scholarly journals Um Novo Lenho Gimnospérmico da Formação Rio Bonito, SC, Brasil - Aterradoxylon solidum gen. et sp.nov.

1999 ◽  
Vol 26 (2) ◽  
pp. 79
Author(s):  
SHEILA MERLOTTI
Keyword(s):  
South Africa ◽  
Secondary Xylem ◽  
Vascular System ◽  
Fossil Wood ◽  
New Taxon ◽  
Santa Catarina ◽  
Bordered Pits ◽  
Secretory System ◽  
Primary Vascular System

The morphoanatomic study of a taphoflora from the Rio Bonito Formation, Pouso Redondo County, Santa Catarina State, Brazil, resulted in the determination of new gymnospermous genera, among them a fossil wood that, by being represented by 9 of the 25 samples studied, constitutes the second form with significant representation in the assemblage (36%). By virtue of the solid and heterocelular pith, the centrifugal differentiation of the primary vascular system and the large pits in the cross-field of the secondary vascular system, the wood in question is similar to the morfogenus Megaporoxylon KRÄUSEL, 1956 from the Permian of South Africa. However, the presence of singular characters, like the nature of the secretory system and the outline of pith as well as the configuration of the bordered pits on radial walls of the secondary xylem cells, evidences the necessity of its segregation in new taxon which is named Aterradoxylon solidum gen. et sp. nov.

scholarly journals Sommerxylon spiralosus from Upper Triassic in southernmost Paraná Basin (Brazil): a new taxon with taxacean affinity

2004 ◽  
Vol 76 (3) ◽  
pp. 595-609 ◽  
Author(s):  
Etiene F. Pires ◽  
Margot Guerra-Sommer
Keyword(s):  
Northern Hemisphere ◽  
Secondary Xylem ◽  
Upper Triassic ◽  
New Taxon ◽  
Axial Parenchyma ◽  
Primary Xylem ◽  
Bordered Pits ◽  
The Family ◽  
Paraná Basin ◽  
Parana Basin

The anatoical description of silici?ed Gymnospermae woods from Upper Triassic sequences of southernmost Paraná Basin (Brazil) has allowed the identi?cation of a new taxon: Sommerxylon spiralosus n.gen. et n.sp. Diagnostic parameters, such as heterocellular medulla composed of parenchymatous and sclerenchymatous cells, primary xylem endarch, secondary xylem with dominant uniseriate bordered pits, spiral thickenings in the radial walls of tracheids, medullar rays homocellular, absence of resiniferous canals and axial parenchyma, indicate its relationship with the family Taxaceae, reporting on the first recognition of this group in the Triassic on Southern Pangea. This evidence supports the hypothesis that the Taxaceae at the Mesozoic were not con?ned to the Northern Hemisphere.

scholarly journals Contramolde medular em conexão orgânica com fragmento lenhoso de Retemedulloxylon da Formação Rio Bonito (Eopermiano da Bacia do Paraná), Santa Catarina, Brasil

1999 ◽  
Vol 26 (2) ◽  
pp. 73
Author(s):  
SHEILA MERLOTTI
Keyword(s):  
Secondary Xylem ◽  
Environmental Influences ◽  
Longitudinal Axis ◽  
Fossil Wood ◽  
Cylindrical Shape ◽  
Santa Catarina ◽  
Taxonomic Affinity ◽  
Primary Xylem ◽  
Secondary Wood ◽  
Wood Fragment

This work records the occurrence of a pith cast connected with wood fragment in a fossil assemblage proceeding from Pouso Redondo County, Santa Catarina State, Brazil, in sediments from the Rio Bonito Formation, Eopermian of the Paraná Basin. The pith cast, cylindrical, is highly siliceous and unprovided of diagnosis impressions and tissular vestiges. The fragment, which has a half-cylindrical shape and a concavity along the longitudinal axis, is devoid of primary xylem and reveals a secondary xylem with few defined axial and radial systems. The anatomic characteristics of the secondary wood body indicate taxonomic affinity of the fossil wood with the most representative genus in the assemblage, increasing the establishing of relationships between the pith casts and the gondwanic taxa describe until the present, and suggest that the occurrence of these pith casts in the gondwanic sediments is probably because of environmental influences.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

scholarly journals Anatomy of Brazilian Cereeae (subfamily Cactoideae, Cactaceae): Arrojadoa Britton & Rose, Stephanocereus A. Berger and Brasilicereus Backeberg

2007 ◽  
Vol 21 (4) ◽  
pp. 813-822 ◽  
Author(s):  
Patricia Soffiatti ◽  
Veronica Angyalossy
Keyword(s):  
Secondary Xylem ◽  
Sieve Tube ◽  
Vascular Bundles ◽  
Campos Rupestres ◽  
Espinhaço Range ◽  
Diagnostic Characters ◽  
Bordered Pits ◽  
Companion Cells ◽  
Southern Bahia ◽  
Perforation Plates

(Anatomy of Brazilian Cereeae (subfamily Cactoideae, Cactaceae): Arrojadoa Britton & Rose, Stephanocereus A. Berger wâBrasilicereus Backeberg). Arrojadoa, Stephanocereus and Brasilicereus are endemic Brazilian Cereeae, occurring along the Espinhaço Range, in the campos rupestres, cerrados and caatingas, from northern Minas Gerais to southern Bahia. The genera are columnar, erect to semi-erect cacti, except for one species, A bahiensis, which is globose. This study describes the anatomy of dermal, fundamental and vascular systems, aiming to find diagnostic characters for the genera and species. Basal portions of stems were sectioned transversely and longitudinally, and stained with Astrablue and Safranin. The species share a uniseriate epidermis, with thick cuticle; well developed collenchymatic hypodermis, containing prismatic crystals; cortex with numerous mucilage cells, druses and vascular bundles; outside cortex as a palisade parenchyma; periderm composed of lignified cork cells alternating with suberized cells; pheloderm consisting of a few layers of thin-walled cells; phloem composed of solitary or multiple of two to three sieve tube elements, companion cells, axial and radial parenchyma; secondary xylem with solitary to multiple vessels, with simple perforation plates and alternate bordered to semi-bordered pits; axial parenchyma scanty vasicentric to incomplete; libriform septate fibres; large rays. Unlignified parenchyma is seen in the secondary xylem, varying from a few cells to bands among axial and radial elements. The following are considered diagnostic characters: the shape of lignified phellem cells, cubic to radially elongate, which individualizes S. leucostele; an underdeveloped hypodermis and the occurrence of sclereids in the cortex are exclusive to Brasilicereus markgrqfii.

scholarly journals The Theory of Wetting, and the Determination of the Wetting Power of Dipping and Spraying Fluids containing a Soap Basis

1915 ◽  
Vol 7 (2) ◽  
pp. 219-239 ◽  
Author(s):  
W. F. Cooper ◽  
W. H. Nuttall
Keyword(s):  
United States ◽  
South Africa ◽  
Active Substance ◽  
Sodium Arsenite ◽  
The United States ◽  
Active Constituent ◽  
Wetting Power ◽  
The Government

The dipping of sheep and cattle, as a means of eradicating ‘scab,’ lice, ticks, etc., and the diseases which it is now known the latter may transmit, has met with such success, that compulsory dipping is now in vogue in most pastoral countries. Where compulsory dipping obtains, there must of necessity be some system of the standardisation of dips. In Queensland and South Africa, the respective Governments issue official formulae from which the stockbreeder can prepare his own dipping fluid. Only such proprietary dips, as are duly recognised by the Government, may be employed. In the United States, the regulations for the sale of proprietary dips are still more stringent. The quantity of active substance, usually sodium arsenite, nicotine or cresylic acid, is defined within very narrow limits. Further, no proprietary dip is now recognised, unless the manufacturer can furnish a ‘Field Tester,’ by means of which the stockbreeder can himself determine, in a simple and fairly trustworthy manner, the percentage of active constituent in his bath.

scholarly journals Ppd-1 Remodels Spike Architecture by Regulating Floral Development in wheat

2020 ◽  
Author(s):  
Yangyang Liu ◽  
Lili Zhang ◽  
Michael Melzer ◽  
Liping Shen ◽  
Zhiwen Sun ◽  
...  
Keyword(s):  
Grain Yield ◽  
Floral Development ◽  
Vascular System ◽  
Dry Weight ◽  
Expression Data ◽  
Loss Of Function ◽  
Distinct Allele ◽  
Underlying Mechanisms ◽  
Photoperiod Sensitive

AbstractThe determination of spike architecture is critical to grain yield in wheat (Triticum aestivum), yet the underlying mechanisms remain largely unknown. Here, we measured 51 traits associated with spike architecture and floral development in 197 wheat accessions with photoperiod sensitive and insensitive alleles. We included five distinct allele combinations at the Photoperiod-1 (Ppd-1) loci. A systematic dissection of all recorded phenotypes revealed connections between floral development, spike architecture and grain yield. Modifying the durations of spikelet primordia initiation did not necessarily affect spikelet number. In addition, Ppd-1 loci clearly influenced rachis dry weight, pointing to the rachis vascular system as a potential target for higher yield. Ppd-1 displayed opposite effects on the durations of pre and post-anthesis phases. Ppd-1 controlled carpel size, but not anther size. Finally, the photoperiod-insensitive alleles of Ppd-1 triggered floral degeneration. In parallel, we profiled the spike transcriptome at six stages and four positions in three Ppd-1 genotypes which consists of 234 samples. Integrating phenotypic and expression data suggested that loss of function in Ppd-1 loci delayed floral degeneration by regulating autophagy and extended floret development by regulating genes in different families. Therefore, we concluded that Ppd-1 remodels spike architecture by regulating floral development in wheat.

scholarly journals Triassic Wood from the Gordon Valley, Central Transantarctic Mountains, Antarctica

IAWA Journal ◽  
1995 ◽  
Vol 16 (2) ◽  
pp. 111-126 ◽  
Author(s):  
Georgina M. Dei Fueyo ◽  
Edith L. Taylor ◽  
Thomas N. Taylor ◽  
N. Rubén Cúneo
Keyword(s):  
Middle Triassic ◽  
Fossil Wood ◽  
New Taxon ◽  
Axial Parenchyma ◽  
Transantarctic Mountains ◽  
The Antarctic

Wood from an in situ permineralized forest from the Middle Triassic of Gordon Valley (Queen Alexandra Range, central Transantarctic Mountains) in Antarctica is described as a new taxon, Approximately 100 trunks in growth position are present at the site; they range from 13-61 cm in diameter and suggest that some of the trees were up to 20 m tall, Pits in the radial walls of the tracheids are of the abietinean type, Rays are uniseriate and 1-9 cells high; cross fields include one to two pits that appear to be simple, Axial parenchyma is absent. Pith and cortex are not preserved. The Antarctic wood is compared with existing fossil wood types from Antarctica and other parts of Gondwana. Although the fossil wood shares a number of characteristics with the Podocarpaceae, it differs from any existing genera and is described as a new taxon, Jeffersonioxylon gordonense.

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