bluuebunny/crossref_metadata_2025_split huggingface dataset:
Breaking dormancy of Avena fatua L. seed by treatment with ammonia
Authors: CAIRNS A. L. P. , de VILLIERS O. T. 
Published: August 2006

Summary: Résumé: ZusammenfassungWild oat (Avena fatua L.) seed dormancy was broken by treating the air‐dry seed with ammonia. Loss of dormancy was proportional to the concentration and/or time of exposure to the gas. The dormancy of several other grass weed species was also broken by ammonia but the gas had no effect on the dormancy of dicotyledonous weed seeds. The dormancy‐breaking effect of ammonia was irrevocable and treated seeds could be stored for months without any decrease in germination. Germination of seed treated with sub‐optimal concentrations of ammonia increased with after‐ripening. Ammonia caused an increase in leakage of electrolytes from treated seeds, indicating an increase in permeability of the seed coat. The increase in permeability cannot, however, explain the loss of dormancy in deeply dormant wild oat where dormancy resides in the embryo. Des traitements à l'ammoniaque pour lever la dormance de graines de Avena fatua L.La dormance de graines de la folle avoine (Avena fatua L.) a pu être levée en traitant à l'ammoniaque les graines séchées à l'air. La perte de dormance s'est révélée fonction de la concentration et/ou du temps d'exposition au gaz. La dormance de plusieurs autres graminées a pu être levée par l'ammoniaque mais le gaz n'a pas eu d'effet sur les graines d'adventices dicotylédonées. L'effet de l'ammoniaque en levant la dormance était irréversible; le stockage des graines traitées pendant plusieurs mois n'a amené aucune diminution de la germination. La germination de graines traitées avec des concentrations d'ammoniaque sous‐optimales a augmenté suite à une maturation après la récolte. L'ammoniaque a amené une fuite d'électrolytes plus importante chez les graines traitées, ce qui indique une plus grande perméabilité du tégument. La plus forte perméabilité, cependant, n'explique pas la perte de dormance chez des folles avoines profondément dormantes, car chez cette espèce la dormance réside dans l'embryon. Abbruch der Ruheperiode von Avena fatua L.‐Samen durch Behandlung mit AmmoniakDie Behandlung lufttrockener Samen von Avena fatua L. mit Ammoniak führte zu einem Abbruch ihrer Ruhezeit. Der Verlust der Ruheperiode war proportional zu Konzentration und/oder Expositionszeit. Ammoniak brach ebenfalls die Samenruhe verschiedener anderer Ungrasarten, zeigte aber keine Wirkung bei zweikeimblättrigen Unkräutern. Die Beendigung der Samenruhe durch Ammoniak war unwiderruflich und behandelte Samen konnten während Monaten ohne Abnahme ihrer Keimfähigkeit gelagert werden. Mit zunehmender Dauer einer Nachreifung nahm die Keimung der Samen zu, die mit unteroptimalen Konzentrationen von Ammoniak behandelt worden waren. Ammoniak verursachte ein verstärktes Austreten von Elektrolyten aus den Samen, was auf eine erhöhte Permeabilität der Samenschale hinweist. Dieser Permeabilitätsanstieg kann jedoch den Verlust der Samenruhe bei Wildhafer nicht erklären, da die Ursache der Ruheperiode im Embryo zu suchen ist.
Community participation in organising rural general practice: Is it sustainable?
Authors: Taylor Judy , Wilkinson David , Cheers Brian 
Published: July 2006

AbstractObjective:  We analysed community participation in organising rural general medical practice in order to suggest ways to extend and sustain it. Design:  A multisite, embedded case‐study design collecting data through semistructured interviews, non‐participation observation and a document analysis. Setting:  One remote and two rural communities in Australia. Participants:  Community members, GPs, health professionals, government officers and rural medical workforce consultants. Results:  High levels of community participation in recruiting and retaining GPs, organising the business model, and contributing to practice infrastructure were evident. Community participation in designing health care was uncommon. Participation was primarily to ensure viable general practice services necessary to strengthen the social and economic fabric of the community. There were factors about the decision‐making and partnership processes in each of the communities that threatened the viability of community participation. Conclusions:  We recommend that a concept of community development and explicit facilitation of the processes involved is necessary to strengthen participation, create effective partnerships and ensure inclusive decision‐making.
Variation in drought resistance in adjacent edaphic populations of Eucalyptus viminalis Labill.
Authors: LADIGES PAULINE Y. 
Published: July 2006

AbstractPopulation differences in growth rate, drought resistance, and aspects of tissue water relations in seedlings of two neighbouring populations of E. viminalis on basalt and granite soils have been reported previously (Ladiges 1974a, b). The present work has confirmed these differences and field studies have related them to differences in edaphic factors.The granite soil supports the slower growing, more drought‐resistant population. Moisture contents for this soil were lower over a twelve‐month period than for the basalt soil. Estimated pF values for granitic top‐soil were higher and above 5 for six months of the year. During the drier months, leaf water potentials of mature trees on the granite were lower than for trees on the basalt and reached average values of ‐28 bars in March 1974.A comparison of open‐pollinated seedlings on two areas of granite, 0–4 km and 2–0 km from the trees on the basalt, suggested that there is a degree of gene flow between trees on the basalt and trees on the nearer granite site. The results therefore suggest some outcrossing in E. viminalis. Prior to 1900, stands on the basalt area were probably continuous with those on the more distant granite site and a degree of gene flow would have occurred.It appears that differential selection pressures have been primarily responsible for the population differences noted in growth rate and drought resistance.
Studies in the ecology of coastal heath in New South Wales
Authors: SIDDIQI M. Y. , MYERSCOUGH P. J. , CAROLIN R. C. 
Published: July 2006

Abstract Effects of heating dry seed were investigated in Banksia serratifolia and B. ericifolia. Seeds were inviable after 7 min exposure at 150°C or higher temperatures but remained viable after exposure at 100°C and lower temperatures. Imbibed seeds show no dormancy, and seeds survive fire insulated from heat in the thick woody follicles which may persist unopened for several years on the parent plant but open following fire. Effects of nutritional supplements were observed in the seed germination and seedling survival and growth of Banksia serratifolia, B. aspleniifolia and B. ericifolia. Germination with radicle and hypocotyls extension was not significantly affected by a wide range of mineral nutrient regimes. In pot experiments using a heath soil seedling survival and growth were adversely affected by moderate additions of phosphate with surviving seedlings showing toxicity symptoms and poor development of proteoid roots. Moderate supplements of potassium had no adverse effect, and in B. serratifolia and B. ericifolia lessened the adverse effects of phosphate addition. The slow growth of the seedlings accords with the normal low nutrient availability in heath soils but seedlings show little capacity for rapid exploitation of any temporary increase of available nutrients after fire.
Polyploidy, flowering phenology and climatic adaptation in Heteropogon contortus (Gramineae)
Authors: TOTHILL J. C. , HACKER J. B. 
Published: July 2006

AbstractChromosome numbers of 2n = 39, 40, 50, 60, 69, 70, 80 and 90 are reported for Heteropogon contortus from a world collection. The numbers 2n = 39, 69, 70 and 90 are new to the literature. The cytogeographic distribution indicates that the tropical latitudes are almost exclusively occupied by tetraploids while the sub‐tropical latitudes are characterized by a wide range of ploidy levels from tetraploid to nonaphid.Observations on the time of flowering of these accessions using uniform grass garden techniques indicate that pan‐tropical populations are made up almost exclusively of late flowering lines and those from subtropical areas are of mixed lines showing great diversity from early to late flowering types. The association of polyploidy and flowering time are discussed in relation to the possible origin of H. contortus, to its adaptation and migration. It seems reasonable to suggest that polyploidy and the development of an earlier flowering response are both adoptively advantageous and have been selected for the species’migration into sub‐tropical latitudes.
Vegetation succession after fire in sclerophyll woodland communities in south‐eastern Australia
Authors: PURDIE ROSEMARY W. , SLATYER R. O. 
Published: July 2006

AbstractThe dynamics of vegetation regeneration after burning were examined in three dry sclerophyll communities near Canberra, in south‐eastern Australia. Changes in seedling and regrowth populations were followed in permanent quadrats during the first two years after burning, compared with both the preburn vegetation and population changes over the same period in adjacent, unburnt plots.All species represented either by living plants in the tree and shrub strata and/or by seed in the soil and litter prior to burning regenerated during the first year after the fire treatments. No new species invaded the areas after burning. Species varied in their regenerative strategy and recovered after the fires either by germination of seed residual in the soil and ash or released from trees after burning, by regrowth from surviving vegetative organs, or by a combination of germination and regrowth. Both seedling input and the vegetative recovery of populations were higher during the first than second year after burning. The vegetative multiplication and seed gertnination of many species were stimulated by fire.It was concluded that the regeneration of the communities studied, as well as the post‐fire recovery of numerous different communities reported in the literature, closely resembled an initial floristic composition model. It is considered that the process of vegetation redevelopment after a disturbance (i.e. secondary succession) will be influenced greatly by the species composition at the time of disturbance, and by the type of disturbing agent. A single model would not be expected to adequately describe secondary succession following disturbance by agents imposing different stress conditions on a community.
Resource partitioning and competition in honeyeaters of the genus Meliphaga
Authors: FORD HUGH A. , PATON D. C. 
Published: July 2006

AbstractSix species of Meliphaga studied in detail in South Australia all differ in some important aspect of their ecology consistent with the concept of interspecific competition. Four species are very similar in their feeding ecology but show distinct habitat preferences. The two remaining species are rather different in their feeding ecology and frequently overlap with their congeners in habitat. Two other species, not studied in detail, also appear to have distinct habitat preferences.One species has increased its range of habitat on Kangaroo Island, in the absence of potential competitors.The case for interspecific competition playing a part in the moulding of the niches of species in this genus is thus strengthened.
Ecological paradoxes*
Authors: KIKKAWA JIRO 
Published: July 2006

AbstractTwo controversial areas of ecology are examined critically to ascertain the limits of some current theories. In the field of population ecology it is argued that no general theory can explain the regulation of animal numbers. Existing theories are considered inadequate because either (1) evidence points to multiple causes rather than a single cause, (2) propositions lose scientific appeal by accumulating qualifiers, or (3) conflicting theories are irrefutable in scientific inquiry. Different research strategies are required to discover generalities in population regulation. In the field of community organization it is pointed out that too much emphasis on the competitive exclusion principle has blinded ecologists from the clustering of resources and of species populations. Conditions of co‐existence as well as segregation are considered important in the organization of communities, which allow elements of chance in small scale distribution. The ecological world is likened to the physical world in which small scale disorder leads to order on a large scale. For the development of a global ecology the acceleration of studies in the tropics and the southern hemisphere is urged.
Variations in vegetation and soil pattern across the Hawkesbury Sandstone plateau from Barren Grounds to Fitzroy Falls, New South Wales
Authors: BURROUGH P. A. , BROWN L. , MORRIS E. C. 
Published: July 2006

AbstractThe regional variations of vegetation, soil and rainfall over the Hawkesbury Sandstone plateau from Barren Grounds Nature Reserve to Fitzroy Falls, N.S.W., were described by aerial photo interpretation, field surveys, ordination techniques and trend surface analysis. The results show that on well‐drained middle to upper slopes the regional gradient in mean annual rainfall is the main factor controlling soil morphology, vegetation formation and species composition. Local deviations from the regional patterns result from topographic modifications of the regional climate or variations in soil drainage impedance. Other minor variations in vegetation species composition may be the result of small differences in soil texture or fertility.
A comparison of some populations of Eucalyptus viminalis Labill. growing on calcareous and acid soils in Victoria, Australia
Authors: LADIGES PAULINE Y. , ASHTON D. H. 
Published: July 2006

AbstractA study of populations of Eucalyptus viminalis found on both acid and alkaline soils showed that seedlings differ in their tolerance of calcareous soils and their susceptibility to lime chlorosis.Seedlings from an open‐forest population on calcareous dunes in the Otway Ranges, Victoria, averaged a significantly greater yield than seedlings of three other populations found on acid soils when all were grown on calcareous soil of pH 6.8. A tall ribbon gum form of E. viminalis, from Paradise gully in the Otways, was the least tolerant of alkaline conditions and showed severe signs of chlorosis and reddening of leaf margins. The latter appeared to be related to high uptake of phosphorus. This population showed rapid growth on a fertile acid loam.The data presented also emphasize the need to consider the variation in soils which can occur at any one site. Population differences were most marked when seedlings were grown on soils of pH near 7.0. Yield was reduced in the Otways calcareous population when seedlings were grown on the more leached soil from swales (pH 6.5) between dunes and on the highly calcareous soil from the dune crests (pH 7.8–8.0).The failure of any of the populations of E. viminalis studied to grow well on soils of high pH suggest that this species is not tolerant of highly calcareous soils. This may in part explain the absence of this species from the drier calcareous areas on the Mornington Peninsula and the Yanakie Isthmus, Victoria. Since seedlings had reduced root development on the soil collected from the Peninsula, E. viminalis may be restricted, in effect because of drought stress, to non‐calcareous sites in the eastern part of Victoria.
Observations on changes in the quality of food eaten by the wild rabbit*
Authors: MYERS K. , BULTS H. G. 
Published: July 2006

AbstractThe quality of the food eaten by rabbits can be predicted from the quality of the recently ingested food in the anterior portion of the stomach using the equation: crude protein in food (% dry weight) = 1.42 × crude protein in stomach (% dry weight).The relationship which food bears to the ecology of rabbits differs from population to population. In semi‐arid north‐western and mediterranean New South Wales changes in food quality are closely related to changes in climate and to various important aspects of rabbit biology. In southern Queensland and subalpine New South Wales, quality of food in the stomach is less significantly related to changes in climate and the biological parameters measured.
A note on the selection of seed types by harvester ants in northern Australia
Authors: MOTT J. J. , McKEON G. M. 
Published: July 2006

AbstractSeed harvesting ants (mainly Pheidole spp.) in the Katherine area of the Northern Territory have been observed to actively forage seed in both native and sown pasture areas. Using discrete mixtures of seeds it was found that ants from colonies in both sown and native pastures would preferentially remove seed of the native grass species, Themeda australis and Digitaria ciliaris, to the introduced legume Stylosanthes humilis. This difference in selection could not be explained solely on a basis of size or weight differences between the species.The preference for grass species over introduced legumes indicates that ant predation is not the main factor in the low seed survival to germination in introduced pastures.
An improved model for simulating the penetration, propagation and absorption of radiation within plant canopies
Authors: TORSSELL B. W. R. , McPHERSON H. G. 
Published: July 2006

AbstractA mathematical model for simulating the penetration, propagation and absorption of radiation within crop canopies of random leaf distribution is presented. Although the treatment of radiation penetration is based on well known theory, a new approach is developed for tracing the quantity and direction of reflected and transmitted radiation. This approach allows for multiple reflection and transmission up to any required level of accuracy, reflection from the soil, upward as well as downward flux and provides an explicit account of the quantities and direction of scattered radiation. These features will be of most significance at wavelengths where absorption is lowest such as the near‐infrared wavebands which are important in remote sensing applications. The approach taken also allows for more flexible consideration of foliage angle which will be most relevant in the photosynthetically active waveband where absorption is high.The predictions of the downward and upward travelling flux densities are compared under ideal conditions with measurements made in canopies of known architecture with three different species, under both clear and overcast skies. Good agreement was obtained in all cases. The expected model deviation in the case of non‐random foliage distribution is demonstrated, and the implications for further model development indicated.
Aspects of the biology of the Japanese snipe Gallinago hardwickii
Authors: FRITH H. J. , CROME F. H. J. , BROWN B. K. 
Published: July 2006

AbstractThe Japanese snipe Gallinago hardwickii breeds in Japan and migrates south, through New Guinea, to spend the southern summer in Australia. There is no acceptable evidence yet that it reaches the continent other than in north Queensland. Its movement in Australia is mainly coastal Most of the population spends the summer south of the Richmond River, New South Wales: elsewhere it is a passage migrant. Little is known of the movements of individual birds as few have been banded. The distribution of the species and that of G. megala in Australia is discussed.There is no evidence of sexual activity whilst the birds are in Australia. Pre‐migratory fattening begins in February and in birds that had spent the summer in the highlands most fattening takes place at lower altitudes. There is a complete moult while the birds are in Australia. The food consists of animal and plant material, including seeds. The principal animals eaten are the larvae of insects and earthworms.In Japan the bird breeds away from water in grassland, often in elevated dry situations. In Australia it frequents highland and lowland freshwater and occasionally saline habitats. In Japan much habitat has been destroyed but areas cleared for re‐afforestation provide suitable breeding places and the continued production of these disclimax communities results in regeneration of suitable breeding habitat. In Australia most habitat alteration is detrimental to the species and hence its population is not secure.
Field measurements of ingestion and assimilation for the Australian brine shrimp Parartemia zietziana Sayce (Crustacea: Anostraca)
Authors: MARCHANT R. , WILLIAMS W. D. 
Published: July 2006

AbstractIngestion and assimilation of the brine shrimp Parartemia zietziana were measured in the field. Populations in Pink Lake and Lake Cundare were used; both lakes are shallow (< 1 m), saline (> 60°/00), and located in western Victoria; they have tow primary production. P. zietziana relies largely on organic matter in lake sediment for food. Ingestion rate was measured in situ in Pink by following the uptake of 14C from labelled sediment. The rate of faecal pellet production was measured (in both lakes) by allowing animals to defaecate for 24 h in a net suspended in the lake. Ingestion rate varied from 0.35 to 13 01 × 10–1 mg dry wt h‐1 individual‐1 for a range in dry weight of shrimp from 0.2 to 2.3 mg individual‐1; for a similar range in weight, defaecation varied from 0.08 to 2.03 × 10‐1mg dry wt h‐1 individual‐1. These rates were converted to joules and assimilation efficiencies of 30–60% calculated. Regressions showed that change in dry weight of shrimp accounted for > 90% of the variance in both rates.
The gum tree thrips Isoneurothrips australis Bagnall. Survival at different temperatures and humidities and its relation to capacity for dispersal
Authors: LAUGHLIN ROGER 
Published: July 2006

AbstractThrips are carried long distances on the wind. Their ability to survive periods of fasting may determine their chance of completing such journeys alive. Thrips’survival was measured at various temperatures and humidities. Survival is best related to saturation deficit. This relation can be combined with meteorological data to calculate the survival time of thrips migrating at various times of year. From May to September inclusive a thrips can probably survive over 24 h in the air and runs little risk of death from desiccation. From December to March survival times average about 6h but can be as low as 3h on hot summer days.
Themeda australis grasslands on the Basalt Plains, Victoria: floristics and management effects
Authors: STUWE J. , PARSONS R.F. 
Published: July 2006

Abstract The floristic composition of remnants ofThemeda australis grasslands from basaltic areas of western Victoria was described using methods employed by the Zürich‐Montpellier school of phytosociology.Most sites sampled were managed by either regular burning (rail sites) or grazing, or were not subject to any regular management practices (roadside sites). Rail sites contained relatively open, species‐rich vegetation with a smaller proportion of introduced species than the other two types of site. Grazed paddock sites contained relatively open, species‐poor vegetation, whilst roadside sites contained relatively dense, species‐poor vegetation. Such site differences appear to be related to the effect of management practices upon the competitive ability of T. australis and to species tolerance of them.
The function of sound in male spacing behaviour in bush‐crickets (Tettigoniidae, Orthoptera)
Authors: THIELE D. , BAILEY WINSTON J. 
Published: July 2006

AbstractThis paper examines the spatial dynamics of an aggregation of singing male bush‐crickets (Tettigoniidae) in respect to the degree of regularity between males. Our results establish that singing males of the genus Mygalopsis are regularly spaced within aggregations and that sound is involved in spacing. Attention is focussed on the male strategy of regular spacing within a widely dispersed aggregation in order to attract females reaching sexual maturity within the confines of that population. This is seen as an alternate to male aggregations attracting females from outside their boundary.