450 research outputs found
In vitro propagation of Eucalyptus species
Introduction
The importance of eucalypts and reasons for tissue culture Eucalypts are Australia's most distinctive plant group. They are contained within the genus Eucalyptus which consists of over 500 named species, with more as yet unnamed (Brooker & Kleinig 1983; 1990 Chippendale 1988). The natural distribution of the genus is almost completely confined to the Australian continent and Tasmania with only two species, E. deglupta and E. urophylla, occurring naturally in other countries. Since European settlement of Australia, seeds of eucalypts have been sent to countries throughout the world and they are now commonly grown in tropical and temperate areas for timber, pulp wood, eucalyptus oil, fuelwood, charcoal and as ornamentals.
Exploitation of eucalypts outside Australia was initiated by the French. During the nineteenth century, eucalypts were planted in Europe and North America, and European imperial governments introduced them to colonies in South America, Africa and Asia. The presence of eucalypts in some of these countries is now so familiar to the native peoples that many consider them to be indigenous (Zacharin 1978).
Although eucalypts in early plantations often grew very quickly the wood was sometimes of poor quality due to wood splitting and distortion (Clarke 1957; Penfold & Willis 1961; Pryor 1976). In many cases this was because the species chosen were inappropriate for local climatic and edaphic conditions (Evans 1980; Durand-Cresswell et al. 1982), the trees had been planted for the wrong purposes (Penfold & Willis 1961; Pryor 1976), or given incorrect fertilisers (Savory 1962; Stone 1968).
The poor quality of the wood led to a slump in enthusiasm for growing eucalypts until about 1945 when world demand for pulpwood started to increase (Pryor 1976). Today the major uses of eucalypt wood are for fuelwood and pulpwood. There has been a 150 fold increase in pulpwood production from eucalypts since the early 1960s (Molleda 1984). They are now the most widely planted hardwood group in the world (Boland et al. 1984; Eldridge et al. 1993)
The flora of Murdoch University: A guide to the native plants on campus
Western Australia's wildflowers are recognized throughout the world for their colour, form and uniqueness. Many can be observed in the metropolitan area close to the city of Perth. Despite this, there has been very little scholarly documentation of them. This book provides an account of the flora of Murdoch University. Though the campus was disturbed first by farming and later by arboriculture, small but significant areas of the original bush remain. This scholarly account provides a valuable record of those native species that enrich the Murdoch campus after the first ten years of its operation. It should prove useful as a data base for future conservation and planning strategies, as well as providing a valuable reference source for staff and students. It should also have strong appeal to local residents who are curious about the plants which characterize the white and yellow sands of their surrounds and as a guide for visitors to the campus. The work, though written for the amateur naturalist, is scientifically sound and attempts to simplify the identification of plants using ink drawings and colour photographs in combination with keys. The Murdoch University community is grateful to those of its members whose enthusiasm and skill have made possible this lasting contribution to the celebration of our tenth anniversary. I congratulate them.
RONALD WILSON KBE, CMG, LLM Penn., LLB HonLLD W.Aust Chancellor, Murdoch University
INTRODUCTION TO THE VEGETATION
Background
Murdoch University lies at the interface of two dune systems on the western third of the Swan Coastal Plain. To the west lie the tall Spearwood Dunes, mainly yellow sands over limestone. The older and highly leached white sands of the Bassendean Dune system lie to the east. Separating the two systems is a chain of freshwater lakes and wetlands, the closest to Murdoch being North Lake.
Murdoch is part of the once extensive eucalypt/banksia woodland that clothed the well-drained ridges of much of the metropolitan area. Quite subtle changes in elevation, slope, drainage and soil chemistry provide a range of habitats resulting in a rich and diverse flora. As a result the Murdoch flora contains not only elements of the Kwongan sandplain vegetation (heathlands on infertile soils, e.g. Calectasia cyanea, Daviesia triflora), but units or species characteristic of the jarrah forest (e.g. Banksia grandis, Eucalyptus marginata), coastal woodlands on calcareous soils (e.g. Eucalyptus gomphocephala, Olearia axillaris) and freshwater wetlands (e.g. Astarte a fascicularis, Melaleuca preissiana).
Trees form the dominant and most familiar components in the region. Of the 200 indigenous species now on campus it is perhaps surprising that only fifteen reach the stature of trees (defined as plants with a single woody trunk and over 4 metres in height). There are four species of eucalypts, two paperbarks, five banksias, and one she-oak, Christmas tree, woody pear and acacia. Clearly, therefore, most diversity is to be found in the shrub and herbaceous communities and much of this book is devoted to these groups. The number of species and their present distributions have been strongly affected by agriculture and forestry pursuits.
Recent History
Parts of the southern half of Murdoch were used to graze cattle, horses and sheep until the mid 1970s. The grazing must, however, have been light in the existing Banksia Woodland because the under-storey is quite intact and there is little weed growth. Limited cropping was also undertaken. Earlier, Chinese market gardeners established vegetable plots near the south-east corner of Melaleuca Swamp. Part of the market garden now has Melaleuca regrowth and the raised beds can still be seen in aerial photographs. Just to the west of the old gardens lies a narrow raised track lined on the eastern side by a single row of Pinus trees. This track once passed north, up the main campus ridge and onto where Riseley Street is today. These and other tracks i n the area were probably once used to haul jarrah logs and billets to small local saw-pits or further afield on the limestone track (now Leach Highway) to mills in Fremantle. A few large jarrah stumps remain on campus, e.g .below Bush Court . In addition to jarrah, tuart was also felled for timber. This species is at the eastern edge of its range, and there are a few remaining trees in Bush Court.
The northern half of, Murdoch was part of the University of Western Australia Endowment Land (Cockburn Sound Location 549). In March 1926 an agreement was made between the University of Western Australia and the Conservator of Forests whereby the Forests Department undertook to establish a pine plantation. The area was to be cleared and planted at the rate of 100 acres per annum and the lease period was fifty years. The scheme was inaugurated at a time when there was a strong movement to get parliamentary permission to sell Endowment Lands, and was a challenge by members of the University of Western Australia Senate to find a way to use them profitably. The following description of the. Somerville plantation is from The West Australian (31 May 1938) - 'The plantation was divided into areas of about 25 acres, each of which was ' surrounded by a firebreak 15 feet wide. Each group of four such areas was surrounded by a firebreak one chain wide and each 300 acre lot was surrounded by a two-chain firebreak. The trees were planted about 7 feet apart'.
Wildfires in the Somerville area were small and frequent, for example there were sixty-one in the 1 973-74 season. In the early 1960s a lookout tower was erected west of Kardinya to replace the treetop lookout on the edge of South Street.
Most of the Murdoch section was planted from 1937 to 1940 with Pinus pinaster. A small area of P. radiata was planted near South Street in 1955. Later, the beginning of the construction programme for Murdoch University was symbolically marked by the felling of one tree on 7 February 1973
Vegetative propagation of Eucalyptus using tissue culture and its application to forest improvement in Western Australia
Conventional vegetative propagation from mature eucalypts is not possible for most species, but micropropagation has been successfully used for several species (1, 2). Jarrah (Eucalyptus marginata Sm.), is an important forest species limited to Western Australia. There are some 1,400,000 ha. in state forest reserves, but 280,000 ha. of these have already been affected by dieback and the increase in a year may be up to 16,000 ha. A root pathogen, Phytophthora cinnamomi Rands appears responsible for the disease (3). Another serious pest is the leaf miner (Perthida glyphopa Common), a moth whose larvae damage leaf tissue (4). Healthy trees are occasionally found in dieback sites, and trees apparently resistant to leaf miner occur in the forest. We wish to clone these trees and test them for genotypically controlled resistance
Biotechnology enhances utilization of Australian woody species for pulp, fuel and land rehabilitation
Selection and micropropagation of superior genotypes of species of Australian genera such as Eucalyptus, Acacia, Melaleuca and Casuarina offers a way of capitalizing on Australia's genetic resources without necessarily breaking the tradition of unrestricted export of seed for international forestry. A collaborative program of research and development between Alcoa (Australia), CSIRO Division of Forestry and Forest Products, The University of Western Australia, Murdoch University, North Broken Hill Ltd (APPM Forest Products) and Plantex (Australia) has examined the potential for the use of selected clones of species tolerant to saline waterlogging, and elite selections of E. Globulus and E. nitens for paper pulp production
Nanoparticles of palladium supported on bacterial biomass : new re-usable heterogeneous catalyst with comparable activity to homogeneous colloidal Pd in the Heck reaction
AbstractThe Heck coupling of iodobenzene with ethyl acrylate or styrene was used to assess the catalytic properties of biogenic nanoparticles of palladium supported upon the surface of bacterial biomass (bioPd), this approach combining advantages of both homogeneous and heterogeneous catalysts. The biomaterial was comparably active or superior to colloidal Pd in the Heck reaction, giving a final conversion of 85% halide and initial rate of 0.17mmol/min for the coupling of styrene and iodobenzene compared to a final conversion of 70% and initial rate of 0.15mmol/min for a colloidal Pd catalyst under the same reaction conditions at 0.5mol.% catalyst loading. It was easily separated from the products under gravity or by filtration for reuse with low loss or agglomeration. When compared to two alternative palladium catalysts, commercial 5% Pd/C and tetraalkylammonium-stabilised palladium clusters, the bioPd was successfully reused in six sequential alkylations with only slight decreases in the rate of reaction as compared to virgin catalyst (initial rate normalised for g Pd decreased by 5% by the 6th run with bioPd catalyst cf. a decrease of 95% for Pd/C). A re-usable Pd-catalyst made cheaply from bacteria left over from other processes would impact on both conservation of primary sources via reduced metal losses in industrial application and the large environmental demand of primary processing from ores
Modeling of the Heat-Affected and Thermomechanically Affected Zones in a Ti-6Al-4V Inertia Friction Weld
Inflation, cold dark matter, and the central density problem
A problem with high central densities in dark halos has arisen in the context
of LCDM cosmologies with scale-invariant initial power spectra. Although n=1 is
often justified by appealing to the inflation scenario, inflationary models
with mild deviations from scale-invariance are not uncommon and models with
significant running of the spectral index are plausible. Even mild deviations
from scale-invariance can be important because halo collapse times and
densities depend on the relative amount of small-scale power. We choose several
popular models of inflation and work out the ramifications for galaxy central
densities. For each model, we calculate its COBE-normalized power spectrum and
deduce the implied halo densities using a semi-analytic method calibrated
against N-body simulations. We compare our predictions to a sample of dark
matter-dominated galaxies using a non-parametric measure of the density. While
standard n=1, LCDM halos are overdense by a factor of 6, several of our example
inflation+CDM models predict halo densities well within the range preferred by
observations. We also show how the presence of massive (0.5 eV) neutrinos may
help to alleviate the central density problem even with n=1. We conclude that
galaxy central densities may not be as problematic for the CDM paradigm as is
sometimes assumed: rather than telling us something about the nature of the
dark matter, galaxy rotation curves may be telling us something about inflation
and/or neutrinos. An important test of this idea will be an eventual consensus
on the value of sigma_8, the rms overdensity on the scale 8 h^-1 Mpc. Our
successful models have values of sigma_8 approximately 0.75, which is within
the range of recent determinations. Finally, models with n>1 (or sigma_8 > 1)
are highly disfavored.Comment: 13 pages, 6 figures. Minor changes made to reflect referee's
Comments, error in Eq. (18) corrected, references updated and corrected,
conclusions unchanged. Version accepted for publication in Phys. Rev. D,
scheduled for 15 August 200
Changes of solar cell parameters during damp-heat exposure
The degradation of PV modules during damp-heat exposure is investigated. Power degradation is analysed in dependence of temperature and humidity during exposure. The module’s equivalent circuit parameters are calculated from I-V characteristics measured during ageing. A dose function is developed and degradations of power as well as equivalent circuit parameters can be analysed against the dose, which provides a better understanding of the module ageing behaviour. EL images of modules before and after ageing support the changes of solar cell parameters
Dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeV and the contribution from open charm
The PHENIX experiement has measured the electron-positron pair mass spectrum
from 0 to 8 GeV/c^2 in p+p collisions at sqrt(s)=200 GeV. The contributions
from light meson decays to e^+e^- pairs have been determined based on
measurements of hadron production cross sections by PHENIX. They account for
nearly all e^+e^- pairs in the mass region below 1 GeV/c^2. The e^+e^- pair
yield remaining after subtracting these contributions is dominated by
semileptonic decays of charmed hadrons correlated through flavor conservation.
Using the spectral shape predicted by PYTHIA, we estimate the charm production
cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) \mu b, which
is consistent with QCD calculations and measurements of single leptons by
PHENIX.Comment: 375 authors from 57 institutions, 18 pages, 4 figures, 2 tables.
Submitted to Physics Letters B. v2 fixes technical errors in matching authors
to institutions. Plain text data tables for the points plotted in figures for
this and previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Inclusive cross section and double helicity asymmetry for \pi^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
The PHENIX experiment presents results from the RHIC 2005 run with polarized
proton collisions at sqrt(s)=200 GeV, for inclusive \pi^0 production at
mid-rapidity. Unpolarized cross section results are given for transverse
momenta p_T=0.5 to 20 GeV/c, extending the range of published data to both
lower and higher p_T. The cross section is described well for p_T < 1 GeV/c by
an exponential in p_T, and, for p_T > 2 GeV/c, by perturbative QCD. Double
helicity asymmetries A_LL are presented based on a factor of five improvement
in uncertainties as compared to previously published results, due to both an
improved beam polarization of 50%, and to higher integrated luminosity. These
measurements are sensitive to the gluon polarization in the proton, and exclude
maximal values for the gluon polarization.Comment: 375 authors, 7 pages, 3 figures. Submitted to Phys. Rev. D, Rapid
Communications. Plain text data tables for the points plotted in figures for
this and previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
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