bluuebunny/crossref_metadata_2025 huggingface dataset:
Water relations and gas exchange of the root hemiparasite Santalum acuminatum (quandong)
Authors: Loveys Beth R. , Loveys Brian R. , Tyerman Stephen D.
Published: September 2002

The water relations and leaf gas-exchange characteristics of the root
hemiparasite quandong (Santalum acuminatum (R.Br.) A.DC)
and its neighbouring plants were examined at three field sites in central
Southern Australia. This paper examines the role of water potential and
osmotic gradients in facilitating the movement of water from host plants to
quandong. Quandong exhibited a significantly more negative water potential
than the neighbouring plant species at both field sites during summer and
winter. A significant proportion of the osmotic potential was accounted for by
mannitol, Na + , K + and
Cl - . A water potential difference of 1.7 MPa was
maintained between quandong and its putative host over a measurement period of
24 h. Xylem sap and leaves of quandong contained considerable concentration
(0.1–0.4 mol (kg tissue water) –1 ) of
mannitol. Stomatal conductance and assimilation of quandong were lower than
those of the neighbouring plants at both Middleback and Aldinga during both
summer and winter measurements. Measurements of transpiration for quandong
differed between the two sites. The lower transpirational water loss resulted
in quandong at Middleback having an instantaneous water-use efficiency higher
(0.13–2.2 µmol (CO 2 ) mmol
–1 (H 2 O)) than the
neighbouring plants. Daily sap flow and calculated hydraulic conductivity were
not significantly different between quandong and putative host plant.
Seed set in two sympatric banksias, Banksia attenuata and B. baxteri
Authors: Wooller S. J. , Wooller R. D.
Published: September 2002

Two species of banksia, studied on the south coast of Western Australia,
flowered simultaneously and had floral characteristics often associated with
vertebrate pollination. The pollen of both was carried by honeyeater birds and
small mammals (honey possums). Despite this, differential exclusion of
vertebrates and invertebrates from inflorescences indicated that
Banksia attenuata set substantial quantities of seed
when visited only by invertebrates, although seed set increased with the
addition of vertebrate visitors. Banksia baxteri set
much seed in the absence of any animal visitors and seed set increased with
invertebrate, but not vertebrate, visitation. We suggest that these
differences in pollination strategies reflect regeneration by
B. baxteri solely from canopy seeds released after fire,
whereas B. attenuata also regenerates from seeds
released between fires, as well as from lignotubers and epicormic buds.
Spectral reflectance characteristics of eucalypt foliage damaged by insects
Authors: Stone C. , Chisholm L. , Coops N.
Published: September 2002

Variables related to foliar damage, leaf morphology, spectral reflectance,
chlorophyll fluorescence and chlorophyll content were measured from leaves
sampled from mature eucalypts exhibiting symptoms of crown dieback associated
with bell miner colonisation located in Olney State Forest, near Wyong, New
South Wales. Insect-damaged mature leaves and healthy young expanding leaves
of some species exhibited a conspicuous red coloration caused by the presence
of anthocyanin pigmentation. For the mature leaves, the level of red
coloration was significantly correlated with insect herbivory and leaf
necrosis. Significant correlations were also found between the level of red
pigmentation and the following four spectral features: maximum reflectance at
the green peak (550 nm); the wavelength position and maximum slope of the red
edge (690–740 nm) and the maximum reflectance at 750 nm in the
near-infrared portion of the electromagnetic spectrum. While it has been shown
that anthocyanin pigments are synthesised in some eucalypt species in response
to certain abiotic stresses causing photoinhibition and activation of
photoprotective mechanisms, this work proposes that biotic agents such as leaf
damaging insects and fungal pathogens may induce a similar response in
eucalypt foliage resulting in increased levels of anthocyanins. The potential
of anthocyanin levels to be related to leaf ontogeny for some eucalypt species
was also illustrated in the reflectance spectra. Thus, it is essential that
leaf age be considered. This work demonstrates that the identification of a
number of key features of leaf spectra can provide a basis for the development
of a robust forest health indicator that may be obtained from airborne or
spaceborne hyperspectral sensors.
Chloroplast DNA phylogeography of Eucalyptus globulus
Authors: Freeman J. S. , Jackson H. D. , Steane D. A. , McKinnon G. E. , Dutkowski G. W. , Potts B. M. , Vaillancourt R. E.
Published: September 2002

The pattern of variability in chloroplast DNA (cpDNA) of
Eucalyptus globulus Labill. (Myrtaceae) was studied
using 270 samples from southern Australia. Forty variable sequence characters
were found, defining 105 haplotypes. Haplotypes were assigned to three major
cpDNA clades based on their phylogeny. The pattern of cpDNA variation did not
conform to subspecies boundaries; however, there was a strong geographic
structure to the distribution of clades and haplotypes. One clade
(JC) was geographically central and widespread and was
found in 163 samples from Tasmania and continental Australia. Less-common
clades occurred in more localised regions—southern
(Js, 77 samples) and eastern (Jet,
12 samples). The distribution of the J et and
Js clades coincides with hypothesised glacial refugia in
Tasmania, suggesting limited seed-mediated dispersal since deglaciation.
The influence of temperature and genotype on the growth and stomatal morphology of southern beech, Nothofagus cunninghamii (Nothofagaceae)
Authors: Hovenden Mark J.
Published: September 2002

Nothofagus cunninghamii (Hook.) Oerst. clones of five
different genotypes from Mt Field National Park, Tasmania, were grown in
controlled environment cabinets at daytime temperatures of 23 and
18°C. These temperatures approximate summer conditions in Tasmania at
sea level and at about 700 m a.s.l., respectively. There was a significant
effect of both temperature and genotype on plant height, but there was no
interaction of these terms. Temperature also had a significant influence on
plant leaf area and biomass. Plants grown at 23°C were significantly
larger and allocated more biomass to leaf tissue than did those grown at
18°C. Importantly, temperature had no impact on the size of leaves,
whether expressed as average weight per leaf or area per leaf, but these
variables were strongly affected by genotype. Specific leaf area, stomatal
density and stomatal index did not vary with either temperature or genotype.
These results have implications for our understanding of altitudinal impacts
on plant morphology and also for the interpretation of the fossil record,
since temperature has little impact on leaf characters in this species.
Metal insensitivity in ericoid mycorrhizal endophytes from Woollsia pungens (Epacridaceae)
Authors: Cairney John W. G. , van Leerdam Darryl M. , Chen David M.
Published: September 2002

The influence of Cd2+,
Cu2+ and Zn2+ on biomass
production by 13 ericoid mycorrhizal endophytes (all putative Leotiales
ascomycetes) from Woollsia pungens (Epacridaceae), along
with three isolates of Hymenoscyphus spp., was
investigated in axenic liquid culture. Inter- and intraspecific variation was
observed in effective concentration values that inhibited growth by 50%
(EC50) for each metal; however, values varied by only a
single order of magnitude for a particular metal (16.67–261.00 mmol
m–3 for Zn2+,
2.50–12.33 mmol m–3 for
Cd2+ and 3.00–43.88 mmol
m-3for Cu2+). Values of
EC50 for the endophytes from
W. pungens were thus broadly similar to those from
H. ericae. Combined metal treatments had either additive
or ameliorative effects on the toxicity of individual metals to the various
isolates. The data suggest that resistance to toxic metals is broadly similar
in ericoid mycorrhizal endophytes from Northern Hemisphere Ericaceae and
Australian Epacridaceae.
Vegetative and reproductive variation among unisexual and hermaphroditic individuals of Wurmbea dioica (Colchicaceae)
Authors: Jones Andrew , Burd Martin
Published: September 2002

Hermaphroditism may constrain the effects of sex-specific selection on life
history and reproductive traits. Wurmbea dioica in
south-eastern Australia has populations with male, female and hermaphroditic
plants, allowing an intraspecific comparison from which inferences may be made
about the nature of evolutionary specialisation for each sexual function. We
found that pistillate plants of W. dioica in a
population in central Victoria were larger than male plants, but that males
produced more and larger flowers. When comparing whole-plant means, males did
not differ from hermaphrodites in pollen investment and females did not differ
from hermaphrodites in fruit mass. However, when data for individual flowers
were analysed with a statistical control for floral size, flowers of
hermaphrodites had less investment in both pollen and fruit compared with
flowers of the corresponding unisexual plants, implying that an intra-floral
allocation trade-off occurs. Investment per flower in pollen had no apparent
trade-off with flower number per plant, while fruit investment did show a
significant relationship to flower number per plant, but the relationship was
in different directions for females and hermaphrodites. Sex-specific selection
has apparently favoured differentiation of investment strategies for males and
females, while hermaphrodites reveal some morphological compromises that must
be made to engage in both sexual functions.
Exotic plants in the soil-stored seed bank of urban bushland
Authors: King Scott A. , Buckney Rod T.
Published: September 2002

Native vegetation reserves in urban areas have been invaded by exotic plants,
particularly along edges. However, it is not known whether the seeds of exotic
plants in the soil-stored seed bank are also largely restricted to edges. Ten
urban bushland sites in northern Sydney were randomly selected and the readily
germinable, soilstored seed bank examined to assess whether the number of
exotic and native species varied with distance from an urban edge. The
similarity of the contents of the seed bank and the composition of the
above-ground vegetation was also examined. Soil samples were collected from
quadrats 0–10, 20–30 and 50–60 m from the edge at each site,
then spread on germination trays in a glasshouse and germinated seedlings
identified. Soil samples were collected every 3 months for a year. The number
of exotic species in the seed bank was found to be highest near urban edges,
as was the total number of species. The above-ground vegetation was found to
be a poor indicator of the contents of the seed bank, for both native and
exotic species. Most of the exotic species found in the seed bank were not
found in the immediately surrounding vegetation. Furthermore, some exotic
species were found in the seed bank at sites where no exotic species were
present in the vegetation. The results suggest that it is the lack of suitable
conditions that is largely restricting invasion of exotic species to edges of
bushland. The results also highlight the need for seedbank studies to assess
the contents of the soil seed bank in urban bushland in order to prevent
further invasions of exotic plants.
Floristic composition and variability of subalpine grasslands in the Mt Hotham region, north-eastern Victoria
Authors: Wearne L. J. , Morgan J. W.
Published: September 2002

Subalpine grasslands in the Mt Hotham area, Victoria, are a common feature of
cold-air drainage valleys at elevations of 1260–1660 m. Here, the
pooling of cold air prevents trees from establishing and results in a distinct
grassland community, composed of tussock grasses and a wide variety of
intertussock species. Despite their common occurrence in the region, such
grasslands have yet to be fully described. This study focused on identifying
the floristic composition of subalpine grasslands across 51 sites in the
vicinity of Mt Cope, Dinner Plain and Mt Hotham. The vegetation was sampled
from 172, 20-m2 quadrats which were analysed by
multivariate ordination techniques. Environmental variables were quantified
(i.e. soil depth, pH, aspect, slope, biomass, grazing intensity, altitude).
Analysis revealed that the grassland sites varied greatly in their composition
and richness. There was a gradual rather than abrupt change in species
composition across grassland sites, thought to be related to both the
geographic proximity of the sites and environmental factors such as geology.
The following five grassland types were identified from the entire data set
and defined primarily by the dominant species:
Poa hiemata, Poa costiniana,
Poa sieberiana, Poa labillardierei
and Themeda triandra. Vector-fitting revealed
significant correlations between the location of the quadrats in ordination
space and altitude, biomass, pH and soil depth. Both increasing altitude and
biomass were associated with the P. costiniana
grasslands and some of the P. hiemata grasslands. The
P. hiemata grasslands were widely distibuted across
altitudes and geology (i.e. basalt and metamorphic). The lower-altitude
grasslands (P. labillardierei,
P. sieberiana, T. triandra) were
associated with increasing pH and increasing soil depth. These grasslands were
of limited extent and usually occupied small areas within larger grasslands
dominated by P. hiemata or
P. costiniana. The floristic composition of the Hotham
grasslands (1260–1630 m a.s.l.), when compared with previously published
data from the higher-elevation subalpine grasslands of both the Dargo High
Plains (1450–1680 m a.s.l.) and Bogong High Plains (>1700 m a.s.l.),
showed that there was no distinct differentiation between grasslands of these
areas. However, there was a suggestion of gradual floristic change across this
geographic range. This study highlights the need for ongoing conservation of
grasslands in the Hotham area, particularly those at lower altitudes
(1260–1450 m a.s.l.), which represent the upper limits of many temperate
grassland species.
Size-specific biomass allocation and water content of above- and below-ground components of three Eucalyptus species in a northern Australian savanna
Authors: Werner Patricia A. , Murphy Peter G.
Published: September 2002

The biomass of component parts of individuals of three dominant canopy tree
species in the northern savannas of Australia was determined from field
populations in World Heritage Kakadu National Park. Forty individual trees of
Eucalyptus tetrodonta F. Muell.,
E. miniata Cunn. ex Schauer and
E. papuana F.Muell., representing a range in size from 4
to 50 cm diameter at breast height (DBH), were felled for dry biomass of
leaves, branches, woody stems and bark. Forty-seven other trees of
E. tetrodonta and E. miniata were
excavated for belowground biomass, by using trenching methods. The average
proportion of aboveground biomass in foliage was 3–5%, to
branches 20–32%, and trunk wood 77–59%, with little
change over the size of a tree. Water content of foliage decreased with size
of tree in all species, indicating an increasing xeromorphy as the trees age.
Gross morphology of roots was bimorphic, with 70% of biomass at
<20-cm soil depth, and large roots running horizontally on top of the
shallow (0.3–1.4 m) ferricrete layer. There was no evidence of roots
having access to water below this layer. Patterns of heights, percentage
biomass allocation, percentage water content, and bark thickness of the three
species were consistent with the rank order of their distributions across a
topographic gradient, reflecting relative capacities to withstand drought,
belowground competition and fire. By using tree diameter as the independent
variable (x in cm DBH), allometric relationships were
calculated to provide a method for calculating growth and productivity by
using non-destructive repeat measures of sizes of trees. The total aboveground
biomass (y in kg) of individual trees is
y =
0.2068x2.3191 for
E. tetrodonta, y =
0.1527x2.390 for
E. miniata and y =
0.0356x2.8567 for
E. papuana. Total belowground biomass per tree for
E. tetrodonta is y =
31.150e0.0601x and for E. miniata,
y = 28.753e0.0644x. As a
tree grows, the aboveground biomass increases as a power function and
belowground biomass as an exponential function of DBH, producing a decreasing
proportion of total biomass below ground, e.g. the root/shoot ratio of
E. tetrodonta is 0.50 for trees <10 cm DBH, 0.40 for
trees 20 cm DBH, and 0.25 for trees 40–55 cm DBH. The overall proportion
of total biomass below ground in Kakadu is well below 50%, contrary to
the commonly accepted notion that the majority of biomass in savannas is below
ground.
Regeneration of Wet Forest flora a decade after clear-felling or wildfire - is there a difference?
Authors: Ough Keely
Published: September 2002

There is increasing recognition of the importance of ecologically sustainable
forest management, including forest biodiversity conservation. Knowledge of
the effects of forest practices on flora values can be gained by comparing the
floristics of natural and harvested forest stands at the same stage of
development. This paper presents the results from a comparative study of
natural and managed forest regeneration in
Eucalyptus regnans F.Muell dominated forests in the
Victorian Central Highlands. The vascular floristics about a decade after
clear-fell harvesting operations differed significantly from the floristics of
similarly aged forest regenerating after wildfire. In clear-felled areas, weed
and sedge species occurred more frequently than on wildfire sites and
Acacia dealbata Link was much more abundant, whereas
resprouting shrubs, tree ferns and most ground-fern species were more abundant
in wildfire regeneration. The low survival rate of resprouting species
reported in an increasing number of studies suggests that soil disturbance is
likely to be a major contributor to differences.
The floristics of sites burned by intense wildfire differed significantly from
those subjected to less intense wildfire, indicating that considerable
variation in floristics can occur under a natural disturbance regime. The
failure of the clear-fell regeneration to fit within this broad natural
variability suggests that clear-fell harvesting alters the natural
regeneration processes. As species composition in these forests is largely
determined by the initial floristic composition after disturbance, this paper
provides evidence that some clear-felled regrowth forests may remain different
in structure and composition to forests regenerating after natural
disturbances.
Somatic embryogenesis in Arachis hypogaea: revisited
Authors: Radhakrishnan T. , Murthy T. G. K. , Chandran K. , Bandyopadhyay A.
Published: September 2002

Direct somatic embryogenesis is an efficient method of plant regeneration,
allowing rapid multiplication of plants in a short period. Six experiments
were conducted to study the influence of auxin level on somatic embryogenesis
and to optimise the concentration of auxins. Immature embryo axis was the
ideal explant and 20–40 mg L–1 of
2,4-dichlorophenoxyacetic acid was the best concentration range for obtaining
the maximum number of free somatic embryos. Significant differences were
observed between the genotypes for induction and the number of somatic embryos
per explant. The cv. Girnar 1 produced the maximum number of somatic embryos
per explant, the number of secondary somatic embryos ranging from 1.5 to 9.4.
The overall germination of somatic embryos was 42.8%, and 65% of
the plantlets transferred to the field survived. The development of somatic
embryos was from the apical region of the embryo axes without undergoing
dedifferentiation. The initial cell divided to form a tier of four cells and
subsequent anticlinal and periclinal division resulted in the development of
globular somatic embryos with small suspensors, followed by heart-shaped,
torpedo-shaped and ‘cotyledonary’ stages.
A Preparative and Solution Study of a Modified b-Cyclodextrin and its Europium(III) Complex, and their Interactions with Racemic Amino Acid Anions
Authors: Kean Suzanna D. , Easton Christopher J. , Lincoln Stephen F. , Parker David
Published: September 2002

The synthesis and characterization of
6A-deoxy-6A-(1,4,7-tri(carboxylatomethyl)-1,4,7,10-tetraazacyclododecan-10-yl)-β-cyclodextrin
(1b) are reported. A fluorescence lifetime study of its
Eu3+ complex (1c) is consistent with one water
coordinating Eu3+ in addition to hepta-coordination
by (1b). 1H NMR studies are consistent with (1b) forming
host–guest complexes with (R/S)-histidinate
(2a), (R/S)-tyrosinate (2b),
(R/S)-phenylalaninate (2c), and
(R/S)-tryptophanate (2d), with enantioselectivity
shown for (2b). Similar studies are consistent with (1c) complexing
(2a–d), with enantioselectivity shown for (2a).
Reduced Benzimidazo[2,1-a]isoquinolines. Synthesis and Cytotoxicity Studies
Authors: Deady Leslie W. , Rodemann Thomas
Published: September 2002

6-Butyl-5,6-dihydrobenzimidazo[2,1-a]isoquinoline,
3,9- and 3,10-dimethoxy, and 3,9- and 3,10-dihydroxy analogues, and their
12-methyl quaternary salts were prepared by a multistep route. Cytotoxicities
against 55 human cancer cell lines were measured in the National Cancer
Institute screen. The quaternary salts of the dimethoxy compounds (15b/c)
were clearly the most active overall, with a mean graph midpoint (MGM) value
of 2 m.
Review: Deformation and Adhesion of Viscoelastic Particles: Theory and Experiment
Authors: Attard Phil , Gillies Graeme
Published: September 2002

A summary is given of the authors’ recent research on viscoelastic
theory and its application to colloid probe atomic force microscopy. A general
computational approach for the interaction of viscoelastic colloids
interacting with realistic surface forces of extended range is outlined, and
the origins of velocity- and time-dependent effects including hysteresis are
discussed. A general method for establishing the zero of separation in atomic
force microscopy of deformable bodies is described and utilized in force
measurements made on viscoelastic poly(dimethylsiloxane) colloid particles. A
quantitative analysis of the velocity and load dependence of the hysteresis in
the measurements yields the viscoelastic parameters of the colloid.
Creation of 3-D Crystals from Single Cobalt Nanoparticles in External Magnetic Fields
Authors: Hilgendorff Michael , Tesche Bernd , Giersig Michael
Published: September 2002

Using monodisperse nanocrystalline cobalt (Co) particles in non-polar
colloidal dispersions, large areas of symmetric multi-dimensional structures
were created using magnetophoretic deposition (MPD). To overcome the van der
Waals and magnetic dipole–dipole interactions, the particles were
stabilized with hydrophobic amines, phosphines, carboxylates and/or
polymers. Depending on the preparation parameters, our particles had either
bcc or ε-Co crystalline structures. Using MPD with magnetic fields up to
1 T, it was possible to create two-dimensional (2-D) arrays of near-perfect
symmetry up to 1 m2 in size on various substrates, e.g.
carbon-coated copper grids, silicon, or glass. Growth of the 2-D crystal was
shown to be dependent on the direction of the applied external magnetic field.
Three-dimensional (3-D) crystals could be created by increasing the magnetic
field strength up to 6 T.
Electroacoustic Study of n-Hexadecane/Water Emulsions
Authors: Kong Linggen , Beattie James K. , Hunter Robert J.
Published: September 2002

n-Hexadecane-in-water emulsions were investigated by
electroacoustics using a prototype of an AcoustoSizer-II apparatus. The
emulsions were formed by passing the stirred oil/water mixture through a
homogenizer in the presence of sodium dodecyl sulfate (SDS) at natural pH
(6–7). With increasing oil-volume fraction, the particle size increased
linearly after 5 and also after 20 passages through the homogenizer,
suggesting that surface energy was determining particle size. For systems in
which the surfactant concentration was limited, the particle size after 20
passages approached the value dictated by the SDS concentration. With ample
surfactant present, the median diameter was a linear function of the inverse
of the total energy input as measured by the number of passes. There was,
however, a limit to the amount of size reduction that could be achieved in the
homogenizer, and the minimum size was smaller at smaller volume fractions.
Dilution of the emulsion with a surfactant solution of the same composition as
the water phase had a negligible effect on the particle size and changed the
zeta potential only slightly. This confirms results from previous work and
validates the equations used to determine the particle size and zeta potential
in concentrated suspensions.
The minimum concentration of SDS that could prevent the emulsion from
coalescing for the system with 6% by volume oil was 3 mM. For this
dilute emulsion, the particle size decreased regularly with an increase in SDS
concentration, but the magnitude of the zeta potential went through a strong
maximum at intermediate surfactant concentrations.
The nutritive value of frosted wheat for sheep
Authors: Richardson E. C. , Kaiser A. G. , Piltz J. W.
Published: September 2002

The effect of frosting on the nutritive value of wheat grain was determined in
a digestibility experiment with sheep. Thirty-six Merino wethers were
maintained on diets of lucerne chaff (30%) and whole wheat grain
(70%) which was sourced from either severely frosted (SF), lightly
frosted (LF) or unfrosted (UF) crops. The experiment was conducted in a
repeated balance study with 8 replications per treatment diet for each of the
7 treatment diets, new animals were assigned to the chaff control (treatment
diet 8). The diets were offered at the liveweight maintenance level of feeding
and the digestibility of the wheat component was calculated by adjusting for
the digestibility of the lucerne component. Frosting had a relatively small
effect on the nutritive value of wheat grain for sheep. Dry matter
digestibility for UF, LF and SF wheats did not differ significantly (0.886,
0.854 and 0.839, respectively), although the SF wheat had a lower
digestibility than the UF wheat at P<0.10. The
organic matter digestibility, digestible organic matter in the dry matter and
estimated metabolisable energy (ME) content were all significantly
(P<0.05) lower for SF compared with UF wheat grain
(0.856 v. 0.908, 0.859 v. 0.915
and 13.5 v. 14.3 MJ/kg DM respectively). This study
demonstrated that wheat from the severely frosted wheat crop had a lower
estimated ME content of about 1 MJ/kg DM (equivalent to about 6%
less ME) than wheat from the unfrosted crop fed in this study. However, the
resultant ME of all samples fed fell within the normal observed ME range for
wheat.
Relationship between objective measurements and taste panel assessment of beef quality
Authors: Perry D. , Thompson J. M. , Hwang I. H. , Butchers A. , Egan A. F.
Published: September 2002

The relationship between objective measurements (shear force, compression,
drip loss, cooking loss) and sensory evaluation of tenderness and juiciness of
samples of M. longissimus thoracis et lumborum was
examined using data from 2 experiments which imposed different electrical
stimulation and aging treatments post mortem, with resultant differences in
sensory and objective measures of tenderness. The relationships were tested
first in separate models for each objective measurement, and then in multiple
regressions containing all measurements. These models were then repeated with
the inclusion of stimulation and aging treatments and their interactions with
each objective measurement. Shear force by itself was a useful predictor of
sensory tenderness score, with which it had a quadratic relationship.
Compression and cooking loss, when used by themselves, accounted for
substantially less variation in sensory tenderness scores than did shear
force, with larger residual standard deviations (r.s.d.). Drip loss had no
significant relationship with sensory tenderness scores. Inclusion of
post-slaughter treatment in the analyses increased the amount of variation in
sensory tenderness scores accounted for by only a small amount in the case of
shear force, with a substantial increase in the case of compression and
cooking loss. Use of all objective measurements in the 1 model had a similar
predictive ability (r2 , r.s.d.)
as the use of shear force plus treatment variables. Aging affected the sensory
tenderness scores given by taste panellists, in that they gave 14-day aged
meat higher tenderness scores (more tender) than they gave 1-day aged meat
with the same shear force, compression or cooking loss values. Electrical
stimulation did not affect the relationship between sensory tenderness scores
and shear force, but did affect that between sensory scores and compression.
The effect was similar to that seen for aged meat, with stimulated meat being
scored as more tender by a taste panel than non-stimulated meat, at the same
compression values. Post-slaughter treatment did not affect the slope of these
relationships. When all objective measurements were analysed together, aging
period affected the relationship between tenderness scores and objective
measures, with tenderness scores being lower in 1-day aged samples than 14-day
aged samples at the same combination of objective measures. There was only a
poor relationship between shear force, compression, drip loss, cooking loss
and sensory juiciness scores.
Meat quality and the calpain system of feedlot steers following a single generation of divergent selection for residual feed intake
Authors: McDonagh M. B. , Herd R. M. , Richardson E. C. , Oddy V. H. , Archer J. A. , Arthur P. F.
Published: September 2002

Residual feed intake (RFI) is calculated as the difference between an
animal’s actual feed intake and its expected feed intake based on its
size and growth over a specified test period. Following a single generation of
divergent selection for postweaning RFI, Angus steers and Angus ×
Hereford, Angus×Poll Hereford and Angus × Shorthorn
crossbred steers born in 1996 and 1997 were fed in a feedlot. Cohorts of
steers were slaughtered at the same age and had attained similar
(P>0.05) final liveweights: 467 kg for steers
selected for low RFI (high efficiency; HE, n
= 91) and 459 kg for steers selected for high RFI (low efficiency;
LE, n = 98). The HE and LE steers had similar
(P>0.05) carcass weight (247 and 244 kg),
dressing percentage (53.1 and 53.2%) and eye-muscle area (58.9 and
60.3 cm 2 ). The HE steers had slightly less
subcutaneous fat over the rib than the LE steers (9.2 v.
10.1 mm, P<0.05), and there was a trend towards
less fat over the rump of HE steers (11.5 v. 12.1 mm,
P = 0.10). For meat samples taken from the
M. longissimus dorsi (LD) there were no differences
(P>0.05) between the HE and LE steers in content
of intramuscular fat (5.4 and 5.3% fresh weight), marbling scores, meat
colour and fat colour. There were also no differences
(P>0.05) between HE and LE steers in shear force
and compression values for samples of LD aged for 1 day (4.6 and 4.6 kg shear
force, 1.45 and 1.44 kg compression), or for 14 days (3.8 and 3.5 kg, 1.36 and
1.32 kg). Myofibril fragmentation index (MFI) measures the breakdown of these
structural elements which occurs as an initial step in the process of protein
degradation and meat tenderisation. MFI was lower (i.e. less fragmentation;
P<0.05) in LD samples from HE steers than from LE
steers, both in samples aged for 1 day (67.7 v. 72.5
units) and in samples aged for 14 days (87.8 v. 91.1
units). The rate of decline in MFI between 1 and 14 days post slaughter was
similar in the LD samples from both lines of steers. There were no differences
(P>0.05) between HE and LE steers in the activity
of m-calpain and µ-calpain in LD immediately after slaughter (HE
steers: 1.9 and 2.3 units, LE steers: 1.8 and 2.1 units). The level of
calpastatin in LD from the HE steers was 13% higher than in the LD from
the LE steers (5.2 and 4.6 units respectively,
P<0.05). Rate of myofibril fragmentation was
positively correlated (P<0.01) with the ratios of
both m-calpain and µ-calpain to calpastatin, but not
(P>0.10) with levels of either calpain or
calpastatin. A single generation of divergent selection for RFI produced
differences in calpastatin and myofibril fragmentation that may, with on-going
selection for low RFI, negatively affect meat tenderness.
Genetic variances for liveweight and fleece traits in Merino, Dohne Merino and South African Meat Merino sheep
Authors: Cloete S. W. P. , Schoeman S. J. , Coetzee J. , Morris J. de V.
Published: September 2002

(Co)variance estimates for weaning weight, yearling liveweight, clean fleece
weight and fibre diameter at yearling age were obtained for Merino, Dohne
Merino and South African Meat Merino flocks maintained on the same property.
Direct additive genetic variances for weaning weight [expressed as a
ratio of the total phenotypic variance
(h2, direct heritability)]
were estimated at 0.15 for Merinos, 0.21 for Dohne Merinos and 0.32 for South
African Meat Merinos. Corresponding maternal variance ratios
(m2, including direct maternal
variance and permanent environmental maternal variance) were estimated at
0.15, 0.30 and 0.24, respectively. The correlation between direct and maternal
variance ratios was high and negative in Dohne Merinos and South African Meat
Merinos (–0.72 and –0.53, respectively). Direct heritability
estimates for yearling liveweight were 0.30 for Merinos, 0.33 for Dohne
Merinos and 0.45 for South African Meat Merinos. Corresponding maternal
variance ratios were only significant in the latter 2 breeds, amounting to
0.13 in Dohne Merinos and 0.12 in South African Meat Merinos. For yearling
clean fleece weight, h2 and
m2 were estimated at 0.28 and
0.12, respectively, for both Merinos and Dohne Merinos. In the case of South
African Meat Merinos, only the h2
estimate was significant, at 0.68. Maternal variance ratios for yearling fibre
diameter were not significant in any of the breeds, while
h2 ranged from 0.58 in Merinos to
0.75 in South African Meat Merinos. Selection progress for yearling traits
seems likely in all breeds, depending on the breeding objectives being strived
for.
Net nitrogen balances for cool-season grain legume crops and contributions to wheat nitrogen uptake: a review
Authors: Evans J. , McNeill A. M. , Unkovich M. J. , Fettell N. A. , Heenan D. P.
Published: September 2002

The removal of nitrogen (N) in grain cereal and canola crops in Australia
exceeds 0.3 million t N/year and is increasing with improvements in
average crop yields. Although N fertiliser applications to cereals are also
rising, N2-fixing legumes still play a pivotal role
through inputs of biologically fixed N in crop and pasture systems. This
review collates Australian data on the effects of grain legume
N2 fixation, the net N balance of legume cropping,
summarises trends in the soil N balance in grain legume–cereal
rotations, and evaluates the direct contribution of grain legume stubble and
root N to wheat production in southern Australia.
The net effect of grain legume N2 fixation on the soil N
balance, i.e. the difference between fixed N and N harvested in legume grain
(Nadd) ranges widely, viz. lupin
–29–247 kg N/ha (mean 80), pea –46–181 kg N/ha
(mean 40), chickpea –67–102 kg N/ha (mean 6), and faba bean
8–271 kg N/ha (mean 113). Nadd is found to be
related to the amount (Nfix) and proportion
(Pfix) of crop N derived from N2
fixation, but not to legume grain yield (GY). When Nfix
exceeded 30 (lupin), 39 (pea) and 49 (chickpea) kg N/ha the N balance was
frequently positive, averaging 0.60 kg N/kg of N fixed. Since
Nfix increased with shoot dry matter (SDM) (21 kg N
fixed/t SDM; pea and lupin) and Pfix (pea, lupin and
chickpea), increases in SDM and Pfix usually increased
the legume’s effect on soil N balance.
Additive effects of SDM, Pfix and GY explained most
(R2 = 0.87) of the
variation in Nadd. Using crop-specific models based on
these parameters the average effects of grain legumes on soil N balance across
Australia were estimated to be 88 (lupin), 44 (pea) and 18 (chickpea) kg
N/ha. Values of Nadd for the combined legumes were
47 kg N/ha in south-eastern Australia and 90 kg N/ha in south-western
Australia. The average net N input from lupin crops was estimated to increase
from 61 to 79 kg N/ha as annual rainfall rose from 445 to 627 mm across 3
shires in the south-east. The comparative average input from pea was 37 to 47
kg N/ha with least input in the higher rainfall shires. When the effects
of legumes on soil N balance in south-eastern Australia were compared with
average amounts of N removed in wheat grain, pea–wheat (1:1) sequences
were considered less sustainable for N than lupin–wheat (1:1) sequences,
while in south-western Australia the latter were considered sustainable.
Nitrogen mineralised from lupin residues was estimated to contribute
40% of the N in the average grain yield of a following wheat crop, and
that from pea residues, 15–30%; respectively, about 25 and 15 kg
N/ha. Therefore, it was concluded that the majority of wheat N must be
obtained from pre-existing soil sources. As the amounts above represented only
25–35% of the total N added to soil by grain legumes, the
residual amount of N in legume residues is likely to be important in
sustaining those pre-existing soil sources of N.
Pasture management in semi-arid tropical woodlands: regeneration of degraded pastures protected from grazing
Authors: McIvor J. G.
Published: September 2002

Regeneration of native and oversown pastures following exclusion of grazing
was studied over 3 years on a fertile soil at Hillgrove, near Charters Towers,
north-east Queensland. The pastures covered a wide range of initial conditions
reflecting the grazing pressures they had been exposed to during 2 dry years
before enclosure. Pasture measurements made before the exclusion of grazing
(yield, botanical composition, basal area, ground cover, height, soil seed
banks) were related by regression analysis to subsequent changes in site
condition described by a site condition value, calculated from herbage yields
and botanical composition, to determine suitable predictors of regeneration
during resting from grazing.
The pastures recovered (increases in soil cover, grass basal area and the
proportion of desirable species) under the generally favourable growing
conditions during the period of enclosure although some plots, initially in
poor condition, had not recovered after 3 years. There were only minor
differences between the native and oversown pasture types in their recovery.
Relative yields and site condition values were not affected by pasture type
and botanical composition index values differed with pasture type in 1989
only.
The site condition values of both pasture types after the first year of
enclosure were closely and positively related to all the pasture
characteristics measured the previous year except for soil seed numbers in the
native pastures. All characteristics could be used to predict site condition
value and potential of the pasture to regenerate, and their merits are
discussed. The proportion of desirable species in the pasture combined with
level of ground cover is suggested as a useful means of predicting
regeneration and potential for future grazing.
The yield, quality and irrigation response of summer forage crops suitable for a dairy pasture renovation program in north-western Tasmania
Authors: Eckard R. J. , Salardini A. A. , Hannah M. , Franks D. R.
Published: September 2002

The yield and quality of perennial ryegrass, short-rotation
ryegrass–perennial ryegrass mix, oats, millet, maize, rape, kale, pasja
and turnips were determined over a 13-week summer period in 1995–96 and
1996–97. The experiment was conducted on the Elliott Research Station in
north-western Tasmania (145˚E, 41˚S) and consisted of 2 irrigated
and 2 dryland main plots. Within each main plot was a randomised complete
block design with 9 forage crop subplots.
Where forage is required through the summer, there is little advantage in
establishing millet or oats over a spring-sown ryegrass pasture, mainly as the
former still require replacement with permanent pasture in the autumn.
However, if additional forage is required from late January then turnips are
clearly superior to the other forages evaluated in all respects, apart from a
low bulb crude protein (CP) content. Turnips responded significantly to
irrigation, producing between 15 and 22 kg DM/ha.mm irrigation applied,
with yields ranging between 7.9 and 10.6 t DM/ha dryland and between 13.5
and 14.4 t DM/ha under irrigation. The metabolisable energy (ME) and CP
contents of turnips were 12.5 MJ/kg DM and 12.4% in the shoots and
13.4 MJ/kg DM and 7.0% in the bulbs, respectively. In comparison,
the other fodder crops tested yielded between 4 and 6 t DM/ha under
dryland conditions and between 5 and 7 t DM/ha under irrigated conditions.
Turnips were most economic, costing on average A$120/t DM irrigated
and $160/t DM dryland, while spring renovation to perennial
ryegrass cost $385/t DM irrigated and $344/t DM dryland;
clearly more expensive than purchased feeds for this period. These findings
confirm the choice of many farmers that, of the species examined, turnips are
the most suitable as a summer fodder crop, both irrigated or dryland, and
integrate well with a pasture renovation rotation.
Salt tolerance of cowpea genotypes in the emergence stage
Authors: Murillo-Amador B. , Troyo-Diéguez E. , López-Cortés A. , Jones H. G. , Ayala-Chairez F. , Tinoco-Ojanguren C. L.
Published: September 2002

The effect of NaCl salinity (0, 85 and 170 mmol/L) during emergence of 25
genotypes of cowpea [Vigna unguiculata (L.)
Walp.] was studied under growth chamber conditions. Seed emergence
percentage and rate, root:shoot ratio, and biomass per plant were affected by
genotype, salinity and genotype salinity interaction; this interaction showed
that salinity effects differed among genotypes. The criterion used to classify
genotypes with respect to their salt tolerance was based on their germination
percentages in both 85 and 170 mmol NaCl/L. One genotype was grouped into
class ‘A’ (CB27) which had the highest salt tolerance at
emergence, and was classified as salt tolerant. Another group consisting of
Paceño, CB88, CB3, CB5, Tardón, Cuarenteño and CB46 was
placed into class ‘B’; these genotypes showed total emergence
percentages up to 75% in both 85 and 170 mmol NaCl/L. A third group
of genotypes was placed into class ‘C’ which had the lowest
emergence percentages in both 85 and 170 mmol NaCl/L. It was confirmed
that salinity treatments affect the emergence of cowpea, delaying both
emergence percentage and rate. We conclude that selection and classification
for salt tolerance in cowpea genotypes can be successfully undertaken at early
seedling stages, because the same genotypes were classified similarly during
the germination stage in previous research.
CRC breeding program design, measurements and database: methods that underpin CRC research results
Authors: Upton W. , Burrow H. M. , Dundon A. , Robinson D. L. , Farrell E. B.
Published: September 2002

The Cooperative Research Centre (CRC) for the Cattle and Beef Industry (Meat
Quality) developed an integrated research program to address the major
production and processing factors affecting beef quality. Underpinning the
integrated program were 2 large-scale progeny testing programs that were used
to develop genetic, nutritional, management and beef processing technologies
to overcome deficiencies in beef quality. This paper describes the
experimental design, generation of experimental cattle and the collection and
storage of data derived from these straightbreeding and crossbreeding progeny
testing programs.
Prevalence of blackleg (Leptosphaeria maculans) on canola (Brassica napus) in Western Australia
Authors: Khangura R. K. , Barbetti M. J.
Published: September 2002

Canola crops were monitored throughout the Western Australian wheatbelt during
1996–99 to determine the incidence and severity of crown cankers caused
by the blackleg fungus (Leptosphaeria maculans). All
crops surveyed had blackleg. The incidence of crown canker was
48–100%, 15–100%, 9–94% and
48–100% during 1996, 1997, 1998 and 1999, respectively. The mean
incidence of crown cankers statewide was 85, 63, 55 and 85% in 1996,
1997, 1998 and 1999, respectively. The severity of crown canker (expressed as
percentage disease index) ranged between 30 and 96%, 3 and 94%,
5 and 78% and 21 and 96% during 1996, 1997, 1998 and 1999,
respectively. These high levels of blackleg can possibly be attributed to the
accumulation of large amounts of infested canola residues. In 1999, there were
effects of variety, application of the fungicide Impact, distance to last
year’s canola residues and rainfall on the incidence and severity of
blackleg. However, there were no effects of sowing date or region on the
disease incidence or severity once the other factor effects listed above had
been considered. In 1995, an additional survey of 19 sites in the central
wheatbelt of Western Australia assessed the survival of the blackleg fungus on
residues from crops grown in 1992–94. The residues at all sites carried
blackleg. However, the extent of infection at any particular site varied from
12 to 100% of stems with the percentage of stems carrying pseudothecia
containing ascospores varying between 7 and 96%. The high levels of
blackleg disease found in commercial crops are indicative of significant
losses in seed yields, making it imperative that management of blackleg be
improved if canola is to remain a viable long-term cropping option in Western
Australia.
Alternatives to polyethylene mulch film — a field assessment of transported materials in capsicum (Capsicum annuum L.)
Authors: Olsen J. K. , Gounder R. K.
Published: September 2002

Materials used as mulches may be either transported to the farm then laid on
the soil surface or grown in situ. To assess
biodegradable alternatives to non-degradable polyethylene film, the response
of capsicum (Capsicum annuum L. cv. Target) grown in
soil beds covered with hessian (burlap), hardwood sawdust, sugarcane
(Saccharum spp.) trash, paper film, black biodegradable
polymer film, white polyethylene film, or left uncovered was investigated in a
field trial during the autumn–winter growing season in subtropical
Australia. Use of a split-plot design (mulch whole plots with weeded or
unweeded subplots) permitted both weed growth and the effect of weed
competition on fruit yield to be measured. The presence of substances within
the materials that were possibly detrimental to plant growth was assessed in a
separate experiment. The weight of marketable fruit was highest for capsicum
plants grown in the weeded subplots of biodegradable polymer and polyethylene,
although the yields from these subplots were not different from those for
plants grown in the weeded subplots of the paper and sawdust or the unweeded
subplots of the biodegradable polymer and paper. The reduction in weight of
marketable capsicum fruit from weed competition was ranked for the various
mulch treatments as follows: paper < biodegradable polymer < cane trash
< polyethylene < hessian < sawdust < bare soil. More hours at
optimum soil temperature for root growth (18.9–30˚C) before canopy
closure probably accounted for the variation in marketable yield of the
capsicum crop. Results from the mulch toxicity experiment indicated that the
mulch materials were unlikely to contain phytotoxic substances. Provided the
practical difficulties of laying paper film can be overcome and the high cost
of biodegradable polymer is reduced, these materials appear to be the best of
the biodegradable alternatives tested to polyethylene film.