Mixoploidy and cytotypes: a study of possible vegetative species differentiation in stapeliads (Asclepiadaceae)

Bothalia ◽  
1991 ◽  
Vol 21 (1) ◽  
pp. 67-72 ◽  
Author(s):  
F. Albers ◽  
U. Meve
Keyword(s):  
Chromosome Number ◽  
Adventitious Roots ◽  
Growth Form ◽  
Field Studies ◽  
Species Differentiation ◽  
Polyploid Species ◽  
Polyploid Cells ◽  
Vegetative Origin ◽  
Secondary Roots

Mixoploidy is common in proembryos and embryos as well as in meristems of radicles, primary, secondary and adventitious roots and in innovation shoots of stapeliad species (Asclepiadaceae). The proportion of polyploid cells in the meristem of single adventitious roots is significantly higher than in meristems of primary and secondary roots. This may lead to a complete polyploidisation of adventitious roots. Innovation shoots display a low percentage of polyploid cells, comparable to the condition found in primary and secondary roots. Nevertheless cells of different euploid levels are frequently found. During field studies, however, individuals of a given population were always found to have the same chromosome number: infraspecific polyploidy was found in only three out of 305 investigated stapeliad species. Genera with an orthotropic growth form were found to be diploid throughout, whereas the genera of which the members spread vegetatively by means of innovation shoots, comprise di-, tetra- and polyploid species. This phenomenon can be ascribed to ecological rather than morphological factors. The often proposed hypothesis that new cytotypes can have a vegetative origin is not found to be acceptable.

Period of harvest, sprouting ability of cuttings, and in vitro plant regeneration in Fraxinus excelsior

1994 ◽  
Vol 72 (2) ◽  
pp. 261-267 ◽  
Author(s):  
Conceição Eneida Silveira ◽  
Alain Cottignies
Keyword(s):  
Chromosome Number ◽  
In Vitro Culture ◽  
Adventitious Roots ◽  
Woody Plant ◽  
Fraxinus Excelsior ◽  
Stem Cuttings ◽  
Natural Conditions ◽  
Apical Bud ◽  
Woody Plant Medium

Propagation by stem cuttings and in vitro culture of apical bud explants were studied on Fraxinus excelsior L. Stem cuttings from 4- to 7-year-old trees growing under natural conditions sprouted only when cuttings were taken from dormant material. Only 6% of those that had sprouted developed roots by the 7th month of culture. Similarly, only apical bud explants harvested during the dormant period sprouted in vitro. Up to 87% of these sprouts developed two to four branching adventitious roots after 5 months of culture. During the initial phase of in vitro culture, the Quoirin and Lepoivre medium and the woody plant medium favoured sprout lengthening. During the phase of multiplication, up to three sprouts per explant developed with the woody plant medium in the presence of a combination of high 6-benzylaminopurine (3.0–4.0 mg∙L−1) and low indole-3-butyric acid (0.01–0.03 mg∙L−1) concentrations. Rooting was obtained in a medium without any growth regulators. Microscopic analysis showed a direct connection between the vascular elements of adventitious roots and stem of plantlet. Chromosome number in root apices of ash plantlets and ash trees grown under natural conditions was 2n = 46. Key words: chromosome number, Fraxinus excelsior L., in vitro plants, micropropagation, stem cuttings.

Two new genera and species of Linderniaceae (Lamiales) from inselbergs in northeastern Brazil: morphological and karyological evidence

Phytotaxa ◽  
2019 ◽  
Vol 400 (4) ◽  
pp. 215
Author(s):  
ERTON M. ALMEIDA ◽  
ARTUR MAIA WANDERLEY ◽  
AMANDA DE SOUZA SANTOS ◽  
JOSÉ IRANILDO MIRANDA DE MELO ◽  
GUSTAVO SOUZA ◽  
...  
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Field Studies ◽  
Morphological Characters ◽  
Northeastern Brazil ◽  
New Genera ◽  
Glandular Hairs ◽  
Two New Species ◽  
Morphological Differences

During field studies of the inselbergs of northeastern Brazil, two potentially new species of were discovered. They share morphological characters with several genera of Linderniaceae (Lamiales) such as Ameroglossum, Cubitanthus and Stemodiopsis, but the morphological differences are such that they do not make a good fit with any of the known genera in Linderniaceae. They are most likely related to Ameroglossum, and like most members of this genus the plants have a conserved chromosome number of 2n = 60. Their exclusive occurrence on inselbergs in northeastern Brazil also hint at this relationship, but because their morphology differs greatly from Ameroglossum and each other, the two new species are described in separate genera. Catimbaua is a pendent plant somewhat similar to Cubitanthus, but with different stem morphology and indumentum. Isabelcristinia grows in habitats similar to, but drier than, Ameroglossum and is vegetatively similar. However, it is covered in glandular hairs and has open-throated white flowers rather than the red or orange tubular flowers found in Ameroglossum. Catimbaua pendula and Isabelcristinia aromatica are rare, and both are likely to fall in a category of threat.

A revision of trifoliolate Indigofera (Tribe Indigofereae: Fabaceae) in India

Phytotaxa ◽  
2015 ◽  
Vol 220 (1) ◽  
pp. 1
Author(s):  
Vibha Chauhan ◽  
Arun Pandey
Keyword(s):  
Chromosome Number ◽  
Field Studies ◽  
Species Description ◽  
Herbarium Specimens ◽  
Ethnobotanical Uses

A revision of trifoliolate Indigofera in India is provided based on field studies, and examination of herbarium specimens. In India, 11 species and 4 varieties of trifoliolate Indigofera are recognized: Indigofera barberi, I. deccanensis, I. glandulosa, I. glandulosa var. sykesii, I. karuppiana, I. pedicellata, I. prostrata, I. santapaui, I. thothathrii, I. tirunelvelica, I. trifoliata, I. trifoliata var. duthiei, I. trita, I. trita var. maffeii and I. trita var. purandharensis. Of 11 species, seven species and three varieties are endemic. A key to the species, description and illustrations are provided along with data on flowering and fruiting, distribution, habitat, chromosome number, and ethnobotanical uses.

scholarly journals A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

2019 ◽  
Author(s):  
Warren Williams ◽  
Isabelle M Verry ◽  
Helal A Ansari ◽  
S Wajid Hussain ◽  
Ihsan Ullah ◽  
...  
Keyword(s):  
Chromosome Number ◽  
White Clover ◽  
Interspecific Hybrids ◽  
Species Complex ◽  
Embryo Rescue ◽  
Polyploid Species ◽  
Trifolium Ambiguum ◽  
Breeding Populations ◽  
Fertile Hybrids ◽  
First Time

Abstract Background Trifolium ambiguum occurs as a 2x, 4x, 6x polyploid series in W Asia, The 6x form is the most agronomically desirable, having strong rhizomatous spread and drought tolerance. These traits would be potentially very valuable if they could be transferred to white clover (T. repens) which is the most important agronomic clover species. However, to-date, no fertile interspecific hybrids with 6x T. ambiguum are available. Previously, 2x T. occidentale from W Europe has produced synthetic fertile hybrids with both 2x and 4x T. ambiguum and these were inter-fertile with white clover. Here we ask whether 2x T. occidentale can form fertile hybrids with 6x T. ambiguum and act as a genetic bridge to white clover and bring these species together as part of a common gene pool. Results Ten verified F1 (6x T. ambiguum x 2x T. occidentale) hybrids were produced by embryo rescue and seven were studied further. All four investigated for chromosome number were 2n=4x=32 and FISH confirmed the expected 21 T. ambiguum and 8 T. occidentale chromosomes. Hybrid fertility was extremely low but 2n female gametes functioned with white clover pollen to produce seeds. Derived plants were confirmed using FISH and were successfully backcrossed to white clover to produce partially fertile breeding populations. Conclusions Although T. occidentale and 6x T. ambiguum are widely separated by geography and ecological adaptation they have maintained enough genomic affinity to produce partially fertile hybrids. Inter-fertility of the hybrids with allotetraploid T. repens showed that T. occidentale can provide a genetic bridge between 6x T. ambiguum and white clover to produce plants with new phenotypes combining the traits of all three species. Use of this information should enable potentially valuable stress tolerance traits from 6x T. ambiguum to be used in white clover breeding for the first time.

Antennaria howellii subsp. gaspensis comb, et stat. nov. (Asteraceae : Inuleae): justification for change

1995 ◽  
Vol 73 (9) ◽  
pp. 1366-1370 ◽  
Author(s):  
Jerry G. Chmielewski
Keyword(s):  
Data Analysis ◽  
Discriminant Analysis ◽  
Chromosome Number ◽  
Cross Validation ◽  
Growth Form ◽  
Taxonomic Status ◽  
Canonical Discriminant Analysis ◽  
New Combination ◽  
Quantitative Morphology ◽  
Antennaria Microphylla

Canonical discriminant analysis was used to assess the taxonomic status of Antennaria neodioica Greene var. gaspensis Fernald. Results based on these analyses indicate that Antennaria howellii Greene, Antennaria microphylla Rydberg, A. neodioica var. gaspensis, Antennaria pulvinata Greene, and Antennaria rosea Greene are morphologically distinct. High cross-validation assignment rates as well as high Geisser assignment probabilities for each of the taxa support this statement. Elevating var. gaspensis to the rank of species is in part supported by the data analysis, but doing so would be contrary to the species standard method and inconsistent with recent practice in revisions of the genus. The presence of scarious appendages at the tips of the upper cauline leaves, the open pedicellate inflorescence, the whitish-green capitula, general growth form, agamospermous reproduction, chromosome number, provenance, and quantitative morphology, in addition to the results of the canonical discriminant analysis, support recognition of var. gaspensis at an infraspecific rank. In keeping with the criteria utilized in recent revisions of the genus, var. gaspensis should more appropriately be treated as a subspecies. Recent nomenclatural rearrangements in A. neodioica and A. howellii founded on the priority of the latter lead to the following new combination: Antennaria howellii subsp. gaspensis (Fernald) Chmielewski. Key words: Antennaria howellii var. gaspensis, Asteraceae, Newfoundland flora, Gaspé Bay Peninsula flora.

scholarly journals Global-scale drivers of ploidy state in aquatic macrophytes

2020 ◽  
Author(s):  
Tatiana Lobato-de Magalhães ◽  
Kevin Murphy ◽  
Andrey Efremov ◽  
Victor Chepinoga ◽  
Thomas Davidson ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Aquatic Macrophyte ◽  
Diploid Species ◽  
Global Scale ◽  
Boosted Regression Trees ◽  
Polyploid Species ◽  
Latitude Range ◽  
Macrophyte Species ◽  
Latitudinal Patterns ◽  
Relationship Of

To determine potential drivers of the global distribution of ploidy in aquatic macrophyte species we allocated ploidy state to 1572 species occurring in 238 10 × 10° gridcells worldwide. Analysis of the relationship of 16 global-scale spatial, landscape, environmental, and biotic variables with ploidy state using Boosted Regression Trees revealed temperature variables and evapotranspiration as the strongest predictors. There were contrasting latitudinal patterns between haploid/diploid and polyploid species, while species richness measures also influenced ploidy state. Polyploid species occupied larger geographical ranges than haploid/diploid species. Mixed ploidy species showed the highest latitudinal range size and maximum latitude of species occurrence. Our findings suggest that increased chromosome number is associated with tolerance of a wider range of environmental conditions in macrophyte species. Mixed ploidy could reflect adaptability to expand geographical occurrence via chromosome number change, with such species predominantly occupying a latitude range intermediate between haploid/diploid and polyploid macrophyte dominance.

scholarly journals A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

2019 ◽  
Author(s):  
Warren Williams ◽  
Isabelle M Verry ◽  
Helal A Ansari ◽  
S Wajid Hussain ◽  
Ihsan Ullah ◽  
...  
Keyword(s):  
Chromosome Number ◽  
White Clover ◽  
Interspecific Hybrids ◽  
Species Complex ◽  
Embryo Rescue ◽  
Polyploid Species ◽  
Trifolium Ambiguum ◽  
Breeding Populations ◽  
Fertile Hybrids ◽  
First Time

Abstract Background Trifolium ambiguum occurs as a 2x, 4x, 6x polyploid series in W Asia, The 6x form is the most agronomically desirable, having strong rhizomatous spread and drought tolerance. These traits would be potentially very valuable if they could be transferred to white clover (T. repens) which is the most important agronomic clover species. However, to-date, no fertile interspecific hybrids with 6x T. ambiguum are available. Previously, 2x T. occidentale from W Europe has produced synthetic fertile hybrids with both 2x and 4x T. ambiguum and these were inter-fertile with white clover. Here we ask whether 2x T. occidentale can form fertile hybrids with 6x T. ambiguum and act as a genetic bridge to white clover and bring these species together as part of a common gene pool. Results Ten verified F1 (6x T. ambiguum x 2x T. occidentale) hybrids were produced by embryo rescue and seven were studied further. All four investigated for chromosome number were 2n=4x=32 and FISH confirmed the expected 21 T. ambiguum and 8 T. occidentale chromosomes. Hybrid fertility was extremely low but 2n female gametes functioned with white clover pollen to produce seeds. Derived plants were confirmed using FISH and were successfully backcrossed to white clover to produce partially fertile breeding populations. Conclusions Although T. occidentale and 6x T. ambiguum are widely separated by geography and ecological adaptation they have maintained enough genomic affinity to produce partially fertile hybrids. Inter-fertility of the hybrids with allotetraploid T. repens showed that T. occidentale can provide a genetic bridge between 6x T. ambiguum and white clover to produce plants with new phenotypes combining the traits of all three species. Use of this information should enable potentially valuable stress tolerance traits from 6x T. ambiguum to be used in white clover breeding for the first time.

scholarly journals A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

2019 ◽  
Author(s):  
Warren Williams ◽  
Isabelle M Verry ◽  
Helal A Ansari ◽  
S Wajid Hussain ◽  
Ihsan Ullah ◽  
...  
Keyword(s):  
Chromosome Number ◽  
White Clover ◽  
Interspecific Hybrids ◽  
Species Complex ◽  
Embryo Rescue ◽  
Polyploid Species ◽  
Trifolium Ambiguum ◽  
Breeding Populations ◽  
Fertile Hybrids ◽  
First Time

Abstract Background Trifolium ambiguum occurs as a 2x, 4x, 6x polyploid series in W Asia, The 6x form is the most agronomically desirable, having strong rhizomatous spread and drought tolerance. These traits would be potentially very valuable if they could be transferred to white clover (T. repens) which is the most important agronomic clover species. However, to-date, no fertile interspecific hybrids with 6x T. ambiguum are available. Previously, 2x T. occidentale from W Europe has produced synthetic fertile hybrids with both 2x and 4x T. ambiguum and these were inter-fertile with white clover. Here we ask whether 2x T. occidentale can form fertile hybrids with 6x T. ambiguum and act as a genetic bridge to white clover and bring these species together as part of a common gene pool. Results Ten verified F1 (6x T. ambiguum x 2x T. occidentale) hybrids were produced by embryo rescue and seven were studied further. All four investigated for chromosome number were 2n=4x=32 and FISH confirmed the expected 21 T. ambiguum and 8 T. occidentale chromosomes. Hybrid fertility was extremely low but 2n female gametes functioned with white clover pollen to produce seeds. Derived plants were confirmed using FISH and were successfully backcrossed to white clover to produce partially fertile breeding populations. Conclusions Although T. occidentale and 6x T. ambiguum are widely separated by geography and ecological adaptation they have maintained enough genomic affinity to produce partially fertile hybrids. Inter-fertility of the hybrids with allotetraploid T. repens showed that T. occidentale can provide a genetic bridge between 6x T. ambiguum and white clover to produce plants with new phenotypes combining the traits of all three species. Use of this information should enable potentially valuable stress tolerance traits from 6x T. ambiguum to be used in white clover breeding for the first time.

scholarly journals Differentiation of two swim bladdered fish species using next generation wideband hydroacoustics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah M. Gugele ◽  
Marcus Widmer ◽  
Jan Baer ◽  
J. Tyrell DeWeber ◽  
Helge Balk ◽  
...  
Keyword(s):  
Gasterosteus Aculeatus ◽  
Community Dynamics ◽  
Spatial Scales ◽  
Field Studies ◽  
Fishing Effort ◽  
Species Differentiation ◽  
Species Identity ◽  
Additional Species ◽  
Random Forest Classification ◽  
Forest Classification

AbstractMonitoring fish populations in large, deep water bodies by conventional capture methodologies requires intensive fishing effort and often causes mass mortality of fish. Thus, it can be difficult to collect sufficient data using capture methods for understanding fine scale community dynamics associated with issues such as climate change or species invasion. Hydroacoustic monitoring is an alternative, less invasive technology that can collect higher resolution data over large temporal and spatial scales. Monitoring multiple species with hydroacoustics, however, usually requires conventional sampling to provide species level information. The ability to identify the species identity of similar-sized individuals using only hydroacoustic data would greatly expand monitoring capabilities and further reduce the need for conventional sampling. In this study, wideband hydroacoustic technology was used in a mesocosm experiment to differentiate between free swimming, similar-sized individuals of two swim-bladdered species: whitefish (Coregonus wartmanni) and stickleback (Gasterosteus aculeatus). Individual targets were identified in echograms and variation in wideband acoustic responses among individuals, across different orientations, and between species was quantified and visually examined. Random forest classification was then used to classify individual targets of known species identity, and had an accuracy of 73.4% for the testing dataset. The results show that species can be identified with reasonable accuracy using wideband hydroacoustics. It is expected that further mesocosm and field studies will help determine capabilities and limitations for classifying additional species and monitoring fish communities. Hydroacoustic species differentiation may offer novel possibilities for fisheries managers and scientists, marking the next crucial step in non-invasive fish monitoring.

Senecio L. (Asteraceae) in Australia: Rcombination systems of a polyploid series

1985 ◽  
Vol 33 (2) ◽  
pp. 209 ◽  
Author(s):  
M.E. Lawrence
Keyword(s):  
Chromosome Number ◽  
Breeding System ◽  
Chromosome Numbers ◽  
Native Species ◽  
Polyploid Species ◽  
Ploidy Levels ◽  
Basic Chromosome ◽  
High Polyploid ◽  
Evolutionary Changes ◽  
Extreme Phenotypes

Recombination systems of 32 species of Senecio are discussed in terms of chromosome number, chiasma frequency and position, breeding system and generation length. Darlington's recombination index cannot be applied to Senecio as several ploidy levels are represented. Increases in basic chromosome numbers promote recombination but increases by polyploidy buffer intermediate genotypes and retard evolutionary changes when selection is for homozygous or extreme phenotypes. High polyploid species of Senecio may therefore have recombination systems as restrictive as those produced by aneuploid reduction. When viewed in this manner, the majority of native species examined have recombination systems that contain a balance of restrictive and expansive factors regulating recombination.

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