scholarly journals Discovery of a Possibly Relict Outbreeding Morphotype of Sparrow's-egg Lady's-slipper Orchid, Cypripedium passerinum, in Southwestern Yukon

2007 ◽  
Vol 121 (3) ◽  
pp. 295 ◽  
Author(s):  
Paul M. Catling ◽  
Bruce A. Bennett
Keyword(s):  
Breeding System ◽  
Widespread Occurrence ◽  
Slipper Orchid

An outbreeding morphotype of Cypripedium passerinum with separate anthers and stigma was discovered in the Beringian region of southwestern Yukon. The occurrence of this breeding system in Beringia is attributed to the persistent advantage of outbreeding over hundreds of thousands of years in this unglaciated area, whereas the widespread occurrence of exclusively self-pollinating races elsewhere in Canada is attributed to advantages in colonization of recently deglaciated territory which first became available less than 10,000 years ago, and/or to a changing and more forested habitat.

Analytical Electron Microscopy of Extraterrestrial Ice Analogs

1990 ◽  
Vol 48 (1) ◽  
pp. 594-595
Author(s):  
D.F. Blake ◽  
LJ. Allamandola ◽  
G. Palmer ◽  
A. Pohorille
Keyword(s):  
Solar System ◽  
Analytical Electron Microscopy ◽  
Biogenic Elements ◽  
Widespread Occurrence ◽  
Interstellar Ice ◽  
Analytical Electron ◽  
History Of ◽  
Interstellar Material ◽  
Astrophysical Ices ◽  
Interstellar Molecular Clouds

The natural history of the biogenic elements H, C, N, O, P and S in the cosmos is of great interest because it is these elements which comprise all life. Material ejected from stars (or pre-existing in the interstellar medium) is thought to condense into diffuse bodies of gravitationally bound gas and dust called cold interstellar molecular clouds. Current theories predict that within these clouds, at temperatures of 10-100° K, gases (primarily H2O, but including CO, CO2, CH3OH, NH3, and others) condense onto submicron silicate grains to form icy grain mantles. This interstellar ice represents the earliest and most primitive association of the biogenic elements. Within these multicomponent icy mantles, pre-biotic organic compounds are formed during exposure to UV radiation. It is thought that icy planetesimals (such as comets) within our solar system contain some pristine interstellar material, including ices, and may have (during the early bombardment of the solar system, ∼4 Ga) carried this material to Earth.Despite the widespread occurrence of astrophysical ices and their importance to pre-biotic organic evolution, few experimental data exist which address the relevant phase equilibria and possible structural states. A knowledge of the petrology of astrophysical ice analogs will allow scientists to more confidently interpret astronomical IR observations. Furthermore, the development and refinement of procedures for analyzing ices and other materials at cryogenic temperatures is critical to the study of materials returned from the proposed Rosetta comet nucleus and Mars sample return missions.

The floral ecology and breeding system of Veratrum virginicum (Melanthiaceae)1

2020 ◽  
Vol 147 (3) ◽  
Author(s):  
Daniel Weiherer ◽  
Kayla Eckardt ◽  
Peter Bernhardt
Keyword(s):  
Breeding System ◽  
Floral Ecology

The Breeding System of Lithospermum caroliniense: Adaptation and Counteradaptation

1968 ◽  
Vol 102 (927) ◽  
pp. 427-441 ◽  
Author(s):  
Donald A. Levin
Keyword(s):  
Breeding System

Effects of potato peel extract on semen quality, sex hormones and immunity of rabbit bucks under intensive breeding system

Andrologia ◽  
2020 ◽  
Vol 52 (11) ◽  
Author(s):  
Yassmine Moemen El‐Gindy ◽  
Salma Hashem Abu Hafsa ◽  
Waleed Mostafa Dosoky
Keyword(s):  
Sex Hormones ◽  
Breeding System ◽  
Semen Quality ◽  
Potato Peel ◽  
Peel Extract ◽  
Intensive Breeding

scholarly journals Identifying the stakeholders and sustainability indicators for sonok breeding system

2019 ◽  
Vol 387 ◽  
pp. 012133
Author(s):  
T Nugroho ◽  
D Maharani ◽  
T S M Widi
Keyword(s):  
Breeding System ◽  
Sustainability Indicators

Widespread occurrence of circular RNA in eukaryotes

2021 ◽  
Author(s):  
Irene Bozzoni
Keyword(s):  
Circular Rna ◽  
Widespread Occurrence

scholarly journals Rapid Organocatalytic Chirality Analysis of Amines, Amino Acids, Alcohols, Amino Alcohols and Diols with Achiral Iso(thio)cyanate Probes

2021 ◽  
Author(s):  
Eryn Nelson ◽  
Jeffrey S. S. K. Formen ◽  
Christian Wolf
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Rapid Determination ◽  
Amino Alcohols ◽  
Enantioselective Synthesis ◽  
Widespread Occurrence ◽  
Chiral Compounds ◽  
New Methods ◽  
The Absolute

The widespread occurrence and significance of chiral compounds does not only require new methods for their enantioselective synthesis but also efficient tools that allow rapid determination of the absolute configuration,...

scholarly journals Ecophysiological Aspects and sxt Genes Expression Underlying Induced Chemical Defense in STX-Producing Raphidiopsis raciborskii (Cyanobacteria) against the Zooplankter Daphnia gessneri

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 406
Author(s):  
Mauro C. P. Vilar ◽  
Thiago F. C. P. Rodrigues ◽  
Luan O. Silva ◽  
Ana Beatriz F. Pacheco ◽  
Aloysio S. Ferrão-Filho ◽  
...  
Keyword(s):  
Induced Defense ◽  
Toxin Production ◽  
Grazing Pressure ◽  
Chemical Defenses ◽  
Widespread Occurrence ◽  
Genes Expression ◽  
Freshwater Bodies ◽  
Predator Response ◽  
Aquatic Food ◽  
Shed Light

Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton–cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success.

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