Sexual dimorphism in clonal growth forms and ramet distribution patterns in Rumex acetosella (Polygonaceae)

2006 ◽  
Vol 22 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Teruya Fujitaka ◽  
Satoki Sakai
Phytotaxa ◽  
2021 ◽  
Vol 480 (2) ◽  
pp. 103-124
Author(s):  
ABUBAKAR BELLO ◽  
FATIMA BATUL MUKHTAR ◽  
ALEXANDRA NORA MUELLNER-RIEHL

This study provides the first comprehensive checklist and analysis of the species of Fabaceae from Nigeria, based on over 5000 herbarium collections and the completed "Flora of West Tropical Africa (FWTA)". We report 552 taxa, belonging to 540 species in 155 genera from six subfamilies, with an outstanding number of taxa (36) representing new records for the country. We mapped the distribution of the species using their occurrence records obtained from GBIF and our own field and herbarium collections. The majority of taxa (43%) was distributed in the savanna vegetation of northern Nigeria, followed by the adjacent tropical forest formations of southern Nigeria (34%), and they were found in highest percentages in Papilionoideae (67%) and Caesalpinioideae (19%), followed by Deterioideae (11%), Cercidoideae and Dialioideae (6% each) and Duparquetioideae (<1%) subfamilies. Endemic and native taxa were 5 and 73% respectively. The most prevalent subfamilies in terms of endemicity were Papilionoideae (14 species), and Deterioideae (11 species), while the most prevalent genera were Indigofera (three species), Dalbergia (three species), Brachystegia (two species) and Cryptosepalum (two species). We found that the majority (37%) of the species were phanerophytes and the fewest were cryptophytes (0.7%). These results suggest that Nigeria has a considerable diversity of legumes, with a predominant distribution in the savanna, probably due to the demanding environmental conditions limiting the dispersion of generalists or invasive species. The diversity of growth forms and distribution patterns of Nigerian legumes could be useful in screening these plants for other potential uses, such as conservation planning or specific agricultural purposes. We recommend a similar study on other families as this will help locals, natural scientists, governments and conservation bodies to recognise and appreciate the flora of the country.


2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Miguel Gallach ◽  
Susana Domingues ◽  
Esther Betrán

In species that have two sexes, a single genome encodes two morphs, as each sex can be thought of as a distinct morph. This means that the same set of genes are differentially expressed in the different sexes. Many questions emanate from this statement. What proportion of genes contributes to sexual dimorphism? How do they contribute to sexual dimorphism? How is sex-biased expression achieved? Which sex and what tissues contribute the most to sex-biased expression? Do sex-biased genes have the same evolutionary patterns as nonbiased genes? We review the current data on sex-biased expression in species with heteromorphic sex chromosomes and comment on the most important hypotheses suggested to explain the origin, evolution, and distribution patterns of sex-biased genes. In this perspective we emphasize how gene duplication serves as an important molecular mechanism to resolve genomic clashes and genetic conflicts by generating sex-biased genes, often sex-specific genes, and contributes greatly to the underlying genetic basis of sexual dimorphism.


2019 ◽  
Vol 146 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Franziska Clausen ◽  
Hans-Michael Behrens ◽  
Sandra Krüger ◽  
Christoph Röcken

Abstract Purpose Tumor-associated neutrophils (TANs) are part of the tumor immune microenvironment (TIME) and may contribute to gastric cancer (GC) biology. We hypothesized that TAN are enriched in the TIME, show sex-specific differences, and correlate with patient outcome. Methods We analyzed the distribution and putative tumor biological significance of TANs in a well-characterized, therapy-naïve, European GC cohort using immunohistochemical staining of myeloperoxidase (MPO), and digital image analysis using Definiens Tissue Studio®. Results Different tumor compartments were examined, and TAN densities were correlated with various clinicopathological patient characteristics. TAN density showed a large interindividual variability ranging from 0 to 6711.0 TANs/mm2. Intratumoral distribution patterns were inhomogeneous (tumor surface vs. tumor center vs. invasion front) and correlated significantly with Laurén phenotype, tumor grade, and microsatellite status in the tumor center and invasion front. In the multivariate analysis, TAN density in the invasion front was an independent predictor of tumor-specific survival only for women (HR = 2.77, p   < 0.001). In men, no correlation was found between TAN density and survival. Conclusion With regard to TANs, our study independently validates sexual dimorphism in GC biology.


Ecology ◽  
2003 ◽  
Vol 84 (11) ◽  
pp. 2979-2988 ◽  
Author(s):  
Sean R. Connolly ◽  
Soyoka Muko

1999 ◽  
Vol 77 (2) ◽  
pp. 219-229
Author(s):  
Teresa Valverde ◽  
Irene Pisanty

The architecture resulting from the iteration of modules during plant growth affects resource capture. Phalanx and guerrilla growth forms have been described as ends of a continuum regarding the spacing of modules in plants. In this study we investigated the growth form of the perennial, tussock-forming grass Schizachyrium scoparium Michx. var. littoralis (Nash) Hitchc. in three dune microhabitats at El Morro de la Mancha, southeastern Mexico: a mobile, a semi-mobile, and a stabilized site. We followed the growth of 15 genets at each site for two consecutive years and found that daughter-tussock formation was more frequent in the stabilized than in the semi-mobile or the mobile sites. Individual tussocks had a higher number of tillers in the mobile site than in the other two. Tiller production occurred within parental tussocks in the mobile site and in the form of daughter tussocks in the stabilized site. Reciprocal transplants suggested that phenotypic plasticity was responsible for the differences observed. Fertilization enhanced tiller production within parental tussocks but did not affect daughter tussock formation. Clearing experiments resulted in enhanced tiller production within tussocks. In these experiments, daughter-tussock production did not occur directionally towards nutrient-rich microsites. It appears that S. scoparium tillers are spaced at longer distances when resources are scarce and intraclonal competition is severe.Key words: clonal growth, growth form, nutrient availability, phalanx-guerrilla continuum.


1986 ◽  
Vol 64 (10) ◽  
pp. 2192-2196 ◽  
Author(s):  
Akira F. Peters ◽  
Dieter G. Müller

Life histories of two ligulate forms of Desmarestia with different phylloid width from one site on the Canadian Pacific coast were studied in culture. Meiospores from a form with narrow phylloids germinated into monoecious gametophytes. Meiospores from a form with broad phylloids developed into dioecious gametophytes, showing sexual dimorphism characteristic for dioecious species of Desmarestia. The two growth forms also differed in culture conditions required for gametogenesis. We conclude that at least two different species of ligulate Desmarestia occur on the Pacific coast of North America.


2016 ◽  
Vol 371 (1706) ◽  
pp. 20150535 ◽  
Author(s):  
David Haig

Haploid gametophytes of bryophytes spread by clonal growth but mate locally, within an area defined by the range of sperm movement. Rarity of establishment from spores or vegetative competition can result in unisexual populations unable to reproduce sexually. Females typically outcompete males, probably because females expend fewer resources than males on the production of gametes. Extreme sexual dimorphism—tiny males growing as epiphytes on much larger females—has evolved many times. Haploid selfing is common in bryophytes with bisexual gametophytes, and results in completely homozygous sporophytes. Spores from these sporophytes recapitulate the genotype of their single haploid parent. This process can be considered analogous to ‘asexual’ reproduction with ‘sexual’ reproduction occurring after rare outcrossing between haploid parents. Ferns also produce bisexual haploid gametophytes but, unlike bryophytes, haploid outcrossing predominates over haploid selfing. This difference is probably related to clonal growth and vegetative competition occurring in the haploid but not the diploid phase in bryophytes, but the reverse in ferns. Ferns are thereby subject to stronger inbreeding depression than bryophytes. This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’.


Ecology ◽  
1987 ◽  
Vol 68 (6) ◽  
pp. 2056-2058 ◽  
Author(s):  
Lesley Lovett Doust ◽  
Jon Lovett Doust

2010 ◽  
Vol 92 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Monika Sosnová ◽  
Rudy van Diggelen ◽  
Jitka Klimešová
Keyword(s):  

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