bluuebunny/crossref_metadata_2025 huggingface dataset:
Drying of surface soil decreased Lupinus angustifolius root length and manganese uptake in a split-root experiment
Authors: Crabtree W. L. , Robson A. D. , Ritchie G. S. P.
Published: August 2004

In a glasshouse, a split-root experiment was used to determine the ability oflupins (Lupinus angustifolius L.) to take up manganese(Mn) from dry soil either when young or at mid-flowering of the primarybranches. Three soil-watering regimes (maintained at field capacity,maintained below wilting point, and alternating from field capacity to wellbelow wilting point) were imposed after taproots had grown through topsoil andinto a nutrient solution below. Four sequential harvests (11, 22, 37, and 49days after sowing) were taken to determine the effect of soil drying on lupingrowth, Mn uptake, and soil-extractable Mn.Soil drying early in the lupin plant's life stopped the growth of lateralroots in the soil and slowed the growth of roots grown in subsoil solution andthe growth of lupin tops. Soil drying decreased uptake of Mn in the tops to13% of that under continuous wet soil conditions. Of the 13%,most (11%) was taken up while the soil was drying. Soil re-wettingenabled the plants to resume uptake of Mn and soil re-drying (just beforeanthesis) decreased the Mn concentration in the lupin stems to 4·8µg/g, whereas stems of lupins grown in the wet and dry soilscontained 10·3 and 3·3 µg/g, respectively. Easilyreducible and plant-available soil Mn were not affected by soil wetting anddrying treatments.This study confirms that the uptake of Mn by lupin may be severely restrictedby drying of surface soil at both the beginning and the end of the lupinplant's life. The decrease in root length rather than the chemical form of Mn restricted Mn uptake.
Influence of four commonly used pesticides on the survival, growth, and reproduction of the earthworm Aporrectodea trapezoides (Lumbricidae)
Authors: Choo L. P. D. , Baker G. H. , Choo L. P. D. , Baker G. H.
Published: August 2004

The effects of 4 commonly used pesticides, endosulfan (insecticide),
fenamiphos (nematicide), methiocarb (molluscicide), and ridomil (fungicide) on
the survival, growth, and reproduction of the earthworm
Aporrectodea trapezoides (Lumbricidae) were measured in
laboratory and field experiments. When the earthworms were exposed to the
pesticides on moist filter paper for 48 h, fenamiphos and, to a lesser extent,
endosulfan caused significant mortality. In contrast, the survival of
A. trapezoides was rarely affected by the pesticides
during exposure for 5 weeks in pots and cages containing soil (only noted
under 10 × normal application rate of endosulfan against adult worms).
However, endosulfan did significantly reduce the weight of juvenile
A. trapezoides within 5 weeks when applied to soil at
normal application rate in both the field and laboratory. Fenamiphos did so at
normal application rate in the field only. Fenamiphos and methiocarb reduced
earthworm weight in the laboratory when applied at 10 × normal rate. The
clitella of adult earthworms regressed with exposure to endosulfan at normal
rate and also exposure to fenamiphos at 10 × normal rate. Cocoon
production was inhibited by endosulfan and fenamiphos at normal application
rates and methiocarb at 10 × normal rate. The use of some pesticides, in
particular endosulfan, could significantly reduce the establishment of
abundant and beneficial populations of earthworms in Australian pastures.
Liveweight and wool growth responses to a Mediterranean environment in three strains of Merino sheep
Authors: Adams N. R. , Briegel J. R.
Published: August 2004

The present study examined changes in wool growth, liveweight, and body
composition in groups of fine, medium, and broad wool Merino wethers grazed
together at pasture in the highly seasonal Mediterranean environment, to
determine the sources of variation in wool growth that may affect staple
strength (SS). Seasonal changes in wool growth were measured using 6 dyebands
placed at times of seasonal change in the nutrient supply from pasture, and
liveweights were recorded fortnightly. Dilution of deuterated water was used
to determine changes in body composition between the beginning of summer and
the end of autumn. The sheep lost liveweight over this period, but loss of
protein relative to fat over this period was unexpectedly high (7 : 1). The
relative changes in liveweight, and loss of its components (fat and lean)
during summer and autumn, were similar in all 3 groups, even though the Broad
group was heavier than the other 2 genotypes at all times
(P < 0·01). In contrast to the similar pattern
of liveweight change, wool growth rates and changes in the fibre diameter were
less variable throughout the year in the Broad group than the other 2 groups
(P < 0·001). Stepwise regression indicated
that the characteristics related to SS were standard deviation in fibre
diameter (SDfd; P <
0·001), mean fibre diameter (P <
0·001), and variation in diameter within a 200-mm length of wool fibre
(Sdfdwithin; P < 0·05).
However, the relative importance of different factors for SS differed within
each group. The most important factors were mean fibre diameter in the Fine
group, the variation in fibre diameter along the staple
(SDfdalong) in the Medium group, and the variation in
diameter between fibres (SDfdbetween) in the Broad
group.
It is concluded that SS is a complex characteristic, depending on both the
fibre diameter and several sources of variation in fibre diameter, all of
which can differ among flocks. Protein loss made a disproportionate
contribution to liveweight loss over summer and autumn, but the amino acids
made available did not contribute substantially to wool growth or SS.
Effects of genotype and environment on architecture and flowering time of indeterminate Andean lupins (Lupinus mutabilis Sweet)
Authors: Hardy A. , Huyghe C. , Rahim M. A. , Roemer P. , Neves-Martins J. M. , Sawicka-Sienkiewicz E. , Caligari P. D. S.
Published: August 2004

Plant structure was shown to limit the seed yield of
Lupinus mutabilis through low dry matter production. The
genetic and environmental variations of architectural and phenological traits
of indeterminate Andean lupin were evaluated. Twelve genotypes were sown at
6–8 dates at 5 locations in Europe in 1994 and 1995. Wide variation was
observed for phenological and architectural characters. The variation in the
number of mainstem leaves was partly explained by the temperature. The
mainstem height and flowering date were related to the number of mainstem
leaves but flowering time was also affected independently by the enviromental
conditions. The mainstem structure determined the potential number of
first-order branches through the number of axillary buds. The actual number of
branches was also determined by the prevailing environmental conditions during
branch growth. The number of leaves on the second first-order branch was less
susceptible to the environmental conditions than the number of leaves on the
mainstem. Heritabilities were high for all characters except for the number of
leaves on the second first-order branch, and the interactions between genotype
and environmental condition were low. Breeding for architecture modification
would thus be possible in L. mutabilis.
Composition of Subtidal Macroalgal Communities of the Lower Gulf Waters of South Australia, with Reference to Water Movement and Geographical Separation
Authors: Cheshire Anthony C. , Collings Gregory J.
Published: August 2004

Differences exist in the floristic composition of the canopy of macroalgal
communities in the partially protected waters of sites on the Yorke and
Fleurieu peninsulas, South Australia. These differences were quantified and
related to the effects of wave force and geographical separation. The canopies
of the communities were dominated by species of
Cystophora J.Agardh and/or
Sargassum C.Agardh and the biomass ratio of these genera
was found to be highly correlated with wave force. Diversity was maximal at
sites of intermediate exposure, whereas total biomass increased with the wave
energy of the site. The common occurrence of some species at a number of sites
supports the proposition that these sites occur within a single biogeographic
province. The composition of these protected gulf communities is consistent
with the trends previously demonstrated for exposed oceanic sites of the same
region.
Quantum Efficiency and Photosynthetic Production of a Temperate Turf Algal Community
Authors: Westphalen Grant , Cheshire Anthony C.
Published: August 2004

A preliminary investigation of the production and photosynthetic efficiency of
a temperate, sub-tidal, turf algal community using
in situ measurements of photosynthesis and respiration
is reported. Results indicated that temperate turfs have high biomass specific
productivity, but are less productive on an areal basis than either the
surrounding macro-algal community or their tropical counterparts. Net 24 h
production ranges between 12 and 78 mmol O2
m-2 d-1 (corresponding to a carbon
fixation rate of 0.1–0.9 g C m-2
d-1). Inefficient use of the available substrata, due to
the early successional nature of these communities, is considered to be the
cause of this low productivity. A quantum efficiency of 0.034 µmol
O2 µmol photons-1 and a
sub-saturating light itensity of 134–210 µmol photons
m-2 s-1 indicate that
photosynthetic saturation was easily achieved and suggests that self-shading
in the turf community was not significant.
An Expanded Recent Pollen Database from South-eastern Australia and its Potential for Refinement of Palaeoclimatic Estimates
Authors: D'Costa Donna , Kershaw A. Peter
Published: August 2004

Seventy-one pollen spectra from prior to the period of European impact were
extracted from fossil pollen diagrams on mainland south-eastern Australia in
1991 to use as a modern reference for refinement of vegetation and climatic
histories constructed from the region. This paper presents results of an
extension of this recent database to 135 spectra, derived from additional
fossil pollen sites on the mainland and also from sites in Tasmania. The sites
include those of almost all late Quaternary pollen studies ever undertaken.
Estimates of climate for each site, derived by BIOCLIM, have allowed an
examination of patterns of representation of individual recorded taxa in
relation to regional variation in major climatic parameters. Pollen taxa show
variable representation in relation to their inferred presence and abundance
in parent vegetation due to differential pollen production and dispersal
characteristics. However, patterns of pollen representation do appear to
relate, in broad terms, to climatic variation. It is considered that this
modern pollen and climate database should lead to more certain interpretation
of future pollen records including some quantification of palaeoclimatic
conditions.
Architecture of the Wollemi Pine (Wollemia nobilis, Araucariaceae), a Unique Combination of Model and Reiteration
Authors: Hill K. D.
Published: August 2004

The Wollemi pine (Wollemia nobilis W.G. Jones, K.D. Hill & J.M. Allen) is shown to possess a unique architecture. The model is notdescribed by any of the 23 basic models previously described (Bell 1991), butcan be described by a modified Cook model whereby growth is rhythmic ratherthan continuous. This differs from all other extant members of Araucariaceae,which conform to the models of either Rauh or Massart. The branching andcoppicing habits can both be interpreted as adaptive reiterations. Both thearchitectural model and the two types of adaptive reiteration are advanced orautapomorphic conditions in the Wollemi pine.
Cytoembryology of Paspalum chaseanum and Sexual Diploid Biotypes of Two Apomictic Paspalum Species
Authors: Espinoza Francisco , Quarín Camilo L.
Published: August 2004

This study was undertaken to determine the cytology, method of reproduction,
and flowering behaviour of three Paspalum species.
Paspalum plicatulum has long been considered a segmental
allotetraploid that reproduces by obligate apomixis with the type being
apospory followed by pseudogamy. Paspalum simplex is an
apomictic autotetraploid species, while P. chaseanum is a rare species for which no information
regarding cytology and reproduction is available. This investigation concerns
diploid cytotypes (2n = 2x
= 20) of P. plicatulum and
P. simplex that were recently collected in subtropical
South America. In addition, two accessions of
P. chaseanum were also recorded and both had
2n = 2x = 20
chromosomes. Meiosis showed regular bivalent chromosome pairing. Embryological
observations indicated that the three species reproduce sexually at the
diploid level. Pollen–pistil interaction following self-pollination
suggested the presence of a self-incompatibility system responsible for
allogamy. The results indicate that P. plicatulum and
P. simplex complexes consist of diploid sexual
allogamous cytotypes in addition to the known tetraploid apomictic cytotypes.
Diploid strains constitute a source of sexuality for plant improvement.
Chromosome doubling will likely produce sexual tetraploids to be used as
females in crosses with natural apomictic tetraploid biotypes. Since diploid
self-incompatible sexual Paspalum plants usually have
apomictic tetraploid co-specific counterparts, the self-incompatible diploid
P. chaseanum described in this study warrants further
exploration for its apomictic counterpart.
Dormancy in seeds of Hibbertia cuneiformis and H. huegelii (Dilleniaceae)
Authors: Schatral A. , Osborne J. M. , Fox J. E. D.
Published: August 2004

Dormancy delays the germination of seeds in two species of the primitive
angiosperm genus Hibbertia
(H. cuneiformis and H. huegelii,
family Dilleniaceae). After seed coat removal, germination increased in
18-month-old seeds of H. cuneiformis and 6- to
8-month-old seeds of H. huegelii. Hence, seeds of the
two species exhibit seed coat dormancy. The removal of the seed coat may
stimulate germination, as the result of increased water uptake, and/or the
removal of mechanical and chemical inhibition. However, the occurrence of
imbibitional injury and a reduced percentage of vigorous seedlings in decoated
seeds suggest that embryo dormancy, as a second type of dormancy, impedes
germination in H. cuneiformis. Embryo dormancy also
delays the germination of seeds of H. huegelii, since a
high percentage of seeds did not germinate after removal of the seed coat.
Embryo dormancy appears to vary among individual seeds and between species.
The germination experiments suggest a high percentage of non-dormant and
weakly dormant embryos for 18-month-old seeds of
H. cuneiformis. By contrast, many seeds of
H. huegelii appear to contain deeply dormant embryos. In
H. cuneiformis, the depth of the seed dormancy varied
with the age of the seeds. Freshly harvested seeds did not germinate for 3
months. Treatment with gibberellic acid (GA3) (120 mg
L-1) significantly enhanced germination of freshly
harvested and 18-month-old, intact seeds of
H. cuneiformis and the germination of decoated
18-month-old seeds of H. huegelii. The plant hormones
kinetin and abscisic acid did not affect the final germination percentage in
18-month-old seeds of H. cuneiformis. For
H. huegelii, germination was reduced in decoated seeds
and seeds with cracked coats exposed to an 8 h day: 16 h night diurnal cycle
compared with complete darkness.
Biomass, Nutrient Content and Growth Response to Fertilisers of Six-year-old Eucalyptus globulus Plantations at Three Contrasting Sites in Gippsland, Victoria
Authors: Bennett L. T. , Weston C. J. , Attiwill P. M.
Published: August 2004

Factorial combinations of three rates of N (up to 400 kg
ha-1 elemental) and four rates of P (up to 200 kg
ha-1) were applied during the establishment phase of
Eucalyptus globulus Labill. plantations on three
contrasting sites in Gippsland, south-eastern Australia. Mean annual
increments of volume at 71 months ranged from 8 m3
ha-1 year-1 in control treatments
on a duplex sandy loam (annual rainfall 850 mm) and a uniform sand (620 mm
rainfall) to 23 m3 ha-1
year-1 at the highest combined additions of N and P on a
gradational clay loam (1000 mm rainfall). Volumes to 71 months were greatest
at the highest combined additions of N and P on the uniform and gradational
soils, but significant effects of N and P additions were not sustained on the
duplex soil, where the availability of K was limiting after 45 months. Trees
were sampled for above-ground biomass and nutrient content at 6 years from
four treatments involving the highest additions of N and P and treatment
responses were interpreted using vector analysis. The greater magnitude of P
vectors than N vectors at all sites indicated that P additions, in particular,
were important for good early growth. However, relationships between
above-ground biomass and P content indicated accumulation of P in excess of
growth requirements and reduced efficiency of P additions at the highest
rates. The paper concludes with general recommendations for fertiliser
additions during the establishment phase of E. globulus
plantations.
Use of Gas Chromatograms of the Essential Leaf Oils of the Genus Eucalyptus for Taxonomic Purposes
Authors: Dunlop Peter J. , Bignell Caroline M. , Hibbert D. Brynn
Published: August 2004

Using morphological observations, botanists have classified
Eucalyptus species into characteristic series. A new
vacuum distillation technique has been employed to obtain the characteristic
leaf oils, which are very close to their in vivo compositions, from 35 species
belonging to series Tetrapterae, series
Torquatae and series Rufispermae.
Accurate gas chromatograms have been obtained for each species and three
analytical techniques (principal component analysis (PCA), hierarchical
cluster analysis (CA) and linear discriminant analysis (LDA)) have been used
to process these chromatograms to see if agreement with these classifications
could be achieved without using any auxiliary morphometric data. For the
species chosen for the present study, linear discriminant analysis was the
most successful in assigning species to their present botanic classifications.
These analytical methods were also used with some success in searching for
groupings within a series and within a species.
Seasonal Trends in Carbon Assimilation, Stomatal Conductance, Pre-dawn Leaf Water Potential and Growth in Terminalia ferdinandiana, a Deciduous Tree of Northern Australian Savannas
Authors: Prior L. D. , Eamus D. , Duff G. A.
Published: August 2004

Seasonal trends in pre-dawn leaf water potential and morning and afternoon
rates of light-saturated assimilation and stomatal conductance were studied in
saplings of the deciduous tree Terminalia ferdinandiana
Excell. Mean daily maximum assimilation rates ranged from 11 µmol
m-2 s-1 in the wet season to 8
µmol m-2 s-1 during the
transition from the wet to the dry season. Saplings were without leaves from
June to October inclusive (dry season). There was a log–linear
relationship between stomatal conductance and pre-dawn leaf water potential
(r = 0.76, n = 325),
and a weak linear relationship between daily maximum assimilation and pre-dawn
leaf water potential (r = 0.39,
n = 184). Assimilation rates were higher in the
morning than in the afternoon in April and May, but were similar throughout
the day from December to March. Seasonal trends in assimilation could be
attributed primarily to stomatal closure, but diurnal differences could not.
High leaf temperatures may have been responsible for observed lower
assimilation rates in the afternoon in April and May. Assimilation and
stomatal conductance decreased when leaf temperatures rose above 38˚C
and/or the leaf-to-air vapour pressure difference exceeded 4–4.5
kPa. Pre-dawn leaf water potentials decreased more quickly, and stomatal
conductance was more sensitive to this decrease, in
T. ferdinandiana saplings than in saplings of
Eucalyptus tetrodonta F.Muell. a co-occurring evergreen
tree. Specific leaf area and assimilation per unit dry weight were higher in
T. ferdinandiana than in
E. tetrodonta which is consistent with other studies of
costs and benefits of deciduousness.
Population Structure, Spatial Pattern and Seedling Establishment of the Grey Mangrove, Avicennia marina var. australasica, in New Zealand
Authors: Osunkoya O. , Creese Robert G.
Published: August 2004

Avicennia marina (Forsk.) Vierh. var.
australasica (Walp.) Moldenke occurs as monospecific
stands in the North Island of New Zealand. Using 5 m wide strip transects,
A. marina adult plants and seedlings were mapped out in
eight distinctive mangrove forests. All forests showed reversed
‘J’ size distributions of adult plants. In most cases, seedling
density increased with increasing distance from the seaward edge of the
mangrove forests. Mean plant size and density with respect to tidal position
showed no consistent pattern across forests. Plant size seemed correlated with
latitudinal gradient, with taller trees in relatively warmer regions and
shorter, stunted, dwarf-like types in colder areas. The survival and growth of
(a) naturally occurring seedlings in and out of tree-fall gaps and at various
distances from the seaward edge of the forest, and (b) transplanted seedlings
of different sizes (small, medium and large propagules: ≤ 10 cm,
10–20 cm and 21–40 cm tall, respectively) and densities (2, 5 and
9 seedlings m-2) in three delineated (low, mid and high)
intertidal positions were monitored over 18-month periods. Establishment of
both natural and transplanted seedlings varied significantly between
locations, canopy light conditions, intertidal levels and seedling sizes, but
not with density. Generally, seedling survival and growth were better in gaps
than under closed canopy, irrespective of tidal position. Intertidal level
significantly affected survival of transplanted seedlings, but did so only
marginally for the natural ones, with survival being greatest in the high
intertidal zone. By contrast, increases in plant height and leaf production
were best promoted in the low intertidal position of the forest floor.
Survival of the transplanted seedlings was of the order: large > small ≥
medium-sized. However, the small seedlings grew best both in terms of height
and accumulation of new leaves. These patterns of survival and growth were
consistent across intertidal position and seedling density. The implication of
these results for the conservation and possible restoration of mangrove
forests, especially in New Zealand, are discussed.
Effects of High Frequency Fire on Floristic Composition and Abundance in a Fire-prone Heathland near Sydney
Authors: Bradstock R. A. , Tozer M. G. , Keith D. A.
Published: August 2004

The effect of high frequency fire regimes on a coastal heathland north of
Sydney was examined. Plant community composition and species frequency and
density (of a subset of species) were compared among sites burnt by either
one, two or three fires in the period 1988-1990 inclusive. Constrained
ordination indicated that number of fires had a significant effect on
floristic composition. Site variables also had a significant effect on
floristics and frequency and accounted for a larger proportion of variation
than did number of fires. Analyses of deviance indicated that frequency in 13
species was unaffected by fire regimes or site factors. Site factors
significantly affected frequency in 42 species. Frequency in seven species was
significantly affected by fire regimes (no site effect). In six of these,
frequency was lower in areas subjected to either two or three fires compared
to one fire. Three of these species were obligate seeders. Frequency in the
other species (a herbaceous resprouter) was significantly higher in the area
subjected to two fires. There was no significant effect of fire on species
richness. Densities of seven out of a subset of eight species were also
significantly affected by fire (two obligate seeder spp.) and site factors
(four spp.), Significantly lower densities were related to multiple fires. The
study indicated that regimes of frequent fire can deplete populations of some
heathland species with the dominant shrub species,
Banksia ericifolia L.f., being most affected.
Pestalotiopsis guepinii, a Taxol-producing Endophyte of the Wollemi Pine, Wollemia nobilis
Authors: Strobel Gary A. , Hess W. M. , Li Jia-Yao , Ford Eugene , Sears Joe , Sidhu Rajinder S. , Summerell Brett
Published: August 2004

Wollemia nobilis (Wollemi pine), an araucariaceous
plant, whose closest known relatives are from the Jurassic period, occurs in
the Wollemi National Park near Sydney, Australia. This tree is host to many
endophytic fungi, including Pestalotiopsis guepinii
which produces taxol, an important anticancer drug. It was shown by
immunological, spectroscopic and chromatographic means to be identical with
authentic taxol obtained from Taxus brevifolia (Pacific
yew). Since the Wollemi pine does not produce taxol, how might a
taxol-producing fungus be present in this unusual tree? Spores of
P. guepinii possess several appendages which strongly
interact with hydrophobic surfaces including plastics and the pinnae of
birds’ feathers. Scanning electron microscopy of the conidia of
P. guepinii clearly shows the spores on the feathers of
a green-checked conure and a cockatiel. Conceivably, the fungus may have
acquired the ability to produce taxol from a foreign or local yew and then is
carried to the Wollemi pine site by native birds.
Flowering of Xanthorrhoea fulva: the Effect of Fire and Clipping
Authors: Taylor Jennifer E. , Monamy Vaughan , Fox Barry J.
Published: August 2004

Xanthorrhoea fulva (A.Lee) Bedford is a dominant plant
of wet heath at Myall Lakes National Park, New South Wales, Australia. As for
many other members of the genus, fire is the main stimulus for flowering of
X. fulva. The stimulus to flowering provided by fire and
by crown removal (clipping) of X. fulva was compared in
two different seasons and for two different between-fire intervals. The
percentage of X. fulva crowns flowering was greater
following: (i) summer disturbance when compared with winter disturbance; (ii)
short between-fire intervals (3.75 or 5.25 years) when compared with long
between-fire intervals (9.3 or 16.9 years); and (iii) burning when compared
with clipping. This demonstrates that the stimulus to floral induction in
X. fulva is a combination of a seasonal component and
crown removal, a component related to the interval since the last fire, and
perhaps some other factor(s) not tested for in this study. This variation in
flowering response of X. fulva shows the importance of
considering immediate and historic characteristics of fire and other
disturbances when management decisions are being made.
Comparative Germination Responses of 28 Temperate Grassland Species
Authors: Morgan J. W.
Published: August 2004

The comparative germination biology of 28 perennial species native to the
temperate grasslands of southern Victoria was tested using a single
temperature regime (20/10˚C) in either constant darkness or 12 h
diurnal white-light conditions. This temperature regime was chosen because it
corresponds to the temperature found to produce substantial or optimal
germination in other germination studies of grassland plants. Four germination
attributes—time to the beginning of germination (germination lag), time
taken to achieve 50% of final germination (germination speed
–t50), percentage
germination in diurnal light conditions and percentage germination in
continuous darkness—were calculated for each species and correlated to
three plant attributes: plant family, life form and seed weight. Germination
lag was short for many species: 50% had a lag of less than 7 days,
whilst 96% of species had begun germinating within 28 days. Germination
speed was moderately fast for most species: 75% of species had a
t50 of less than 28 days. Total
percentage germination in diurnal light or continuous darkness was variable
(0–98%), but many species (64%) germinated readily (>
50%) in at least one treatment. Twenty-four percent of species had
germination substantially inhibited by darkness (i.e.
Acaena echinata, Bulbine bulbosa,
Eryngium ovinum, Podolepis sp.
aff. jaceoides, Velleia paradoxa
and Wahlenbergia luteola). No species had its
germination promoted by darkness. Few correlations between plant and
germination attributes were detected. Seed weight was not correlated with any
of the three germination attributes, nor was life form or plant family
correlated with germination speed or percentage germination in the light or
dark. Germination lag, however, was significantly associated with plant family
and, in a related way, with life form: species from the Liliaceae (geophytes)
took longer to begin germination than species from the Asteraceae
(hemicryptophytes). The ecological implications of the observed germination
biology on the potential formation of persistent soil seed banks and seedling
recruitment dynamics are discussed.
Response of Vegetation on Subantarctic Macquarie Island to Reduced Rabbit Grazing
Authors: Copson Geof , Whinam Jennie
Published: August 2004

The responses of vascular plant species to a reduction in grazing pressure
were monitored as part of a rabbit-control program on Macquarie Island. The
initial response of the vegetation was more luxuriant growth with changes in
abundance recorded after 2–3 years. After 8–10 years the relative
abundance of several species had changed while species not previously recorded
had appeared on study sites and others had disappeared. Of the 32 species
recorded on study sites, 11 species
(Agrostis magellanica,
Deschampsia chapmanii,
Festuca contracta,
Juncus scheuchzerioides,
Luzula crinita,
Pleurophyllum hookeri, Poa annua,
P. foliosa, Stilbocarpa polaris
and Uncinia spp. (two species)) were found to form the
major portion of the rabbits’ diet while another four species
(Acaena magellanica,
Cerastium fontanum,
Isolepis aucklandica,
Polystichum vestitum) were moderately grazed. The other
species were either rarely grazed or occurred too infrequently to assess. Of
the 25 species that were recorded over 30 times, 17 were considered to have
benefited from the introduction of rabbits.
Estimating Clearance of Acacia-dominated Ecosystems in Central Queensland Using Land-system Mapping Data
Authors: Fensham R. J. , McCosker J. C. , Cox M. J.
Published: August 2004

Preferential clearance of productive Acacia-dominated
ecosystems was determined using digital land-system mapping and a
1994–1995 native vegetation remnant coverage from central Queensland.
The previously mapped land systems are composed of complexes of land units,
covering a range of productive potentials that are not individually mapped but
defined according to their proportions within the land systems. Some land
units were grouped into 11
‘Acacia ecosystems’ composed of unique
combinations of geology and vegetation dominated by brigalow
(Acacia harpophylla F.Muell. ex Benth.), gidgee
(A. cambagei R.T.Baker) or blackwood
(A. argyrodendron Domin). Calculation of the remnant
area of these Acacia ecosystems, assuming equal
proportions of vegetation clearance of the land unit components within the
land-system complexes (equal proportion calculation), was compared with a more
accurate calculation based on interpretation of aerial photography
(aerial-photograph calculation) data. The aerial photograph calculation of
remnant area was 44% of the equal proportion calculation for brigalow
on Tertiary clay and the ratio between these calculations was greater than
100% for only one Acacia ecosystem of relatively
low production potential. The proportion of the remnant
Acacia ecosystems relative to less productive ecosystems
on tenures assigned to production (leasehold and freehold) was consistently
lower than on other tenures. The use of mapping consisting of composite
ecosystems with various production potentials for area-based assessment of
vegetation clearance will overestimate the remnant areas of the relatively
productive types unless a procedure such as that outlined here is used to
correct for preferential clearance. This study provides near-complete and
accurate data on the 1994–1995 status of Acacia
ecosystems in central Queensland. Relative to their original area, values
ranged from 6.8% for brigalow on Tertiary clay to 37.6% for
gidgee–blackwood on alluvium.
Allozyme and Morphometric Variation in Two Closely Related Mallee Species from Western Australia, Eucalyptus argutifolia and E. obtusiflora (Myrtaceae)
Authors: Kennington W. J. , James S. H.
Published: August 2004

The Eucalyptus series Dumosae is ataxonomic group noted for its complex patterns of variation andintergradations between species. In this study, allozymes and morphometricanalysis of adult characters were used to assess the relationship between twomorphologically similar and geographically contiguous member species endemicto Western Australia, E. argutifolia Grayling & Brooker and E. obtusiflora DC. The results showed noevidence of clinal variation between the two species using either technique,and thus supported the current taxonomy. In addition, morphometric analysisrevealed two discrete groups within E. obtusiflora, andit was suggested that formal recognition of the two different forms waswarranted. Consistent with expectations based on earlier studies, all measuresof genetic variability calculated from allozyme data indicated thatpopulations of the widespread E. obtusiflora maintainmore genetic variation than the geographically restrictedE. argutifolia. Factors contributing to reducedvariation in E. argutifolia are discussed, and it wassuggested that it was primarily due to founder events. Strategies for theconservation of genetic resources of both species are also discussed in lightof the data presented.
Susceptibility of Plant Species in Coastal Dune Vegetation of South-western Australia to Killing by Armillaria luteobubalina
Authors: Shearer B. L. , Crane C. E. , Fairman R. G. , Grant M. J.
Published: August 2004

Estimates of the susceptibility of plant species of coastal dune vegetation tokilling by Armillaria luteobubalina Watling & Kilewere obtained from the occurrence of mycelial sheaths of the pathogen beneaththe bark of the root collars of dead plants in 62 disease centres.Dicotyledons (Magnoliopsida) outnumbered monocotyledons (Liliopsida), being81% of the 330 plant species found in disease centres in coastalvegetation. Fifty-one percent of the species were from five Magnoliopsidafamilies with the largest number of species from the Myrtaceae and Proteaceae.Eleven percent of the species were from three Liliopsida families with thelargest number of species from the Cyperaceae. Thirty-four percent of speciesoccurred in three or more disease centres. Thirty-eight percent, or a total of125 of all species, were killed by A. luteobubalina incoastal vegetation. Hosts on which the pathogen did not reach the root collarwould not have been detected. The largest number of species killed were fromthe Proteaceae (26% of species killed) followed by Myrtaceae,Epacridaceae, Papilionaceae and Mimosaceae. Only 6% of species killedwere from the Liliopsida. The distribution of species frequency and thosekilled by infection is positively skewed, with 40% of species notkilled in any centre and 8% killed in greater than 75% of thecentres in which they occurred. The percentage of disease centres in which aspecies occurred and was killed by A. luteobubalina issignificantly linearly correlated with mortality rating and relativeimportance. Cross-tabulation of species by disease centres in which plantswere killed provided the opportunity to classify the relative susceptibilityof plant species to killing by A. luteobubalina.
Insect Herbivory in a Eucalyptus maculata Forest on the South Coast of New South Wales
Authors: Pook E. W. , Gill A. M. , Moore P. H. R.
Published: August 2004

In most years between 1977 and 1992, insect defoliation was negligible in a
regrowth stand of E. maculata Hook. on the south coast
of New South Wales. However, leaf consumption by winter–spring
infestations of cup moth larvae accounted for c.
6%, 19% and 4% of the total leaf loss from the canopy in
1989–90, 1990–91 and 1991–92, respectively. During the most
serious infestation of 1990, cup moth larvae produced 0.56 t
ha–1 of frass, equivalent to the consumption of
c. 0.8 t ha–1, or
c. 0.5 m2
m–2 of eucalypt leaf (c.
12% of winter leaf area index). In early November 1990, shortly after
the infestation, an assessment of insect defoliation in the crown of a
dominant tree revealed that (i) 47% of the leaf population was damaged,
(ii) a larger proportion of older than younger leaves was damaged, (iii) the
proportion of damaged leaves increased down the tree-crown profile, and (iv)
13% of the potential leaf area was missing. In the absence of further
insect attack, the process of canopy renewal (leaf production and leaf fall)
reduced the proportion of damaged leaves to 23% by June 1991.
Phylogenetics and Evolution of Epacrids: a Molecular Analysis Using the Plastid Gene rbcL with a Reappraisal of the Position of Lebetanthus
Authors: Crayn D. M. , Kron K. A. , Quinn C. J. , Gadek P. A.
Published: August 2004

An expanded rbcL sequence dataset has been assembled forall capsular-fruited genera and a majority of fleshy-fruited genera inEpacridaceae sensu Powell et al.(1996), including a new accession of the South American monotypicLebetanthus Endl. Parsimony and maximum likelihoodanalyses strongly support an epacrid clade which includes bothLebetanthus and Prionotes R.Br.These two taxa are robustly grouped and placed sister to the rest of thefamily. Most of the remaining epacrids fall into several well-supportedgroups, some of which correspond to previously recognised infrafamilial taxa:the Cosmelia, Epacris,Richea and Styphelia groups.Needhamiella L.Watson andOligarrhena R.Br. form a clade that is distant from theStyphelia group, to which they have traditionally beenallied on the basis of their fleshy fruit and uniovulate locules.Archeria Hook.f., a small genus found in New Zealand andTasmania, is distant from all of these well-supported groups, including itstraditional ally, the Epacris group. Several novelgeneric relationships are evident on the rbcL tree.Epacris Cav. is paraphyletic; one of the includedspecies clusters robustly with Budawangia Telford andRupicola Maiden & E.Betche. Strong evidence is alsoadvanced for the position of Pentachondra R.Br. assister to the remainder of the Styphelia group. Beyondthis, however, relationships within the Styphelia groupare poorly supported. On the basis of these results, a new taxonomy of theepacrids, comprising seven tribes, is proposed. Six of these correspond topreviously recognised taxa; one new tribe, Archerieae, is recognised. A key tothe tribes is provided. Character evolution within the family is discussed andreinterpreted in the light of the rbcL tree.
Comparative Foliar Anatomy of South American Proteaceae
Authors: Torres Fresia
Published: August 2004

The family Proteaceae Knight is represented in South America by over 100
species that belong to eight genera, all Grevilleoideae. Nine species that
represent all of the tribes established by Johnson and Briggs (1975) that
occur in South America were studied:
Embothrium coccineum,
Lomatia dentata, L. ferruginea,
L. hirsuta, Gevuina avellana,
Roupala mollis, R. montana,
Panopsis polystachia and
Orites myrtoidea. We found anatomical and structural
similarities between these species and the taxonomic scheme proposed by
Johnson and Briggs (1975). In the Embothrieae, each species of Lomatiinae
exhibits individual structural features, although in every case, there is at
least one or more feature shared with the Embothriinae; suggesting a common
phylogenetic origin, whereas E. coccineum preserves a
larger number of ancestral features. Of the three subtribes of Macadamineae,
the Roupalinae are a natural group with individual features, the Gevuininae
share a few characters with the Lomatiinae and the Macadamiinae with the
Oriteae. This last one is the most peculiar, although it shares a few
characters with Embothrieae and Macadamieae.
Biology of Mesostoa kerri (Insecta: Hymenoptera: Braconidae: Mesostoinae), an Endemic Australian Wasp that Causes Stem Galls on Banksia marginata
Authors: Dangerfield P. C. , Austin A. D.
Published: August 2004

The biology of Mesostoa kerri Austin & Wharton, amember of the endemic Australian subfamily Mesostoinae, was investigated inthe laboratory and at the only known field site at Reedy Creek, SouthAustralia, where it causes stem galls onBanksia marginata Cav. Galls vary in shape fromspherical to elongate, with larger elongate galls appearing to inhibit distalfoliage growth. Their internal structure is characterised by a large number ofchambers occupied by wasp larvae, a melanised cambial layer, and partialdisruption and proliferation of xylem tissue. Larvae were observed to feeddirectly on the walls of their chambers. There is a direct relationshipbetween the size of galls and number of resident wasps, with the largest gallscontaining up to 300 individuals. Total wasps dissected from galls had a sexratio close to 1 : 1, although the ratio varied among galls from strongly maleto strongly female biased. Females are sluggish in behaviour and have not beenobserved to fly. They oviposit into preapical green stems and the pattern ofoviposition may determine the shape and size of the resultant gall. Male waspsemerge just prior to females and probably wait on galls for females to emergebefore mating. A number of factors, including the absence of early-stage gallsand substantial foliage growth distal to some galls inSeptember–October, indicates that M. kerri has anannual life cycle. Other gall residents occurred in 57% of sampledgalls, and included 11 species of Hymenoptera, 3 of Coleoptera and 1 ofLepidoptera. Data available for other Mesostoinae suggest thatBanksia is the exclusive host group and all species aregall formers.
Very Low Fruit : Flower Ratios in Grevillea (Proteaceae) are Independent of Breeding System
Authors: Hermanutz Luise , Innes David , Denham Andrew , Whelan Robert
Published: August 2004

Members of the family Proteaceae have extremely low mature fruit : flower (FR
: FL) ratios (range 0.001–0.163) compared with other temperate,
hermaphroditic, woody perennials. Sutherland’s (1986) survey of FR : FL
ratios indicated that compatibility was an important factor explaining levels
of fruit set. The role of compatibility in regulating FR : FL ratios was
tested in five closely related species of Grevillea
(Proteaceae). Species-specific compatibility was compared using the
self-compatibility index (SI = ratio of selfed fruit set to crossed
fruit set) calculated at fruit initiation to minimise the confounding effect
of other post-fertilisation fruit losses, such as inbreeding depression and
pre-dispersal predation. Fruit : flower ratios at initiation ranged from
0.041–0.249, and at maturity 0.015–0.096.
Grevillea species showed highly variable breeding
systems: G. linearifolia was self-incompatible (SI
= 0.003), G. sphacelata,
G. mucronulata, and G. oleoides
were partially self-compatible (SI = 0.07–0.28) and
G. longifolia was self-compatible (SI = 0.61).
Intrapopulation variability in the level of self-incompatibility was high in
all species but G. linearifolia. The correlation between
SI and FR: FL ratios was non-significant, indicating that compatibility has a
minimal effect on fruit set in the Grevillea species
studied, and that these data, together with other data on proteaceous species
do not support trends observed in Sutherland’s survey. Low FR : FL
ratios resulted from of a combination of pollen limitation, and high levels of
flower and fruit predation.
Distribution of the Soil Seedbank and Influence of Fire on Seedling Emergence in Acacia saligna Growing on the Central Coast of New South Wales
Authors: Tozer M. G.
Published: August 2004

The distribution of seed in the soil and its response to simulated fires were
examined in a population of Acacia saligna (Labill.)
H.L.Wendl. on the central coast of New South Wales (NSW). Soil seed density
was measured by excavating and sieving soil samples, and was estimated to be
1389 ± 297 seeds m–2 and 3600 ± 279
seeds m–2 at two sites within the population. Seed
density declined with depth, with 80% of the seedbank located in the
upper 6 cm of soil. The passage of fire was simulated by heating the soil
surface with a propane burner over an area of 0.25 m2
for durations of 2 or 4 min. A large percentage (88–94%) of the
seedbank remained dormant following heating. Temperatures measured in the soil
during heating showed that the 4-min treatment approximated the level of soil
heating expected during a fire in which all fine ground fuel was consumed;
therefore, the seedbank of A. saligna is unlikely to be
significantly depleted following a single fire. A frequency distribution of
the depths from which seedlings emerged was constructed using measurements of
the distance between the soil surface and the hypocotyl–radical
junction. A zone of lower than expected seedling emergence occurred from
0–2 cm, but the depth of this zone was not consistent with seed
mortality due to excessive heating. Reduced emergence from 0–2 cm may be
the result of seedling mortality due to temperature or water stress, which may
be influenced by changes in the soil structure or chemistry caused by heating.
Importance of Canopy Gaps for Recruitment of some Forbs in Themeda triandra-dominated Grasslands in South-eastern Australia
Authors: Morgan J. W.
Published: August 2004

The effect of grassland gap size on the establishment of five non-clonal
perennial forbs, comprising a range of seed masses, was investigated in two
Themeda triandra Forsskal grasslands by sowing seed in
the centre of artificially created 6 cm (36 cm2) and 18
cm (324 cm2) wide canopy gaps. Undisturbed vegetation (0
cm gap) was used as a control. Initial seedling establishment and growth in
gaps was measured over 24 weeks, as was that of transplanted juvenile plants,
and all were related to light availability at ground level. The rate at which
natural canopy gaps in grasslands disappear with time since burning was also
quantified in a chronosequence study to infer how long gaps persist after
disturbance by fire. For four of the five species, relatively few seedlings
emerged (< 30% of sown seed germinated), and emergence was largely
independent of the effects of gap size, sward structure and seed mass. Only
Plantago gaudichaudii Barneoud germination was inhibited
under a closed sward (0 cm gap). Hence, the presence of vegetation
per se largely did not affect germination for most
species. Survival of seedlings, however, was negatively affected by
vegetation, presumably because of low light levels in the small gaps.
Eryngium ovinum Cunn.,
P. gaudichaudii and
Velleia paradoxa R.Br. failed to establish in 0 cm gaps
in the 3-year-old sward. Gaps in the vegetation, however, enabled all species
to survive at low levels in at least one of the grasslands, with survival of
seedlings in 18 cm gaps usually greater than that in 6 cm gaps. Survival of
transplants was initially high (> 50%) for all species in the
2-year-old sward, but E. ovinum and
Senecio macrocarpus Belcher mortality was substantial in
0 cm gaps in the 3-year-old sward where light levels were lowest (i.e. <
9% of available light). For these species, small gaps are likely to be
hostile microsites for establishment at all times. Growth was also affected by
gap size, most species positively responding to 18 cm gaps by growing
substantially bigger than transplants in 0 cm gaps, particularly in the more
shaded 3-year-old sward gaps. The large canopy gaps (i.e. > 300
cm2) that enable the most effective recruitment in this
grassland are rare in the years after fire and constitute only
8–19% of all gaps that are present at 1 and 2 years after
burning. By 3 years after fire, canopy gaps are small (< 30
cm2) and infrequent (< 3 gaps
m–2) as a result of rapid recovery of the dominant
grass. These small gaps would appear to provide few opportunities for
substantial seedling recruitment of many species by this time. If seedling
recruitment events are to be optimised for the herbaceous dicotyledons that
characterise this community, disturbance to the canopy is required at
intervals of 1–3 years. This regime becomes particularly important when
other features of the recruitment ecology of this grassland are considered.