bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Coronal Mass Ejections. I. Loop-type with Arcade Flare between the Fixed Legs, and Bubble-type Due to Flare Blast Waves
Authors: Uchida Y. , Tanaka T. , Hata M. , Cameron R.
Published: September 2002

In this paper, we give arguments that there are two types of coronal mass ejection (CME).The first type of CME discussed here is the ‘loop-type’, whose occurrence is related to an arcade flare somewhere between the footpoints. It was found that there were pre-event magnetic connections between the flare location and the locations of the footpoints of a CME of this type, and that these connections disappeared after the event. This suggests that the footpoints of loop-type CMEs are special prescribed points, and this was verified by the observation that the footpoints do not move in this type of CME.

The other type of CME is the ‘bubble-type’, which is associated with the flare blast from explosive flares. We confirmed the association of this type of CME with the so-called EIT (Extreme Ultra-violet Imaging Telescope) waves, but the velocity of expansion of the bubble is twice or more greater than that of the EIT waves depending on events. Although EIT waves were widely considered to be Moreton waves viewed by SoHO/EIT in the solar activity minimum period, recent simultaneous observations of both have revealed that the EIT wave is something different from the Moreton wave, and propagates separately with a velocity less than half that of a Moreton wave.We therefore propose a new overall picture: the bubble-type CMEs are the flare-produced MHD blast waves themselves, whose skirt is identified as a Moreton wave. EIT waves may be interpreted as follows: the slow-mode gas motions from the source cause secondary longwavelength fast-mode waves which are trapped in the “waveguide” in the low corona. The secondary long-wavelength wave in the fast-mode, which is trapped in the low corona, has a slower propagation velocity due to the nature of the waves trapped in a “waveguide”. This trapped wave induces slow-mode motions of the gas through a mode-coupling process in the high chromosphere, where the propagation velocities of the fastand slow-mode waves match.

Three-dimensional MHD simulations for these two types of CME are in progress, and are previewed in this paper.
A Test to Confirm the Source of Energy for Solar Flares
Authors: Wheatland M. S.
Published: September 2002

A test of the hypothesis that flares derive their energy from large scale current systems inferred from active region vector magnetograms is proposed. The test involves a statistical comparison of the flarerelated change in coronal magnetic energy (based on the magnetohydrodynamic virial theorem) and an independent measure of the energy of the flare. A simulation suggests that — assuming the hypothesis is correct—the test requires around 50 flares with energy greater than 5×1023 J to return a significant result. Existing archives of vector magnetograms should provide sufficient data for such a study.
X-ray Variability of Blazars
Authors: Pian Elena
Published: September 2002

Critical progress in our understanding of high energy emission from AGN has been determined in the last 10 years by X-ray monitoring campaigns with many space missions, notably ROSAT, ASCA, RXTE, BeppoSAX, and XMM, often in conjunction with observations at other frequencies. The emphasis of the present review is on recent findings about X-ray variability of blazars. Among AGN, these exhibit the largest amplitude variations of the X-ray emission, often well correlated with variations at higher energies (GeV and TeV radiation). The accurate sampling of the X-ray spectra over more than three decades in energy, made possible by the wide energy range of BeppoSAX, has also shown strong spectral variability in blazar active states, suggesting extreme electron energies and leading to the identification of a class of ‘extreme synchrotron’ sources.
Very High Energy Gamma-ray Observations of AGN with CANGAROO
Authors: Nishijima Kyoshi
Published: September 2002

We have observed eight AGN since 1993 in the energy region above several hundred GeV using the CANGAROO telescopes. We observed Mrk 421 for ten nights with the CANGAROO-II 10 m telescope during its active state in early 2001 using the very large zenith angle technique. Our preliminary result implies the detection of gamma-ray emission from Mrk 421 in the energy range above 9.3 TeV. The high energy peaked BL Lacs (HBLs) PKS 2005–489 and PKS 2155–304 have been also observed. No statistically significant signals are found for both HBLs and flux upper limits are obtained. A summary of results of observations of AGN is presented in this paper.
High Energy Radiation Generated at Boundary Shear Layers of Relativistic Jets
Authors: Stawarz Ł. , Ostrowski M.
Published: September 2002

A simple model of cosmic ray electron acceleration at the jet boundary yields a power law particle energy distribution of ultra-relativistic electrons with an energy cut-off growing with time, and, finally, a growing particle bump at the energy where energy gains equal radiation losses. For such electron distribution, in tens-of-kpc scale jets, we derived the observed time-varying spectra of synchrotron and inverse Compton radiation, including Comptonisation of synchrotron and cosmic microwave background photons. Slowly varying spectral index along the jet in the ‘low frequency’ spectral range is a natural consequence of boundary layer acceleration. Variations of the high energy bump of the electron distribution can give rise to anomalous behaviour in the X-ray band in comparison to the lower frequencies.
Multifrequency Monitoring of the Blazar PKS 2005-489
Authors: Rector Travis , Perlman Eric , Sambruna Rita , Madejski Greg , Rantakyro Frederik ,   CANGAROO collaboration
Published: September 2002

We present a multifrequency monitoring campaign of PKS 2005–489, a bright and highly variable blazar. Simultaneous observations were completed over a 13 day period in the X-ray with RXTE, in the optical at the CTIO 0.9 m telescope, at TeV energies with CANGAROO-II, and at submillimetre wavelengths with SEST. Previous multiwavelength monitoring campaigns of PKS 2005–489 and other blazars have found complex flux and spectral variability behaviour, with different modes and timescales from days to hours and shorter.

PKS 2005–489 was observed in transition from a quiescent state into the early stages of a flare. A gradual increase in flux density was observed at optical and X-ray wavelengths during 19–27 August 2000, and a dramatic increase in X-ray emission was observed starting on 2 September 2000. Intraday and spectral variability were not detected during the campaign.
Millimetre Continuum Variations, VLBI Structure and Gamma-rays: Investigating Shocked Jet Physics
Authors: Valtaoja E. , Savolainen T. , Wiik K. , Lähteenmäki A.
Published: September 2002

We compare the total flux density variations and the VLBI structural variations in a sample of 27 gamma-ray blazars. We find that all the radio variations are due to shocks; the flux of the underlying jet remains constant. A large fraction of the shocks grow and fade within the innermost 0.1 mas, appearing only as ‘core flares’. Comparisons with the EGRET data show that gamma-ray flares must come from the shocks, not from the jet. At the time of an EGRET flare, the shock is typically already over a parsec downstream from the radio core, beyond the accretion disk and/or the broad line region (BLR) photon fields. Thus, present models for gamma-ray production are inadequate, since they typically model the gamma-ray inverse Compton flux as coming from the jet, with significant disk or BLR external Compton components.
Using molecular methods to understand the Gondwanan affinities of the New Zealand biota: three case studies
Authors: Chambers Geoffrey K. , Boon Wee Ming , Buckley Thomas R. , Hitchmough Rodney A.
Published: September 2002

The application of new molecular technologies is central to the search for
causal mechanisms capable of explaining the modern-day biogeography of the
southern continents. Projects have previously focused on marine mammals and
birds, but in recent years they have begun to expand in scope. We now describe
the results from three studies carried out recently on parakeets (genus
Cyanoramphus), cicadas (genus
Maoricicada) and geckos (genera
Hoplodactylus and Naultinus) in
the context of the Gondwanan affinities of the New Zealand biota. The work
described here has been the subject of independent reports (see text for
individual references) and their findings have been brought together for the
first time here in a more general synthesis.
The family Convolvulaceae in the Tertiary of Australia: evidence from pollen
Authors: Martin Helene A.
Published: September 2002

A study of fossil and modern pollen of the family Convolvulaceae is presented
and five fossil types are identified. Two types, one a large tricolpate of the
form species Perfotricolpites digitatus, with
similarities to Convolvulus,
Operculina and probably other genera, and the second, a
small tricolpate, Tricolpites trioblatus, with
affinities to Wilsonia and possibly
Cressa, first appear in the late Eocene of southern
Australia. Fossil pollen is found worldwide, with the oldest occurrence being
Calystegiapollis microechinatus from the early Eocene of
Africa. Perfotricolpites digitatus first appears in the
mid-Eocene of Brazil, and specimens similar to
P. digitatus from Antarctica suggest that it migrated
into Australia by the Antarctic route. Wilsonia is
endemic to Australia today, but it was in New Zealand in the mid–late
Miocene.
From Dampier to DNA: the 300-year-old mystery of the identity and proposed allopolyploid origin of Conostylis stylidioides (Haemodoraceae)
Authors: Krauss Siegfried L. , Hopper Stephen D.
Published: September 2002

The tetraploid Conostylis stylidioides
(n= 16) has been proposed to be a stabilised
hybrid between the diploid (n = 8) species
C. prolifera and C. candicans
because of morphological and geographical intermediacy, as well as a polyploid
chromosome number. To test this hybrid-origin hypothesis, we used the
DNA-fingerprinting technique amplified fragment length polymorphism (AFLP) and
measured genetic variation within these taxa, as well as the putative
outgroups C. robusta and
C. aculeata. One AFLP primer pair generated 192 dominant
markers for 36 samples from these species, of which 189 were polymorphic.
Polymorphism within populations was uniformly high for all species, with
66–86% of all fragments polymorphic and estimates of
heterozygosity ranging from 0.36 to 0.41. Ordination, UPGMA and maximum
parsimony analyses of these genetic data consistently clustered species,
supporting the current species’ level taxonomy. The intermediate
placement of C. stylidioides between
C. proliferaand C. candicans on
the maximum parsimony tree supports the hybrid-origin hypothesis, although
other interpretations are possible. The phenetic results for AFLP data, in
which C. stylidioides is not strictly intermediate
between C. prolifera and
C. candicans, are either concordant with recent research
suggesting that rapid intra- and inter-genomic rearrangements occur with the
origin of polyploid taxa, or indicate an ancient hybridisation event. While
our results do not reject the hybrid origin hypothesis, the extremely high
levels of genetic variation detected with AFLP within these populations, in
combination with extensive genomic reorganisation with the origin of
C. stylidioides and the possibility of independent
origins for different populations, make it difficult to confidently exclude
other scenarios.
Wall ultrastructure and cytochemistry and the longevity of pollen of three grass species
Authors: Fu Jian-Hua , Lei Li-Gong , Chen Liang-Bi , Qiu Guan-Zhou
Published: September 2002

The ultrastructures and cytochemistry of pollen grains with different
longevities of three grass species, rice (Oryza sativa
L.), maize (Zea mays L.) and pennisetum
(Pennisetum alopecuroides Spreng.), were studied by
transmission electron microscopy. The pollen wall of rice is the thinnest and
that of pennisetum the thickest. The exine of rice pollen grains is loose and
porous with communication channels, or microchannels, and thick columellae,
but that of pennisetum pollen grains is very dense and nearly without
microchannels and columellae. The tectum of pennisetum pollen wall is also the
thickest of the three species. In the pollen walls of rice and maize, the
microchannels traverse the tectum and foot layer. The exinous microchannels
are slightly more abundant in rice pollen wall than in pennisetum pollen wall
and the intines of the pollen walls of rice and pennisetum have higher
electron densities than that of maize. In rice pollen wall glucose-6-phosphate
dehydrogenase (G6PD) and succinate dehydrogenase (SDH) are located in the
exine, mainly on the surface, along the microchannels and in the spaces
between columellae, and in the intine. However, they occur mainly in the
intine of maize pollen wall and on the surface of pennisetum pollen wall.
Under natural conditions, rice’s thinnest pollen wall with richer
exinous microchannels, G6PD and SDH, appears to be related to the short life
of the pollen grains, while the opposite characteristics of pennisetum pollen
grains are associated with greater longevity.
Growth, seed production and effect of defoliation in an early flowering perennial grass, Alloteropsis semialata (Poaceae), on Cape York Peninsula, Australia
Authors: Crowley Gabriel M. , Garnett Stephen T.
Published: September 2002

Alloteropsis semialata (R.Br.) A.Hitchc. is one of the
first perennial grasses in monsoonal Australia to produce seed at the start of
the wet season. Patterns of growth and seed production and seed dynamics of
Alloteropsis semialata were examined in this study,
along with the effects of partial defoliation. Growth of
Alloteropsis semialata tussocks started with the first
pre-wet-season rains, and was then interrupted during a period with little
rain. Growth ceased before the end of the wet season, indicating that factors
other than moisture availability were limiting. Seeds of
Alloteropsis semialata were germinable on production,
but did not remain viable or persist on the soil surface through the dry
season. Most seeds and young seedlings were harvested and no seedlings were
recruited. Inflorescence production increased with plant size. Moderate
defoliation in the early wet season had no impact on plant growth, but reduced
inflorescence and seed production for at least 2 years. Absence of a seed bank
and early wet-season flowering mean that
Alloteropsis semialata is likely to be sensitive to
long-term over-grazing.
Floristic description and environmental relationships of Tasmanian Sphagnum communities and their conservation management
Authors: Whinam J. , Barmuta L. A. , Chilcott N.
Published: September 2002

A floristic data set spanning 15 years was compiled from vegetation surveys of
Sphagnum peatlands across Tasmania. The data were
ordinated by hybrid multi-dimensional scaling and a three-dimensional solution
was most satisfactory. The strongest floristic gradient corresponded to
changes in altitude and moisture. Original data were included from
Sphagnum peatlands outside their commonly recorded
altitudinal, geologic and geographic ranges. Several new types of
Sphagnum peatland are described. While many of
Tasmania’s subalpine and alpine Sphagnum peatlands
are protected within reserves, this is not the case for montane and lowland
Sphagnum peatlands. During the past decade, the pressure
on Sphagnum peatlands outside the Tasmanian reserve
system has continued to increase. Threats such as
Sphagnum-moss harvesting, peat mining, burning, grazing
and forestry operations have an impact on both the number and condition of
Sphagnum peatlands.
Pre- and post-dispersal seed predation in a mediterranean-type climate montane sclerophyllous forest in central Chile
Authors: Figueroa Javier A. , Muñoz Alejandro A. , Mella Jorge E. , Arroyo Mary T. K.
Published: September 2002

Most seed-predation studies have evaluated pre- or post-dispersal predation
separately, in one or a few species. Assessments of the overall importance of
pre- v. post-dispersal seed predation at the community
level are generally lacking. Here, we quantify levels of pre and
post-dispersal seed predation in >25 plant species in a mediterranean-type
climate montane forest in central Chile in two periods of study
(1995–1996 and 1997–1998). Almost all species analysed suffered at
least some seed losses to pre-dispersal and/or post-dispersal seed
predation. However, among species, magnitudes of both pre- and post-dispersal
seed predation proved highly variable, ranging between 0 and 100% and
exceeding 50% in five and nine species, respectively. High inter-annual
variability in both pre- and post-dispersal seed predation, at both the
species and overall community levels, was observed, with only a small number
of species suffering large losses during both periods of study. At the overall
community level, percentage seed losses to pre-dispersal predation were not
significantly different from those experienced in the postdispersal phase.
Rodents were the most important seed removers in seven species. However, the
three groups of granivores analysed (rodents, birds and insects) were similar
in their importance as post-dispersal predators in most plant species. Groups
of species suffering similar levels of seed losses to pre- or post-dispersal
predators did not share any particular seed characteristics, suggesting that
differences in the seed traits studied seem to be relatively unimportant in
determining variation in seed predation.
Alleviation of salinity stress and the response to temperature in two seed morphs of Halopyrum mucronatum (Poaceae)
Authors: Khan M. Ajmal , Ungar Irwin A.
Published: September 2002

Halopyrum mucronatum (L.) Stapf. is a coastal dune grass
that produces seeds twice during each growing season. Seeds produced during
May (summer seed) were black and heavier (2.8 0.09 mg) than brown seeds (2.1
0.04 mg; winter seed) that were produced in November. There was greater than
95% germination in both seed morphs in the non-saline controls at all
temperature regimes, but germination was inhibited more by low than high
temperatures in the salinity treatments. Summer seeds were more tolerant of
salinity than the winter seeds. Highest germination was obtained in all
salinity treatments at a 20/30˚C (12-h night/12-h day)
temperature regime for the winter seeds and at 25/35˚C for the summer
seeds. Gibberellic acid, thiourea and nitrate partially alleviated the effects
of salinity in summer seeds and gibberellic acid, kinetin and betaine were
able to alleviate the inhibitory effects of salinity on the germination of
winter seeds. The seeds of Halopyrum mucronatum
exhibited seed dimorphism and a difference in physiological response in the
two seed morphs, which could provide them with multiple opportunities to
germinate and establish in the hot, dry, saline and unpredictable maritime
coastal-dune environment along the Arabian Sea coast of Karachi, Pakistan.
Bioclimatic assessment of the geographic and climatic limits to hybridisation in a sexually deceptive orchid system
Authors: Peakall Rod , Jones Lauren , Bower Colin C. , Mackey Brendan G.
Published: September 2002

Australia is a major centre of diversity for pollination by sexual deception,
a pollination syndrome unique to orchids and characterised by highly specific
pollinator relationships. Chiloglottis
pescottiana is a rare natural hybrid between sexually
deceptive C. trapeziformis and
C. valida. We utilised bioclimatic models to predict the
potential range of the parental orchid species, the hybrid and their
pollinators. The predicted ranges of the parental orchid species rarely
overlapped (only 2% of the core range), with the geographic separation
of the species reflecting the occupation of largely distinct climatic niches
and limiting opportunities for hybridisation. Comparison of the predictions
with independent distributions of the orchid taxa revealed a close match.
Unexpectedly, our results revealed that several related and morphologically
similar orchid species are, nevertheless, ecologically distinct from
C. valida. Our study demonstrates that bioclimatic
modelling provides an additional tool for exploring a range of ecological and
evolutionary questions.
Mud, mines and rainforest: a short history of human impact in western Tasmania, using pollen, trace metals and lead-210
Authors: Harle Katherine J. , Britton Kate , Heijnis Hendrik , Zawadzki Atun , Jenkinson Andrew V.
Published: September 2002

Lead-210, pollen and trace-element analyses of a finely sampled 7.5-cm sediment core from a subalpine tarn in western Tasmania have provided a detailed record of post-colonial human impact in the region. Lead-210 analysis indicated that the record extends back to about 1811 AD, with several changes in sediment rates evident. These have been tentatively related to disturbance in the catchment associated with ore prospecting. The regional vegetation has been reconstructed for this period using pollen abundances. Prior to 1860 AD, there appears to have been little disturbance in the regional vegetation, with relatively high taxon diversity and pollen concentrations. Important communities included rainforest dominated by Nothofagus cunninghamii and subdominated by Phyllocladus and Eucryphia, eucalypt-dominated mixed and wet sclerophyll forest and subalpine and/or alpine complexes. From the 1860s, the evidence suggests an overall reduction in the extent of regional forests, particularly rainforest and subalpine woodland. Initially, this appears to have been associated with both elevated charcoal levels and minor increases in concentrations of trace metals, particularly lead, tin, arsenic and copper. By the 1950s, however, significant reductions in taxon diversity and pollen abundance (particularly for rainforest and subalpine woodland) were strongly associated with rapidly increasing concentrations of trace metals. This evidence corresponds with historic records of mineral prospecting and mining in the region, especially around Queenstown where significant deforestation occurred due to logging and pollution from smelters. Interestingly, the evidence for the most significant impacts coincided with the escalation of open-cut mining from the 1950s to the 1970s, rather than earlier phases of smelter-produced pollution.
Long-term storage of mycorrhizal fungi and seed as a tool for the conservation of endangered Western Australian terrestrial orchids
Authors: Batty A. L. , Dixon K. W. , Brundrett M. , Sivasithamparam K.
Published: September 2002

The impact of seed drying, seed storage and development of testing procedures
for seed viability assessment was undertaken for a selection of common taxa
with congeners that are rare and endangered (Caladenia,
Diuris, Pterostylisand
Thelymitra). Freshly collected seed showed significantly
lower levels of germination compared with seed that had been subjected to
drying over silica gel for 24 h. Seed dried over silica gel for 24 h and
plunged into liquid nitrogen exhibited a further increase in germination
levels. Germination of seed stored at 4, 18 or 22˚C for 1 year was
substantially higher than freshly collected seed (4 weeks after dehiscence),
but germination was highest overall after storage of dried seed in liquid
nitrogen (–196˚C). Mycorrhizal fungi that promote the germination
and growth of plants were also successfully preserved in liquid nitrogen. The
use of cryoprotectants on fungal isolates had no observable deleterious
effects on fungal regeneration. Histochemical staining procedures
(tetrazolium, fluorescein diacetate and Evans blue) substantially
overestimated seed viability, relative to symbiotic seed germination, for most
seed treatments indicating a need for re-evaluation of the effectiveness of
staining procedures for testing viability. The implications of the long-term
ex situ storage of orchid seed and fungal symbionts for
the conservation of endangered orchids is discussed.
Effects of sodium, magnesium and calcium salts on seed germination and radicle survival of a halophyte, Kalidium caspicum (Chenopodiaceae)
Authors: Tobe Kazuo , Li Xiaoming , Omasa Kenji
Published: September 2002

Kalidium caspicum (L.) Ung.-Sternb. is a common species
of highly saline habitats of north-western China, which in previous
germination research has been shown to be rather sensitive to NaCl toxicity.
To investigate the effects of different salts on the seed germination and
radicle survival of this halophytic shrub, seeds were incubated in various
salt (NaCl, Na2SO4,
MgCl2, or MgSO4 with or without
CaCl2) or polyethylene glycol-6000 solutions. The
germination percentage and the percentage of emerging radicles surviving to a
length of at least 4 mm were examined. The survival of
K. caspicum radicles depended mainly on the cation
composition of the media: both Na+ and
Mg2+ had toxic effects on the radicles, while
Ca2+ alleviated the toxicity of these cations.
Mg2+ was more toxic than
Na+ and a higher concentration of
Ca2+ was needed to alleviate its toxicity. It was
suggested that the establishment of seedlings of
K. caspicum in the field is facilitated by the marked
alleviation of salt toxicity by Ca2+ and that the
proportion of soluble Na, Mg and Ca ions in the soil determines the
distribution of K. caspicum in the field.
Morphological variation within the Drosera indica (Droseraceae) complex in northern Australia
Authors: Susandarini Ratna , Conran John G. , Collins Graham G. , Lowrie Allen
Published: September 2002

Morphological variation in northern Australian
Drosera indica L. specimens, mainly from northwestern
Australia, was studied by cluster analysis and ordination (MDS). Sixty-two
accessions were scored for 26 morphological characters representing five
vegetative, nine floral and 12 seed features. The accessions were
differentiated into three distinct morphotypes mainly on the basis of seed and
stamen characters. These morphotypes occurred sympatrically at a number of
localities over a wide area across northern Australia, but without obvious
evidence of intergradation. This suggests that these morphotypes represent
cryptic species within the D. indica complex.
Evolutionary strategies for reproduction and dispersal in African Restionaceae
Authors: Caddick L. R. , Linder P. L.
Published: September 2002

The wide variation of diaspore types in African Restionaceae reflects two different evolutionary strategies for utilisation of resources for reproduction and propagation. The interplay between fecundity and seedling survivorship has apparently resulted in reproductive strategies ranging from the production of a few large dispersal units with comparatively high drought resistance, to production of numerous, smaller dispersal units which experience high levels of drought mortality. A sample of Restionaceae representing all the major African lineages in the family was examined to investigate the influence of diaspore size on diaspore production, seedling growth and seedling survival in the fynbos vegetation of the Western Cape. Correlates of diaspore size were investigated by using phylogenetically independent contrasts to assess which ecological factors may have influenced the evolution of different dispersal mechanisms. Results indicate that diaspore size strongly influences the size to which a seedling can grow in its first few months, which in turn influences the plant's ability to survive summer drought. Larger seedlings, produced by larger diaspores, are less likely to succumb to drought-induced mortality than the smaller seedlings produced by smaller diaspores. The evolution of large, drought-resistant diaspores coincides with a hypothesised drying of the Western Cape climate between 5 and 7 million years ago. This occurrence of seasonal drought may have opened up a new ecological opportunity for plants producing drought-resistant propagules, which, under wetter conditions, would be overwhelmed by less robust seedlings through sheer weight of numbers produced.
In vitro propagation of Epacris impressa (Epacridaceae) and the effects of clonal material
Authors: Anthony J. , McLean C. B. , Lawrie A. C.
Published: September 2002

A system of micropropagation has been developed for
Epacris impressa Labill. (pink heath) (Epacridaceae),
the floral emblem of Victoria, Australia. Only explants from glasshouse-grown
plants treated with 1.2 g L–1 mancozeb were
established successfully in vitro. Shoot material was
very sensitive to surface-sterilisation, with 0.5% NaOCl for 5 min
being optimal. Multiple shooting was induced optimally on Woody Plant Medium
(WPM, Lloyd and McCown 1980) with 12–25 µM of the cytokinin 2iP
(6-(γ,γ-dimethylallylamino) purine). Inclusion of the auxin IBA
(indole-3-butyric acid) induced callus and reduced shooting. Rooting
in vitro was greatest (up to 40%) with
half-strength WPM and 16 µM IBA. Clones from individual plants varied in
multiple shooting response to 2iP (0–49 µM) and root induction
response to auxins (IBA and NAA (α-naphthaleneacetic acid), 0–43
µM). These results suggest that explant materials are the main
determinant of success in in vitro propagation and that
they require individual optimisation of treatments to maximise shoot and root
formation.
Effects of clonal integration on response to sand burial and defoliation by the dune plant Ipomoea pes-caprae (Convolvulaceae)
Authors: Bach Catherine E.
Published: September 2002

This study examined the importance of clonal integration on the growth and
mortality of a tropical dune plant, Ipomoea pes-caprae
L. (Roth), in response to two stresses: sand burial and defoliation. Sand
burial and artificial defoliation treatments were applied to one shoot on
daughter ramets, some of which were connected to other ramets and some of
which were not connected to other ramets. Sand burial significantly enhanced
both stem growth and leaf production of the buried shoots, both for connected
and unconnected ramets. Defoliation decreased stem growth of shoots other than
the defoliated shoot, but only for unburied ramets. Defoliation also had a
greater negative effect on growth of other shoots on connected ramets than on
unconnected ramets. At the level of the entire ramet, burial stimulated both
stem growth and leaf production for connected ramets, but not for unconnected
ramets. These results support the hypothesis that physiological integration
between ramets mediates the response to both sand burial and defoliation in
Ipomoea pes-caprae.
Genetic diversity in natural populations of Acacia mearnsii
Authors: Searle S. D. , Bell J. C. , Moran G. F.
Published: September 2002

Twenty-three isozyme loci were used to examine genetic diversity within and
between 19 natural populations of Acacia mearnsii De
Wild. selected to represent its entire geographic range.
Acacia mearnsii was found to have moderate genetic
diversity (species level gene diversity HT =
0.201) with the majority (89.2%) of variation occurring within
populations. All measures of population diversity were higher in the northern
(New South Wales) than the southern (Victoria, South Australia, Tasmania)
populations. There was some evidence of differentiation between populations
but no strong clustering at a regional level.
Stomatal parameters and atmospheric change since 7500 years before present: evidence from Eremophila deserti (Myoporaceae) leaves from the Flinders Ranges region, South Australia
Authors: Atchison J. M. , Head L. M. , McCarthy L. P.
Published: September 2002

Stomatal parameters (stomatal density, stomatal index and stomatal
conductance) have been widely used to study vegetation response to long-term
CO2 change, mostly in the Northern Hemisphere. We tested
the applicability of the methods and interpretations to Australian desert
vegetation, by using Eremophila deserti A.Cunn.
(Myoporaceae) leaves. Subfossil samples dated at 7500 years before present and
3700 years before present from Leporillus species
(stick-nest rat) middens from the Flinders Ranges were compared with herbarium
and modern samples from the area. Stomatal density and stomatal conductance
are problematic in their application to this species, probably because of the
effect of the moisture regime on epidermal cell size. Stomatal index, which
takes some account of independent variations in cell size, did allow the
differentiation of long-term trends. In contrast to most other studies, these
trends show an increase in stomatal index with increasing
CO2, particularly over the last century. From 7500
years before present until about 1950, it is unclear whether
CO2 was the most influential among a complex set of
factors including different aspects of the moisture regime. In recent decades,
the influence of CO2, as demonstrated statistically,
accounts for most but not all the observed variation.
Germination response of seven east Australian Grevillea species (Proteaceae) to smoke, heat exposure and scarification
Authors: Morris E. Charles
Published: September 2002

Seeds of plant species from fire-prone vegetation often show dormancy, and
germinate in response to fire-related cues. Seeds of some east Australian
Grevillea species were known from earlier studies to
germinate in response to fires, but gave mixed results when heat shock was
tested as a germination stimulus. In the current study, seeds of seven east
Australian Grevillea species were tested for their
germination response to smoke, to short heat exposure, and to scarification.
Seeds were smoked in a chamber by using a mixture of native woodland
vegetation as fuel. The smoking and heating treatments were administered to
seeds in bulk: this meant that subsequent germination data for these two
treatments were not independent. Cumulative germination in the laboratory was
scored for up to 60 days. All three germination treatments, when administered
singly, increased germination: smoke increased germination in all seven
species, heat in four species, and scarification in a different four species.
Pairwise combinations of the three treatments also increased germination in
some species e.g. smoke and heat treatments combined led to the highest
germination observed in four species, and to increased germination compared
with either treatment singly, in another species. Some treatment combinations
appeared to interact: heat and scarification combined led to decreased
germination in three species. The role of heat exposure and scarification in
increasing germination was not due to the breaking of an impermeable seed
coat: water uptake of both scarified and unscarified seeds was rapid and equal
(after 24 h) in all seven species. The results indicate that seeds of the
Grevillea species investigated are responsive to one or
more fire-related germination cues.
New desiccation-tolerant plants, including a grass, in the central highlands of Mexico, accumulate trehalose
Authors: Iturriaga G. , Gaff D. F. , Zentella R.
Published: September 2002

A grass endemic to Mexico, Sporobolus atrovirens, was
identified for the first time as a desiccation-tolerant resurrection plant.
Nine species of desiccation-tolerant vascular plants were found in the
highland area of Mexico, including four species of ferns
(Cheilanthes and Pellaea species)
and three species of Selaginella. Two other grasses
collected were known desiccation-tolerant species distributed from South
America (Cordoba) to North America (Georgia). The ferns
Ch. bonariensis, Ch. integerrima,
Ch. myriophylla and P. sagittata
are newly reported as desiccation-tolerant plants. The osmoprotectant
trehalose which has been recorded as rare in plants was found in air-dry
foliage of representative species of widely different taxa (9–291
µM g–1 dry weight). The flora of
desiccation-tolerant species in Mexico is discussed in connection with its
ability to accumulate trehalose.
Impacts of grazing by vertebrate herbivores on the flower stem production of tall alpine herbs, Eastern Central Plateau, Tasmania
Authors: Bridle K. L. , Kirkpatrick J. B.
Published: September 2002

Some species and genera of tall herbs that are widespread both in Tasmanian
and in mainland Australian alpine vegetation are dominant or codominant over
large areas in the Australian Alps, while being typically subordinate species
in Tasmania. This difference has been attributed to the impact of vertebrate
herbivores, which are abundant in the Tasmanian high country but rare in or
absent from the higher altitudes in the Australian Alps. The present study
tests the hypothesis that lack of dominance (>50% cover) of tall
alpine herbs in Tasmanian alpine and subalpine areas could be at least
partially caused by grazing of their reproductive parts. Both in experimental
plots and a clipping experiment, tall herbs produced more flowering stems
under lower grazing/clipping pressure. In the field, the greatest
reduction in flowering occurred under a grazing regime of sheep plus rabbits
plus native herbivores. There was no consistent difference in the number of
flowering stems between rabbit-grazed and rabbit plus native-grazed areas.
However, there was a significant negative relationship between the number of
flower heads and wallaby scats and a non-significant positive relationship
between the number of flower heads and rabbit scats, suggesting that
wallabies, not rabbits, were largely responsible for flower head depletion.
Many species had more flowering stems in rabbit plus native vertebrate-grazed
areas than in ungrazed exclosures. Therefore, it seems possible that the
effects of vertebrate herbivory on flowering may have contributed to the lack
of tall alpine herbfields in Tasmania.
Floral morphology and embryology of two Australian species of Citrus (Rutaceae)
Authors: Clarke Kerri , Prakash Nallamilli
Published: September 2002

The floral morphology and embryology of two species of Australian
Citrus L. occurring in the most southerly range of the
genus, C. australasica F.Muell. and
C. australis (Mudie) Planchon, have been studied.
Cytokinesis in the microsporocytes was simultaneous resulting in tetrahedral
tetrads. Tapetal cells were bi- to multinucleate and unevenly one- or
two-layered. Microspore development was frequently asynchronous. Anther wall
consisted of a layer of endothecium, three to five middle layers and one or
two layers of Secretory tapetum. The ovules were anatropous, bitegmic and
crassinucellate. Although multiple sporogenous cells that grew into multiple
megasporocytes were common, occurrence of twin or multiple gametophytes was
rare. Development of the female gametophyte was of the Polygonum type, with
antipodal cells frequently persisting until after fertilisation. Endosperm was
of the Nuclear type while embryogeny was of the Onagrad type. Both integuments
contributed to the seed coat. Cells of the outer layer of the testa developed
fibrous thickenings and secreted mucilage. Seeds were monoembryonate and seed
germination was hypogeal. The recent move incorporating Australian native
citrus species in to the genus Citrus was supported on
the grounds of close embryological similarities.
Thermodynamics of Protonation and Sodium Binding of Sulfate in Concentrated NaCl and CsCl Solutions Studied by Raman Spectroscopy
Authors: Kratsis Steven , Hefter Glenn , May Peter M. , Sipos Pal
Published: September 2002

The protonation constant (pKa) of
SO42–(aq) has been
determined at ionic strengths 0.5 M ≤I ≤4.0 M in
NaCl and CsCl media at 25˚C by using Raman spectroscopy. These data were
used to calculate the association constant of the
NaSO4–(aq) ion pair in CsCl
media. The results are in excellent agreement with previous values obtained by
other techniques. The (pKa) was
also measured at I = 4 M in both media at
temperatures up to 85˚C and the associated enthalpy and entropy changes
were calculated. However, reliable thermodynamic data for the ion-pairing
reaction could not be obtained at higher temperatures probably because of
competition from CsSO4–(aq).
An Approach to Some Spiro Oxindole Alkaloids Through Cycloaddition Reactions of 3-Methylideneindolin-2-one
Authors: Bell Stephanie E. V. , Brown Roger F. C. , Eastwood Frank W. , Horvath Julianna M.
Published: September 2002

3-Methylideneindolin-2-one (3-methylideneoxindole) (1) was prepared in
60–89% yield by flash vacuum pyrolysis of the acetate or methyl
carbonate of 3-hydroxy-3-methylindolin-2-one, and was fully characterized, but
application of the same procedure to 3-hydroxy-5-methoxyindolin-2-one did not
give useful yields. Cycloaddition reactions of
CH2=
+NR–CH2
– and of the related ylide (25) (from
1-(trimethylsilylmethyl)piperidine-2-carbonitrile and AgF) to
3-methylideneindolin-2-one (1) gave 4–20% yields of spiro
oxindoles, but yields were markedly below those achieved in cycloadditions to
the more electrophilic N-phenylmaleimide (70–79%). Attempted
alkylation of weakly basic secondary amines, e.g. piperidine-2-carbonitrile,
with Me3SiCH2Cl in dimethyl
sulfoxide/K2CO3 gave only
carbamates
Me3SiCH2OOCNR2.
1 : 1 Molecular Complexes of 4-Amino-N-(4,6-dimethylpyrimidin-2-yl)benzene-sulfonamide (Sulfamethazine) with Indole-2-carboxylic Acid and 2,4-Dinitrobenzoic Acid
Authors: Lynch Daniel E. , Sandhu Pardeep , Parsons Simon
Published: September 2002

The 1 : 1 molecular adducts of
4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide
(Sulfamethazine) with respectively indole-2-carboxylic acid (1) and
2,4-dinitrobenzoic acid (2) have been prepared and their X-ray crystal
structures determined. The acid groups in both structures form associative
R22 (8)
graph set hydrogen-bonding interactions across the N(11)–H/N(17)
site of Sulfamethazine. Acomparison of the two distances between relevant
non-hydrogen atoms in this configuration reveals that this association is not
symmetrical. An average difference of 0.144 Å is observed for seven
listed complexes of Sulfamethazine, five having been previously reported. This
average difference compares with a value of 0.265 Å for the same
interaction seen in carboxylic acid adducts of 2-aminopyrimidine.
Pigments of Fungi. LXVI. The Gentiobiosides of (R)- and (S)-Torosachrysone from Australian Toadstools and Methods for Assaying the Enantiomeric Purity of Natural Torosachrysone
Authors: Gill Melvyn , Saubern Simon , Yu Jin
Published: September 2002

The diastereoisomeric 8-O--b-gentiobiosides (2) and (10)
of (S)- and (R)-torosachrysone (1)
and (11), respectively, are isolated in admixture to varying degrees from
toadstools belonging to the genera Cortinarius and
Dermocybe. (R)-Torosachrysone (11)
is characterized for the first time from a fungus and spectroscopic and
chromatographic methods are described that show that torosachrysone, as it
occurs in several fungi, is anisochiral and its stereochemical composition is
species-dependent.
Molecular Cocrystals of Aromatic Carboxylic Acids with Unsymmetrically Substituted Ureas. The Structures of Phenylurea and the 1 : 1 Adducts of Phenylurea with a Series of Nitro-Substituted Acids
Authors: Bott Raymond C. , Smith Graham , Wermuth Urs D. , Dwyer Nathan C.
Published: September 2002

The crystal structure of phenylurea (1),
[(C7H8N2O)],
has been determined and revealed a simple cyclic dimer involving hydrogen
bonding between the two nitrogen atoms of one molecule and the oxygen atom of
a second molecule. The system is completed by a hydrogen bond between the
non-substituted nitrogen atom of a third molecule and the oxygen atom of the
second molecule to form a chain polymer. The 1 : 1 molecular adducts of
phenylurea with 2-nitrobenzoic acid,
[(C7H5NO4)(C7H8N2O)]
(2), 3-nitrobenzoic acid,
[(C7H5NO4)(C7H8N2O)]
(3), 3,5-dinitrobenzoic acid,
[(C7H4N2O6)(C7H8N2O)]
(4), 2,4,6-trinitrobenzoic acid,
[(C7H3N3O8)(C7H8N2O)]
(5), 5-nitrosalicylic acid,
[(C7H5NO5)(C7H8N2O)]
(6), and 3,5-dinitrosalicylic acid,
[(C7H4N2O7)(C7H8N2O)]
(7) have been prepared and characterized by infrared spectroscopy and, for
compounds (2), (4), (5) and (6), by single crystal X-ray diffraction methods.
The adduct involving phenylurea and 4-nitrobenzoic acid could not be isolated
from this system. In all examples, cyclic hydrogen-bonding interactions are
found between the phenylurea and the carboxylic acid groups. All display
further peripheral hydrogen bond associations that result in the formation of
predominantly simple chain polymeric structures.
Synthesis of Hippospongic Acid A Analogues Designed for Investigating the Structure-Activity Relationship of its Biological Activity
Authors: Hiraga Yoshikazu , Ago Mariko , Tokumasu Munetaka , Kaku Ken , Ohkata Katsuo
Published: September 2002

Analogues of hippospongic acid A, which inhibit the gastrulation of sea urchin
embryos, were synthesized. From a study on structure—activity
relationships, the conjugated carboxylic acid moiety was found to be an
essential feature for biological activity.
Facets of Induced Internal Redox Involving WS42 - and WSe42 - : Synthesis and X-Ray Crystal Structures of syn-W2S2(μ-S)2(S2PPh2)2 and WO(Se2)(S2CNEt2)2
Authors: Tiekink Edward R. T. , Eagle Aston A. , Young Charles G.
Published: September 2002

Reaction of
(NEt4)2[WS4]
and
[S2PPh2]2
in acetonitrile results in the formation of diamagnetic, orange
syn-W2S2(µ-S)
2(S2PPh2)2
by an induced internal redox process. Crystals of the toluene solvate
W2S2(µ-S)
2(S2PPh2)2
. C7H8 are triclinic and belong to
space group P1– with a
13.845(5), b 16.536(7), c 8.387(2)
Å, α 99.75(3), β 95.51(3), γ 83.08(3)˚, and
Z 2. Refinement of 5445 data converged at
R 0.038 and
Rw 0.038. The complex possesses a
syn-[W V
2S2(µ-S)2]2+
core with a W–W bond of 2.8161(5) Å and two terminal W=S
bonds of 2.097(3) and 2.096(3) Å. The W-(µ-S) bond distances are
in the range 2.310(2)–2.315(2) Å. Each of the five-coordinate,
square-pyramidal tungsten atoms is further coordinated by a bidentate
dithiophosphinate ligand with W–S bond distances ranging from 2.464(2)
to 2.481(2) Å. Extended reaction of
(NH4)2[WSe4]
and
[S2CNEt2]2
in acetonitrile produces green
WS(Se2)(S2CNEt2)2
and red
WO(Se2)(S2CNEt2)2
in 40% and 15% yields, respectively. Crystals of
WO(Se2)(S2CNEt2)2
are monoclinic and belong to space group
P21/n
with a 9.609(6), b 15.053(7),
c 13.120(9) Å, β 100.08(4)˚, and
Z 4. Refinement of 2473 data converged at
R 0.039 and
Rw 0.039. The seven-coordinate,
pentagonal bipyramidal complex features C1
symmetry, an axial oxo ligand (W=O 1.705(6) Å), an equatorial,
side-on bonded diselenido ligand (W–Se(1) 2.509(1), W–Se(2)
2.547(1) Å, Se(1)–Se(2) 2.306(2) Å) and two bidentate
dithiocarbamate ligands.
X-Ray Study of Two Novel Nickel(II) - Thiosulfate Compounds
Authors: Freire Eleonora , Baggio Sergio , Suescun Leopoldo , Baggio Ricardo
Published: September 2002

Two novel nickel thiosulfate complexes have been prepared and their crystal
structures determined:
NiS2O3(dmph)(H2O)·H2O·CH3OH
(1) (dmph = 2,9-dimethyl-1,10-phenanthroline), which to our knowledge
is the first pentacoordinated nickel thiosulfate complex described so far, and
NiS2O3(dmph) (2), a
hexacoordinated complex which displays a thiosulfate binding mode with no
precedents in the literature, viz. bridging solely through oxygen. Compound
(1) is monoclinic, C2/c,
a 26.269(5), b 7.641(3),
c 18.381(3) Å, β 97.00(2)˚,
V 3662(2) Å 3
,Z 8, conventional R (on
F) being 0.049 for 2217
No observed reflections
(I > 2σ(I)). Compound (2)
is also monoclinic,
P21/n,
a 11.108(2), b 10.955(2),
c 11.666(2) Å, β 103.32(3)˚,
V 1381.4(5) Å 3 ,
Z 4, R 0.036,
No 2497.
Synthesis of an Oxaspirolactone Intermediate for the Synthesis of Spirolides
Authors: Brimble Margaret A. , Fares Fares A. , Turner Peter
Published: September 2002

A new method has been established for the preparation of C 2-oxidized
5,5-spiroacetals, which are key intermediates for the synthesis of the
bis-spiroacetal moiety of the spirolides. A bridged
orthoester was used as a masked carboxylic acid in the preparation of these
bicyclic oxaspirolactones. The synthesis of chiral lactone (12), a building
block for the synthesis of the spirolides, is also reported. The two chiral
centres in lactone (12) were assembled by addition of a chiral crotyl borane
to an aldehyde. The structure of lactone (12) was determined by single-crystal
X-ray diffraction; orthorhombic space group
P212121
(No. 19), a 12.437(2), b
23.881(4), c 7.545(1) Å, V
2240.9(5) Å3, R(F) 0.0460,
and Rw(F)
0.0458.