bluuebunny/crossref_metadata_2025 huggingface dataset:
Genotypic variation in cadmium accumulation by seed of linseed, and comparison with seeds of some other crop species
Authors: Hocking P. J. , McLaughlin M. J.
Published: September 2002

The accumulation of cadmium (Cd) in plants is a health issue because a range
of grain and vegetable crops can accumulate levels of Cd that are in excess of
limits set by the World Health Organization and individual countries. Many
Australian agricultural soils used to produce confectionery linseed have a
history of intensive use of Cd-contaminated phosphatic fertilisers and this,
combined with soil properties such as high chloride salinity, can result in
enhanced availability of Cd to crops. We investigated genotypic variation in
Cd accumulation in seed of 17 linseed and Linola (termed linseed) lines from
Australia and elsewhere in a glasshouse study using a soil from southern
Australia that had a history of the application of Cd-contaminated phosphatic
fertiliser. Canola, Indian mustard, lupins, and wheat were also included in
the study for comparison. Under the experimental conditions, Cd concentrations
in seed of all but one of the linseed lines exceeded the maximum permitted
concentration (MPC) of 250 µg/kg for confectionery linseed traded on
the international market. There was a 2.3-fold variation in seed Cd
concentrations between all the linseed lines (range, 233–545
µg/kg). Linseed lines from Australia and overseas were equally
capable of accumulating Cd in seed. Brown-seeded and golden-seeded lines
accumulated similar concentrations of Cd. Canola, Indian mustard, lupins, and
wheat accumulated about 10-fold lower concentrations of Cd in seed than
linseed, and did not exceed Australian or other MPCs. There was little
difference in Cd concentrations between the seed and de-seeded capsules of
linseed, but a large difference in Cd concentration between the seed and
de-seeded fruit parts of the other crops. The mean seed to de-seeded fruit
part Cd concentration ratio for linseed was 0.87 : 1 compared with a ratio of
0.35 : 1 for the other crops, suggesting that linseed has comparatively
ineffective barriers discriminating against the transport of Cd to seed.
Analysis of seed lots of confectionery linseed sampled from a grain receival
depot showed that seed lots from farms in Victoria (range 140–560
µg Cd/kg) had 5-fold greater Cd concentrations than those from farms
in New South Wales (range 20–160 µg/kg). This is presumably
due to a more intensive history of the application of Cd-contaminated
phosphatic fertiliser to pastures and crops in Victoria, as well as
differences in environmental and soil conditions.
The distribution of errors associated with genotype and environment during the prediction of the water-soluble carbohydrate concentration of perennial ryegrass cultivars using near infrared reflectance spectroscopy
Authors: Smith K. F. , Kearney G. A.
Published: September 2002

Significant deviations associated with site or cultivars within sites were
detected in 4 of 6 independent near infrared reflectance spectroscopy (NIRS)
calibrations developed to predict water-soluble carbohydrate (WSC)
concentrations in perennial ryegrass herbage harvested from 2 sites. These
effects were observed both when calibration subsets were selected on the basis
of spectral characteristics, and when calibration sets were balanced with
respect to a priori knowledge of the structure of the
data set. However, there were also instances when non-random deviations were
not significant, demonstrating that it was possible to develop broadly based
NIRS calibrations to predict WSC in perennial ryegrass. Deviations between
NIRS predictions and reference values should be monitored, with reference to
the structure of the experiment from which the samples were derived, before
NIRS estimates of WSC concentration are used in agronomy or plant breeding.
Genotypic variation for seed yield components in white clover (Trifolium repens L.)
Authors: Jahufer M. Z. Z. , Gawler F. I.
Published: September 2002

Seed yield is an important criterion that determines the commercial
acceptability of new cultivars. Often, the seed yielding capacity of a forage
cultivar is tested only in the final stages of its development. A more
efficient strategy would be to screen and select plants for seed yield at an
early stage of breeding. An important objective of the National White Clover
Breeding Program based at the Agriculture Victoria Pastoral and Veterinary
Institute, Hamilton, is to assess the genetic diversity for important
morphological attributes among germplasm accessions. A set of 53 accessions,
which included germplasm collected from Morocco and Tunisia and a range of
commercial cultivars, was characterised for seed yield components. The seed
yield components were number of ripe inflorescences, number of florets per
ripe inflorescence, number of seeds per pod, floret size, and inflorescence
height. Potential seed yield was estimated. The magnitude of genotypic
variation, together with the accession mean repeatability estimates, indicated
the presence of genetic variation among the 53 accessions for all attributes.
Both phenotypic and genotypic correlation coefficients indicated a strong
positive association between total number of ripe inflorescences and seed
yield. There was also a positive phenotypic and genotypic correlation between
seed yield and number of florets per inflorescence. Cluster analysis of the 53
accessions based on seed yield components resulted in the generation of 6
groups. Principal component analysis helped to identify 5 accessions that
could be potentially useful in improving the seed yield of white clover
germplasm selected for superior agronomic and herbage yield attributes.
Nitrogen budget of wheat growing on a Riverine clay soil
Authors: Smith C. J. , Dunin F. X. , Poss R. , Angus J. F.
Published: September 2002

The fate of nitrogen in wheat grown on a Mesotrophic, Red Kandosol near Wagga
Wagga was studied in the 1993 growing season, which had above-average
rainfall: 417 mm (31 May–30 November 1993) compared with an average
(June–November) of 289 mm. Nitrogen supply (fertiliser and
mineralisation) was partitioned between crop uptake, gaseous and leaching
losses, and residual mineral N in the soil profile. The study plots were 2
adjacent 5-ha areas. At stem elongation (Zadock’s decimal code 31), one
area was topdressed with urea at 14 g N/m2
(fertilised crop). The total N supply to the fertilised crop was 29 g
N/m2—8 g N/m2 of
mineral N in the soil at sowing, net mineralisation of 5.3 g
N/m2, and fertiliser inputs of 1.7 and 14 g
N/m2. The corresponding value for the non-fertilised
crop was 15 g N/m2.
The urea application produced a 50% increase in above-ground biomass
(1521 and 1008 g/m2 dry matter at harvest) and a
1.8-fold increase in grain yield (692 and 384 g/m2).
The proportion of the total N supply recovered in the crops was similar
(55% and 60% for the non-fertilised and fertilised treatments,
respectively). Leaching losses were low (0.4 and 0.5 g
N/m2), even though ≈100 mm drained beyond the
root-zone (equivalent to 24% of the seasonal rainfall). The periods of
saturated soil required to generate drainage also caused denitrification
losses of 1.7 and 3.4 g N/m2 for the non-fertilised
and fertilised treatments, respectively. Increased net mineralisation and
reduced crop N uptake that began a month prior to anthesis were responsible
for the substantial amounts of mineral N remaining in the soil after harvest
(4.7 and 4.3 g N/m2, respectively). The low
NO3 leaching loss associated with high drainage was
explained by displacement flow mechanics operating in soil that has a high
water retention capacity, which is confirmed by Br and
15N tracer analysis. The N balance was closed for the
non-fertilised crop, but a discrepancy of 2.8 g N/m2
remains for the fertilised crop. The uncertainty of ≈10% of the
fertilised treatment may possibly be due to ammonia volatilisation following
topdressing with urea.
Australian Cosmic Ray Modulation Research
Authors: Duldig M. L.
Published: September 2002

Australian research into variations of the cosmic ray flux arriving at the Earth has played a pivotal role for more than 50 years. The work has been largely led by the groups from the University of Tasmania and the Australian Antarctic Division, and has involved the operation of neutron monitors and muon telescopes from many sites. In this paper, the achievements of the Australian researchers are reviewed and future experiments are described. Particular highlights include: the determination of cosmic ray modulation parameters; the development of techniques for modelling ground-level enhancements; the confirmation of the Tail-In and Loss-Cone sidereal anisotropies; the Spaceship Earth collaboration; and the Solar Cycle latitude survey.
The Structure of the Gravitational Lens System B1152+199
Authors: Edwards P. G. , Lovell J. E. J. , Hirabayashi H. , Jauncey D. L. , Toft S.
Published: September 2002

We have commenced a program to monitor the gravitational lens B1152+199 with the Australia Telescope Compact Array (ATCA) to search for variability of the lensed components with the goal of measuring the lensing time delay. As part of this program we made a 9 hour full-synthesis observation in June 2000 to derive a ‘template’ for model-fitting the shorter, multi-epoch, monitoring observations. We report here on the results of this full-synthesis observation and on three additional epochs of monitoring for time variation.
Gravitational Lensing and Modified Newtonian Dynamics
Authors: Mortlock Daniel J. , Turner Edwin L.
Published: September 2002

Gravitational lensing is most often used as a tool to investigate the distribution of (dark) matter in the universe, but, if the mass distribution is known a priori, it becomes, at least in principle, a powerful probe of gravity itself. Lensing observations are a more powerful tool than dynamical measurements because they allow measurements of the gravitational field far away from visible matter. For example, modified Newtonian dynamics (MOND) has no relativistic extension, and so makes no firm lensing predictions, but galaxy–galaxy lensing data can be used to empirically constrain the deflection law of a MONDian point-mass. The implied MONDian lensing formalism is consistent with general relativity, in so far as the deflection experienced by a photon is twice that experienced by a massive particle moving at the speed of light. With the deflection law in place and no invisible matter, MOND can be tested wherever lensing is observed.
The Hubble Constant from (CLASS) Gravitational Lenses
Authors: Koopmans L. V. E. , Collaboration The CLASS
Published: September 2002

One of the main objectives of the Cosmic Lens All-Sky Survey (CLASS) collaboration has been to find gravitational lens (GL) systems at radio wavelengths that are suitable for the determination of time delays between image pairs. The survey is now near completion and at least 18 GL systems have been found. Here, I will discuss our efforts to measure time delays from several of these systems with the ultimate aim of constraining the Hubble Constant (H0). Thus far three CLASS GL systems (B0218+357, B1600+434 and B1608+656) have yielded measurements of time delays, from which values of H0 ≈ 60–70 km s−1 Mpc−1 have been estimated. Although most GL systems give similar values of H0, statistical and systematic uncertainties are still considerable. To reduce these uncertainties, I will mention two monitoring programs that we are undertaking to (re)measure time delays in 14 CLASS GL systems and address several important issues for the near future.
From Amateur Astronomer to Observatory Director: The Curious Case of R. T. A. Innes
Authors: Orchiston Wayne
Published: September 2002

Robert Innes was one of a select band of amateur astronomers who made the transition to professional ranks towards the end of the nineteenth century. Initially he had a passion for mathematical astronomy, but after settling in Sydney he developed a taste for observational astronomy, specialising in the search for new double stars. He quickly became known for his success in this field and for his publications on solar system perturbations, and with John Tebbutt's patronage managed to secure a clerical position at the Royal Observatory, Cape of Good Hope. Once there he continued to observe in his spare time and to publish, and, with strong support from Sir David Gill, was appointed founding Director of the Transvaal Observatory. By the time he died in 1933, Innes had received an honorary D.Sc. from Leiden University, and had established an international reputation as a positional astronomer.This paper provides an interesting case study of a well-known ‘amateur-turned-professional’, and an example of the ways in which patronage played a key role in nineteenth and early twentieth century Australian and South African astronomy.
Lower Hybrid Drive in Solar Magnetic Reconnection Regions: Implications for Electron Acceleration and Solar Heating
Authors: Cairns Iver H.
Published: September 2002

Lower hybrid (LH) drive involves the resonant acceleration of electrons parallel to the magnetic field by lower hybrid waves, often driven by ions with ring or ring-beam distributions. Charge-exchange between hydrogen atoms and protons with relative motions perpendicular to the magnetic field leads to ring distributions of pickup ions, with concomitant perpedicular ion ‘heating’. This paper considers the combination of LH drive and charge-exchange in the outflow regions of magnetic reconnection sites in the solar chromosphere and lower corona, showing that the combined mechanism naturally predicts major perpendicular ion heating and parallel electron acceleration, and exploring the mechanism’s relevance to specific solar reconnection phenomena, heating of the solar atmosphere, and production of energetic electrons that generate solar radio emission. Although primarily qualitative, analysis shows that the mechanism has numerous attractive aspects, including perpendicular ion heating that increases linearly with ion mass, parallel electron acceleration, predicted ion and electron temperatures that span those of the chromosphere and lower corona, and parallel electron speeds spanning those for type III bursts. Applications to chromospheric explosive events and low-lying active regions, and to heating the chromosphere, appear particularly suitable. Sweeping of plasma frozen-in to chromospheric and coronal magnetic field lines across the neutral atmosphere due to motions of sub-photospheric fields represents an obvious and important generalisation of the mechanism away from reconnection sites. The requirements that the neutrals not be strongly collisionally coupled to the plasma and that sufficient neutrals are available for charge-exchange restricts the LH drive mechanism to above the photosphere but below where the corona is essentially fully ionised. LH drive may thus be important in heating the chromosphere and low corona while other heating mechanisms dominate at higher altitudes. Although attractive thus far, quantitative analyses of LH drive in these contexts are necessary before definitive conclusions are reached.
Generation of Coronal Currents by the Solar Convection Zone
Authors: Galloway D. J. , Uchida Y. , Weiss N. O.
Published: September 2002

Solar flares are thought to be caused by reconnection of magnetic fields and their associated electric currents in the solar corona. The currents have to be there to provide available energy over and above the current-free minimum energy state, but what generates them has been little discussed. This paper investigates the idea that twisting motions in the turbulent convection zone below may provide a natural source for the currents and explain some of their properties. The twists generate upward-propagating Alfvén waves with a Poynting flux of the right order of magnitude to power a flare. Depending on the depth it takes place, the twisting event that initiates a particular flare may occur hours, days or even months before the flare itself.
Filaments in the Galactic Centre—with Special Reference to the ‘Snake’
Authors: Bicknell Geoffrey V. , Li Jianke
Published: September 2002

The non-thermal filaments in the Galactic centre constitute one of the great mysteries of this region of the Galaxy. We summarise the observational data on these filaments and critically review the various theories which currently outnumber the observed filaments. We summarise our theory for the longest of these filaments, the Snake, and discuss the relevance of this model for the other filaments in the Galactic centre region. The physics involved in our model for the Snake involves much of the physics that has dominated the career of Professor Don Melrose. In particular, the diffusion of relativistic electrons in the Snake is determined from the theory of resonant scattering by Alfvén waves.
Probing the pc- and kpc-scale Environment of the Powerful Radio Galaxy Hercules A
Authors: Gizani Nectaria A. B. , Garrett M. A. , Leahy J. P.
Published: September 2002

We present the kpc-scale behaviour of the powerful extragalactic radio source Hercules A and the behaviour of the intracluster gas in which the radio source is situated. We have found that Hercules A exhibits a strong Laing-Garrington effect. The X-ray observations have revealed an extended X-ray emission elongated along the radio galaxy axis. The estimated temperature of the cluster is kT=2.45 keV and the central electron density is n○≃7.8×10−3 cm−3 which reveals a hot, dense environment in which Hercules A is situated. From the combined study of the radio and X-ray data we have estimated a central value of 3 ≲ B○(μG)≲9.

We also present the most recent results from the analysis of the radio data on the pc-scale structure of the radio galaxy, observed at 18 cm by the EVN–MERLIN array. A faint but compact radio source, coincident with the optical centre of Hercules A, was detected by the EVN at 18 mas resolution. The total flux density of the EVN core is 14.6 mJy. Its angular size is 18×7 mas with a position angle of ≃139°. There is also evidence for extended emission in the NW–SE direction, most probably from the eastern pc-scale jet. If this is true then there is a misalignment between the direction of the pc-eastern and the aligned kpc-scale jets of ≃35°.
Multi-wavelength Behaviour of III Zw2
Authors: Salvi Nikita , Page Mat J. , Stevens Jason A. , Mason Keith O. , Wu Kinwah
Published: September 2002

III Zw2 was observed with XMM-Newton in July 2000. Its X-ray spectrum can be described by a power law of photon index Γ≈1.7 with a Gaussian line at 6.7 KeV. There is no significant evidence of intrinsic absorption within the source or of a soft X-ray excess. Multi-wavelength light curves over a period of 25 years show related variations from the radio to X-rays. We interpret the radio to optical emission as synchrotron radiation, self-absorbed in the radio/millimetre region, and the X-rays as mainly due to Compton up-scattering of low energy photons by the population of high energy electrons that give rise to the synchrotron radiation.
Radiation Fields in Blazars — a Possible Extension of the Small Scale Symbiosis (Disk/Jet) into a Large Scale (Dust/Dust) Symbiosis
Authors: Donea Alina-C. , Protheroe Raymond J.
Published: September 2002

In blazar models both protons and electrons may be efficiently accelerated in jets and produce γ-rays. Here we discuss the interactions of these γ-rays with different radiation fields. The external radiation fields within a few parsecs from the black hole involved in such interactions could be the direct radiation from the accretion disk coupled with the jet, the infrared radiation from a dusty torus, and the emission line radiation from the broad line region surrounding the accretion disk. The optical thickness for absorption of γ-ray photons in the external radiation fields is analysed for blazars and quasars.

Based on the unification theory of active galactic nuclei we briefly review the evidence for the existence of small scale dust tori in blazars/FR I. We propose that the existing jet–accretion disk symbiosis extrapolates to a large scale symbiosis between other important dusty constituents of the blazar/FR I family.
Models of Variability in Blazar Jets
Authors: Mastichiadis Apostolos , Kirk John G.
Published: September 2002

During the last decade multiwavelength observations of blazars have revealed many interesting patterns in their emission across the EM spectrum. In the present article we will review the time-dependent one-zone models and the models which advocate an acceleration and a radiation zone, and we will make some comparisons between them, especially in light of recent observations of the so-called TeV blazars.
Optical to Far-IR Observations of 3C 446
Authors: Leech K.J. , Saxton R. , Barr P. , Santos-Lleo M. , Jiminez-Bailon E. , Diaz R. , Ghosh K. , Soundararajaperumal S.
Published: September 2002

The OVV blazar 3C 446 was monitored over seven months in 1997 with ground based telescopes and instruments on ESA's Infrared Space Observatory (ISO). The aim was to try to detect variations in the IR and see if these were correlated with optical variations. The object varied in the optical and near-IR during this period, but did not vary in the far-IR. Despite being a factor of ten weaker than in 1983, the optical-IR SED exhibited the same slope. The new far-IR observations from ISO allow us to determine the location of the turnover in the spectrum, caused by synchrotron self-absorption. It occurs just longwards of 100 μm.
Phosphite and mycorrhizal formation in seedlings of three Australian Myrtaceae
Authors: Howard Kay , Dell Bernie , Hardy Giles E.
Published: September 2002

Currently in Western Australia, phosphite is being used to contain the root
and collar rot pathogen, Phytophthora cinnamomi, in
native plant communities. There have been reports of negative effects of
phosphite on arbuscular mycorrhiza (AM), so there are concerns that it may
have a deleterious effect on other mycorrhizal fungi. Two glasshouse
experiments were undertaken to determine the impact of phosphite on
eucalypt-associated ectomycorrhizal fungi. In the first experiment,
non-mycorrhizal seedlings of Eucalyptus marginata,
Eucalyptus globulus and
Agonis flexuosa were sprayed to runoff with several
concentrations of phosphite, and then planted into soil naturally infested
with early colonising mycorrhizal species. Assessments were made of percentage
of roots infected with mycorrhizal fungi. There was no significant effect on
ectomycorrhizal formation but there was a four-fold increase in AM
colonisation of A. flexuosa roots with phosphite
application. In the second experiment, E. globulus
seedlings mycorrhizal with Pisolithus,
Scleroderma and Descolea were
treated with different levels of phosphite and infection of new roots by
ectomycorrhizal fungi was assessed. There was no significant effect on
ectomycorrhizal formation when phosphite was applied at the recommended rate
(5 g L–1), while at 10 g
L–1 phosphite significantly decreased infection by
Descolea.
Community-wide germination strategies in a temperate rainforest of Southern Chile: ecological and evolutionary correlates
Authors: Figueroa J. A. , Armesto J. J.
Published: September 2002

Delayed seed germination (‘dispersal in time’), as a component of
a plant’s germination strategy, was studied in dicotyledoneous species
of a temperate rainforest flora in Chiloé Island
(42°30′S), southern Chile. The objective of this
investigation was to assess, for this temperate rainforest flora, what
proportion of interspecific variation in the time of seed
germination—measured in days since the onset of seed dispersal in
space—could be attributed to the plants’ historical and
phylogenetic background and what proportion was associated with life history
and ecological attributes such as seed mass, life form, dispersal syndromes
and dispersal periods. To characterise germination times for 44 species from
Chiloé forests (n = 150 seeds
sowed per species in laboratory assays), we computed the mean germination time
(GT), in days since sowing, for all seeds germinated of each species. Seeds
were taken from the plants at the onset of dispersal and germinated in Petri
dishes at 10/20°C. Considering all species, GTs varied between 3
and 385 days and presented an L-shaped frequency distribution. One-way ANOVAs
measured the effects of each factor across all other variables. Two-way ANOVAs
were used to assess significant interactions between factors. Multifactorial
ANOVAs were used to evaluate the independent effects of each of six
historical, phylogenetic and ecological factors on GT and to detect
associations between factors. In one-way ANOVAs, phylogenetic grouping (at or
above order) explained 12% of the variance in GT; dispersal period
(summer v. mainly autumn dissemination of ripe seeds),
biogeographic element (endemic, austral, neotropical or cosmopolitan) and
dispersal syndrome (fleshy v. dry propagules) explained
7, 6 and 5% of the variance in GT, respectively. The factors life form
(trees, shrub and woody vines combined, herbs and non-woody epiphytes) and
seed mass (light v. heavy) explained the 4 and 2%
of the variance in GT, respectively. Taxa related to Ranunculales presented
the longest mean GT (148 days). Endozoochorous species had a more delayed
germination than species with other dispersal syndromes. Herbs and non-woody
epiphyte species showed mean GT (41 days) significantly shorter than trees and
shrubs plus woody vines combined (86 and 85 days, respectively). All
interactions in two-way ANOVAs were significant. Multifactorial ANOVAs
revealed that the three major factors contributing to differences in GT in
this temperate rainforest flora were phylogenetic relatedness, dispersal
syndromes and life form (7, 6 and 6% of the interspecific variation,
respectively). In this analysis, biogeographic element, dispersal period and
seed mass were not significantly related to GT. For the factors examined,
failure-time analysis, which takes into account all viable seeds not
germinating in laboratory assays, confirmed results from multifactorial
ANOVAs.
Most parsimonious areagrams versus fossils: the case of Nothofagus (Nothofagaceae)
Authors: Swenson Ulf , Hill Robert S.
Published: September 2002

Vicariance biogeography uses most parsimonious areagrams in order to explain
biogeographic patterns. One notion is that areagrams convey biogeographic
information to the extent that alternative palaeogeographic hypotheses are
suggested. However, extinctions may distort biogeographic information, leading
to areagrams showing area relationships not supported by geological data, and
plausible dispersal events might also be overlooked. By the use of the
software COMPONENT 2.0, Nothofagus phylogeny was
reconciled with the most parsimonious areagrams. Well-preserved fossils,
identified to subgenera, were optimised to the reconciled tree. Not all past
distributions were predicted by the analysis, and
Nothofagus has clearly been present in areas where it
cannot have been if strict vicariance is followed. It can therefore be
demonstrated that the biogeographic signal in Nothofagus
areagrams is incomplete, and that most parsimonious areagrams can be flawed.
Areagrams can be a useful tool in historical biogeography, but must be
scrutinised within a known geological context and not accepted uncritically as
alternative palaeogeographical hypotheses.
Vertical disease transmission in the Cakile-Alternaria host-pathogen interaction
Authors: Oliver Elizabeth J. , Thrall Peter H. , Burdon J. J. , Ash J. E.
Published: September 2002

Cakile maritima (Brassicaceae) is an introduced herb
growing on temperate beaches in Australia. In these situations it is attacked
by the fungal pathogen Alternaria brassicicola
(Dematiaceae), which forms necrotic lesions on all above-ground parts.
Cakile plants produce dimorphic fruits, with half of the
seeds produced by C. maritima being adapted for
dispersal by water. This raises the possibility that pathogen movement among
host populations may occur as a consequence of wave action and ocean currents.
A field survey showed that 30% of the seeds were infected with
A. brassicicola, with the frequency of infection
positively correlated with lesion density on the fruit surface. Glasshouse
inoculation trials demonstrated that infection of seeds could occur either
through the flowers or, more readily, when spores were deposited on fruits.
Seedlings grown from field-collected seeds were found to emerge with
infections, indicating seed infection may lead to disease in emergent plants.
Overall, the findings of this study suggest that vertical transmission is
likely to be by far the most important component of disease transmission among
separate host populations in this host–pathogen system. However, once
disease is established in a host population, both vertical and horizontal
transmission will contribute to epidemic development. A second species of
Alternaria (A. alternata) was
detected in many isolates from disease lesions. Simple pure culture and mixed
competition trials between this fungus and
A. brassicicola on
C. maritimashowed both to be capable of establishing
infections, although A. brassicicola was much more
successful both on its own and when both fungi were applied simultaneously.
Location and activity of hyphae of the downy mildew, Peronosclerospora noblei (Family Peronosporaceae), and its relationship to symptom expression on wild sorghum (Sorghum leiocladum)
Authors: Ryley Malcolm J.
Published: September 2002

A study of the temporal and spatial relationships between the downy mildew,
Peronosclerospora noblei and its host,
Sorghum leiocladum (wild sorghum) has been undertaken.
Hyphae of P. noblei perennate in the tiller bases of
wild sorghum when the grass is dormant over the winter months. In early
summer, hyphae grow into some tiller buds but not into others. Tillers that
develop from invaded buds become systemically invaded by the hyphae, in most
cases remain vegetative and bear the anamorph and teleomorph of the downy
mildew. Tillers that develop from buds that are not invaded become short
vegetative tillers or tall flowering tillers. On infected tillers symptom
development is delayed until at least the third leaf, as a direct result of
hyphal activity in the developing tiller. The location and activity of hyphae
of P. noblei in tiller bases and developing tillers are
responsible for the perennation of the pathogen and for the expression of
symptoms in infected tillers of S. leiocladum. There may
be similar relationships between hyphal location and activity and symptom
development in other systemic pathogens of perennial grasses.
Biomass allocation to vegetative and reproductive organs in Lotus glaber and L. corniculatus (Fabaceae)
Authors: Vignolio O. R. , Fernández O. N. , Maceira N. O.
Published: September 2002

Comparative studies on reproductive and vegetative attributes between
Lotus glaber Mill. and
L. corniculatus L. showed that under identical growth
conditions seed and pod production were higher in
L. glaber than in L. corniculatus.
The objective of this work was to determine whether differences in
reproductive output between L. glaber and
L. corniculatus are related to differences in biomass
allocation and whether they can be related to the habitats of each species. We
compared, in two studies, the allocation of vegetative and reproductive
biomass of both species' growth in pots outdoors. The shoot to root
ratio was higher in L. glaber than in
L. corniculatus. Both species allocated the same biomass
to stems but L. corniculatus produced fewer reproductive
stems of higher specific weight. The number of pods per umbel and seeds per
pod did not differ between species, but the total number of umbels, pods and
seeds per plant were higher in L. glaber than in
L. corniculatus. Weight per pod was higher in
L. corniculatus than in L. glaber.
The reproductive biomass in L. glaber was distributed in
a higher number of pods and seeds that were of lower weight than in
L. corniculatus. In both species, pod length and seed
number per pod showed a decreasing trend during the reproductive season and
both attributes were positively correlated. Some of the differences reported
in reproductive and vegetative attributes are consistent with the conditions
of habitat where each species grows. The results are discussed in relation to
the agronomic values of these species and the factors determining their
persistence and distribution in the grassland.
Root and shoot development in Corymbia calophylla and Banksia brownii after the application of the fungicide phosphite
Authors: Barrett S. R. , Shearer B. L. , Hardy G. E. St J.
Published: September 2002

The effects of low-volume foliar application (24, 48, 96 kg
ha–1) of phosphite on root and shoot development
in Corymbia calophylla Lindley and
Banksia brownii ex R.Br. were investigated in a
glasshouse study. Shoot growth, root and shoot dry weight and root length were
not significantly reduced by phosphite application in
C. calophylla 2 weeks and 4 months after phosphite
application. Shoot growth, shoot dry weight and root length were not
significantly reduced in the non-mycorrhizal B. brownii.
However, in plants treated with 24 and 96 kg ha–1,
root dry weight was significantly reduced 4 months but not 2 weeks after
spray. A discoloration of the root stele was also observed in
phosphite-treated plants of this species. At 2 weeks after spray, root
concentrations of phosphite in C. calophylla were up to
five times higher than shoot concentrations. At 4 months after application,
growth abnormalities were observed in B. brownii and
these included spindly new shoot growth with rosetted foliage of reduced leaf
size. The results of this study, which assessed one mycorrhizal and one
non-mycorrhizal native species, suggest that species may vary in their
response to phosphite in terms of root development and phosphite applied at
rates of 24 kg ha–1 or higher may result in
reduced root growth, particularly in non-mycorrhizal species. Further studies
on root development in a wider range of species are needed to validate these
findings.
Vegetation change over twenty years at Bathurst Harbour, Tasmania
Authors: Brown M. J. , Balmer J. , Podger F. D.
Published: September 2002

A study of floristic change in buttongrass moorlands over a 20-year period in a perhumid oligotrophic environment is presented. We first demonstrate that our study site at Bathurst Harbour in south-western Tasmania is typical and representative of such environments and then discuss the impacts of fire and Phytophthora cinnamomi on vegetation at the local scale. The results have implications for interpretation and management of disturbance in the landscape and highlight the need for longer-term studies to complement place-for-time substitutions.
Effect of shadecloth tree shelters on cold-induced photoinhibition, foliar anthocyanin and growth of Eucalyptus globulus and E. nitens seedlings during establishment
Authors: Close Dugald C. , Beadle Chris L. , Holz Greg K. , Brown Philip H.
Published: September 2002

The effects of shadecloth tree shelters on cold-induced photoinhibition,
foliar anthocyanin and growth of Eucalyptus globulus
Labill. and Eucalyptus nitens (Deane & Maiden)
Maiden seedlings were assessed between planting (in early spring) and the age
of 23 weeks. The experimental site was at 350 m above sea level (asl), which
is considered marginal for establishment of E. globulus
(but not E. nitens) plantations in Tasmania because of
low mean minimum temperatures. Conditions within 3 weeks of planting induced
severe photoinhibition in non-shaded seedlings. This was associated with
increased anthocyanin and photodamage in non-shaded
E. nitens and E. globulus. As a
result, there was 20% mortality in non-shaded
E. globulus. In contrast, shaded seedlings of both
species had levels of photoinhibition and anthocyanin that were largely
similar to those before planting and there was no photodamage. Levels of
anthocyanin indicated that its synthesis responded to the severity of
photoinhibition. Height growth and levels of mortality indicated that
cold-induced photoinhibition, and not frost tolerance alone, determines the
range of environments where E. globulus can be
successfully planted. In contrast, the tolerance of
E. nitens seedlings to cold-induced photoinhibition may
be a factor in the demonstrated success of this species as a high-altitude
plantation species.
Reproductive ecology and the effect of altitude on sex ratios in the dioecious herb Aciphylla simplicifolia (Apiaceae)
Authors: Pickering Catherine Marina , Hill Wendy
Published: September 2002

The reproductive ecology of the dioecious herb Aciphylla simplicifolia (F.Muell.) Benth. (Apiaceae, Mountain Aciphylla) was examined in Kosciuszko National Park. Differences in floral display and flowering phenology between male and female plants were consistent with predictions based on theories concerning sexual dimorphism in dioecious plants. For example, male plants had larger floral displays than females at the alpine sites sampled. Male inflorescences had four times as many flowers as females and more than three times the area of floral display. In addition to differences in floral display, there was a sex-specific pattern in flowering phenology at six alpine sites. At these sites, there were more male inflorescences with buds and flowers and more female inflorescences finished flowering than would be expected if gender did not affect flowering phenology. To determine whether increasingly severe conditions associated with higher-altitude sites were associated with male-biased sex ratios, the number of male and female plants were compared for 20 sites over a 600-m altitudinal range from montane to alpine (total 4274 plants). As altitude increased and as the vegetation zone changed from subalpine to alpine, the sex ratio became increasingly male-biased, with sites in the alpine ranging from 1.45 males per female to 8.53 males per female. Sexual dimorphism in floral display, flowering phenology and sex ratios was consistent with what would be predicted for plants with sex-specific differences in resource allocation.
Cytotaxonomic studies in five species of Rutidosis (Asteraceae) endemic to south-eastern Queensland
Authors: Kokubugata Goro , Holland Ailsa E.
Published: September 2002

Somatic chromosomes of five species of Rutidosis endemic
to south-eastern Queensland were analysed by the aceto-orcein staining method.
The five species were classified into two major groups by their basic
chromosome number and asymmetry of chromosome length.
Rutidosis glandulosa and
R. murchisonii exhibited a basic chromosome number of
x = 11 and a gradual change in chromosome length.
Rutidosis crispata, R. lanata and
R. leucantha exhibited a basic chromosome number of
x = 12 and the karyotype was bimodal with respect
to chromosome length. On the basis of chromosome evidence, we hypothesise that
(1) R. glandulosa and
R. murchisonii are closely related, (2)
R. crispata and R. leucantha are
closely related and (3) R. lanata is most likely to be
derived from R. crispata by a hexaploidisation. The
present results support Holland’s (1994, 1999) taxonomic treatment of
the five species.
High-resolution data from Australian trees
Authors: Pearson Stuart G. , Searson Matthew John
Published: September 2002

Dendrochronology offers data with unparalleled spatial and temporal resolution but the technique has received only sporadic attention in Australia. The techniques deserve wider application in the resolution of contentious issues such as tree population dynamics, fire histories and atmospheric change. Convergence of ecological and palaeoecological research scales, recent technical developments and a growing willingness to experiment mark a watershed in Australian dendrochronology. Progress in dendrochronology in Australia requires transect studies to examine species and site effects by rapid survey techniques, interdisciplinary approaches to extract the full range of proxy data in wood and environmental modelling to calibrate and interpret tree records. Future rewards include annually resolved data across the landscape for the last few hundred years providing answers to questions regarding tree recruitment, fire regimes and the impact of CO2 enrichment.
Vegetation of Phytophthora cinnamomi-infested and adjoining uninfested sites in the northern jarrah (Eucalyptus marginata) forest of Western Australia
Authors: McDougall K. L. , Hobbs R. J. , Hardy G. E. St
Published: September 2002

The vegetation of seven sites in the northern jarrah forest of Western Australia infested with Phytophthora cinnamomi was recorded and compared with adjoining vegetation. The number of species per quadrat was found to be the same in vegetation affected by P. cinnamomi as in healthy vegetation, although there were more species overall in affected vegetation. Vegetation of uninfested sites had a higher cover and more species per quadrat of trees and shrubs and lower cover and fewer species per quadrat of annual plants than vegetation of infested sites. Although many species that are known to be highly susceptible to infection by P. cinnamomi were rare at infested sites, only two (Banksia grandis and Tetratheca hirsuta) were absent from all of the 50-year-old infested parts of sites. Several species that are known to be highly susceptible to infection by P. cinnamomi were as common at infested as at healthy sites. The presence of such species at infested sites and the capacity of P. cinnamomi to infect species it does not kill suggest that this pathogen will persist and continue to influence future vegetation in the jarrah forest.
Century-scale environmental reconstruction by using stable carbon isotopes: just one method from the big bag of tricks
Authors: Witt Bradd
Published: September 2002

The field of 'historical ecology' is coming to maturity at a time when we, in Australia, are reflecting on our relationship with, and place in, the land. After an essentially ahistorical approach to land use we are now attempting to place land management into the context of environmental change since and immediately preceding Western European settlement. This volume reflects an emerging concern that, collectively, non-indigenous Australians have no 'environmental history'.
One component of 'living in' rather than 'battling against' the land is developing a sense of our history. Without an oral narrative that is commonly shared, attempts to develop the story of environmental change have to be based on retrospective and reconstructive research. This volume captures part of this movement to develop an environmental narrative and context for our future relationship with the land.
There are many methodological approaches to reconstructing a story of the past, from local knowledge and oral history to the 'high-tech' and hard sciences. This paper reviews methods that apply stable carbon isotope techniques to reconstruct environmental change. Although well suited to environmental history, carbon isotope techniques remain under-utilised in the Australian context. Here I review applications to highlight the strengths and limitations of carbon isotope techniques in the reconstruction of century-scale vegetation change. There have been two dominant applications of carbon isotope techniques to environmental reconstruction. These applications fall broadly into either stable carbon isotope analysis of organic matter in soils and sediments, or inferences of environmental states have been drawn from carbon isotope analysis of animal tissues and residues. The main strength of stable carbon isotope techniques is that they can be spatially precise while integrating a range of environmental information into one isotopic signal. This integrative strength is at the same time one of the major limitations of carbon isotope techniques because floristic (taxonomic) resolution is low.
Further assessment of pollen limitation in the waratah (Telopea speciosissima)
Authors: Goldingay Ross L.
Published: September 2002

The literature contains much debate about whether pollen limitation results in
a cost to plants. A population of the waratah,
Telopea speciosissima (Proteaceae), was found to be
pollen limited in 1985. The present study examines the consequences and causes
of this pollen limitation. In the 2–3 years following the original
experiment, there was no difference in vegetative growth, flower production or
fruit production between the hand-pollinated or control plants. There was no
difference in inflorescence or fruit production between these two plant groups
up to 9 years later. There was no cost of the experimental increase in
reproduction. Experiments in 1988 failed to reveal further pollen limitation,
suggesting that it may only occur in some years in this population. The
retention of self-pollen on stigmas after anthesis was implicated as a cause
of the original demonstration of pollen limitation because the waratah is
self-incompatible, has highly synchronous flowering and, typical of the
Proteaceae, deposits self-pollen on its stigmas at anthesis. These traits
should provide a continuing influence on fruit set in all years. However,
plants did not produce more fruits when the self-pollen was experimentally
removed. This suggests that the waratah experiences pollen limitation in years
when pollination and nutrient levels are not in equilibrium. Further studies
of pollen limitation are required to fully understand the fitness consequences
of this phenomenon, and to fully describe its frequency among different plant
families and among plants with differing flowering strategies.
Cyathodes divaricata (Epacridaceae)—the first record of a bird-pollinated dioecious plant in the Australian flora
Authors: Higham R. K. , McQuillan P. B.
Published: September 2002

The geographically restricted Tasmanian endemic
Cyathodes divaricata Hook.f. is functionally dioecious
but, unusually, is pollinated by several species of nectarivorous birds
including honeyeaters (Meliphagidae). It has evolved in a clade otherwise
conforming to the typical dioecious pollination syndrome of small white
flowers serviced by small insects. A number of its features are consistent
with ornithophily in other Epacridaceae, including a tubular pendant odourless
corolla, a winter peak in flowering and a copious diurnal nectar flow.
However, the flower largely retains the white, insect-attractive colour of its
congeners. Male plants have more and larger flowers, begin flowering earlier
in the season, and yield significantly more nectar per flower than female
plants. The fruits produced on female plants were 22% larger than the
few produced on male plants. These findings are consistent with recent
theories on the biology of dioecy. The species has a high level of
self-fertility, and dioecy presumably serves to increase the rate of
outcrossing.