Conservation in relation to mating system in Nesohedyotis arborea (Rubiaceae), a rare endemic tree from St Helena

1997 ◽  
Vol 80 (2) ◽  
pp. 135-145 ◽  
Author(s):  
D.M. Percy ◽  
Q.C.B. Cronk
Keyword(s):  
2000 ◽  
Vol 30 (7) ◽  
pp. 1156-1164 ◽  
Author(s):  
F Thomas Ledig ◽  
Basilio Bermejo-Velázquez ◽  
Paul D Hodgskiss ◽  
David R Johnson ◽  
Celestino Flores-López ◽  
...  

Martínez spruce (Picea martínezii T.F. Patterson) is a conifer currently passing through a bottleneck, reduced to a few relict populations totaling less than 800 trees. We used isozyme markers to analyze the mating system and survey the level of genic diversity in two populations. The mating system was characterized by a high frequency of selfing. The multilocus outcrossing rates (tm) and 95% confidence intervals were only 0.399 (0.197 < tm < 0.601) for the smallest population and 0.589 (0.475 < tm < 0.703) or 0.685 (0.465 < tm < 0.905), depending on year, for the largest. These are among the lowest rates of outcrossing observed in conifers. The fixation indices for the two populations were -0.058 and 0.121, less than expected for such high levels of selfing. Expected heterozygosity, unbiased He, based on 22 loci in 13 enzyme systems, was 0.121 and 0.101 in the two populations. The proportion of the total genic diversity between populations, FST, was 2.4%. Nm, the number of migrants per generation, was about 1.00 or 10.17, depending on the method of estimation. The time since the two populations were isolated was estimated from Nei's genetic distance as only 150 to 15 000 years, which is consistent with a hypothesis of population collapse during late Pleistocene or Holocene warming. We discuss the implications for conservation.


2018 ◽  
Vol 8 (1) ◽  
pp. 84-99
Author(s):  
Eleonora Sasso

This paper takes as its starting point the conceptual metaphor ‘life is a journey’ as defined by Lakoff and Johnson (1980) in order to advance a new reading of William Michael Rossetti's Democratic Sonnets (1907). These political verses may be defined as cognitive-semantic poems, which attest to the centrality of travel in the creation of literary and artistic meaning. Rossetti's Democratic Sonnets is not only a political manifesto against tyranny and oppression, promoting the struggle for liberalism and democracy as embodied by historical figures such as Napoleon, Mazzini, Cavour, and Garibaldi; but it also reproduces Rossetti's real and imagined journeys throughout Europe in the late nineteenth century. This essay examines these references in light of the issues they raise, especially the poet as a traveller and the journey metaphor in poetry. But its central purpose is to re-read Democratic Sonnets as a cognitive map of Rossetti's mental picture of France and Italy. A cognitive map, first theorised by Edward Tolman in the 1940s, is a very personal representation of the environment that we all experience, serving to navigate unfamiliar territory, give direction, and recall information. In terms of cognitive linguistics, Rossetti is a figure whose path is determined by French and Italian landmarks (Paris, the island of St. Helena, the Alps, the Venice Lagoon, Mount Vesuvius, and so forth), which function as reference points for orientation and are tied to the historical events of the Italian Risorgimento. Through his sonnets, Rossetti attempts to build into his work the kind of poetic revolution and sense of history which may only be achieved through encounters with other cultures.


2019 ◽  
Vol 37 (4) ◽  
pp. 222-232 ◽  
Author(s):  
Melissa A Millar ◽  
Janet M Anthony ◽  
David J Coates ◽  
Margaret Byrne ◽  
Siegfried L Krauss ◽  
...  

2017 ◽  
Vol 51 ◽  
pp. 71-105 ◽  
Author(s):  
N. A. Davidovich

The absence of a conceptual terminology, sufficiently developed and widely accepted in the Russian literature, significantly hinders progress in the field of reproductive biology of diatoms, restricts communication and debate, prevents training and transfer of knowledge. The present work is an attempt, based on world literature and our own research experience, to summarize, systematize, add, and clarify the existing terms, concepts and definitions related to research which are focused on sex and sexual reproduction in diatoms. A glossary of key terms (more than 200, including synonyms) is provided. Terms refer to diatom reproductive biology, life cycles, fertilization, mating system, gender (including inheritance and determination of sex, as well as inheritance associated with sex). Contradictions between possible interpretations of certain terms are briefly discussed.


2013 ◽  
Vol 20 (6) ◽  
pp. 676-684 ◽  
Author(s):  
Wang Xia ◽  
Wang Jing ◽  
Jiang Jinghu ◽  
Kang Ming

Crop Science ◽  
1984 ◽  
Vol 24 (4) ◽  
pp. 793-796 ◽  
Author(s):  
L. M. Pollak ◽  
C. O. Gardner ◽  
A. L. Kahler ◽  
M. Thomas‐Compton
Keyword(s):  

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