutrient-rich and Nutrient-poor Conditions: Growth Response, ATPases and Lipids of the Roots, as Affected by the Level of Mineral Nutrition

Two groups of Plantago species, one of relatively nutrient-rich habitats (Plantago major L., P. major L. ssp. pleiosperma Pilger and P. martrima L.) and the other of relatively nutrient poor habitats (P. lanceolata L., P. media L. and P. coronopus L.), were compared with respect to the response of the plants to alterations of the level of mineral nutrition. The comparison deals with growth response and root cell membrane functions (Ca²⁺ and Mg²⁺ stimulated ATPases and lipids). As far as these parameters are concerned species from relatively nutrientpoor habitats are not much affected by bringing the plants to high-salt conditions, while the reverse was true for species from relatively nutrient-rich habitats when transferred to low salt medium.     

Establishment of Plantago lanceolata L. and Plantago major L. among grass

Summary Establishment of Plantago lanceolata and P. major ssp major among grass was studied in a field experiment in which survival and selection on date of seedling emergence and plant size was investigated in relation to the vegetation structure. P. major — in contrast to P. lanceolata — was not able to establish itself in grass because of its lower competitive ability caused by later germination, smaller seedling size, and shorter leaves. In both species there was selection for early germination. For P. lanceolata a significant correlation was found between the strength of selection and the light climate, determined by the structure of the grass sward. Plants that germinated early were at an advantage because they were larger, especially the leaves, when compared with plants that germinated late. It seems likely that selection was mainly by competition for light. Contrary to expectation P. major-seedlings had a higher shade tolerance than those of P. lanceolata. The performance of both species is discussed in relation to their different life strategies.Grassland species research group publication no 142     

Integrated analyses of chromosome, molecular and morphological variability in the Andean mice Eligmodontia puerulus and E. moreni (Rodentia, Cricetidae, Sigmodontinae)

Patterns of evolution and systematics of sigmodontine rodents are matters of continuous revision and debate. The silky mouse, Eligmodontia, is a phyllotine rodent adapted to arid environments. Chromosomal and molecular data have identified six species in this genus. Among these E. puerulus and E. moreni are sister taxa from the high Andean and lowland deserts, respectively, with large chromosomal differences and intermediate levels of molecular divergence. The purpose of our study was to quantify the degree of variability (morphological, cytogenetic, and molecular) and to analyze its evolutionary implications within, and between, these sister species in the Monte and Puna biomes of Argentina. Our results show a high variability at the chromosomal and molecular level, but low morphological differentiation among populations of E. puerulus. Diploid numbers vary from 31 to 37 due to a complex Robertsonian system, whereas cytochrome-b distances range from 0.15% to 5.75%. On the other hand, E. moreni shows high morphological differentiation between populations, but low intraspecific differentiation at the molecular (from 0.73% to 1.4%) and chromosomal level (2n = 52). Comparison of E. puerulus with E. moreni reveals high morphological and chromosomal distinction between them, but absence of molecular differentiation. Our results suggest that: (1) the high genetic variability of E. puerulus could be associated to its geographic distribution in the complex topography of the high Andean Puna; (2) the high morphological differentiation between E. moreni and E. puerulus could be the result of natural selection; and (3) molecular polyphyly between E. puerulus and E. moreni could be due to introgression or a recent split of these taxa. Finally, our results emphasize the need to integrate different datasets in the analysis of species variability and diversification, as tools for understanding their evolutionary histories.     

Genetic structure and differentiation of Plantago major reveals a pair of sympatric sister species

Seeds of the widespread weed Plantago major were collected from 10 European countries, as well as Trinidad and North America. The seed collections were from populations of two taxa which are ecologically rather than geographically separated and formally recognized as the subspecies Plantago major ssp. major and P.m. ssp. intermedia (also called P.m. ssp. pleiosperma). Eight polymorphic allozyme loci and 73 random-primed DNA fragments were scored, as well as 11 morphological characters. Complete concordance between morphological traits and genetic data provides evidence that these two taxa, although very similar, are distinct species. They are both widespread, they are broadly sympatric and capable of interbreeding. However, slight morphological and ecological differences coincide with genetic clustering of populations from widely separated locations. In addition, P. major and P. intermedia differ in their population structure: P. intermedia has greater genetic diversity among populations and less genetic variance within populations than P. major. We suggest that differences between the two species in their levels of selfing may explain the distinctive genetic structure of each species. We hypothesize a link between selfing rate and lifespan of the two taxa. P. major is characterized by lower genetic variation among populations, a higher rate of outcrossing, longer lifespan and production of fewer seeds per seed capsule. P. intermedia is more highly structured with much differentiation among populations, a higher rate of inbreeding and it often grows as an annual.     

Polymorphic microsatellite loci in Plantago lanceolata

The genus Plantago is particularly interesting for evolutionary studies because of its wide range of mating systems. We have developed primers for five highly polymorphic microsatellite loci isolated from P. lanceolata. All five loci amplified and were polymorphic in the two populations examined, Lowsteads Beach in the United Kingdom and Duke in the United States. These new markers will allow a comparison of population structure between the outcrossing species P. lanceolata, and the highly selfing species P. major.     

Anti-mitotic and anti-genotoxic effects of Plantago lanceolata aqueous extract on Allium cepa root tip meristem cells

Plantago is the most important genus of Plantaginaceae family and is used in traditional medicine around the world for different purposes. Plantago coronopus L., Plantago major L., Plantago media L. and Plantago lanceolata L. are most commonly used species of Plantago in traditional medicine in Turkey. The main goal of this study was to investigate the eventual anti-mitotic and anti-genotoxic effects of P. lanceolata L. leaf aqueous extracts (15 g/L and 30 g/L) on Allium cepa L. root tip meristem cells which were treated with 0.7% hydrogen peroxide. For this purpose, two different experiments were performed under the same conditions. In the first experiment, Allium cepa onion bulbs were treated with 0.7% H₂O₂ for 1 h. After the H₂O₂ treatment, the onion bulbs were treated with two different concentrations (15 g/L and 30 g/L) of P. lanceolata extracts for 24 h. In the second experiment, A. cepa onion bulbs were treated with two different extract concentrations (15 g/L and 30 g/L) for 24 h and then with 0.7% H₂O₂ for 1 h. The test concentrations were determined according to doses which are recommended in alternative medicinal usage by people. As positive and negative control 0.7% H₂O₂ and tap water was used, respectively. As a result, it was determined that aqueous extracts reduced mitotic index and chromosome aberrations in treatment groups in comparison with controls. These results showed that P. lanceolata aqueous extracts have anti-mitotic and anti-genotoxic effects.     

中甸灯台报春与鹅黄灯台报春的系统演化

中甸灯台报春和鹅黄灯台报春在形态上较为相似,通常被认为是亲缘关系较近的物种。该研究选取核基因ITS序列和叶绿体trn L-F为分子标记,利用贝叶斯的方法构建系统树,在用两种分子标记构建的系统树中,两种报春均以0.81的支持率聚成一个分支,明确了两种报春的姐妹种关系。首先,通过选取两个物种的五个形态学性状,进行主成分分析,聚类结果中两种报春各自的个体分别聚在两块区域,表明两种报春的形态学性状产生了明显的分化,且中甸灯台报春的花部各性状值明显大于鹅黄灯台报春,表明花部综合征和繁育系统间的相关联系。然后,通过用8对SSR分子标记对两种报春进行STRUCTURE聚类分析,结果检测K的最适值为2,此时中甸灯台报春和鹅黄灯台报春的个体各自以不同颜色聚成界限清晰的两块区域,揭示了两种报春在分子水平上也产生了显著而稳定的分化,通过Ima2软件,依据叶绿体联合序列,计算了两种报春的分化时间大约是在更新世,推测这两个姐妹种的物种分化受更新世气候动荡和一些地质历史事件的影响。最后,运用maxent软件分析两个物种的生态位差异,结果表明最干季节降水量、年均降水量和季节性降水量对中甸灯台报春的分布有重要影响,最冷季节平均温度、最干月降水量、年均降水量和季节性降水量对鹅黄灯台报春的分布有重要影响,两个物种间的生态位产生了分化。由此推测,这种生态位的差异是物种分化的结果,同时也是物种间系统演化的重要驱动力。     

Dental variation ofProconsulfrom the Tinderet region, Kenya

The morphology of mandibular molars of the twoProconsulspecies,Proconsul majorandProconsul africanus, from the Tinderet region, Kenya was analyzed. While the molar size variability within the TinderetP. majorwas slightly greater than those of local African ape subspecies, the shape variability was comparable. Because the twoProconsulspecies show some differences in cusp areal proportions,P. majoris not just a largerP. africanusin molar morphology. Napak specimens are generally similar to the TinderetP. major.     

Local adaptation at range edges: comparing elevation and latitudinal gradients

Local adaptation at range edges influences species’ distributions and how they respond to environmental change. However, the factors that affect adaptation, including gene flow and local selection pressures, are likely to vary across different types of range edge. We performed a reciprocal transplant experiment to investigate local adaptation in populations of Plantago lanceolata and P. major from central locations in their European range and from their latitudinal and elevation range edges (in northern Scandinavia and Swiss Alps, respectively). We also characterized patterns of genetic diversity and differentiation in populations using molecular markers. Range‐centre plants of P. major were adapted to conditions at the range centre, but performed similarly to range‐edge plants when grown at the range edges. There was no evidence for local adaptation when comparing central and edge populations of P. lanceolata. However, plants of both species from high elevation were locally adapted when compared with plants from high latitude, although the reverse was not true. This asymmetry was associated with greater genetic diversity and less genetic differentiation over the elevation gradient than over the latitudinal gradient. Our results suggest that adaptation in some range‐edge populations could increase their performance following climate change. However, responses are likely to differ along elevation and latitudinal gradients, with adaptation more likely at high‐elevation. Furthermore, based upon these results, we suggest that gene flow is unlikely to constrain adaptation in range‐edge populations of these species.     

The effect of nitrate concentration in a flowing solution system on growth and nitrate uptake of twoPlantago species

Summary Juvenile plants ofPlantago lanceolata andP. major ssp.major were grown in a flowing solution system at 7.5 mM or 9.5 M NO₃. The parameters investigated were: RGR, shoot weight percentage, leaf length, length of main root axis, shoot concentrations of major ions and organic N, and the specific uptake rate for NO₃. At 9.5 M NO₃ growth ofP. major was not hampered, whereas shoot growth and leaf length ofP. lanceolata were reduced. The NO₃ concentration ofP. lanceolata decreased more than that ofP. major. The different performances of the species at 9.5 M NO₃ were associated with different specific uptake rates. In both treatments the root system ofP. major was shorter than that ofP. lanceolata. P. lanceolata accumulated more NO₃ in the leaves. The performance of thePlantago species is discussed in relation to the availability of nutrients in their habitats.Grassland Species Research Group. Publication no. 37.     

Genetic variability in Plantago species in relation to their ecology

Summary A survey of enzyme variability in several populations of Plantago major in the Netherlands has been made. Nine of 36 loci were found to be polymorphic. The most extensively studies population showed 7 polymorphic loci (19%). The average heterozygosity was 0.005, a low value since P. major is predominantly inbreeding; a first estimate of the outcrossing rate is only 10%. All nine variable loci show simple Mendelian inheritance, seven of them could be placed into four different linkage groups. Marked differences in allele frequencies were found between two subspecies: ssp. major and ssp. pleiosperma. Two enzyme loci possess subspecies-specific alleles, Pgm-1 and Got-1. The most likely explanation of this phenomenon is the existence of fitness differences, caused either by the enzyme loci themselves or by linked loci.Grassland Species Research Group Publication no. 14     

Consistency of population genetics parameters estimated from isozyme and RAPDs dataset in species of genus <Emphasis Type="Italic">Prosopis</Emphasis> (Leguminosae,Mimosoideae)

Genetic variability, population structure and differentiation among 17 populations of 5 species and 2 natural interspecific hybrids of section Algarobia of genus Prosopis were analyzed from data of 23 isozyme and 28 RAPD loci. Both markers indicated that the studied populations are highly variable. P. alba populations in average showed lower values of genetic variability estimates from isozyme data, but this trend was not observed for RAPD markers. The hierarchical analyses of the distribution of genetic variability showed that the highest proportion of variation occurred within populations, the differentiation among species was intermediate and the lowest component was observed among populations within species. The consistency between results from both dataset implies that they are not biased and reflect the actual genetic structure of the populations analyzed. The matrices of Euclidean distances obtained from the two sets of markers were highly correlated according to Mantel test. In both cases the corresponding phenogram and MDS plot tended to cluster conspecific populations while hybrid populations were not intermediate between putative parents. Some disagreements between isozyme and RAPD phenograms were observed mainly in the affinities of hybrid populations. Such inconsistencies might result from reticular rather than dichotomic evolutionary relationships. The phenetic associations retrieved gave no support to the division of the section Algarobia into series.