bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Geographical Variation in Seedling Morphology of Three Closely Related Red Mahoganies, Eucalyptus Urophylla, E. pellita and E. scias
Authors: Pinyopusarerk K , Gunn BV , Williams ER , Pryor LD
Published: December 2005

Twenty two populations of Eucalyptus urophylla, 13 of E. pellita and two of E. scias were selected throughout the species' natural distributions in Indonesia, Papua New Guinea and Australia, and the morphology of seedlings compared under greenhouse conditions. Leaf length, width, length/width ratio, base angle, stem shape and, to a lesser extent, intranode length provided good discrimination between species and provenances. Canonical variate analysis revealed four groups, two of which contain E. urophylla, one E. pellita and one E. scias. Wetar Island provenances formed one of the two E. urophylla groups, distinguished from the other group consisting of Alor, Adonara, Flores, Pantar and Timor provenances on the basis of narrower leaves, greater length/width ratios, more acute leaf base angles and square stems. Seedling leaves of E. pellita were generally longer and broader than the other species, with a tendency for a separation between the northern occurrences (New Guinea and northern Cape York Peninsula, Queensland) and southern occurrences (Helenvale to Rockhampton, Queensland); those from the north had smaller leaves and more distinctly square stems. E. scias is clearly distinguished by its narrower leaves and longer intranode length.
Fruit and Seed Structure of Thryptomene calycina (Myrtaceae)
Authors: Beardsell DV , Knox RB , Williams EG
Published: December 2005

At anthesis the receptacle of flowers of T. calycina (Lindl.) Stapf is enclosed by a layer of small cells with a thick cuticle. The hypodermis consists mostly of large oil-containing cells interspersed with much smaller cells. The tissue surrounding the ovary consists mostly of spongy parenchyma. The micropyle of the ovule is formed only by the inner integument which is double-layered. The embryo sac at anthesis is typical of the Myrtaceae, and appears to follow the monosporic polygonum type, with considerable nucellar tissue surrounding it. In a mature fruit the parenchyma is compressed into a thin band surrounding the seed. The integuments form a two-layered seed coat within the fruit. The aborted ovule is displaced below and to one side of the developing seed. In fruit weathered for several years there is an accumulation of phenolic material giving the fruit a black appearance. The two layers of the seed coat within freshly shed fruit lie closely together and stain strongly with the lipid stain auramine O. In fruit weathered for at least 2 years the two layers of the seed coat become separated for at least part of their length and staining from auramine O is less intense. The breakdown in seed dormancy in weathered fruits is probably due to a less complete barrier to water uptake provided by the separation of the two layers. This would increase lateral and radial movement of water. The observed reduction in the hydrophobic lipid content of the testa layers probably also aids water entry into the seed in a weathered fruit.
Genotype and Environment Strongly Influence Barley Anther Culture Response Using Australian Genotypes
Authors: Logue SJ , Giles LC , Sparrow DHB
Published: December 2005

A screening of several Australian barley cultivars of commercial interest has identified a number of genotypes that respond well to anther culture, with average levels of green plant regeneration between 23 and 134 plants/100 anthers cultured. Donor plant growth conditions have a large impact on anther culture response and, although optimal conditions for specific genotypes could possibly be identified, it is likely to be more effective for the production of large numbers of doubled haploids to settle for a broadly acceptable environment. Recent advances in methodology and the identification of responsive genotypes makes anther culture a feasible procedure for Australian barley breeding programs.
Mineral Nutrition In vitro ̵1 a Mechanistic Approach
Authors: Williams RR
Published: December 2005

The supply of minerals in the medium is an essential part of plant tissue culture systems. Currently used media are largely based on empirical modifications to a few basic formulations. Optimum requirements vary widely between plant genotypes and culture systems and, as yet, it is not possible to predict the mineral requirements of untried species. A more mechanistic approach is presented which may improve this situation. Published literature and some current research aimed at a better understanding of the process of mineral nutrition in vitro are reviewed.
The Environmental Relations of Vegetation Pattern on Chenier Beach Ridges on Bathurst Island, Northern Territory
Authors: Fensham RJ
Published: December 2005

Radiocarbon dates confirm a chronological sequence for late Holocene beach ridges at Wangiti Beach on Bathurst Island. The vegetation on these beach ridges can be clearly related to topography and distance from the sea. Monsoon rainforest occurs on the fore-dunes where the nutrient levels of the young sediments are relatively high. The mid-dunes support woodland dominated by Melalueca viridiflora and have nutrient-poor acid soils. Vegetation with a high component of monsoon rainforest species occupies the rear dunes, which have a high concentration of seawater macronutrient cations despite their older age than more seaward dunes. The relatively low elevation of the rear dunes supports the suggestion that soil nutrient levels are enriched by sea water or marine sediments during infrequent inundation events such as those during cyclones.
What Induces Central Australian Arid Zone Trees and Shrubs to Flower and Fruit?
Authors: Friedel MH , Nelson DJ , Sparrow AD , Kinloch JE , Maconochie JR
Published: December 2005

We developed two sets of regression models for flowering and fruiting of arid zone trees and shrubs, based on (i) rainfall in the current and preceding seasons and (ii) soil moisture lagged over varying time periods combined with mean maximum temperature and daylength in the month prior to phenological observations. Using up to 4 years of flowering and fruiting records, we found that both approaches identified responses matching those reported in two other long-term data sets or in the literature, for some species but not for all. The second approach appeared to provide better correlations than the first but we were unable to predict flowering and fruiting effectively. Flowering and fruiting of central Australian trees and shrubs were least in late summer, creating potential limitations on animal populations dependent on them for food. With better predictive capabilities, there is some scope for managing the trees and shrubs for particular purposes. However, very long-term phenological records are needed to improve predictions.
A Major Disjunction in Genetic Diversity Over the Geographic Range of Acacia melanoxylon R.Br
Authors: Playford J , Bell JC , Moran GF
Published: December 2005

A study of allozyme variation in Acacia melanoxylon R. Br. in 27 populations from across the geographic range of the species indicated high genetic diversity compared to other Australian trees and plants generally. Clines of increasing genetic variability with increasing latitude were found for four measures of genetic diversity. Most of the genetic diversity is found within populations but there was an unusually high level of the variation between populations (37.7%). A distinct genetic separation between the northern and southern populations was located approximately at the Hunter River region, where there is also a disjunction in the distribution of the species. The Nei (1978) genetic distance between these populations within this species is larger than observed between some plant species. Clearly the species has evolved separately in the two regions for a considerable time.
Pollinator Requirements and Flowering Patterns of Macadamia integrifolia
Authors: Heard TA
Published: December 2005

A study of insect pollination of macadamia, Macadamia integrifolia Maiden & Betche (Proteaceae) was undertaken in southern Queensland. Both initial nut set and final nut set increased with increasing insect visitation. Pollination was not limiting yield at this site, however, as racemes exposed to 6 h of bee visitation per day had similar final nut set to racemes constantly exposed (10 h of bee visitation). Honey bees and Trigona spp. bees visited the racemes in approximately equal numbers at the site. Approximately 50 bee visits were made per day to the racemes exposed for 6 h. Individual flowers remained attractive to insects for approximately 3 days. Hence approximately 150 visits per raceme are required to ensure adequate pollination. The flowers on a raceme opened over a period of approximately 7 days with peak opening at around day 2. Flowers opened during the day, peaking in the early afternoon.
Selective Fruit Abortion in Grevillea barklyana (Proteaceae)
Authors: Harriss F , Whelan RJ
Published: December 2005

The breeding system of Grevillea barklyana F. Muell. ex Benth. was studied using experimental hand pollinations. Fruit set was generally low (less than 5%), and equivalent for autogamy, self-pollination, outcross-pollination and inflorescences left exposed to natural pollination. Pollen tubes were produced in only a low proportion of flowers in the autogamy treatment, with few pollen tubes per flower and short pollen tubes in styles at both 24 and 48 h after anthesis. Selfing and cross-pollination produced equal numbers of pollen tubes in an equivalent and high proportion of flowers (ranging from 40% to 80%). However, pollen tubes resulting from selfing were shorter than from outcrossing after 24 and 48 h. Hand pollination experiments in which half of the flowers on inflorescences were pollinated with self pollen and the other half with outcross pollen generally produced a slightly skewed pattern of fruit set, with a higher proportion of the outcrossed flowers setting fruit. The following processes could contribute to the selective development of outcrossed fruit in this self-compatible species: (1) pollen tubes from outcrossed pollinations reach ovules before those growing from self pollen; (2) fruits that start to develop first obtain first call on limited resources; (3) fruits that are initiated later abort when other fruits on an inflorescence are developing.
Contrasting Diaspore and Vegetation Attributes of Grasses From Natural and Disturbed Habitats in an Urban Eucalypt Forest Reserve
Authors: Odgers BM , Rogers RW
Published: December 2005

Forty one species of grasses from a eucalypt forest reserve near Brisbane, Australia, were allocated to groups characteristic of undisturbed forest, regularly mown areas, and road banks. Morphological attributes of diaspores, height and growth habit of mature plants, species origin, flowering times and life history were determined for each species. Species characteristic of the mown areas had lighter diaspores than the forest gasses and did not possess awns; if a callus was present it was blunt and did not have antrorse hairs. Species from mown areas also differed from the forest species in being mainly short stoloniferous exotics which flowered for longer than the forest species. Species characteristic of the natural forest and road bank areas had diaspores of similar mass, similar diaspores attributes (awns, callus and antrorse hairs) and species of both habitats were mainly tall and tufted. The road bank species differed from the forest species in being mainly of exotic origin and in flowering for up to 9 months per year longer than the forest species. That grass species of mown areas successfully compete with forest species in mown areas may be because of a mowing regime which selects for short, mainly stoloniferous, species which have longer periods of diaspore production than the forest species. As road banks are not subjected to regular mowing, an extended pattern of flowering which ensures a continuous supply of diaspores may account for road bank species successfully competing with forest species in disturbed areas.
Key Periods in the Evolution of the Flora and Vegetation in Western Tasmania .I. The Early-Middle Pleistocene
Authors: MacPhail MK , Jordan GJ , Hill RS
Published: December 2005

The relatively simple flora and structure of Nothofagus cunninghamii cool temperate rainforest in Tasmania is widely accepted to be the result of repeated glaciation during the Pleistocene. Plant macrofossils, spores and pollen preserved at Regatta Point, western Tasmania, indicate that several gymnosperms and subcanopy angiosperms with warm temperate affinities had survived one to several episodes of cold, possibly glacial climates, before becoming extinct in the early to middle Pleistocene: Callitris/Actinostrobus, Dacrycarpus, Austromyrtus, Eucalyptus spathulata-type, Haloragodendron-type, Loranthaceae, Quintinia and Symplocos. These co-existed in Nothofagus-Lagarostroboss franklinii rainforest with a number of taxa that are now restricted to upper subalpine-alpine habitats in Tasmania, such as Astelia, Gunnera and Microcachrys. The community is difficult to interpret in terms of modem species and we propose that either extinct taxa are being concealed by essentially modern pollen morphologies, that ecological preferences have altered since the early-middle Pleistocene, or both. Patterns of extinctions in Tasmania (and New Zealand) suggest that Pleistocene climatic change at middle-high latitudes presented an environmental stress not previously experienced during the Cenozoic, perhaps through widespread periglacial conditions, but also provided ecological and evolutionary opportunities for rainforest species tolerant of a wide range of conditions experienced during the late Pleistocene.
Floral Morphology, Biology and Sex Allocation in Disjunct Populations of Christmas Bells (Blandfordia grandiflora, Liliaceae) With Different Breeding Systems
Authors: Ramsey M
Published: December 2005

Evolutionary shifts in breeding systems are often accompanied by changes in reproductive attributes
such as floral morphology and biology, and pre- and post-zygotic allocation patterns. The effects
of breeding system variation on several such attributes were examined in self-fertile tableland
and outcrossing coastal populations of Blandfordia grandiflora R. Br. In general, overall flower
size was similar in both populations, although pedicel and pistil stipe diameters were greater in
coastal plants, and pistil length and stigma-anther separation were greater in tableland plants.
Although all floral parts from coastal flowers weighed more, proportional biomass allocation to
floral parts was similar in both populations. Daily nectar production per flower was similar
in both populations. Tableland flowers produced more ovules but fewer pollen grains than did
coastal flowers. Pollen-ovule ratios were 11 500 in coastal flowers and 5600 in tableland flowers.
Open-pollinated tableland fruits produced more seeds than coastal fruits, but individual seeds
weighed less; total seed biomass of tableland fruits was greater than coastal fruits. Prezygotic
relative male biomass did not differ significantly between populations. Relative male biomass,
estimated from stamen and seed weights, was 5% greater in coastal plants, although populations
did not differ significantly. Similarly, relative biomass allocation to pollinator attraction (i.e.
coralla and nectar) did not differ between populations. The onset and duration of stigmatic
receptivity and pollen longevity of flowers from the two populations were similar.
The large differences in ovule, seed and pollen production supports sex allocation theory
which predicts that in self-fertile plants resource allocation should be female biased whereas
in outcrossing plants, allocation should be male biased. The lack of differences between the
Christmas bell populations in other aspects of floral morphology, allocation pattterns and biology
suggests that changes in ovule and pollen production precedes changes in other traits during the
evolution of autonomous selfing. Overall, these findings suggest that tableland plants may have
evolved self-fertility only recently and selection has had insufficient time to change floral traits.
Alternatively, self-fertility may not have evolved recently and floral traits promoting outcrossing
have been maintained by selection, imposed by inbreeding depression and/or overdominance.
Base-Line Studies of Temperate Mangrove Growth and Reproduction; Demographic and Litterfall Measures of Leafing and Flowering
Authors: Clarke PJ
Published: December 2005

Growth and reproduction in two species of mangrove, Avicennia marina and Aegiceras corniculatum, were measured over three years in Jervis Bay, New South Wales, by demographic censuses of leaf and floral components supplemented by litterfall collections. Sampling was designed to assess spatial and temporal variability for purpose of a baseline against which future variation can be compared. In terms of annual litterfall Avicennia produces about 310 g/m2 whereas Aegiceras produces 210 g/m2 with 9.2 and 32.2 % of litterfall respectively devoted to reproductive parts. Both mangrove species showed much spatial and temporal variation in growth and reproduction and, in general, leafing and litterfall declined from 1989 through to 1990. This decline may be related to regional climatic phenomena but longer-term data are required to confirm this relationship. Over the period of a year, Avicennia and Aegiceras each has a single peak of leafing and reproduction, although the timing of this differs between them. Phenologically, in both species, reproductive events and leaf demography were correlated. It is suggested that demands of precocious embryos for assimilates affects the timing of leafing. The relatively high resource demand of the reproductive pool may also be a factor that contributes to low productivity and stature at high latitudes.
A Time-Dependent Model of Fire Impact on Seed Survival in Woody Fruits
Authors: Mercer GN , Gill AM , Weber RO
Published: December 2005

Many plants rely on the survival of seed in woody fruits for their post-fire regeneration. A mathematical model of seed survival in woody fruits was constructed using heat-flow equations with time-dependent temperature inputs. The model was then used to predict the survival of seed in fruits exposed to both laboratory heating and field fires as reported in the literature. Due to a lack of data for woody fruits, thermal diffusivity values appropriate to bark were used as inputs. The lethal threshold temperature for seeds was taken as 70°C which is at the lower end of the range reported in the literature. The inclusion in the model of thermal arrest within fruits gave the upper bounds for estimated times of seed survival. The model yielded reasonable predictions of seed fate when compared with experimental results. It was shown that the location of seed within the fruit is not critical to its survival provided it lies within the central core of the fruit. The applicability of the model was also demonstrated using published time-temperature curves from experimental fires.
Mixed Mating in Banksia brownii Baxter ex R. Br. (Proteaceae)
Authors: Sampson JF , Collins BG , Coates DJ
Published: December 2005

Mating system parameters of the rare and endangered species Banksia brownii were estimated for two populations using both the mixed mating and effective selfing models. Estimates of outcrossing rate were similar in both populations for both models (mixed mating t Pop. 1=0.68, Pop. 2=0.75; effective selfing t Pop. 1=0.65, Pop. 2=0.73) and were among the lowest reported for undisturbed Banksia populations. Banksia brownii is killed by fire and the high level of selfing found may be associated with this trait. Multilocus and minimum variance mean i estimates were similar and the covariance of selfing with gene fixation (D) was not significantly different from zero indicating that populations were not structured and that most of the inbreeding was the result of self-fertilisation. The absence of structure was attributed to gene dispersal through pollen disperse by birds, and selection against inbred seed. It is suggested that several entire, large populations of this species together with habitat sufficient to support pollinators be reserved to conserve this species.
Phyllocladus aspleniifolius: Variability in the Population Structure, the Regeneration Niche and Dispersion Patterns in Tasmanian Forests
Authors: Barker PCJ , Kirkpatrick JB
Published: December 2005

This study aimed to determine the range of the regeneration niches of Phyllocladus aspleniifolius (Podocarpaceae) in terms of differential microsite occupation, population structure and dispersion pattern at 50 sites. The distribution and sizes of stems were mapped on belt transects to within 0.5 m, and the microsites of seedlings and saplings were recorded. A variety of population structures exist and are related to community floristics and structure. Community variation provides different microsite opportunities. Phyllocladus aspleniifolius showed a preference for elevated sites, including logs, buttresses and old stump mounds. Aggregation of regeneration is common and is determined by microsite distribution and seed dispersal characteristics. It is concluded that although the regeneration of P. aspleniifolius is favoured by catastrophic disturbance, smaller scale processes such as those evoked in the concept of non-equilibrium coexistence are likely to allow P. aspleniifolius to persist in all communities throughout its range in the absence of large scale disturbances.
Measuring the Diameter of Xylem: a Short Communication
Authors: Mapfumo E
Published: December 2005

The magnitude of error in estimating axial resistances was assessed using the diameters of xylem vessels of different shapes, measured using four different methods. Statistical analyses showed that the diameter measurements obtained using the different methods, were significantly different at the 0.001 level of significance. Using the Tukey test, the diameters obtained using the 'four axes' method were not significantly different from the actual diameters obtained using the Chromatic Color Image Analysis System. By using the 'Lewis' method for measuring the xylem diameter, axial resistance was overestimated by a factor of 1.6. Thus, the error caused by the method of measurement may partly explain why, in some studies, the estimated axial resistances have always been different from the measured resistances. The 'four axes' method is the simplest and most reliable and gives results very close to the actual diameters, compared with the other three methods.
Seed Banks and Vegetation of Three Contrasting Sites in an Urban Eucalypt Forest Reserve
Authors: Odgers BM
Published: December 2005

Grass species, sedges and dicotyledons in the vegetation and the buried germinable seed of a natural
subtropical eucalypt forest, a mown and a road bank site were identified in four consecutive seasons and
the data pooled to give a more precise assessment of taxa present each year. Differences in the relative
proportions of taxa, differences in species density, origin and life history of grass species in the seed
bank and vegetation, as well as differences in biomass and rate of germination of buried germinable
grass seed, in the three sites were investigated. In all three sites, grasses were the dominant taxa of the
ground stratum of the vegetation with each site having its own group of mainly perennial grasses. The
seed banks were dominated by grasses in the forest site, sedges in the mown site and dicotyledons in the
road bank site.
There were significant differences in species density of grasses in both the vegetation and buried
germinable seed between sites, with the forest site having a significantly lower species density in its
seed bank than the mown and road bank sites, and the vegetation of the forest and mown sites having a
lower species density than the road bank site. However, there was a high correlation between the grass
species of the vegetation and the buried germinable seed in each of the three sites - the species which
dominated the vegetation also dominated the biomass of buried germinable seed in each site. The mown
and road bank sites had larger numbers and biomass of buried germinable grass seed than the natural
forest site. There were no differences in the number of days to first germination and the number of days
to 50% germination of the buried germinable seed between any of the sites. Exotic grass species were
present in the seed banks of the forest, mown and road bank sites. Exotics were prevalent in the
vegetation of the mown and road bank sites but not evident in the vegetation of the forest site. Exotic
species with higher buried germinable seed numbers and similar germination rates to the native species
are likely to have a competitive advantage over the native species. It appears that the mown and road
bank sites, may act as reservoirs for the more competitive exotic grass species, enabling them to invade
the seed banks of the forest areas.
The Spatial Pattern and Scale of Variation in Eucalyptus globulus ssp Globulus: Variation in Seedling Abnormalities and Early Growth
Authors: Potts BM , Jordan GJ
Published: December 2005

Variation in seedling abnormalities and 2- and 4-year growth were studied in a trial in north-westem
Tasmania established from 594 open-pollinated families from throughout the geographical range of
Eucalyptus globulus Labill. ssp, globulus and populations intergrading with other subspecies. Most
(77-80%) of the total (phenotypic) variation in growth traits occurred within families. The genetic
variation between families within localities (within c. 10 krn; 13-15% of the total variation), between
localities within regions (within c. 100-150 km; c: 4%) and between regions (3-8%) was generally
highly significant. However, regional and locality components together accounted for only a small
proportion of the total phenotypic variation. Little differentiation was detected between separate
sampling sites within localities. Estimates of individual narrow-sense heritabilities were markedly
higher than previous reports and were 0.38 for conic volume and 0.41 for height at 4 years, assuming a
coefficient of relatedness of 0.4 amongst open-pollinated sibs. On average, progenies from the Otway
Ranges region were the fastest growing at the test site, followed by those from King Island. Parent trees
with high breeding values were concentrated in the Otway Ranges, Strzelecki Ranges and far southeastem
Tasmania with the Bass Strait island localities having intermediate frequencies.
Forest fragmentation through clearing for agriculture appears to have had a deleterious effect on the
quantitative genetic structure of intergrade populations consistent with high levels of inbreeding.
Remnant populations tended to have higher levels of severely abnormal seedlings, higher mortality and
poorer growth, and higher heritability estimates and variability both within and between families.
Advanced generation hybridisation and inbreeding due to long periods of isolation in small, relict
populations may also have had similar effects. Populations sampled are, therefore, likely to have
markedly different levels of inbreeding which may have inflated differences between localities and may
have important consequences for the exploitation of this material for breeding.
The Expansion of Leptospermum laevigatum on the Yanakie Isthmus, Wilson's Promontory, Under Changes in the Burning and Grazing Regimes
Authors: Bennett LT
Published: December 2005

The distribution of selected vegetation types on the Yanakie Isthmus, Wilson's Promontory National
Park, was mapped from aerial photographs from 1941, 1972 and 1987. The main changes in the
vegetation dynamics were: (1) an expansion of Leptospevmum laevigatum into grasslands and into
Banksia integrifolia woodlands with herbaceous understoreys, and (2) a stabilisation of dunes by shmbs
dominated by Leptospennum laevigatum. The total area of L. laevigatum shrubland and scrub increased
from 2179 ha in 1941 to 3436 ha in 1972 and 4516 ha in 1987. Land-use changes in this period
included the exclusion of fire in the early 1970s, after a history of regular burning, and an increase in
grazing pressure primarily due to population expansions of the rabbit and the eastern grey kangaroo.
Fire was not a prerequisite of the L. laevigatum expansion on the Isthmus because the spread continued
after fire was excluded; nor was fire the primary cause of the expansion because the percentage yearly
increase in the area of L. laevigatum was, on average, similar before and after 1972. An increase in
grazing pressure was identified as the probable cause of the L. laevigatum expansion due to: (1) the
exposure of bare ground, and (2) the restriction of the feeding range of cattle (known to graze both
L. laevigatum and Acacia sophorae on the Isthmus).
Stimulation of Germination of Quandong (Santalum acuminatum) and Other Australian Native Plant Seeds
Authors: Loveys BR , Jusaitis M
Published: December 2005

Intact seeds of quandong (Santalum acuminatum), Ixodia achillaeoides, Ptilotus exaltatus, Codonocaupus pyramidalis and Exocarpos aphyllus which are normally difficult to germinate responded to vacuum infiltration with gibberellins. In most cases GA4 was far more effective than GA3. Cytokinins, ethylene and silver ions did not affect quandong germination but abscisic acid (ABA) was inhibitory. If imbibed quandong seeds were subject to a rapid drying and re-wetting cycle, subsequent germination was inhibited. This transient drying was associated with a rise in endogenous ABA and the effect of the drying could be overcome by gibberellin. There was no correlation between ABA level and state of dormancy in recently imbibed seed suggesting that ABA was not necessary for the maintenance of dormancy. These results suggest that the mechanisms controlling quandong seed germination are hormonally based although the mechanical constraints imposed by the rigid shell may also be important.
The Effect of Photoperiod, Temperature and Photon Flux Density on Flowering in Pimelea ciliata
Authors: Slater AT , Franz PR , Thompson WK
Published: December 2005

A range of photoperiods were investigated to determine their effect on newer induction in Pimelea ciliata. Temperatures and photon flux densities were also investigated to determine their effect on modifying the response to photoperiod. Pimelea ciliata developed flowers on all plants after exposure to at least 4 weeks of an 8 h photo- and thermoperiod at a high photon flux density. As the time under the 8 h photo- and thermoperiod increased, the total number of flowers produced and the percentage of buds which were floral on each flowering plant increased. Plants gown under a 16 or 10 h photoperiod for up to 8 weeks did not produce any flowers. Under a 12 h photoperiod, only two plants out of 36 flowered, and they produced a low number of flowers. Under the conditions tested, temperature had no apparent effect on the number of plants which flowered or the number of flowers on each flowering plant. However, a vernalisation response may be increasing the rate of flowering. The flowering response was reduced when plants were grown under a low photon flux density. Few plants produced flowers, and the percentage of shoots that were floral was also reduced under low light.
Long-Term Vegetation Change in Relation to Cattle Grazing in Sub-Alpine Grassland and Heathland on the Bogong High-Plains: an Analysis of Vegetation Records From 1945 to 1994
Authors: Wahren CHA , Papst WA , Williams RJ
Published: December 2005

Changes in vegetation composition and structure are described for grassland and heathland communities on the Bogong High Plains, in the Victorian Alpine National Park. The data are based on long-term records collected from permanent reference plots over the period 1945 to 1994 from plots established in 1945, 1946 and 1979. In the Pretty Valley grassland plots, established in 1946, cattle grazing has prevented the large-scale regeneration of a number of tall, palatable forbs and short, palatable shrubs, while in the absence of grazing, the cover of these Life forms increased substantially. The amount of bare ground and loose litter was significantly greater on the grazed compared with the ungrazed plot. Between 1979 and 1994, there was little or no identifiable trend in the cover of Vegetation or bare ground at either the Pretty Valley grazed site, or two additional grazed grassland sites established nearby in 1979. The current condition of grazed grassland on the Bogong High Plains is interpreted as stable, yet degraded. Improvement in condition will occur in the absence of grazing. In the Rocky Valley open heathland plots, established in 1945, increases in shrub cover over the study period were due to growth of shrubs following the 1939 bushfires that burnt much of the Bogong High Plains. From 1945-1979 shorter-lived shrubs increased in cover; since 1979, these shrubs have senesced, and are being replaced mainly by grasses. On the grazed plot longer lived, taller shrubs have continued to increase in cover and are not senescing. Between 1979 and 1989, total shrub cover declined on the ungrazed plot, but increased on the grazed plot. There was no evidence that grazing has reduced shrub cover, and therefore potential fire risk, in open heathland. These findings have significant management implications for the Alpine National Park and are consistent with those from other regions in the Australian alps.
Germination in Stylosanthes humilis Populations in the Presence of NaCl
Authors: Lovato MB , Martins PS , Lemos Filho JPD
Published: December 2005

The germination response to NaCl treatments (0, 67, 134, 201 and 268 mol m-3) was investigated in 6 natural populations of Stylosanthes humilis from 3 ecogeographic regions of Pernambuco State, north-east Brazil. In general, salt tolerance was high, with percentage germination unaltered up to 67 mol m-3 NaCl in 2 populations and unaltered up to 134 mol m-3 NaCl in the remaining 4. The estimated concentration which reduced percentage germination to 50% varied between populations from 200 to 295 mol m-3 NaCl. Salt affected germination rate even more than it did the germination percentage, being altered at 67 mol m-3 NaCl in all populations. The germination rate was reduced to 50% in the range of 131-176 mol m-3 NaCl. There was a significant variation in salt tolerance between these natural populations, and no relation was found between salt tolerance of the populations and the aridity of their provenance.
The Ash-Bed Effect in Eucalyptus regnans Forest: Chemical, Physical and Microbiological Changes in Soil After Heating or Partial Sterilisation
Authors: Chambers DP , Attiwill PM
Published: December 2005

The ash-bed effect (the enhanced growth of plants on soil which has been heated) following fire in Eucalyptus regnans forest is dramatic. The results are presented of studies of the effects of a range of heating and partial sterilization treatments on chemical, microbiological and physical properties in soil from a 250-year-old E. regnans forest in Victoria. Soil treatments not involving heat (chemical sterilization, γ -irradiation and air-drying) and the lower temperature heat treatments (100 and 200°C) had no marked effects on physical characteristics. All treatments produced more or less similar effects on microbial populations. On the other hand, heating the soil to 400-600°C produced large, significant and sustained increases in the availability of nitrogen and phosphorus and these increases were enhanced by a decrease in clay colloid. The results support the hypothesis that the ash-bed effect following fire in E. regnans forest is due to an increase in the availability of nutrients, and in the availability of nitrogen and phosphorus in particular. A transitory increase in the concentration of manganese caused by heating the soil may account for initial toxicity in plants grown in soils which have been heated. Since species within the subgenus Monocalyptus are characterized by lower tissue concentrations of manganese than those within Symphyomyrtus, it could be hypothesized that the potential for toxicity following bushfire varies between the two subgenera. The literature on the effects of soil-sterilising treatments is highly variable; the causes of variability include soil type and moisture content, treatment (sterilizing by steam, chemicals or heat) and the method of treatment (time, how the soil was contained, and how the treatment was applied).
Andromonoecy and Fruit Set in Leptospermum myrsinoides and L. continentale (Myrtaceae)
Authors: Obrien SP
Published: December 2005

Leptospermum myrsinoides and L. continentale (Myrtaceae) are andromonoecious. All flowers of these species are potentially bisexual in function and male flowers result when pistil development ceases after floral initiation. All male flowers possess vestigial pistils. The proportion of male flowers within three populations was recorded over three seasons. In both species, the proportion of male relative to bisexual flowers increased as the flowering season progressed. A strong relationship exists between flower sex and branch position, with bisexual flowers tending to occur on upper and outer positions on plants. Fruit set is not limited by pollination but by some other resource, possibly nutrients. Whilst andromonoecy sets the upper Limit of the number of fruit which may be formed, the number of fruit set on a plant is always less than the number of bisexual flowers. It is suggested that andromonoecy in L. myrsinoides and L. continentale is an evolutionary response to low resource availability allowing optimal resource allocation to reproduction in these species.
Pattern and Change in an Acacia aneura Shrubland and Triodia Hummock Grassland Mosaic on Rolling Hills in Central Australia
Authors: Bowman DMJS , Latz PK , Panton WJ
Published: December 2005

The environmental correlates of a mosaic of Acacia aneura F.Muell. ex Benth. shrublands and Triodia hummock grasslands on rolling conglomerate hills in central Australia were explored by indirect gradient analysis. A non-metric multidimension scaling ordination, based on the presence or absence of plant species, clearly separated the A. aneura shrubland from the Triodia hummock grassland; there were few intermediate quadrats. The A. aneura shrublands occurred on relatively deeper skeletal soils than the Triodia hummock grasslands. Unlike unidirection successional gradients from frequently burnt, treeless vegetation to very infrequently burnt forest vegetation, the ordination presented here is unusual because the quadrats with the greatest cover of A. aneura and Triodia occur on the poles, and quadrats from the most recently burnt vegetation and with the least cover of A. aneura and Triodia occur in the centre of the ordination. Interpretation of aerial photography taken in 1950 and 1987 showed that there has been no statistically significant change in the coverage of these two communities over that time period. Some quadrats that contained Triodia on the boundary of A. aneura shrublands had numerous charred A. aneura stumps which was interpreted as indicating some retreat of the shrublands. Experimental studies are required to determine the stability of the current pattern. Biogeographic evidence, however, shows that the spatial distribution of both communities has fluctuated at a continental scale through geological time.
Sustainability of Beilschmiedia tawa-Dominated Forest in New Zealand: Population Predictions Based on Transition Matrix Model Analysis
Authors: West CJ
Published: December 2005

Beilschmiedia tawa (Lauraceae) is a common canopy tree which is often dominant in lowland forests in the North Island and northern South Island of New Zealand. The sustainability of B. tawa-dominated forests was investigated at Pureora Forest Park, west of Lake Taupo, central North Island, where a range of sites with different extents of disturbance by logging was studied. Demographic studies-estimates of seedfall, recruitment, growth, and mortality rates-yielded data for life history tables. Based on these, Leslie matrix models were used to determine the rate of increase of five populations. Of these, three logged populations were apparently declining, whereas unlogged forest showed moderate population increase. These population studies suggested that B. tawa is a K-selected species capable of regeneration only within forest. The smaller size-classes are shade tolerant and stems accumulate in the stripling size-class. High light conditions are needed for growth from this class to the sapling class.
The Effect of Temperature, Light and Gibberellic Acid (Ga3) on the Germination of Australian Everlasting Daisies (Asteraceae, Tribe Inuleae)
Authors: Plummer JA , Bell DT
Published: December 2005

Australian everlasting daisies have considerable potential as bedding plants, but little is known about their germination requirements. In ten taxa of everlasting daisies (Asteraceae, Tribe Inuleae) examined, germination in petri dishes was optimum over the temperature range 10-20°C with little or no germination at more extreme temperatures (5 and 30°C). Light stimulated germination in seven of the ten tare; Erymophyllum ramosum (A. Gray) Wilson, Craspedia sp., Leucochrysum fitzgibbonii (F. Muell.) Wilson, Waitzia suaveolens var. flava Wilson, Rhodanthe chlorocephala subsp. rosea (Hook.) Wilson, R. chlorocephala subsp. splendida (Hemsley) Wilson and R. floribunda (DC.) Wilson. In the dark, gibberellic acid (GA3, 50 mg L-1) stimulated germination to similar levels observed in light-treated seed. Schoenia filifolia subsp. subulifolia and S. cassiniana were not affected by light regime, but in both taxa germination was improved by the addition of GA3. By contrast, germination in Rhodanthe humboldtiana, which also had no response to light, was inhibited by GA3. In most species, germination in the dark was similar over the GA3 concentration range 1-100 mg L-1, but 500 mg L-1 was often inhibitory. Germination was optimised under temperature and light conditions related to maximising survival of seedlings which germinate near the soil surface during winter in the arid interior habitat of central Australia.
Factors Limiting the Recruitment of Eucalyptus salmonophloia in Remnant Woodlands .II. Postdispersal Seed Predation and Soil Seed Reserves
Authors: Yates CJ , Taplin R , Hobbs RJ , Bell RW
Published: December 2005

This study examined post-dispersal seed predation and soil seed reserves in four remnant populations of E. salmonophloia in the central wheatbelt of Western Australia to determine the effect of these factors on recruitment. Diurnal observations of post-dispersal seed predation at regular intervals of 2 months were undertaken over a 12 month period using artificial baits. Four species of ants were seen removing seeds from artificial baits regularly. Surveys of soil seed reserves revealed that E. salmonophloia does not form a soil seed bank despite a continual seed rain from canopy seed reserves. These observations suggest that ants probably destroy a large proportion of E. salmonophloia seed following dispersal. Burial of E. salmonophloia seeds in the soil in autumn, winter, spring and summer suggest that any seeds which do escape predation are unlikely to persist in the soil for much longer than 12 months and probably germinate with the onset of winter rains. Both the depredation of seeds by ants and the short term viability of seed in the soil contribute to the inability of E. salmonophloia to form a soil seed reserve.
Somaclonal Variation in Rice ̵2 Drought Tolerance and Other Agronomic Characters
Authors: Adkins SW , Kunanuvatchaidach R , Godwin ID
Published: December 2005

The ability to withstand drought was studied in R2 families raised by self-pollination from 149 R1 plants regenerated from callus of mature rice seed (cvs FR13A, Kurkaruppan, Khao Dawk Mali 105, Nam Sagui 19, and Calrose 76). Compared to parental controls, significant improvement in drought tolerance as assessed by dry weight production, was found in 6% of the cv. FR13A families, but not in any of Kurkaruppan or Khao Dawk Mali 105 families tested in a controlled-temperature glasshouse. When a similar study was undertaken using an in vitro selection step (using polyethylene glycol), significant improvement in drought tolerance was found in 6% of Khao Dawk Mali 105 families, but not in any of the Nam Sagui 19 families. No improvements were noted in this latter study when in vitro selection was not used. Variation in other agronomically important characters was observed in the R2 families grown under similar, but well-watered, environmental conditions.
Anatomy of Leaf-Margin Lenticels in Eucalyptus denticulata and Three Other Eucalypts
Authors: Neish PG , Drinnan AN , Ladiges PY
Published: December 2005

The anatomy is described of denticulate leaf margins in Eucalyptus denticulata, E. quadrangulata, E. incrassata and E. laevopinea. The leaves had been collected from trees growing in sites in Victoria or New South Wales. Denticulations are formed by individual secondary meristems, initially associated with primary oil glands. Each meristem produces layers of cells containing phenolic compounds towards the outside of the leaf. The structure of the denticulations is most similar to lenticels. The presence of these leaf-margin lenticels in unrelated taxa such as E. incrassata and E. laevopinea indicates that they have evolved more than once; however, they are a possible synapomorphy uniting E. denticulata and E. quadrangulata as sister taxa. They may function in defence against herbivores.
An Early to Middle Pleistocene Flora of Subalpine Affinities in Lowland Western Tasmania
Authors: Jordan GJ , MacPhail MK , Barnes R , Hill RS
Published: December 2005

Macro- and micro-fossil plants are described from Early to Middle Pleistocene sediments at Regatta Point, western Tasmania. The sediments are floristically and lithologically distinct from other sediments at the same site, and contain a precursor to modern subalpine vegetation. The sediments contain foliage, characteristic of modern western Tasmanian subalpine and alpine rainforest species. Pollen and spores suggest the presence of open vegetation similar to modem subalpine heath and herbfield. A number of taxa are inconsistent with modem high altitude vegetation, which suggests re-assortment of plant associations during periods of climate change.
Patterns of Variation in the Seedling Leaf Oils of Eucalyptus urophylla, E. pellita and E. scias
Authors: Doran JC , Williams ER , Brophy JJ
Published: December 2005

The volatile leaf oils of glasshouse-grown plants representing natural populations of E. urophylla S.T.Blake, E. pellita F.Muell. and E. scias L.Johnson from the Lesser Sunda Islands, Australia, Papua New Guinea and Irian Jaya were examined for patterns of variation and relationships. The steam distilled oils of the three species were found to be largely monoterpenoid in character and similar qualitatively but variable quantitatively. The relative proportions of α-terpinyl acetate, 1,8-cineole, β-pinene, caryophyllene, α-phellandrene and p-cymene provided good discrimination between species and provenances. The mix of compounds and relatively low yields were such that the oils have no commercial potential. Principal component analysis of oil compositional data revealed groupings of populations consistent with contemporary thinking on the systematics of this complex. The four populations of E. urophylla from Wetar Island included in this study emerged as a group distinct from the main cluster of populations of that species. There was some support in the data for the distinction of high-elevation populations of E. urophylla from eastern Timor from other populations of the species and for the separation of E. scias from E. pellita, although the data, based on limited sampling, was inconclusive. Patterns in the oils of Cape York, Papua New Guinea and Irian Jaya provenances of E.pellita were variable. Evidence from other characters (e.g. adult morphology) will be needed to support the hypothesis that the Cape York and New Guinea populations of E. pellita constitute a new taxon.