scholarly journals Inside-out flowers ofLacandonia brasiliana(Triuridaceae) provide new insights into fundamental aspects of floral patterning

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1653 ◽  
Author(s):  
Paula J. Rudall ◽  
Marccus Alves ◽  
Maria das Graças Sajo
Keyword(s):  
Pollen Grains ◽  
Sister Species ◽  
Homeotic Transformation ◽  
Evolutionary Origins ◽  
Ontogenetic Study ◽  
Morphological Differences ◽  
Source Populations ◽  
Germinating Pollen ◽  
Inside Out ◽  
Two Populations

Background and Aims. A recently described Brazilian species,Lacandonia brasiliana, shares with its longer established putative sister species from Mexico,L. schismatica, inverted floral patterning (carpels surrounding stamens) that is almost unique among angiosperms. We present a detailed ontogenetic study ofL. brasilianafor comparison with other members of the tribe Triurideae (Triuridaceae) to explore the possible evolutionary origins of “inside-out” flowers.Methods. Wild-source populations ofL. brasilianawere compared morphologically and ontogenetically with related species of Triurideae, using light and scanning electron microscopy.Key Results. Relatively few morphological differences separate flowers ofL. brasilianaandL. schismatica. Both species have tepals with late-developing subapical appendages. In both species, the three central (almost sessile) anthers develop precociously with respect to the carpels; the anthers remain closed, and fertilization is achieved via pollen-tube growth from germinating pollen grains of the same cleistogamous flower. Carpels are initiated on fascicles.Conclusions. The close similarity between the twoLacandoniaspecies makes it unlikely that they arose independently from two separate homeotic transformation events; they could either represent sister species or two populations of a single disjunct species. Our study underlines the problematic generic and species boundaries within Triurideae. We present an evolutionary scenario of character evolution in Triuridaceae. The inside-outLacandoniaflower could have resulted from a stabilized homeotic transformation; this hypothesis is not in conflict with constrasting theories of the origin of the Triuridaceae flower, which coincided with a shift to unisexuality. The unisexual yet highly plastic flowers that are typical of Triuridaceae could have pre-adapted the origin of the extraordinaryLacandoniamorphology.

scholarly journals Tradescantia bracteata pollen in vitro: pollen tubes development and mitosis

2015 ◽  
Vol 46 (4) ◽  
pp. 587-598 ◽  
Author(s):  
E. Lewandowska ◽  
M. Charzyńska
Keyword(s):  
Pollen Tube ◽  
Generative Cell ◽  
Metaphase Plate ◽  
Pollen Grains ◽  
Neutral Red ◽  
Generative Nucleus ◽  
Mitotic Spindles ◽  
Germinating Pollen ◽  
Vacuolar System

About 90 per cent of <i>Tradescantia bracteata</i> pollen germinates <i>in vitro</i> after 15 min. Mitosis starts in the pollen tube after about 3 h. The mitotic trans-formations of chromosomes within the generative nucleus are not synchronized. They involve succesively the linearly arranged chromosomes in the elongated generative nucleus. In metaphase the chromosomes are arranged tandem-like linearly along the pollen tube. The chromatides translocate in anaphase from various distances to the poles in a plane parallel to the metaphase plate. This suggests that chromosomes have individual mitotic spindles and that coordination of the chromosome transformations in the generative cell is much less strict than in a typical somatic mitosis. Starch is the storage material of pollen grains. In the vegetative cytoplasm of mature pollen grains minute reddish-orange vesicular structures are visible after staining with neutral red. They do not fuse with the vacuoles proper arising in germinating pollen grains to form the vacuolar system of the pollen tube.

Molecular Differentiation Within and Between Eucalyptus risdonii, E. amygdalina and Their Hybrids Using RAPD Markers

1996 ◽  
Vol 44 (5) ◽  
pp. 559 ◽  
Author(s):  
MM Sale ◽  
BM Potts ◽  
AK West ◽  
JB Reid
Keyword(s):  
Rapd Markers ◽  
Random Amplified Polymorphic Dna ◽  
Genetic Isolation ◽  
Population Differences ◽  
Genetic Affinity ◽  
Hybrid Swarm ◽  
Leaf Phenotype ◽  
Morphological Differences ◽  
Two Populations ◽  
Advanced Generation

Random amplified polymorphic DNA (RAPD) studies of a natural hybrid swarm between Eucalyptus amygdalina Labill. and E. risdonii Hook.f. and nearby allopatric stands revealed that, despite clear morphological differences, all bands were shared between species. However, frequency differences revealed genetic divergence between species, populations within species, and individuals within populations. Variation was greatest between individuals within populations and lowest between species. For both species, the direction of variation which distinguished the two populations was in a different direction to that which separated the two species, suggesting population differences were not due to introgression but were the result of genetic isolation and/or strong localised selection. Several morphologically typical individuals with intermediate RAPD profiles were detected in the hybrid swarm and nearby allopatric samples of both species, suggesting that some cryptic introgression may be occurring. Controlled F1 crosses generally had closer genetic affinity to E. risdonii, raising the possibility that some parents used may have been advanced generation hybrids. While natural hybrids selected for their intermediate leaf phenotype were usually also intermediate between the two species using RAPD markers, some deviated markedly toward E. risdonii. The study suggests that morphological appearance does not necessarily reflect genetic (RAPD) status and in some cases detectable RAPD differences between spatially close populations of the same species may be as great or greater than the differences between species.

scholarly journals Pollen Dimorphism of Several Members of Nymphaeaceae and Nelumbonaceae: An Index of Geographical and Ecological Variation

2012 ◽  
Vol 4 (3) ◽  
pp. 38-44 ◽  
Author(s):  
Somnath BHOWMIK ◽  
Badal Kumar DATTA
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Size Variation ◽  
Pollen Grains ◽  
Pollen Dimorphism ◽  
Geographical Variations ◽  
Genetic Impact ◽  
The Difference ◽  
Morphological Differences ◽  
Scanning Electron

Pollen morphology of five Nymphaea (Nymphaeaceae) species, growing in Tripura, India were analysed using Scanning Electron Microscopy. Pollen grains of Nymphaea are dimorphic (ellipsoidal and spheroidal). The exine pattern also varies among the species. The variation as reported in the present study in terms of exine pattern of the studied species suggests the feasibility of applying the data in the identification of the genus of Nymphaea. The difference in exine patterns with the earlier reports may be interpreted as reflections of genetic variations possibly due to mutational changes effected by ecological conditions. The present pollen dimorphism may be attributed by introgression of populations. The variability in pollen morphology, including size variation and morphological differences, is often associated with hybrids among angiosperm groups. The examinations of percentages of aborted grains, generally considered a good indicator of hybridity. The occurrence of monosulcate pollens in Nelumbo nucifera along with dominant tricolpate pollens may be considered as aberrant pollens because of very low percentage of occurrence of monosulcate pollens. The ecological and geographical variations in pollen morphology could be an index of the genetic impact of the environment on the plant. Thus the present difference in terms of exine pattern could be useful to separate them at varietal level.

scholarly journals Morphological analysis of pollen grains from heterodynamous stamens of some Aeschynomene L. (Le guminosae - Papilionoideae - Dalbergieae)

Hoehnea ◽  
2018 ◽  
Vol 45 (4) ◽  
pp. 669-676
Author(s):  
Higor Antonio-Domingues ◽  
Angela Maria da Silva Corrêa ◽  
Monica Lanzoni Rossi ◽  
Adriana Pinheiro Martinelli ◽  
Cynthia Fernandes Pinto da Luz
Keyword(s):  
Pollen Morphology ◽  
Morphological Analysis ◽  
Pollen Grains ◽  
Size Group ◽  
Morphological Data ◽  
Pollen Dimorphism ◽  
Standard Methodology ◽  
Morphological Differences ◽  
Taxonomic Studies ◽  
Group Species

ABSTRACT Flowers with heterodynamous stamens can present differences in the pollen grains of each stamen size group. Species of Aeschynomene L. present didynamous stamens (five long and five short) but little is known about their pollen dimorphism. The objective of this study was to increase the knowledge about the pollen characteristics in Aeschynomene and emphasize the possible morphological differences between the pollen grains of long and short stamens in order to contribute to ecological and taxonomic studies. Pollen grains from the two groups of stamens size of ten species were analyzed separately, according to the standard methodology for studies of pollen morphology. In addition, analyses of variance, comparison of means and base index were performed. The results showed that the amb, shape, endoaperture type and sexine ornamentation did not vary in the pollen grains of the long and short stamens in the same specimen, but they varied among the species. However, in relation to the size of the pollen grains of the two groups of stamens, four species presented significant differences regarding the size of the polar and equatorial axes. The pollen morphological data obtained considering the heteromorphism of the stamens can contribute to the knowledge of the repro ductive dynamics of the genus, and to the systematic studies.

scholarly journals Dispersal and selection mediate hybridization between a native and invasive species

2015 ◽  
Vol 282 (1799) ◽  
pp. 20142454 ◽  
Author(s):  
Ryan P. Kovach ◽  
Clint C. Muhlfeld ◽  
Matthew C. Boyer ◽  
Winsor H. Lowe ◽  
Fred W. Allendorf ◽  
...  
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Genetic Admixture ◽  
Phenotypic Traits ◽  
Genetic Introgression ◽  
Selection Coefficient ◽  
Oncorhynchus Clarkii ◽  
Younger Age ◽  
Source Populations ◽  
Two Populations

Hybridization between native and non-native species has serious biological consequences, but our understanding of how dispersal and selection interact to influence invasive hybridization is limited. Here, we document the spread of genetic introgression between a native ( Oncorhynchus clarkii ) and invasive ( Oncorhynchus mykiss ) trout, and identify the mechanisms influencing genetic admixture. In two populations inhabiting contrasting environments, non-native admixture increased rapidly from 1984 to 2007 and was driven by surprisingly consistent processes. Individual admixture was related to two phenotypic traits associated with fitness: size at spawning and age of juvenile emigration. Fish with higher non-native admixture were larger and tended to emigrate at a younger age―relationships that are expected to confer fitness advantages to hybrid individuals. However, strong selection against non-native admixture was evident across streams and cohorts (mean selection coefficient against genotypes with non-native alleles ( s ) = 0.60; s.e. = 0.10). Nevertheless, hybridization was promoted in both streams by the continuous immigration of individuals with high levels of non-native admixture from other hybrid source populations. Thus, antagonistic relationships between dispersal and selection are mediating invasive hybridization between these fish, emphasizing that data on dispersal and natural selection are needed to fully understand the dynamics of introgression between native and non-native species.

Isodon hsiwenii (Lamiaceae: Nepetoideae), A New Species From Yunnan, China

2019 ◽  
Vol 44 (4) ◽  
pp. 913-922 ◽  
Author(s):  
Ya-Ping Chen ◽  
Trevor C. Wilson ◽  
Ya-Dong Zhou ◽  
Ze-Huan Wang ◽  
En-De Liu ◽  
...  
Keyword(s):  
New Species ◽  
Maximum Likelihood ◽  
Ribosomal Dna ◽  
Southwest China ◽  
Plastid Dna ◽  
Sister Species ◽  
Nuclear Ribosomal Dna ◽  
Phylogenetic Placement ◽  
Morphological Differences ◽  
A New Species

Abstract—Isodon hsiwenii, a new species from Yunnan in Southwest China, is here described and illustrated. In order to clarify the phylogenetic placement of the new species within Isodon, Bayesian and maximum likelihood analyses based on two nuclear ribosomal DNA regions and four plastid DNA regions for 71 Asian Isodon species were conducted. The results indicate that I. hsiwenii is a member of the largest and poorly resolved Clade III, as sister species of I. hirtellus. Isodon hsiwenii can be distinguished from I. hirtellus by various morphological differences.

Rediscovery of the Liberian Nimba toad, Nimbaphrynoides liberiensis (Xavier, 1978) (Amphibia: Anura: Bufonidae), and reassessment of its taxonomic status

Zootaxa ◽  
2010 ◽  
Vol 2355 (1) ◽  
pp. 56 ◽  
Author(s):  
LAURA SANDBERGER ◽  
ANNIKA HILLERS ◽  
JOSEPH DOUMBIA ◽  
NÉMA-SOUA LOUA ◽  
CHRISTIAN BREDE ◽  
...  
Keyword(s):  
Taxonomic Status ◽  
Original Description ◽  
Critically Endangered ◽  
Type Locality ◽  
Patchy Distribution ◽  
Open Cast Mining ◽  
Morphological Differences ◽  
Two Populations ◽  
Open Cast ◽  
Genetic Comparison

We report on the search and rediscovery of the Liberian Nimba toad, Nimbaphrynoides liberiensis, 30 years after its original description. A small surviving population could be traced in the surroundings of the type locality Mount Alpha, Liberia. The type locality was meanwhile destroyed by open cast mining. Similar to the Guinean Nimba toad, Nimbaphrynoides occidentalis, the Liberian toad lives exclusively in open, savanna like habitats above 1200 m a.s.l. The presumably few surviving individuals and the small and patchy distribution classify the Liberian toads as Critically Endangered (Stuart et al. 2008). A morphological, acoustical and genetic comparison of Liberian and Guinean populations revealed only minor, but distinct morphological (size, colour) differences. Genetically and acoustically the two taxa were indistinguishable. We therefore propose to consider the two populations as conspecific and to consider Nimbaphrynoides liberiensis (Xavier, 1978) as junior synonym of Nimbaphrynoides occidentalis (Angel, 1943). Because of the morphological differences we propose to treat the Liberian population as a subspecies of the Guinean toad and herein introduce the new name: Nimbaphrynoides occidentalis liberiensis.

scholarly journals Metabolomic Analysis of Pollen Grains with Different Germination Abilities from Two Clones of Chinese Fir (Cunninghamia lanceolata (Lamb) Hook)

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3162 ◽  
Author(s):  
Seif Aldin Dawina Abdallah Fragallah ◽  
Pei Wang ◽  
Nuo Li ◽  
Yu Chen ◽  
Sizu Lin
Keyword(s):  
Pollen Germination ◽  
Early Stage ◽  
Pollen Grains ◽  
Chinese Fir ◽  
Tube Growth ◽  
Metabolomic Analysis ◽  
Factors Affecting ◽  
Germination Process ◽  
Germinating Pollen

Pollen grains produce certain metabolites, which can improve or inhibit germination and tube growth. Metabolomic analysis of germinating and growing Chinese fir pollen has not been reported. Therefore, this study aimed to analyse metabolites changes, content and expression in the germinating pollen of Chinese fir. To understand the metabolic differences, two clones from Chinese fir were selected. Metabolomics analyses were performed on three stages (1-, 24- and 48-h) during in vitro pollen germination. The metabolites profiles at different time points were analyzed by using liquid chromatography-mass spectrometry. The results showed that 171 peaks were screened; the corresponding differential metabolites of 121 peaks were classified into nine types of substances. The expression of metabolites showed significant differences across and between clones, and the variation was evident at all germination stages. The expression was obvious at the early stage of germination, which differed clearly from that of the late stage after pollen tube growth. Moreover, the metabolites were mainly enriched in 14 metabolic pathways. Pollen germination and tube growth and metabolites expressions changed per incubation time. Since this work is preliminary, we suggest further investigations to understand the relationship between the differential metabolites and pollen development, and factors affecting pollen germination process.

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