CYTOTAXONOMIC STUDIES ON NEW WORLD SPECIES OF ANEMONE (SECTION ERIOCEPHALUS) WITH TUBEROUS ROOTSTOCKS

1966 ◽  
Vol 44 (7) ◽  
pp. 899-928 ◽  
Author(s):  
Cecily Joseph ◽  
Margaret Heimburger
Keyword(s):  
North American ◽  
New World ◽  
Diploid Species ◽  
Pollen Grain ◽  
South American ◽  
New Taxon ◽  
South American Species ◽  
The North ◽  
Additional Support ◽  
North And South

The American species of Anemone L. (section Eriocephalus Hook. f. & Thoms.) with tuberous rootstocks were studied by biosystematic methods. Anemone caroliniana Walt., A. heterophylla Nutt. ex Torr. & Gray, A. tuberosa Rydb., and A. edwardsiana Tharp (tentatively) are recognized from North America and A. decapetala Ard., A. triternata Vahl, and A. cicutifolia Johnst. from South America. Karyotypes of the diploid species (2n = 16), A. heterophylla, A. tuberosa, A. decapetala, and A. triternata are described. They resemble the karyotype of A. caroliniana published earlier. Anemone edwardsiana and A. cicutifolia are also presumed diploid from stomatal and pollen grain studies. A new taxon (2n = 32), of undecided status, was obtained from Chile. North American plants included by authors in A. decapetala are here referred to A. heterophylla. The North and South American species appear to form two separate groups, the species of each continent being more closely related among themselves than to those of the other continent. Fewer stomata, larger chromosome size, and higher DNA content are characteristic of the North American species. Additional support for the separation of the two groups derives from limited meiotic studies which indicate a larger number of inversion differences in inter- than in intra-continental hybrids.

RAPD analysis of the relationship of North and South American subspecies of Fragaria chiloensis

1998 ◽  
Vol 76 (10) ◽  
pp. 1812-1817 ◽  
Author(s):  
Sue Porebski ◽  
Paul M Catling
Keyword(s):  
North American ◽  
Random Amplified Polymorphic Dna ◽  
Molecular Evidence ◽  
South American ◽  
Cophenetic Correlation ◽  
The North ◽  
Fragaria Chiloensis ◽  
Protection And Utilization ◽  
Relationship Of ◽  
North And South

To improve the intraspecific classification of Fragaria chiloensis (L.) Duchesne, 35 plants including 5 North American ssp. lucida, 15 North American ssp. pacifica, and 15 South American ssp. chiloensis were analysed using random amplified polymorphic DNA (RAPDs). From 100 primers screened, 12 were selected providing 62 scorable polymorphic bands. The phenogram (cophenetic correlation, r = 0.99) based on UPGMA clustering of Jaccard's coefficients revealed a clear division between North American and South American plants, but only partial separation was shown between the two North American subspecies. This is the first comprehensive molecular evidence for major genetic divergence between the North American and South American subspecies of F. chiloensis and suggests greater genetic variation within the Canadian material of the North American ssp. pacifica than within the South American ssp.chiloensis. These findings strongly support protection and utilization of wild Canadian Fragaria germplasm for crop improvement.Key words: strawberry, Fragaria chiloensis, ssp. chiloensis, ssp. pacifica, ssp. lucida, RAPD, variation, germplasm, Canada, United States, Chile.

scholarly journals Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America

2016 ◽  
Vol 12 (4) ◽  
pp. 20160062 ◽  
Author(s):  
Kieren J. Mitchell ◽  
Sarah C. Bray ◽  
Pere Bover ◽  
Leopoldo Soibelzon ◽  
Blaine W. Schubert ◽  
...  
Keyword(s):  
South America ◽  
North American ◽  
Convergent Evolution ◽  
Phylogenetic Analyses ◽  
Early Pleistocene ◽  
South American ◽  
The North ◽  
Molecular Phylogenetic ◽  
North And South America ◽  
North And South

The Tremarctinae are a subfamily of bears endemic to the New World, including two of the largest terrestrial mammalian carnivores that have ever lived: the giant, short-faced bears Arctodus simus from North America and Arctotherium angustidens from South America (greater than or equal to 1000 kg). Arctotherium angustidens became extinct during the Early Pleistocene, whereas Arctodus simus went extinct at the very end of the Pleistocene. The only living tremarctine is the spectacled bear ( Tremarctos ornatus ), a largely herbivorous bear that is today only found in South America. The relationships among the spectacled bears ( Tremarctos ), South American short-faced bears ( Arctotherium ) and North American short-faced bears ( Arctodus ) remain uncertain. In this study, we sequenced a mitochondrial genome from an Arctotherium femur preserved in a Chilean cave. Our molecular phylogenetic analyses revealed that the South American short-faced bears were more closely related to the extant South American spectacled bear than to the North American short-faced bears. This result suggests striking convergent evolution of giant forms in the two groups of short-faced bears ( Arctodus and Arctotherium ), potentially as an adaptation to dominate competition for megafaunal carcasses.

Differences in bleaching responses from fungal- versus bacterial-derived enzymes

TAPPI Journal ◽  
2012 ◽  
Vol 11 (3) ◽  
pp. 21-27 ◽  
Author(s):  
PETER W. HART
Keyword(s):  
North American ◽  
Cost Savings ◽  
Operating Conditions ◽  
South American ◽  
Oxygen Delignification ◽  
The North ◽  
Eucalyptus Pulp ◽  
The One ◽  
Enzyme Bleaching ◽  
North And South

Several mills in North America have been successful in using xylanase enzymes expressed from Trichoderma reesei (a fungus) as part of their bleaching sequence for many years. These mills process hardwood and softwood species, with and without oxygen delignification. These mills also use three-, four-, and five-stage bleaching sequences. North American mills tend to report increased pulp brightness ceilings and decreased bleaching costs as benefits associated with the application of enzymes in the bleaching process. Laboratory testing suggests that eucalyptus pulp is highly susceptible to fungal- and bacterial-derived enzyme bleaching and should result in significant cost savings in South American mills. At least four different mills in South America have attempted to perform enzyme bleaching trials using bacterial-derived enzymes. Each of these mill trials resulted in significantly increased operating costs and/or unsustainable operating conditions. More recently, one of these South American mills performed a short trial using a commercially available, fungal-derived enzyme. This trial was technically successful. This report attempts to determine why the South American mill experiences with bacterial-derived enzymes have been poor, while North American mills and the one South American mill trial have had good results with fungal-derived enzymes. Operating conditions and trial goals for the North and South American mills also were examined.

scholarly journals Embryo implantation during the short luteal phase of the corn mouse, Calomys musculinus, and the apparent lack of a lactational diapause in South American murid rodents

Reproduction ◽  
2001 ◽  
pp. 815-823 ◽  
Author(s):  
OL Buzzio ◽  
A Koninckx ◽  
NB Carreno ◽  
A Castro-Vazquez
Keyword(s):  
North American ◽  
Luteal Phase ◽  
Embryo Implantation ◽  
South American ◽  
Embryonic Diapause ◽  
South American Species ◽  
Apparent Lack ◽  
The North ◽  
Calomys Musculinus ◽  
Murid Rodents

As the corn mouse, Calomys musculinus, has a short luteal phase (2-3 days) that is not prolonged after copulation, it was hypothesized that (i) implantation would occur at the end of this phase, that is, earlier than it occurs in most murid species that have been studied, and (ii) a lactational embryonic diapause would not occur during the luteal phase. These hypotheses were tested in females that had copulated during postpartum oestrus and were either lactating or not lactating. Data were recorded from day 3 to day 5 of pregnancy (day 1 = day after coitus), at both 03:00-05:00 h and 17:00-19:00 h. Evidence of implantation in both non-lactating and lactating animals was apparent at 03:00-05:00 h on day 4 (endometrial 'blue reaction' in all cases and failure to recover free uterine embryos in some cases) and implantation swellings appeared within 24 h in both groups. In another experiment, the increase in duration of interbirth intervals in continuously mated females and their correlation with the number of suckling young were compared among C. musculinus, C. laucha, Akodon molinae (South American murid species) and Peromyscus maniculatus (a North American murid in which a lactational embryonic diapause has been shown). The results were indicative of a lactational embryonic diapause in the North American species, but not in the South American species. It was concluded that in C. musculinus (i) implantation occurs at the end of the spontaneous luteal phase, and (ii) that a lactational embryonic diapause does not occur: the absence of a lactational embryonic diapause may be common to other South American murid rodents.

Systematics and paleobiogeography of Late TriassicGryphaea(Bivalvia) from the North American Cordillera

1992 ◽  
Vol 66 (1) ◽  
pp. 28-39 ◽  
Author(s):  
Christopher A. Mcroberts
Keyword(s):  
North American ◽  
Late Triassic ◽  
South American ◽  
Long Distance ◽  
Low Latitude ◽  
North American Cordillera ◽  
The North ◽  
North American Craton ◽  
Far Eastern ◽  
North And South

Evaluation of previously undescribed collections of Late TriassicGryphaeafrom the North American Cordillera increases the temporal range and geographic distribution of the genus.Gryphaea(Gryphaea)arcuataeformisKiparisova,G.cf.G.(Gryphaea)keilhauiBöhm, and a new species,G.(Gryphaea)nevadensis, occur in lower Carnian to upper Norian strata from Alaska, British Columbia, Oregon, and Nevada. The distribution is mostly primary with respect to the Upper Triassic North American Craton, and requires long-distance larval dispersal along the latitude of far-eastern Panthalassa. Unlike most modern oysters, the distribution of these Triassic gryphaeids may have been restricted to cool and deeper water environments.An early Carnian age ofGryphaea(Gryphaea)arcuataeformisplaces this species as the oldest knownGryphaea. When combined with late Carnian and Norian occurrences from the North and South American Cordillera, these data indicate that a low-latitude origin for the genus cannot be overlooked. Gryphaeids survived the end-Triassic extinction event presumably by living in refugia.

Taxonomy of the North and South American species of Hordeum section Hordeastrum

1986 ◽  
Vol 64 (8) ◽  
pp. 1745-1759 ◽  
Author(s):  
Bernard R. Baum ◽  
L. Grant Bailey
Keyword(s):  
South American ◽  
Discriminant Functions ◽  
South American Species ◽  
Morphometric Characters ◽  
The North ◽  
Discriminant Analyses ◽  
Morphological Species ◽  
New Evidence ◽  
North And South

The four species H. euclaston Steud., H. flexuosum Nees ex Steud., H. intercedens Nevski, and H. pusillum Nutt. have been regarded as conspecific by some authors, because of a lack of markers for distinguishing among the species. Bothmer and co-workers recently recognized the four species but were unable to demonstrate morphological discontinuities that could be used in keys to permit definite identification to species. This paper provides new evidence from lodicule and epiblast characters for existence of four species. A key based on the rachilla, lodicules, and epiblast is presented. Furthermore, carefully defined morphometric characters of the four species were analysed by various discriminant analyses techniques. These analyses confirm the recognition of four morphological species and enable identification by means of resulting discriminant functions in addition to and complementary to the key.

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