1,929 research outputs found
Notes on the distribution and conservation status of Eucalyptus cannonii R.T. Baker
No full textThe first collections of Eucalyptus cannonii were made by R.T. Baker in 1892, during collecting trips to the Rylstone and Goulburn River areas. Although Baker (1896) made numerous notes on many of the plants collected at that time, he made no remarks on the variation in Eucalyptus macrorhyncha (which then included Eucalyptus cannonii) despite claiming so in his later description of the taxon (Baker 1919).
Recognition of the variation shown in what was to become Eucalyptus cannonii was given by Maiden (1907) in his "Critical revision of the genus Eucalyptus" (as Eucalyptus macrorhyncha "grandiflora" form). Maiden highlighted the collections made by Baker from Rylstone and Mt Vincent as being coarser in form with a very prominent rim.
Baker (1919) described this taxon as Eucalyptus cannonii, named after Herbarium assistant Mr D. Cannon. Despite Maiden's comments, Baker (1919) indicated that data presented to him by Mr G. Harris (collector of the material cited by Baker) convinced him of the distinctiveness of the taxon. Eucalyptus cannonii was separated from Eucalyptus macrorhyncha on the shape of the fruit, buds, inflorescence and features of the timber and bark.
Penfold and Willis (1961) considered Eucalyptus cannonii to be distinctive local race of E. macrorhyncha and Johnson and Blaxell (1973) reduced E. cannonii to a subspecies of E. macrorhyncha, based on the intergradation where their ranges overlap. Hill (1991) retained specific status for Eucalyptus cannonii
Monoterpene synthases responsible for the terpene profile of anther glands in Eucalyptus polybractea R.T. Baker (Myrtaceae)
No full textResearch on terpene biosynthesis in the genus Eucalyptus (Myrtaceae) is poorly developed, but recently large numbers of terpene synthase (TPS) genes have been identified. Few of these have been characterized or their expression localized to specific tissues. A prime candidate for detailed examination of TPS gene expression is the bisexual eucalypt flower - composed of male and female reproductive organs, and vegetative tissues that may express different TPS genes. We aimed to characterize and compare the terpene profile and TPS genes expressed in anthers and gynoecia in the high oil-yielding Eucalyptus polybractea R.T. Baker. We hypothesized that gynoecia will produce greater amounts of defensive terpenes, whereas anthers will have a terpene profile that is biased towards a role in pollination. Microscopy of isolated anthers showed them to possess a single, prominent oil gland. Chemical analysis of whole floral structures at different stages of development showed total oil per unit dry mass increased as flower buds expanded, with highest concentrations in mature flower buds just prior to flower opening. The oil profile of gynoecia was dominated by the monoterpene 1,8-cineole, whereas that of isolated anthers were enriched with the monoterpene α-pinene. Through transcriptomic analysis and recombinant protein expression, we were able to identify monoterpene synthases responsible for the different profiles. Synthases for α-pinene and 1,8-cineole were expressed in each tissue type, but the relative expression of the former was higher in anthers. Sequence comparison and site-directed mutagenesis of the α-pinene synthase allowed us to identify amino acids that influence the α-pinene to β-pinene ratio of the product profile. We suggest the terpene constituents of anthers may have multiple roles including attracting pollinators through emission of volatile α-pinene, deterrence of palynivores through emission of volatile 1,8-cineole and adhesion of pollen to pollinators via the release of sticky α-pinene onto the anther surface
Differential patterns of mono- and sesquiterpenes with leaf ontogeny influence pharmaceutical oil yield in Eucalyptus polybractea R.T. Baker
No full textPharmaceutical 1,8-cineole oil is commercially harvested from Eucalyptus polybractea R.T. Baker grown in short rotation coppice cultivation. Harvests occur throughout the year, with no consideration given to the proportion of leaves present at different ontogenetic stages, and the effect leaf ontogeny may have on harvested oil quality and quantity. To determine the optimal leaf stage to harvest pharmaceutical-grade oil, we quantified the relationship between leaf ontogeny and foliar oil quantity and quality, secretory cavity size, and abundance along branches of two E. polybractea clones. The results show that the desirable attributes of oil yield and 1,8-cineole proportion both reach their maximum in fully expanded leaves and that this coincides with maximum secretory cavity size. Across all leaf ages the amount of various monoterpenes were highly correlated with 1,8-cineole, suggesting a single, multi-product monoterpene synthase may be responsible. In the very young leaves, sesquiterpenes such as β-elemene were the most abundant constituents of the essential oil. This study suggests that there may be differential transcriptional regulation of mono- and sesquiterpene synthases with leaf ontogeny such that sesquiterpene biosynthesis is at a maximum only in young leaves, and that monoterpene biosynthesis dominates during leaf and concomitant cavity expansion. Given E. polybractea leaves are produced during major seasonal flushes, there are times throughout the year when the numbers of young leaves with inferior oil quantity and quality are likely to be proportionally decreased. Therefore harvesting times could be manipulated to take advantage of such times and ensure abundant high quality oil is harvested
Investigação da presença de óleo essencial em Eucalyptus smithii R.T. Baker por meio da anatomia de seu lenho e casca.
No full textThe material used in the present work came from 15 Eucalyptus smithii R. T. Baker trees grown in the experimental field of Embrapa Forests, in Colombo county, that were planted in 1988. The anatomical characterization of the wood and bark was accomplished using material prepared by Wood Anatomy and Identification Laboratory of IPT, and Wood Anatomy Laboratory of Federal University of Parana State. The essential oil extraction and analysis was made using ABNT procedures in the Phytochemistry Laboratory of Federal University of Parana State. The wood and bark of the Eucalyptus smithii had a homogeneous anatomical structure. In bark were found secretory cavities, but in wood they were not present, only quino veins and being the oil presence insignificant. The essential oil from bark had physical-chemistry characteristics in disagreement with international specifications for the eucalypt essential oils, rich in 1,8-cineole; therefore it is not economically viable to explore this component.O material utilizado no presente estudo foi proveniente de 15 árvores de Eucalyptus smithii R.T. Baker cultivadas no município de Colombo - PR, em campo experimental da Embrapa Florestas, plantadas em 1988. Caracterizou-se anatomicamente o lenho e a casca por meio de lâminas preparadas no Laboratório de Anatomia e Identificação de Madeiras do IPT e Laboratório de Anatomia da Madeira, do Centro de Ciências Florestais e da Madeira, da Universidade Federal do Paraná. Para a extração do óleo essencial, a madeira foi transformada em serragem e a casca desfibrada manualmente. Para a determinação do rendimento e análise do óleo essencial, foram efetuadas destilações conforme ABNT no Laboratório de Fitoquímica do Departamento de Farmácia da Universidade Federal do Paraná. Os rendimentos do óleo essencial foram dados em volume (ml) de óleo essencial por massa (g) de material. O Eucalyptus smithii apresenta estrutura anatômica homogênea do lenho e da casca. Na casca, observou-se a presença de cavidades secretoras; no entanto, no lenho, não foi encontrada nenhuma estrutura semelhante, apenas bolsas de quino, sendo desprezível a quantidade de óleo essencial presente na madeira. O óleo essencial da casca apresentou características físico-químicas fora das especificações para óleos essenciais de eucaliptos ricos em 1,8-cineol, não sendo economicamente viável para a exploração desse componente
Investigação da presença de óleo essencial em <i>Eucalyptus smithii</i> R.T. Baker por meio da anatomia de seu lenho e casca.
No full textO material utilizado no presente estudo foi proveniente de 15 árvores de Eucalyptus smithii R.T. Baker cultivadas no município de Colombo - PR, em campo experimental da Embrapa Florestas, plantadas em 1988. Caracterizou-se anatomicamente o lenho e a casca por meio de lâminas preparadas no Laboratório de Anatomia e Identificação de Madeiras do IPT e Laboratório de Anatomia da Madeira, do Centro de Ciências Florestais e da Madeira, da Universidade Federal do Paraná. Para a extração do óleo essencial, a madeira foi transformada em serragem e a casca desfibrada manualmente. Para a determinação do rendimento e análise do óleo essencial, foram efetuadas destilações conforme ABNT no Laboratório de Fitoquímica do Departamento de Farmácia da Universidade Federal do Paraná. Os rendimentos do óleo essencial foram dados em volume (ml) de óleo essencial por massa (g) de material. O Eucalyptus smithii apresenta estrutura anatômica homogênea do lenho e da casca. Na casca, observou-se a presença de cavidades secretoras; no entanto, no lenho, não foi encontrada nenhuma estrutura semelhante, apenas bolsas de quino, sendo desprezível a quantidade de óleo essencial presente na madeira. O óleo essencial da casca apresentou características físico-químicas fora das especificações para óleos essenciais de eucaliptos ricos em 1,8-cineol, não sendo economicamente viável para a exploração desse componente.</p
Ecology of the Festuca Grassland in Central Saskatchewan
No full textFor some time it has been realized that the grassland occuring in the 'park belt' or 'aspen grove region' bounding the Canadian prairies on the north, and forming the transition between it and the boreal forest, does not consist merely of extensions of the adjacent grassland communities (true prairie or mixed prairie) among the patches of woodland which occur in that region; but is characterized by a different group of dominant grasses from those occuring elsewhere in North America.
Although other investigators have mentioned this fact and written about the flora in other parts of the region, their data have been based largely on methods of estimation chiefly of a qualitative nature. In view of this, it was thought that an ecological survey based on quantitative methods might provide a better basis for classifying the vegetation of the area.
Accordingly, while being employed as an assistant in the Department of Plant Ecology of the University of Saskatchewan the author was given the opportunity, under the supervision of Dr. R.T. Coupland, to carry out investigations in those parts of the aspen grove region north and northwest of Saskatoon.
The author is considerably indebted to Dr. B.W. Currie of the Physics Department, for furnishing data on the climate of the area of research, and to Mr. H.C. Moss and his assistants, of the Saskachewan Soil Survey, who kindly undertook to examine and report on the soil samples which were collected in several of the sites studied. The author also wishes to express his gratitide to Mr. Jack F. Alex and Mr. W. Budz of the Department of Plant Ecology, who assisted greatly in both the field and laboratory work for this project. The financial assistance of the Saskatchewan Agricultural Research Foundation, which made this study possible, is also appreciated.
The author experienced a great deal of difficulty as a result of unfamiliarity with the topography, in particular with the vegetation of the plants, since he is more accustomed to the mountains and forests of British Columbia. Many problems of identifications were encountered in dealing with the wealth of species of grasses and composites, as well as problems of relationship between the communities found in certain locations and their topographical situation
Morphological and anatomical studies of the seeds and seedlings of Eucalyptus pilularis and E. umbra
No full textMorphological and anatomical aspects of seeds and seedlings of Eucalyptus pilularis Sm. and E. umbra R.T. Baker were studied in detail and fovnd to be similar, wlth the exception of sorne anatomical features of the testa and the average length of the fertile seeds, which is significantly different for the two species.Se estudiaron en detalle aspectos morfológicos y anatómicos de semillas y plántulas jóvenes de Eucalyptus pilularis Sm. y E. umbra R.T. Baker. Se encontró que eran similares a excepción de algunos aspectos anatómicos de la testa y del promedio de longitud de las semillas fértiles, que es significativamente diferente en estas dos especies
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Tandem metal-mediated synthesis
No full textThis is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Boronic acids RB(OH){sub 2} are currently of interest for applications involving molecular recognition such as amine and sugar sensors and selective transport of biomolecules. They have also been shown to be powerful enzyme inhibitors and alpha-aminoboronic acids (ABAs) are particularly selective inhibitors of serine proteases. Unfortunately, current multistep synthetic routes to the latter compounds do not allow for the incorporation of a wide variety of organic substituents R that may lead to new, more selective enzyme inhibitors. In this work the author describes several direct routes to ABAs based on metal-catalyzed addition of diboron compounds to imines and nitriles. Several other applications of diboron additions to heteroatom-containing unsaturated organics are also described
Some additions to our recorded flowering plants
No full textList includes Eucalyptus dalrympleana, J.H. Maiden; Eucalyptus irbyi, R.T. Baker and Caladenia atkinsoni,n.s. as well as short notes of other plants. Includes Plate VIII which is a coloured plate of Caladenia atkinsoni, n.s
Jack Christian Presides Over the 1957 City Council
No full textMayor President Jack Christian (rear) presides over Woody Dumas' second term on the City Council. (Seated from left) Bonnie V. Baker, William Berhard, Robert P. Breazeale, R.T. "Bobby" Clegg, Woody Dumas, Cotton Harris, Frank McConnell, J.A. "Jimmy" McCur
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