bluuebunny/crossref_metadata_2025 huggingface dataset:
Low- and High-temperature Storage Effects on Viability and Germinability of Seeds of Three Australian Asteraceae
Authors: Peishi Zalynn , Plummer Julie A. , Bell David T. , Turner David W. , Choengsaat D.
Published: September 2002

Commercialisation of many Australian everlasting daisy (Asteraceae) species islimited by poor germination, due in part to dormancy. This study examined theeffect of storage temperatures of 5, 15, 25 and 38°C on seed viability andgerminability of Schoenia filifolia subsp.subulifolia, Rhodanthe chlorocephala subsp.rosea and an unnamed species ofCraspedia. Short-term storage (< 18 months) at cooltemperatures increased seed moisture content, reduced viability and did notpromote germination. However, storage at high temperatures decreased seedmoisture content, maintained viability and improved germination. In tests oflong-term (> 24 months) storage in ambient conditions, both viability andgerminability declined in cohorts of Schoenia andRhodanthe. Detailed tests on 8-month-old seeds ofSchoenia revealed that dormancy was not due tomechanical barriers, as scarification did not improve germination. However,gibberellic acid (GA3) and KNO3applications overcame the dry-storage requirement to break dormancy in thisspecies. High-temperature, dry storage is an important treatment to breakdormancy for planting arid-zone Asteraceae seeds of less than 6 months of age.
Alpine and Subalpine Wetland Vegetation on the Bogong High Plains, South-eastern Australia
Authors: Wahren C.-H. , Williams R. J. , Papst W. A.
Published: September 2002

The botanical composition and structure of wetland vegetation from seven sites
in the alpine and subalpine tracts of the Bogong High Plains was sampled in
1995 and 1996. Sites were in the vicinity of Mts Nelse, Cope and Fainter.
Sampling was based on contiguous 1-m2 quadrats along
transects 20−70 m long across each wetland. Samples were ordinated using
non-metric multidimensional scaling (NMDS). Floristic variation was assessed
both within selected individual wetlands, and between wetlands from different
regions. The relationship between the ordinations and environmental variables
such as soil surface texture, soil depth and the amount of bare ground was
tested by fitting vectors. Three dominant vegetation assemblages were
identified. Closed heath, of hygrophyllous, scleromorphic shrubs such as
Richea continentis and
Baeckea gunniana, the rush
Empodisma minus and the moss
Sphagnum cristatum occurred on the deeper peats. Low
open heath of Epacris glacialis and
Danthonia nivicola occurred on shallow peats. Herbfields
of Caltha introloba and
Oreobolus pumilio occurred on stony pavements in two
different physiographic situations―on relatively steep slopes
(10−20°) at the head of wetlands, and on flat ground (slope <
2°), below the head of wetlands. The pavements on the steeper sites
appeared to be associated with periglacial features such as solifluction lobes
and terraces. Those on the flatter ground appeared to have been derived more
recently. Wetlands in the Mt Cope region consisted of closed heath, low open
heath and pavement herbfield in various proportions. Wetlands on Mt Fainter,
which are subject to heavy trampling by cattle, were in a degraded condition,
with a low cover of major hygrophyllous mosses and shrubs, and a high cover of
introduced species. Long-ungrazed wetlands in a 50-year exclosure at Rocky
Valley had high cover of closed heath, no pavements, numerous ponds and
virtually no entrenched drainage channels or exposed peat. The
Caltha herbfields are significant features nationally,
both floristically and geomorphologically. Alpine and subalpine wetlands have
been listed under the Victorian Flora and
Fauna Guarantee Act 1988, and continued grazing by
cattle is not compatible with the conservation objectives for this alpine
vegetation type.
Establishment of Fine Suspension Cultures of Triticum tauschii ([Coss.] Schmal.) which remain Embryogenic for Several Years
Authors: Afshar-Sterle Shoukat , Kollmorgen James F. , Fincher Geoffrey B.
Published: September 2002

Immature embryos of 10 accessions of Triticum tauschii,
the D genome donor of Triticum aestivum, were used to
produce embryogenic callus for the initiation of suspension cultures. For the
long-term maintenance of embryogenicity of these suspensions, it was necessary
to use different media for the initiation, establishment and maintenance
phases. The initiation phase required media supplemented with L-proline,
L-asparagine and L-glutamine, together with Dicamba at 12 mg L
−1 and maltose. In the establishment phase, it was
essential to reduce the concentration of Dicamba to 6 mg L
−1 for the rapid production of fine suspension
cultures. Finally, the long-term maintenance of a capacity for regeneration
depended on the inclusion of 1.1 mg L −1
2,4-dichlorophenoxyacetic acid and 30 g L −1
sucrose in the medium. By the use of these procedures, long-term embryogenic
fine suspension cultures were established from two accessions, while
non-embryogenic fine suspension cultures were produced from five accessions.
Over 90% of plants regenerated from fine suspensions of 1-year-old
embryogenic cultures were fertile, and embryogenic suspension cultures
retained their regeneration capacity for more than 3 years.
Geographic Patterns of Genetic Variation in Eucalyptus globulus ssp. globulus and a Revised Racial Classification
Authors: Dutkowski G. W. , Potts B. M.
Published: September 2002

The geographic patterns of genetic variation in a wide variety of quantitative
traits were studied in Eucalyptus globulus ssp.
globulus and its intergrades, leading to a revised
racial classification. The analysis was based on 35 traits assessed in five
field trials in northern Tasmania from approximately 500 open-pollinated
families, encompassing 49 collection localities in native stands. There were
significant differences between the collection localities for most traits.
While growth and survival traits exhibited weak spatial structuring, there
were clear regional patterns in bark thickness, wood basic density, flowering
precocity and some aspects of juvenile leaf morphology. There were a number of
significant correlations between trait locality means, but few simple
correlations between the regional patterns observed and climate. Multivariate
analyses indicated that the localities could be effectively amalgamated into
larger, geographically concordant races. A hierarchy of five major groupings
of 13 races and 20 subraces is proposed to account for most of the
quantitative genetic variation while allowing for outliers and intermediate
populations. Some areas of the distribution may need further sampling to more
accurately elucidate their racial affinities, especially those with traits of
high economic importance.
Emergence and Survival of Three Native Grass Species Sown on Roadsides on the Northern Tablelands, New South Wales, Australia
Authors: Huxtable C. H. A. , Whalley R. D. B.
Published: September 2002

A field trial was set up to assess the emergence and survival under natural
rainfall conditions of three species of native grasses when sown monthly for 8
months in seven different roadside environments. Generally, rainfall events of
40 mm or more were associated with substantial emergence events, and seed of
Danthonia richardsonii cv. ‘Taranna’ and
Microlaena stipoides was able to germinate after being
in dry soil for up to 120 days. The highest emergence of
Chloris truncata and ‘Taranna’ occurred from
October and November sowings, whereas that of
M. stipoides was from autumn sowings. For all species,
emergence was highest in roadside environments with topsoil and poorest for a
subsoil environment. Final percent survival of all species closely matched
percent emergence with less than 20% seedling mortality occurring over
time. A higher percentage of seeds sown in October and November germinated and
survived as plants than from December and January sowings. Survival of plants
from the initial seed source was generally greater than 25% for all
species when sown between October and January. The highest seedling mortality
occurred on an old road environment whereas the lowest was in a relatively
undisturbed environment. Management implications are that on the Northern
Tablelands, given adequate rainfall, these three native grasses have the best
chance of successful establishment if sown in spring on a cultivated bed of
topsoil. M. stipoides and
D. richardsonii cv. ‘Taranna’ seed can also
be sown into a dry seedbed in summer and germinate following rainfall several
months later.
SEM Studies on Vessels in Ferns. 8. Platyzoma
Authors: Carlquist Sherwin , Schneider Edward L. , Kenneally Kevin F.
Published: September 2002

Using scanning electron microscopy (SEM), vessels are demonstrated for roots
and rhizomes of Platyzoma microphyllum R.Br. Because
vessels are not in simple linear series, but have tips in contact with tips of
other vessels, vessel elements may have several end walls, and each of these
can bear a perforation plate. Vessels in roots are narrow, but have wide
perforations. In rhizomes, perforation plates have a wide range of morphology.
The most notable of these involves displacement and, frequently, fusion of
adjacent bars of secondary wall material, so that large perforations tend to
alternate with narrow perforations or with two or three fused bars. Porose pit
membranes are present in narrower perforations. The presence of wide
perforations achieved by means of bar displacement characterises not merely
Platyzoma, but other ferns as well:
Microgramma and Phlebodium. These
three genera of ferns experience marked fluctuation in water availability, so
that not only are vessels of potential value for rapid conduction during brief
periods of water availability, but the presence of perforation plates
conducive to such rapid conduction is of theoretical selective advantage as
well. Stelar fibres that bear crystals on external surfaces of walls are
reported for roots of Platyzoma. Such fibres have not
been reported hitherto for ferns.
Biometric Relationships for Estimating Standing Biomass, Litterfall and Litter Accumulation of Acacia salicina on Mined Land in Central Queensland
Authors: Grigg A. H. , Mulligan D. R.
Published: September 2002

Basal stem diameter was found to be a good predictor of above-ground biomass,
canopy litterfall and mass of the accumulated litter layer for
Acacia salicina Lindl., a tree that establishes
successfully on mined land in central Queensland. The relationship between
stem diameter and both biomass and litterfall was best described by an
exponential model, and was related to exponential expansion of the canopy as
tree diameter increased. In contrast, a simple linear model was used to
describe the relationship between stem diameter and accumulated litter, partly
reflecting a constant rate of litterfall per unit area of canopy over the
range of tree sizes. The models were developed as a means of estimating
biomass and nutrient capital and cycling in reconstructed ecosystems following
open-cut coal mining.
Smoke affects the Germination of Native Grasses of New South Wales
Authors: Read Tamara R. , Bellairs Sean M.
Published: September 2002

The germination responses to plant-derived smoke of seeds of 20 native grass
species from New South Wales, Australia, were tested under laboratory
conditions. The species belonged to 14 genera including
Bothriochloa, Chloris,
Cymbopogon, Danthonia,
Dichanthium, Digitaria,
Eragrostis, Eriochloa,
Microlaena, Panicum,
Paspalidium, Poa,
Stipa and Themeda. The interaction
between smoke and husk-imposed dormancy was examined by removing the floral
structures surrounding the seeds, when sufficient seeds were available. Smoke
was shown to be an important environmental stimulus for breaking the dormancy
of native grasses; however, the response differed considerably between
different genera and between species of the same genus. For almost half of the
species, smoke significantly increased the germination percentage.
Panicum decompositum showed the greatest response, with
germination increasing from 7.7 to 63.1% when smoke was applied.
Panicum effusum had no germination in the absence of
smoke, but 16.7% germination when smoke was applied.
Stipa scabra subsp. scabra had
germination significantly reduced by smoke from 30.2 to 19.9%. Five
species had their germination rate, but not the final germination percentage,
affected by smoke, and a third of the species were unaffected by smoke. For
five of the species, Chloris ventricosa,
Dichanthium sericeum,
Panicum decompositum,
Poa labillardieri and Stipa scabra
subsp. falcata, this is the first report of a
smoke-stimulated germination response. For those species with germination
promoted by smoke, retention of the covering structures did not prevent smoke
stimulation of germination. Sowing smoke-treated husked seeds is likely to be
preferable as it would still promote greater germination, whereas dehusking
seeds can result in the seeds being more susceptible to desiccation and fungal
attack in the field. It is suggested that other grassland communities that
respond to pyric conditions may also contain species that respond to smoke.
Ectomycorrhizas in Eucalyptus tetrodonta and E. miniata Forest Communities in Tropical Northern Australia and their Role in the Rehabilitation of these Forests Following Mining
Authors: Reddell Paul , Gordon Victoria , Hopkins Michael S.
Published: September 2002

The importance of ectomycorrhizas in
Eucalyptus tetrodonta F.Muell. and
E. miniata Cunn. ex Schauer dominated forests and
woodland communities in the monsoonal tropics of northern Australia was
assessed. Ectomycorrhizas colonised between 24 and 54% of final order
lateral roots in soil cores collected at 16 native forest sites. Only a
minority of the plant species present formed ectomycorrhizas (mainly eucalypts
and acacias) but these species contributed more than 75% of the basal
area. More than 70 species of putative ectomycorrhizal fungi were collected,
with three hypogeous taxa (Nothocastoreum,
Hysterangium and an undescribed Boletaceae) most
frequently encountered. Glasshouse inoculation experiments confirmed that a
diverse range of fungi was capable of forming ectomycorrhizas with
E. tetrodonta and E. miniata
seedlings, and that the growth of both species could be substantially
increased by inoculation with specific fungi. The fungi most effective in
increasing seedling growth were generally those which most extensively
colonised the seedling roots. A second component of this study investigated
the requirements for ectomycorrhizal fungi in native forest rehabilitation
following mining. Ectomycorrhizal infectivity was low in disturbed soils and
mine spoil materials, with the intensity of disturbance and the presence of
regrowth vegetation key determinants of the level of infectivity. Inoculation
of seedlings of E. miniata with spores of
ectomycorrhizal fungi increased both growth and leaf phosphorus concentrations
by between two- and three-fold at 7 months after planting out on a waste rock
dump devoid of native ectomycorrhizal propagules. The application of these
findings to minesite rehabilitation in the region, and the feasibility of
using spores for broad-scale inoculation, are discussed.
Sphagnum Peatlands of Kosciuszko National Park in Relation to Altitude, Time and Disturbance
Authors: Clarke Peter J. , Martin A. R. H.
Published: September 2002

Sphagnum peatlands or bogs in the Kosciuszko National
Park ranging from montane to alpine in elevation were sampled on two occasions
spanning a maximum interval of 32 years. Data analysed for individual samples
(305 quadrats) clustered into consistent microhabitat (hummock/hollow)
groups and subalpine/alpine subgroups. Quadrat data were aggregated for
sites (13 bogs) and analysed for floristic trends over time. Cluster and
ordination analyses showed a large change in a single montane bog, but
relatively little composition (presence/absence) change for the subalpine
and alpine bogs. Analyses of dominant species in alpine (three) and subalpine
bogs (three) showed some temporal trends in cover. There appears to be an
increase in the cover of Sphagnum and a decrease in
shrub cover in the subalpine bogs over the 20–32 years. Changes in shrub
cover in undisturbed subalpine sites are attributed to shrub senescence and
lack of recruitment. Changes at a site with intensive ski field development
(Smiggin Holes) were analysed separately and compared with adjacent sites with
no such development. Sphagnum cover had not increased at
this site and shrub decline was pronounced. Bare ground and ruderal species
increased in cover whereas 13 native species that were originally recorded in
1959 were not re-recorded in 1991. The detection of vegetation change in bogs
through monitoring is important for adaptive management of vegetation under
intensive use.
Influence of Site and Fertiliser Addition on Nutrient Cycling in Eucalyptus globulus Plantations in Gippsland, South-eastern Australia. I. Foliage and Litter Quality
Authors: Hooda Neeta , Weston Christopher J.
Published: September 2002

The productivity of Eucalyptus plantations on many sites
in south-eastern Australia is limited by nitrogen and phosphorus supply.
Therefore, after canopy closure, nutrient return and decomposition are key
processes maintaining productivity. To gain a better understanding of the
effects of site and fertilisers on these processes, foliage and litter quality
in E. globulus (Labill.) plantations in Gippsland,
south-eastern Australia were characterised on three sites covering a range of
soil types, inherent soil fertility and fertiliser treatments. Foliage and
litter quality were estimated by sequential extraction of labile forms of N, P
and C with cold, then hot, trichloroacetic acid (TCA). Selected treatments
were sampled in N × P factorial fertiliser trials of 6-year-old trees
where nutrients were added up to 2 years of age. Foliage and litter were
categorised as recent or old depending on sampling position. Site
significantly influenced concentrations of total and labile N and P (P <
0.0001) in foliage and litter. Phosphorus fertiliser increased total P
concentrations in old foliage at two sites, with the greatest absolute and
relative increases at the least fertile site (Glencoe). Inorganic P extracted
by cold (4°C) TCA accounted for 30-55% of total leaf and litter P
and was the fraction most responsive to P fertiliser addition. Total N
concentration and N fractions in foliage and litter were not influenced by N
fertiliser addition. Inorganic N extracted by cold and hot (90°C) TCA
accounted for less than 2% of total N and was not significantly
different among fertiliser treatments. Both sugar and phenol concentrations in
foliage and litter varied significantly between sites, with the least fertile
site showing significantly higher concentrations of phenols in recent litter.
Sugars and phenols extracted in cold TCA decreased from old foliage to litter
at all sites and were not influenced by N and P fertiliser addition. The
results show that additions of 200 kg ha-1 of P cause
perturbations in P cycle that are bigger in magnitude and are sustained for
longer periods of time compared to changes in N cycle with 400 kg
ha-1 of N additions.
The Process of Germination in Australian Species
Authors: Bell David T.
Published: September 2002

Australian species germinate under the combination of environmental conditions
where the potential for survival is enhanced. Most species also have dormancy
mechanisms that prevent all seeds from germinating in any particular rainfall
event. Immaturity of the embryo prevents some species from germinating until
environmental parameters change to more favourable conditions. Seed-coat
inhibitors may also delay germination, with some seed requiring ingestion and
dispersal by animals or a series of rainfall cycles to facilitate germination.
Adaptations to fire include germination mechanisms facilitated by impervious
seed coats, seed-coat inhibitors and biochemical sensing of water-soluble
components of smoke and the high soil nitrate levels found following the
burning of vegetation. Germination is generally limited under saline soil
conditions until rainfall dilutes concentrations to near-zero water
potentials. Australian species tend to germinate under temperatures that
approximate the rainfall season in their native habitat. Light sensing by
Australian species ensures germination takes place only near the surface for
some species or only under complete burial conditions in others. More recent
research has emphasised the interaction of multiple and sequential cues to
relieve dormancy and initiate germination. Knowledge of germination mechanisms
provides a basis for better land management, enriched conservation, improved
rehabilitation and advanced horticulture, forestry and farming practices.
Seasonal Changes in Leaf Water Characteristics of Eucalyptus tetrodonta and Terminalia ferdinandiana Saplings in a Northern Australian Savanna
Authors: Eamus D. , Prior L. D.
Published: September 2002

The monsoonal areas of northern Australia experience extreme seasonal
variations in rainfall, with an annual dry season of 7 months or more.
Seasonal changes in leaf water relations were investigated for saplings of two
tree species common in northern Australian savannas:
Eucalyptus tetrodonta F.Muell, an evergreen, and
Terminalia ferdinandiana Excell, which is deciduous.
Saplings may experience more severe water stress than mature trees because
their root systems are less extensive. This study found a positive correlation
between pre-dawn leaf water potential and tree height during the dry season,
but not during the wet season, for both E. tetrodonta
and T. ferdinandiana trees. Pressure–volume curves
were constructed for leaves of E. tetrodonta saplings at
2-monthly intervals throughout the year. Osmotic potential at full turgor
decreased from a maximum of −1.33 MPa in February (wet season) to
−2.25 MPa in October (late dry season), then increased to an
intermediate value of −1.71 MPa in December (early wet season). Leaves
of T. ferdinandiana saplings were compared in February
(wet season) and April (end of wet season; before leaf senescence). Osmotic
potential at full turgor decreased from −1.18 MPa in February to
−1.39 MPa in April. The capacity for turgor maintenance was larger for
E. tetrodonta than for
T. ferdinandiana, with osmotic potential at full turgor
and the turgor loss point, relative water content at the turgor loss point and
the ratio of turgid weight to dry weight all lower in
E. tetrodonta.
Interspecific Hybridisation of Boronias
Authors: Astarini I. A. , Yan G. , Plummer J. A.
Published: September 2002

Interspecific hybridisation within the genus Boronia was
attempted by using species with a range of chromosome numbers. Crosses were
possible between Western Australian species including those with
B. heterophylla as the female parent and pollen from
B. molloyae (n = 8),
B. megastigma (n = 7),
B. purdienana (n = 9) and
B. ramosa (n = 18).
Cytological studies revealed that B. heterophylla
genotypes had different chromosome numbers; ‘Red’ had
2n = 15, whereas ‘Moonglow’ and
‘Cameo’ had 2n = 14. The F
1 hybrid from B. heterophylla
‘Red’ × B. megastigma had
2n = 15. Pollen viability, examined by using
fluorescein diacetate, varied from 20% in
B. crenulata to 80% in
B. purdieana. Pollen of most species could be stored for
12 months in sealed containers at −20°C. Drying with silica gel
desiccant did not improve storage, nor did ultra-low temperature
(−196°C). Stored pollen was successfully used for interspecific
hybridisation.
Drought Resistance and Water Use Efficiency in Acacia saligna
Authors: Nativ Rotem , Ephrath Jhonathan E. , Berliner Pedro R. , Saranga Yehoshua
Published: September 2002

Acacia saligna (Labill.) H.Wendl, a potential crop for
forage and wood production, is considered highly drought-resistant. The aim of
this study was to characterise some of the physiological traits contributing
to drought resistance in A. saligna. Two experiments
were conducted: (i) 4-year-old A. saligna were grown in
the field under dryland and irrigated treatments and (ii) 6-month-old A. saligna were grown in pots and irrigated to replenish 100% of the
transpiration demand (control), or 75% 50% or 25% of the
control. Soil-water deficits in the field elicited an increase in osmotic
potential in phyllodes. Stomatal conductance was negatively correlated with
air vapor pressure deficit under drought conditions in both experiments,
whereas under irrigation in the field it was correlated with solar radiation.
In the field, dry matter (DM) production under irrigation was only 14%
greater (not significant) than under dryland. In the pot experiment, DM
production was significantly reduced, and water use efficiency (WUE) and
chlorophyll content increased with reduced availability of water. The greater
WUE induced by drought could have resulted from stomatal regulation and
increased chlorophyll content. Carbon isotope ratios were correlated with the
WUE, and may be utilised for selection to further improve the WUE of
A. saligna under drought conditions.
Comparative Effects of Stock and Wild Vertebrate Herbivore Grazing on Treeless Subalpine Vegetation, Eastern Central Plateau, Tasmania
Authors: Kirkpatrick J. B. , Bridle K. L.
Published: September 2002

The existence of two 25-year-old grazing exclosures on Liawenee Moor, Eastern
Central Plateau, Tasmania, created an opportunity to investigate the impacts
of vertebrate herbivores on treeless subalpine vegetation. There were three
treatments: sheep-, native herbivore- and rabbit-grazed; native herbivore- and
rabbit-grazed; no grazing. The amount of bare ground was highest in the
sheep-grazed plots, while vegetation cover was greatest in the ungrazed
exclosure. The cover of all lifeform groups, except small herbs, was greater
in the exclosures than in the sheep-grazed plots. The percentage frequency of
tall herbs was significantly less in the sheep-grazed plots than either of the
grazing exclosures.
Tall herbs were more likely to be found under the canopy of other vegetation
in the sheep-grazed plots while the same species were found to be growing in
locations with no other vegetation cover in the ungrazed exclosure.
Revegetation of bare ground averaged 1% per year over a 20-year period
in the ungrazed exclosure. While percentage bare ground has also decreased in
the native- and rabbit-grazed exclosure, it has increased in the sheep-grazed
plots. Domestic stock grazing appears to have a much greater impact on
vegetation cover, species composition and community structure than grazing by
native herbivores and rabbits. No grazing allows for the fastest
rehabilitation of the area. Our results are consistent with those from alpine
and treeless subalpine areas of the Australian mainland.
Remote Sensing of Water Content in Eucalyptus Leaves
Authors: Datt Bisun
Published: September 2002

The spectral reflectance of leaves from several
Eucalyptus species was measured over the 400–2500
nm wavelengths with a laboratory spectroradiometer. The relationship of
reflectance with the gravimetric water content and equivalent water thickness
(EWT) of the leaves was analysed. The results showed that EWT was strongly
correlated with reflectance in several wavelength regions. No significant
correlations could be obtained between reflectance and gravimetric water
content. It was also possible to confirm theoretically that reflectance
changes of leaves could be directly linked to changes in EWT but not to
changes in gravimetric water content. Several existing reflectance indices
were evaluated for estimation of leaf water content and some new indices were
developed and tested. Two semi-empirical indices developed in this study,
(R850 -
R2218)/(R850
- R1928) and
(R850 -
R1788)/(R850
- R1928), were found to show
significantly stronger correlations with EWT than all other indices tested. It
was also shown that these new indices were least sensitive to the effects of
radiation scatter. The indices
(R850 -
R2218)/(R850
- R1928) and
(R850 -
R1788)/(R850
- R1928) are therefore proposed as
two new indices for the remote estimation of vegetation water content.
Short Communication: Fluoroacetate Content of Gastrolobium brevipes in Central Australia
Authors: Twigg Laurie E. , Wright Geoffrey R. , Potts Michelle D.
Published: September 2002

The spectral reflectance of leaves from several
Eucalyptus species was measured over the 400–2500
nm wavelengths with a laboratory spectroradiometer. The relationship of
reflectance with the gravimetric water content and equivalent water thickness
(EWT) of the leaves was analysed. The results showed that EWT was strongly
correlated with reflectance in several wavelength regions. No significant
correlations could be obtained between reflectance and gravimetric water
content. It was also possible to confirm theoretically that reflectance
changes of leaves could be directly linked to changes in EWT but not to
changes in gravimetric water content. Several existing reflectance indices
were evaluated for estimation of leaf water content and some new indices were
developed and tested. Two semi-empirical indices developed in this study,
(R850 -
R2218)/(R850
- R1928) and
(R850 -
R1788)/(R850
- R1928), were found to show
significantly stronger correlations with EWT than all other indices tested. It
was also shown that these new indices were least sensitive to the effects of
radiation scatter. The indices
(R850 -
R2218)/(R850
- R1928) and
(R850 -
R1788)/(R850
- R1928) are therefore proposed as
two new indices for the remote estimation of vegetation water content.
Influence of environmental and instrumental variables on the non-invasive prediction of Brix in pineapple using near infrared spectroscopy
Authors: Guthrie J. , Walsh K.
Published: September 2002

Summary. The Brix content of pineapple fruit can be
non-invasively predicted from the second derivative of near infrared
reflectance spectra. Correlations obtained using a NIRSystems 6500
spectrophotometer through multiple linear regression and modified partial
least squares analyses using a post-dispersive configuration were comparable
with that from a pre-dispersive configuration in terms of accuracy (e.g.
coefficient of determination, R2,
0.73; standard error of cross validation, SECV, 1.01°Brix). The effective
depth of sample assessed was slightly greater using the post-dispersive
technique (about 20 mm for pineapple fruit), as expected in relation to the
higher incident light intensity, relative to the pre-dispersive configuration.
The effect of such environmental variables as temperature, humidity and
external light, and instrumental variables such as the number of scans
averaged to form a spectrum, were considered with respect to the accuracy and
precision of the measurement of absorbance at 876 nm, as a key term in the
calibration for Brix, and predicted Brix.
The application of post-dispersive near infrared technology to in-line
assessment of intact fruit in a packing shed environment is discussed.
Effects of grazing, slashing and burning on Aristida ramosa and sheep productivity in northern New South Wales
Authors: Lodge G. M. , Gogel B. J. , Archer K. A. , Cullis B. R.
Published: September 2002

Summary. Studies were conducted on a natural pasture
dominated by Aristida ramosa (wiregrass) in northern New
South Wales. In each of the 4 studies, treatments were designed to reduce
wiregrass presence by grazing, using stocking rates up to 12.5–15.0 dry
sheep equivalents (dse/ha) in summer and autumn (1983–88), slashing
(1984–86), or burning (2 studies, 1985–88; 1986–88) in
spring before heavily grazing in summer–autumn. Effects of these
treatments on A. ramosa dry matter yield and basal
cover, Danthonia linkii (wallaby grass) basal cover,
sheep liveweight change and fleeceweight were measured for the different time
periods. Wool quality was determined from mid-side samples taken in
1983–85.
All treatments reduced A. ramosa dry matter yield and
basal cover and increased D. linkii basal cover,
compared with control plots continuously grazed at 5 dse/ha. From 1983 to
1988, A. ramosa dry matter yields in the control plots increased from about
1000 to 3500 kg/ha and its basal cover increased from 7 to 13%. In
contrast, A. ramosa dry matter yields in heavily grazed,
and spring burnt and heavily grazed treatments were <500 kg/ha, with
basal cover levels of A. ramosa <0.3% while
those of D. linkii were about 5%. Slashing before
heavy grazing (1984–86) also reduced A. ramosa dry
matter yields and basal cover compared with the control, but higher levels of
A. ramosa (800 kg/ha dry matter, 1% basal
cover) remained at the end of these studies.
Heavy grazing of wiregrass led to significant negative liveweight changes,
compared with sheep in control plots. Slashing or burning of wiregrass to
remove dead material and increase green leaf before grazing at high stocking
rates, markedly reduced rates of liveweight decline. Both grazing at high
stocking rate and slashing in spring followed by heavy grazing, significantly
reduced the amount of wool grown in the spring–winter period and
significantly decreased either wool fibre diameter, strength or
point-of-break. In the long term, sheep in wiregrass control plots lost more
weight than those in treatment plots at equivalent stocking rates. Results
suggest that on-farm control strategies based on late winter or spring
burning, and heavy summer grazing should reduce the presence of wiregrass in
similar pasture system.
Yield and phosphorus nutrition of potatoes (Solanum tuberosum L.) cv. ‘Delaware’ grown on a yellow Karrakatta sand containing freshly- and previously-applied Alkaloam - gypsum
Authors: Robertson W. J. , McPharlin I. R. , Jeffery R. C.
Published: September 2002

Summary. Potatoes
(Solanum tuberosum L.) cv. ‘Delaware’ were
grown over winter on a yellow Karrakatta sand amended with
Alkaloam–gypsum (AG; previously referred to as red mud–gypsum) at
up to 240 t/ha, both freshly-applied (2 experiments) and applied 2.5 years
earlier (1 experiment). Several levels of phosphorus fertiliser (0–600
kg P/ha) were applied to the freshly-applied AG and a single level (600 kg
P/ha) was applied to the previously-applied AG. Amendment of the soil with
60 t AG/ha (freshly-applied) doubled the amount of fertiliser phosphorus
retained in the top 30 cm of soil when 100 kg P/ha was applied. On
freshly-applied AG, bicarbonate-extractable phosphorus showed an upward trend
with level of AG, being 16 mg/kg (0–15 cm) at 0 t AG/ha and 34
mg/kg at 90 t AG/ha. This will decrease phosphorus fertiliser
requirements in the following potato crop by 49% relative to unamended
soil based on previously published soil test standards. Amendment with
freshly-applied AG increased the level of applied phosphorus required for
99% of maximum petiole phosphorus concentration by 46 and 139%
in the 2 experiments compared with unamended soil. Maximum yield was
significantly reduced by 7–10% at 60 t/ha of freshly-applied
AG compared with unamended soil while on residual AG it was only reduced at
240 t/ha (12%) (trend only). Yield reductions were not correlated
with a reduced availability of phosphorus, however, they may have been due to
a reduced availability of potassium. The concentrations in the tubers of
antimony, arsenic, cadmium, chromium, cobalt, lead, mercury and nickel did not
exceed legal limits on soil amended with AG.
Susceptibility of 'Lisbon' and 'Eureka' lemons to chilling injury
Authors: McLauchlan R. L. , Underhill S. J. , Dahler J. M. , Barker L. R.
Published: September 2002

Summary. ‘Eureka’ and ‘Lisbon’
lemons (Citrus limon L.) from the Burnett region in
Queensland were stored for 14, 28 or 42 days at 1˚C followed by 7 days at
20˚C to compare their relative susceptibility to chilling injury. The
potential effect of cultivar on injury development was examined by harvesting
fruit from trees subjected to the same growing conditions to minimise all
other variability. Injury appeared in both cultivars after storage at 1˚C
for 14 days and 7 days at 20˚C. The incidence of commercially
unacceptable chilling injury (moderate and severe) was significantly higher in
Lisbon than Eureka fruit after all storage treatments, except for 42 days at
1˚C plus 7 days at20˚C. Eureka and Lisbon lemons had similar
respiration rates at 20˚C, but respiration of Lisbon following storage at
1˚C for 14, 28 and 42 days was significantly higher than that of Eureka.
Storage at 1˚C for 14 days resulted in elevated respiration in both
cultivars, with a peak occurring during the first 24 h. After 28 days at
1˚C, peak respiration increased to 51 mg/kg.h for Lisbon and 34
mg/kg.h for Eureka lemons. Respiration increased significantly with longer
storage periods, consistent with extensive chilling injury. It is suggested
that the lack of commercial success of cold-treated Queensland-grown Eureka
lemons is not because they are more sensitive to chilling injury than Lisbon
lemons.
Soil water and nitrogen interaction in wheat in a dry season under a fallow - wheat cropping system
Authors: Cantero-Martinez C. , O'Leary G. J. , Connor D. J.
Published: September 2002

Summary. Measurements of water use, growth and yield of
wheat were made in a dry year following 3 methods of long fallow: chemical
(CH) (no tillage), blade plough (CB) (subsurface tillage), and a fully tilled
fallow (CT) following burning of stubble residues (the popular method). Crops
in each fallow method were fertilised with and without nitrogen. All fallow
systems produced relatively high yields in the range 2.7–3.8 t/ha,
despite less than average rainfall over the 18-month fallow period (539 mm)
and a significant dry period extending from before anthesis until maturity. CH
fallow, however, accumulated 83 mm more water than CT fallow by sowing time
and produced 0.74 t/ha additional yield. This can be attributed to
increased water use through greater leaf area index duration during grain
filling. The application of nitrogen fertiliser had no effect on the yield of
the stubble-retained crops (CH and CB). However following nitrogen
application, 1 t/ha less yield was produced under CT fallow than under CH
fallow. There were marginal advantages in growth and biomass partitioning from
applied nitrogen with increased leaf area index during the early stages of
growth. At sowing there was a significant accumulation of mineral nitrogen
below 120 cm as a result of a 6-year history of fertiliser application under
the chemical fallow. This, however, disappeared by anthesis with a greater
nitrogen use. In dry years, that are not catastrophic, fallow with stubble
retention and zero tillage (CH) offers some insurance against low yield. This
was achieved through improved water availability (320 v.
240 mm in CT) which also may reduce the risk of yield loss through haying off
by overdosing with nitrogenous fertilisers when levels of soil mineral
nitrogen at sowing are high (200 kg nitrogen/ha).
Wilt disease of Arachis hypogaea L. in Ekpoma, Edo State, Nigeria
Authors: Osuinde M. I. , Daibo O. O.
Published: September 2002

Summary. A 2-year survey (1993, 1994) of peanut farms in
Ekpoma, Edo State, Nigeria, showed that 21.5 ± 1.1% of the crop
was affected by wilt disease. The microflora associated with the roots of
wilted peanut plants were Penicillium oxalicum Currie
and Thom (15.2%), P. citrinum Thom
(12.3%), Fusarium oxysporum Schlect. I
(35.6%), F. oxysporum II (55.3%),
F. oxysporum III (26.8%),
F. solani (Mart.) Sacc. I (6.3%),
F. solani II (10.5%),
Aspergillus niger Van Tieghem (5.5%),
Trichoderma koningii Rifai (15.0%) and
Botryodiplodia theobromae Pat. (5.0%). Others
included Ralstonia (Pseudomonas)
solanacearum (Smith) Smith (5.0%),
Rhizobium sp. (20.0%) and
Bacillus sp. (15.3%). Pathogenicity tests using
106 fungi spores/mL and 106
cells of bacteria isolates/mL showed that
Fusarium oxysporum was responsible for the wilting of
peanut seedlings in this locality.
Effect of sowing date on the uptake and utilisation of phosphorus by wheat (cv. Osprey) grown in central New South Wales
Authors: Batten G. D. , Fettell N. A. , Mead J. A. , Khan M. A.
Published: September 2002

Experiments were sown at Cowra and Condobolin to determine the effect of
sowing time (April–June) on the response to and utilisation of
phosphorus by the wheat cultivar Osprey which requires vernalisation. Crops
sown in April needed only 0–2 kg/ha of applied phosphorus to achieve
90% of the maximum yield for the site. This contrasts with crops sown
at the traditional sowing time in May–June which needed from 11.5 kg
P/ha, on a site with a moderate soil phosphorus status, to 36 kg P/ha,
on a site with a very low soil phosphorus status, to produce 90% of the
site maximum yield. Crops sown in April had higher yields and even without
applied phosphorus accumulated more phosphorus (kg/ha) than crops sown in
June with 40 kg P/ha. Crops sown in April had a lower dry matter harvest
index, a lower phosphorus harvest index, produced less grain per kilogram of
phosphorus in the shoots at maturity, and had a higher grain phosphorus
concentration than crops sown in June. Grain protein was not affected by
sowing date or the amount of phosphorus applied at sowing. At 90% of
maximum dry matter yield shoots had 0.14–0.20% phosphorus at
growth stage 30. The critical concentration of phosphorus in grain at
90% maximum grain yield increased with yield from 0.19 to 0.25%
phosphorus.
Farmers who sow wheat in April can achieve optimum yields with lower inputs of
fertiliser phosphorus. However, this benefit will be offset by a lower
phosphorus-use efficiency and more rapid depletion of phosphorus reserves from
the soil.
Vegetative cutting and in vitro propagation of the tree waratah, Alloxylon flammeum P. Weston and Crisp (family Proteaceae)
Authors: Donovan N. J. , Offord C. A. , Tyler J. L.
Published: September 2002

Alloxylon flammeum is a rare and threatened Australian
rainforest species that features spectacular red flowers and contrasting dark
green foliage giving it potential as a cut flower crop. It also has potential
as a rootstock for difficult to grow tree waratah species. There is, however,
little published information on the propagation of
Alloxylon spp. Here we show that
A. flammeum can be propagated by vegetative cuttings and
in vitro. The most commercially viable option is to
propagate by cuttings using 8000 mg indole-3-butyric acid/L under
intermittent mist with a root zone temperature of 24 ± 2˚C.
Pre-treatment of A. flammeum stock plants with
gibberellin (A4 and A7) spray before initiation into culture increased the
success of initiation. The use of tip material resulted in minimal explant
contamination and 1% sodium hypochlorite for 15 min was adequate for
surface disinfection of material. Well elongated shoots were multiplied using
6-benzyladenine and 6-dimethylallyaminopurine (isopentyladenine), whilst
thidiazuron-cultured shoots were numerous but short and unusable.
Effect of brassica and weed manures on abundance of Tylenchulus semipenetrans and fungi in citrus orchard soil
Authors: Walker G. E. , Morey B. G.
Published: September 2002

Summary. Brassica cultivars Ebony and Indian mustards,
and Rangi rape residues reduced the soil level of
Tylenchulus semipenetrans by up to 76% compared
with unamended soil, and in a greenhouse reduced levels on the roots of orange
(Citrus sinensis) seedlings.
Paratrichodorus lobatus reached high levels in pots
containing unamended soil but was not detected in pots containing amended
soils. However, Pythium ultimum was isolated more
frequently from roots, and propagule numbers of Pythium
spp. were significantly higher in amended soils. Soil amendment did not affect
growth of orange seedlings, and the benefits from reduced nematode levels may
have been negated by the increase in pythium infection.
In field experiments at 3 citrus orchards cleared for replanting, and at 1
established orchard between tree rows, brassica cultivars were grown
in situ (20 kg seed/ha) as green manure crops.
Highest crop production was at a site with heavier soil under drip irrigation,
where Ebony and Yellow mustards produced 13–15 kg fresh
weight/m2. Although soil levels of
T. semipenetrans were reduced by 79–91% by
incorporation of green manures, brassica cultivars including Ebony, Indian and
Yellow mustards, and Humus and Rangi rapes, were no more effective than were
self-seeding weeds. At 1 site, incorporation of a poor stand of Ebony mustard
(but not of weeds) produced higher soil levels of
T. semipenetrans; Paratrichodorus
sp. numbers declined after mustard incorporation at this site but increased
after weeds. Growth and soil incorporation of either brassicas or weeds
increased soil levels of Pythium spp., but fusarium
levels were decreased by incorporation of weed and Indian mustard residues.
Growth of citrus measured at 2 field sites did not differ between soils
amended with brassica or weed residues.
Quarantine disinfestation of capsicums against Queensland fruit fly (Diptera : Tephritidae) with dimethoate
Authors: Heather N. W. , Peterson P. M. , Kopittke R. A.
Published: September 2002

Summary. A postharvest dimethoate treatment at 400
mg/L applied through a packing-line spray system achieved
>99.99% efficacy as a quarantine disinfestation method against
Queensland fruit fly, Bactrocera tryoni (Froggatt)
infesting capsicums (peppers), Capsicum annuum L. There
were no survivors in confirmatory tests on fruit containing 77 130 eggs, the
most tolerant life stage. The spray system thoroughly wetted fruit at a
delivery rate of 9.2 L/min.m2 for a minimum time of
1 min.
The use of faecal Δ13C values to improve the reliability of estimates of diet quality when sampling tropical pastures with oesophageal fistulated cattle
Authors: Coates D. B.
Published: September 2002

Summary. The nutritive value of extrusa samples
collected from oesophageal fistulated cattle can be an unreliable indicator of
the quality of the diet of resident cattle grazing the same pasture. This is
largely because the botanical composition of the extrusa from 15–30 min
of grazing may differ from that of the whole diet of the resident cattle. A
methodology is described whereby the reliability of some attributes of diet
quality can be improved by correcting for differences between the
C3/C4 proportions of extrusa
samples and the dietary C3/C4
proportions of resident cattle derived from their faecal
δ13C values.
Examples from 23 paddock samplings covering 2 sites, 3 experiments and 6
sampling occasions, are used to illustrate the application of the methodology.
Carbon ratios (δ13C) of the naturally occurring
isotopes 12C and 13C were used as
an index of legume (C3)/grass
(C4) proportions in extrusa samples and in the diet of
resident cattle assuming dietary δ13C =
faecal δ13C + 1. Regression relationships
were developed relating the nitrogen, mineral and digestibility levels of
extrusa samples to extrusa δ13C values. Where
appropriate, these relationships were then used to estimate the level of these
attributes in the diet of resident cattle from their estimated dietary
δ13C values. Nitrogen and calcium concentrations
in extrusa were usually closely related to legume content
(δ13C) so that adjustments were considered very
advantageous with average RSDs of 0.08 and 0.09% for calcium and
nitrogen respectively. Boron and sulfur concentrations were also related to
legume content but only at 1 of 2 sites. There was no apparent relationship
between legume content and the concentrations of aluminium, copper, magnesium,
manganese, selenium, titanium and zinc at either site. In general,
in vitro digestibility of extrusa samples was poorly
related to legume content.
The use of alkane technology is suggested as a more versatile alternative to
the carbon ratio technique and the benefits and limitations of the proposed
methodology are discussed briefly.