bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Environmental Factors on Ectomycorrhizal Infection in Axenically Cultured Eucalypt Seedlings
Authors: Mcinnes A , Chilvers GA
Published: December 2005

The paper-sandwich technique for axenic synthesis of ectomycorrhizae was used to study the effect of various environmental factors on mycorrhizal formation by eucalypt seedlings. This technique involves growing plant roots and fungus separately, then bringing them together in a way which immediately initiates infection. Altering either temperature or the carbohydrate status of the fungus markedly affected the proportion of root apices converted to mycorrhizae. However, altering the light regime or nitrogen and phosphorus availability within wide limits did not affect the proportion of root apices converted to mycorrhizae. We conclude that infectibility of similar root apices remained constant throughout these experiments, and that those changes in the environment which affected the proportion of roots becoming mycorrhizal were mediated through effects on the colonisation capacity of the fungal partner.
Zonation of the Liverwort Riccia in a Temporary Watercourse in Subtropical, Semiarid Australia
Authors: Rogers RW
Published: December 2005

The thallose liverwort Riccia formed a continuous band around the margins of shallow drainage lines at Idalia National Park, south-west of Blackall, in semi-arid, subtropical, central Queensland, Australia. Four species occurred in successive bands from the dry surrounding plain down the slope of the depressions; these were in order Riccia limbata, R. blackii, R. vesiculosa and R. multifida. When air-dry, they contributed a cover in excess of 40% in a band over 2 m wide around the depression, and apparently protected the banks from sheet flow erosion. .Riccia limbata and R. blackii are apparently poikilohydric, and may therefore provide protection for the bank at the time of the onset of rains after drought. The liverwort cover has apparently developed in the 5 years since cattle were removed from Idalia.
Genetic and Ecological Variation in Atherosperma moschatum and the Implications for Conservation of Its Biodiversity
Authors: Shapcott A
Published: December 2005

Population genetics and ecology of Atherosperma moschatum Labill. (sassafras), a major canopy tree of Australian temperate rainforests, were examined and used to identify priorities and strategies for conservation of its genetic diversity. The genetic diversity among populations was fairly low, but higher than average for long-lived late successional or wind dispersed species (Hamrick and Godt 1989). Genetic distances between populations were correlated with geographic distances and climatic differences. The major genetic differentiation was between the mainland populations and those in Tasmania, with the New South Wales populations being quite genetically distinct. Most genetic variation was found within populations, however, most populations were inbred. This is likely to be due to selfing and spatial genetic substructure resulting from vegetative spread and local dispersal. There was evidence of regeneration in all populations, however no consistent regeneration patterns emerged. Population density was inexplicably correlated with genetic distance. There was as much diversity in all variables (ecological and genetic) measured in small isolated populations as there was in stands within larger assemblages; therefore, population size does not appear to be a major factor affecting viability. Genetic variation was spread throughout the distribution of A. moschatum. Therefore, populations from throughout its range would need to be conserved to retain the genetic diversity within this species.
Effects of Supplementary Soil Nutrients on Hummock Grasses
Authors: Rice BL , Westoby M , Griffin GF , Friedel MH
Published: December 2005

Hummocks of Triodia basedowii E. Pritz, T. pungens R.Br. and Plectrachne schinzii Henr. were treated with ash and with standard and high applications of slow-release fertiliser. Following rain and the ensuing growth and flowering, the soils and the hummocks were sampled for biomass and for nutrient content, and compared to controls. In a similar but separate experiment, seed set in inflorescences was assessed for hummocks treated with standard fertiliser application, for hummocks treated by removal of neighbouring hummocks, and for controls. In the absence of nutrient addition, total topsoil nitrogen concentration was higher under hummocks than outside, whereas total topsoil phosphorus concentration was lower under hummocks than outside. The absolute amount of phosphorus in the hummock itself was insufficient to account for the depletion of phosphorus in topsoil under the hummock. Available soil phosphorus was about 1-4% of total phosphorus, and was generally highest towards the edge of hummocks. Additions of ash did not significantly affect soil nutrients, while addition of fertiliser produced substantial increases in total nitrogen and in available and total phosphorus. The increases did not extend to the area surrounding the hummock. The increases in soil nutrients did not result in significant increases in new green growth, or in inflorescence biomass or number. However, nutrients appear to have been taken up into the plants, including into old tissue, because there were increases in nutrient concentration in plant tissues, which sometimes were statistically significant and sometimes not. In the second experiment, neither increased soil nutrients nor removal of neighbours increased the number of inflorescences produced, or the proportion of florets that gave rise to filled grain.
Invasion of Bassendean Dune Banksia Woodland by Phytophthora cinnamomi
Authors: Hill TCJ , Tippett JT , Shearer BL
Published: December 2005

The rate and mechanism of the spread of Phytophthora cinnamomi in Banksia woodland of the Bassendean Dune system north of Perth, Western Australia was studied. Aerial photographs were used to measure the spread of disease in fronts longer than 5 km over 35 years. Fronts in upper slope positions moved downhill and uphill at 1.01 and 1.13 m year-1, respectively, while fronts in low-lying positions moved downgrade and upgrade (with and against the direction of water table flow) at 1.30 and 1.20 m year-1, respectively. Fronts in low-lying areas spread significantly faster than those on upper slopes. Excavations to 2 m depth of the root systems of 21 dying plants of Banksia attenuata R.Br., an overstorey co-dominant, revealed that 28% (3.9 roots/tree) of all first-order roots were infected. Assessment of the proportion of roots infected revealed a significant (P < 0.01) departure from uniform distribution of disease down the profile in both upper slope and drained flat sites. In 14 trees on dune slopes, 6-40 m above the aquifer, infection rate was higher than expected in roots lying at 21-40 cm depth, but lower than expected in roots below 1 m. Seventy three percent of infected roots lay in the top 40 cm of soil. In seven trees on a drained flat, 2-3 m above the aquifer, infection rate was high in the 21-60 cm horizon and also in roots below 1 m. Even though Phytophthora cinnamomi was active in the vicinity of the water table in trees on drained flats, the slow, steady spread of the disease in all landscape positions suggested that the primary mode of fungal invasion was through roots of susceptible vegetation. No evidence was found of accelerated spread of disease caused by the dispersal of zoospores.
A Regeneration Protocol for Spinacia oleracea Using Gibberellic Acid
Authors: Molvig L , Rose RJ
Published: December 2005

A reliable plant regeneration procedure by organogenesis has been obtained for Spinacia oleracea L. cv. Hybrid 102. The optimum procedure utilises a sequence of three different media. Explants from sterile seedling cotyledons or hypocotyls are incubated for 4 weeks in the dark on medium containing 4.6 μM kinetin and 4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The calli are then transferred to medium without 2,4-D but containing kinetin and gibberellic acid (GA3). From this point on, incubation is in the light. A number of passages (usually three) of 4-6 weeks are required on this medium for shoot formation to occur. Calli destined to form shoots usually first undergo some root proliferation ('rooty calli'). Shoots can be induced to form roots by transfer to hormone-free medium. It is suggested that GA3 stimulates the development of shoot primordia induced by 2,4-D. The presence of kinetin (but not 6-benzylaminopurine) results in more rapid shoot formation.
Ecological Studies of the Endangered Rutidosis Leptorrhynchoides .I. Seed Production, Soil Seed Bank Dynamics, Population Density and Their Effects on Recruitment
Authors: Morgan JW
Published: December 2005

The seasonal dynamics of the soil seed bank of Rutidosis leptorrhynchoides F.Muell. were studied by
the seedling emergence technique. Seed longevity in soil was quantified in a seed burial and retrieval
experiment. The importance of annual seed production to recruitment was also determined over a
2-year-period, as was the impact of conspecific neighbour density on seed production per inflorescence.
Rutidosis leptorrhynchoides appears to form a transient seed bank with little capacity to store
germinable seeds in the soil from year to year. No seedlings were observed in soil sampled after the
autumn germination pulse and no viable seed was present in the soil within 16 weeks of burial. The rate
of seed loss was similar when seed was buried under all intact grassland canopy and in 0.25m2 canopy
gaps. It appears that most seeds simply rot in moist soil or are predated by soil invertebrates. Seedling
recruitment was at least 15 times greater in plots where natural seed input occurred than where it was
curtailed. Less than 10% of seed shed resulted in seedling emergence. It is suggested that recruitment in
the large populations studied was limited by germination rather than by microsite availability for
seedling survival. Population density had an impact on seed production with sparsely distributed
individuals producing fewer seeds per inflorescence than plants from denser colonies, although there
was much variation. Sparse plants produced significantly fewer seeds per inflorescence than hand crosspollinated
heads suggesting reduced pollinator efficacy in these colonies relative to larger colonies
where there was no such difference. Rutidosis leptorrhynchoides is dependent on the maintenance of the
standing population for recruitment. Any factors that influence flowering and subsequent seed
production will limit the ability of the species to regenerate. Over sufficient time, this could lead to the
localised extinction of the species and may explain why R. leptorrhynchoides has failed to reappear in
remnants where a suitable fire regime has been re-implemented after a period of management
unfavourable to the survival, flowering and regeneration of this species.
Ecological Studies of the Endangered Rutidosis leptorrhynchoides. II. Patterns of Seedling Emergence and Survival in a Native Grassland
Authors: Morgan JW
Published: December 2005

The emergence, survival and growth of seedlings of the endangered Rutidosis leptorrhynchoides
F.Muell. were followed in a Themeda triandra grassland during 1991 and 1992. The effect of summer
irrigation on seedling survival was also investigated. Seedling emergence occurred in both years within
2 weeks of the 'autumn break' when soil moisture rose above 20%. Ninety percent of emergence was
observed within 4 weeks of the onset of germination and 87% of seedlings were within 20 cm of an
established plant. No emergence was observed after 8 weeks. Thirteen percent of the 1991 cohort
survived for 14 months. Mortality of most seedlings (63%) was attributed to soil moisture stress in
summer. Small seedlings (Ͱ4 3 leaves) were no more susceptible to drought than larger seedlings.
Seventy two percent of the 1991 cohort produced four leaves before subsequently dying. In 1992,
however, most early seedling mortality was amongst cotyledonary seedlings. No seedlings flowered in
their first year. Above-ground growth was slow and by 14 months, 60% of surviving seedlings had
seven or fewer live leaves. Irrigation in a year of below-average rainfall had no significant effect on the
survival and growth of seedlings. This suggests that seedling recruitment is not restricted to climatically
favourable years (i.e. is not episodic) but rather, is potentially on-going provided suitable microsites are
available for seedling survival.
Decline of Eucalyptus tereticornis Near Bairnsdale, Victoria: Insect Herbivory and Nitrogen Fractions in Sap and Foliage
Authors: Marsh NR , Adams MA
Published: December 2005

Eucalyptus tereticornis growing along roadsides and in pastures in eastern Victoria were often in poor health and were repeatedly defoliated by herbivorous insects. Epicormic buds sprouted following bouts of defoliation and the first epicormic leaves produced from such buds were rich in nitrogen and particularly in nitrogenous solutes such as proline compared with adult leaves. Xylem sap collected from declining trees was richer in nitrogenous solutes than that from healthy trees. Concentrations of total nitrogen and specific solutes in foliage were not closely related to pressure potential in shoots or to nitrogen availability in soil. In glasshouse-grown seedlings, foliar concentrations of total nitrogen and of a number of nitrogenous solutes were increased by reduced water availability. Chronic insect infestations and periodic insect outbreaks may be supported by high concentrations of nitrogenous solutes in sap and foliage, especially epicormic foliage, which in turn may be a response to drought or increasing salinity ('physiological drought').
Occurrence of the Unusual Amino Compound S-Methyl Cysteine in Australian Members of the Restionaceae - Biological and Taxonomic Significance
Authors: Pate JS , Rasins E , Thumfort PP , Mcchesney CJ , Meney KA
Published: December 2005

The non-protein amino acid S-methyl cysteine (CH3-S-CH2> CH (NH2) COOH) was identified and assayed by HPLC and GC/MS analyses of ethanolic extracts of freshly-collected culms and rhizomes of Australian species of Restionaceae. Of 140 species examined, only 20 proved positive and two probably positive for the compound. Amounts in culms and rhizomes of these positive species varied from a trace to 74% of the ninhydrin-positive soluble amino N or from a trace to 33 mu mol per g fwt of tissue. Certain species showed substantial Variations in amounts of S-methyl cysteine between sites and seasons. Xylem bleeding sap was collected and analysed from 32 species. The nine species whose xylem sap was positive for S-methyl cysteine (0.5-23.5% of xylem total amino N) also rated positive in culms and rhizomes. Investment of N in S-methyl cysteine ranged from 0.1 to 6.3% of culm total N or 0.2-6.7% of rhizome total N. A possible role of the compound in protection against herbivory was examined. Positive species came from only three of the 19 currently recognized genera, Lepyrodia (16 positive, two possibly positive), Restio (one positive species) Loxocarya, (one positive species) and a further three as yet unnamed species. Under a proposed revision (B. Briggs and L. Johnson, pers. comm.), the positive species of Restio and the three unnamed species would be ascribed to a redefined genus (Loxocarya sens. orig.), thus restricting all species containing S-methyl cysteine to this new genus and Lepyrodia. The latter genus is changed under the proposed classification by transfer of certain species to the genus Sporadanthus. All six species proposed for such transfer lack the compound. Taxonomic implications of the findings are discussed.
Specificity of the Associations Between Microtis parviflora (Orchidaceae) and Its Mycorrhizal Fungi
Authors: Perkins AJ , Masuhara G , Mcgee PA
Published: December 2005

The specificity between Microtis parviflora R.Br. and its mycorrhizal associates was examined in situ and in vitro. Two fungi, Epulorhiza repens (Bernard) Moore and Epulorhiza sp. Moore (synonym Rhizoctonia globularis), were isolated from the roots and protocorms of the orchid from the field. In the laboratory, these fungi and three others that form mycorrhizae with other orchids and two others that are saprophytes, initiated mycorrhizae with M. parviflora. Two pathogenic isolates of Rhizoctonia solani Kuehn killed the germinating seeds. The addition of sucrose to the germination media increased growth and rate of development of seedlings.
Variation in Flowering Parameters Within and Among Five Species of Australian Alpine Ranunculus
Authors: Pickering CC
Published: December 2005

The flowering phenology of the perennial herbs Ranunculus muelleri, R. dissectifolius, R. granticola, R. millanii and R. niphophilus were characterised at two sites over two flowering seasons in the Kosciusko alpine region of Australia. The date a plant started flowering (mean values for species ranged from 8 November to 14 December), the duration of flowering (mean values for species ranged from 14.3 days to 35.1 days), asynchrony of flower production (mean values ranged from 1.38 to 10.4 days), asynchrony of first day of flowering (mean values ranged from 4.61 to 8.13), intraspecific synchrony (mean values ranged from 0.53 to 0.73, where a value of 1 equals perfect synchrony), and number of flowers (mean values ranged from 1.9 to 10.7) all differed between sites and flowering seasons within species, and among the five species. Thus, while temporal and spatial variation in flowering parameters within species occurred, it did not mask variation among species, with each of the five species of Ranunculus having a distinct flowering pattern.
Susceptibility of Plant Species in Eucalyptus marginata Forest to Infection by Phytophthora cinnamomi
Authors: Shearer BL , Dillon M
Published: December 2005

Estimates of the susceptibility of plant species of Eucalyptus marginata forest to Phytophthora
cinnamomi were obtained by determining the frequency of plant death and isolation of the pathogen
from plants occurring in disease centres in the forest. Plant species were assessed and sampled in 63
active disease centres and 17 old centres infested with P. cinnamomi in E. marginata forest north of the
Preston River, south-westem Australia. Impact of P. cinnamomi was intermediate (scattered deaths) in
46% of active disease centres and high (most susceptible plants dead) in 29% of active centres. Impact
in 65% of old disease centres was high. Dicotyledons (Magnoliidae) out-numbered monocotyledons
(Liliidae). Just over half of the species were from six Magnoliidae families with the largest number of
species from the Papilionaceae and Proteaceae. The greatest number of species within the Liliidae were
consistently from Haemodoraceae. Families in which species tended not to die in disease centres were
mainly from the Papilionaceae, Proteaceae, Mimosaceae, Myrtaceae, Dilleniaceae, Apiaceae and
Goodeniaceae for the Magnoliidae and Cyperaceae and Haemodoraceae for the Liliidae. The species
which tended to die frequently in disease centres were mainly from the Magnoliidae families:
Papilionaceae, Proteaceae and Epacridaceae; and the Liliidae family Xanthorrhoeaceae, as well as the
only species of the Zamiaceae. Phytophthora cinnamomi was isolated from 38 of the 105 species
occurring in three or more active disease centres, but from only 17 of the 107 species occurring in old
centres. For most species in active disease centres, the frequency of isolation of P. cinnamomi from
plants was much less than the frequency of recently dead plants sampled. Isolation from plants was less
frequent than from adjacent soil. The pathogen was isolated from plant or soil mainly for species of the
Papilionaceae, Proteaceae, Epacridaceae and Dilleniaceae of the Magnoliideae and the Iridaceae and
Xanthorrhoeaceae of the Liliidae. Cross tabulation of species by frequency of death and isolation of P.
Cinnamomi from plant and soil provided the opportunity to classify the response of plant species to
infection by P. cinnamorni.
Development of an Axillary Bud Culture Technique for Fiji Disease Virus Elimination in Sugarcane
Authors: Wagih ME , Gordon GH , Ryan CC , Adkins SW
Published: December 2005

A technique was developed for culture of axillary buds of sugarcane (Saccharum spp. hybrid) cultivar NCo310. Successful establishment was obtained following surface sterilisation (sodium hypochlorite 4% for 5 min), decontamination (100 mg L-1 carbenicillin, 25 mg L-1 nystatin and 100 mg L-1 benlate) and a double heat treatment applied firstly to setts (single-bud vegetative cuttings; 50°C for 120 min) and then to the isolated axillary buds (61°C for 30 min). The most suitable bud culture medium consisted of half-strength Murashige and Skoog nutrients plus 8 g L-1 agar, 30 g L-1 sucrose, 2 mg L-1 naphthalene-acetic acid and 500 mg L-1 malt extract. Roots and hence plantlets could be developed for all cultures following incubation in distilled water. Decontamination and heat treatment resulted in eradication of pathogens from 94% and Fiji disease virus from 28% of the cultures.
Foliar Uptake of Water by Wet Leaves of Sloanea woollsii, an Australian Subtropical Rainforest Tree
Authors: Yates DJ , Hutley LB
Published: December 2005

At leaf water potentials (ψ) of around -2.5 MPa, detached leaves of Sloanea woollsii F.Muell., an Australian subtropical rainforest tree, were able to absorb small amounts of water vapour from a saturated atmosphere, but absorbed considerably more liquid water if their surfaces remained wet. When leaves attached to small branches exhibiting a ψ of -2 MPa were sprayed with water and maintained in a saturated atmosphere, leaf ψ returned to saturation values within about 6 h. In a further experiment, a ψ of -2 MPa was imposed on detached, forked branches. Branches were then exposed to a saturated atmosphere and leaves on one half of the fork were kept wet whilst the rest remained dry. Leaf ψ was measured periodically for both dry and wet leaves and in both cases was found to increase with time. This indicated that leaf surface water was imbibed by wet leaves and transported into the branch resulting in alleviation of low water potentials in the dry leaves. In the submontane rainforests in which S. woollsii occurs, extended periods with little or no rainfall occur regularly. Throughout the year, foliage is wet by fog or dew alone for about 25% of the time. It is suggested that the presence of leaf surface water during rainless periods when leaf Psi is low may be important for the survival of S. woollsii. The actual mechanism of foliar absorption is uncertain, but is likely to be direct imbibition through the cuticle.
Light Quality and Intensity Effects on the Germination of Species From the Jarrah (Eucalyptus marginata) Forest of Western Australia
Authors: Rokich DP , Bell DT
Published: December 2005

Eucalyptus marginata Donn. ex Sm. (jarrah) produces a canopy that reduces light intensity, but has only minimal effects on the relative proportions of particular wavelengths (light quality). Under controlled laboratory conditions, variation in light quality did not affect the germination of the representative jarrah forest species. In Eucalyptus marginata, E. calophylla Lindley, Acacia drummondii subsp. candolleana Lindley, and Kennedia prostrata R.Br., however, percentage germination under controlled laboratory conditions was greater in full darkness and seven restricted wavelength treatments than in full white light. Difference in response between full white light treatment (86 mu mol m-2 s-1) and the s restricted wavelength trials (2-8 μmol m-2 s-1) indicated a possible effect of light intensity. Compared with complete darkness and a white light intensity of 1 mu mol m-2 s-1, white light intensities of 26 and 146 mu mol m-2 s-1 reduced germination percentage in the canopy species, E. marginata, E. calophylla, and the understorey species, Acacia lateriticola Maslin, Bossiaea aquifolium Benth., Gompholobium knightianum Lindley, G. marginatum R.Br., G. tomentosum Labill. and Sphaerolobium vimineum Smith. By comparison with dark conditions, no light-inhibited germination at 146 mu mol m-2 s-1 was recorded for Acacia drummondii subsp. candolleana, Chorizema ilicifolium Labill., Kennedia coccinea Vent. and Xanthorrhoea gracilis Endl. An ability to sense light and remain dormant is adaptive in relation to seed burial and a subsequent increase in the survival potential of seedlings due to greater moisture availability. This light-sensing capacity was most prevalent in the small-seeded (< 10 mg) species of this Mediterranean-type climate forest. Most of the small-seeded species are likely to be buried by ants facilitated by elaiosomes or by falling into minute cavities in the gravelly soils of the jarrah forest.
Genetic Diversity in the Endangered Phebalium daviesii (Rutaceae) Compared to That in Two Widespread Congeners
Authors: Lynch AJJ , Vaillancourt RE
Published: December 2005

Genetic diversity in the rare and endangered Phebalium daviesii was compared to that in P. squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum using allozyme analysis. Phebalium daviesii was once presumed extinct, but 43 adult plants have so far been rediscovered. Phebalium squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum are widespread in the south-eastern part of the Australian mainland. Morphologically, these two taxa are the closest relatives of P. daviesii and share a similarity with P. daviesii in their ecological habitat. The level of genetic diversity and deviations from Hardy-Weinberg equiibrium were investigated using allozyme data with 18 enzyme systems. Nei's total genetic diversity, the proportion of polymorphic loci and the average number of alleles per locus were all slightly lower in P. daviesii than in P. squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum. Deviations from expected Hardy-Weinberg equilibrium were present in all three taxa and were more frequent in P. glandulosum subsp. glandulosum. This suggests that inbreeding may be occurring in all three Phebalium taxa and that P. daviesii does not suffer from increased inbreeding due to rarity. Phebalium daviesii has a high level of genetic diversity (Ht = 0.30) for such a rare species and should be able to recover from its population bottleneck with appropriate management.
Embryogenic Callus Production, Plant Regeneration and Transient Gene Expression Following Particle Bombardment in the Pasture Grass, Cenchrus ciliaris (Gramineae)
Authors: Ross AH , Manners JM , Birch RG
Published: December 2005

Callus initiated from surface sterilised, mature seeds of buffel grass (Cenchrus ciliaris L.) gave rise to an embryogenic form when cultured on Murashige and Skoog's nutrient medium supplemented with 3% sucrose, 5% coconut water and 4 mg L-1 2,4-D. Multiple green shoots regenerated on 20% to 50% of embryogenic calli after transfer to hormone-free medium and incubation in the light. Variations in cytokinin concentration and light intensity during regeneration did not significantly increase the regeneration frequency or the number of shoots produced. Regenerated plants developed normally when transplanted to soil. A high frequency of transient expression of the β-glucuronidase gene resulted following transfer into embryogenic callus by particle bombardment. This is a promising system for production of transformed buffel grass plants, if the frequency of shoot production can be increased.
Germination of Lomandra sonderi (Dasypogonaceae) Promoted by Pericarp Removal and Chemical-Stimulation of the Embryo
Authors: Plummer JA , Crawford AD , Taylor SK
Published: December 2005

Lomandra Labill. is a common genus in the understorey of the jarrah (Eucalyptus marginata Sm.) forest of Western Australia. Species in this genus are difficult to propagate by seed and do not readily re establish following mining. Limiting factors for germination success were explored and identified. Lomandra sonderii (F.Muell.) Ewart set very few seed (seeds per flower = 0.122). Tetrazolium tests indicated that seed viability was relatively high (50%). Germination was inhibited (0%) by the inner pericarp tissues which surround the seed and are part of the diaspore. Manual removal of the inner pericarp or leaching overcame this inhibition with a fifth of seeds subsequently germinating. Similar treatments improved germination of L. drummondii (F. Muell. ex Benth.) Ewart from 40% to 80%. Soaking L. sonderi seeds in gibberellic acid (GA3, 50 mg L-1) further improved germination (28%). Ants (Camponotus sp. and Iridomyrmex sp.) collected and dispersed L. sonderi seed and are likely to improve germination in the forest by removing and consuming the inner pericarp. Only half of the Viable excised embryos of L. sonderi grew in vitro, indicating the presence of embryo dormancy. Embryo dormancy was overcome by GA3 (0.5 mM) and zeatin (0.5 mM) in the liquid culture medium. In vitro culture may be a practical means of propagating Lomandra if seed is scarce.
The Importance of Comparative Growth Rates in Determining the Canopy Composition of Tasmanian Rainforest
Authors: Read J
Published: December 2005

Growth rates of the rainforest canopy species Atherosperma moschatum Labill., Eucryphia lucida
(Labill.) Baill., Nothofagus cunninghamii (Hook.) Oerst., Athrotaxis selaginoides D.Don and
Phyllocladus aspleniifolius (Labill.) Hook.f. were measured in naturally-occurring seedlings and in
seedlings grown in glasshouse pot trials. The highest field growth rates were recorded in
N. cunninghamii on lowland sites on fertile, well-drained soils. On poorer soils, growth rates of
N. cunninghamii were lower and there was little difference in growth rates between species. On the
most acidic and probably infertile soil, the growth rate of P. aspleniifolius was 1.4 times higher than
that of N. cunninghamii, although not significantly different at the 95% level. Similar trends in growth
rates were recorded in pot trials. High growth rates were recorded in N. cunninghamii and E. lucida on
fertile, well-drained soils, with generally lower growth rates in A. moschatum, P. aspleniifolius and
A. selaginoides. No significant difference in growth rate was recorded among N. cunninghamii,
E. lucida, A. moschatum and P. aspleniifolius when grown in poor soils or in low nutrient treatments.
The trends in comparative growth rates correlate with the measured canopy composition of the study
sites. Nothofagus cunninghamii dominates forest stands on sites where it has a clearly superior growth
rate compared with co-occurring light-demanding species. Mixed canopies occur on sites where there is
little or no difference between species' growth rates. However, not all patterns of canopy dominance
can be explained by comparative growth rates alone. For example, P. aspleniifolius commonly
dominates forest stands at low to mid-altitude where growth rates of all species are very low, but
without necessarily a higher growth rate in P. aspleniifolius than in co-occurring species. The results of
the growth rate studies are integrated with some other aspects of the biology of these species in a
discussion of the mechanisms determining canopy composition of Tasmanian rainforests.
The Impact of CO2 Enrichment on Water Relations in Maranthes corymbosa and Eucalyptus tetrodonta
Authors: Eamus D , Berryman CA , Duff GA
Published: December 2005

Seeds of Maranthes corymbosa Blume and Eucalyptus tetrodonta F.Muell were sown under ambient or CO2 enriched conditions (two replicate tents per treatment) in tropical Australia and allowed to grow, rooted in the ground, for 20 months. For both species, periodic measurements of leaf water potential, stomatal conductance and leaf temperature were made on four replicate leaves on each of four replicate trees within each tent. Measurements were made in November (M. corymbosa) and June (E. tetrodonta). At the same time, atmospheric wet and dry bulb temperatures were recorded and hence leaf-to-air vapour presure difference (LAVPD) calculated. Measurements of pre-dawn leaf water potential were also made on E. tetrodonta. Leaves were also taken to the laboratory, rehydrated to full turgor and pressure-volume analyses undertaken. For M. corymbosa, leaf water potential was lower throughout the day for control leaves compared to leaves growing in CO2 enriched air. Similarly, pre dawn leaf water potential was lower for control E. tetrodonta trees than for trees grown with CO2 enrichment. However, mid-morning and mid-afternoon values of leaf water potential for E. tetrodonta were slightly lower for plants growing in CO2 enriched air compared to control plants. In both species, stomatal conductance was consistently lower for trees grown in CO2 enriched air than for controls. Whole plant hydraulic conductivity of both species was significantly lower for trees grown in CO2 enriched air than for control trees. For both species, maximum turgor and bulk volumetric elastic modulus increased and osmotic potential at zero turgor decreased for trees grown in CO2 enriched air.
Biogeography of Fire-Killed and Resprouting Banksia Species in South-Western Australia
Authors: Lamont BB , Markey A
Published: December 2005

Banksia includes 38 fire-killed (seeders) and 20 resprouting species, and two species with contrasting
ecotypes, in south-western Australia. There may be up to 12 seeders per 50 × 50 km grid cell in the
southern sandplains and 12 resprouters in the northern sandplains. The patterns of distribution of
species across soil type and eight climatic attributes is similar for both life forms, except that greater
numbers of resprouting species occur at higher rainfalls and where there is greater seasonal spread of
rainfall. Most seeders occur on white sands and rocky substrates, and resprouters occur on yellow sands
and the more fertile lateritic soils. Nutrient requirements for both life forms appear to be similar.
Resprouters are more widespread than seeders which suggests that resprouters show greater
environmental tolerances. The distribution of grid cells containing each life form across soil types and
eight climatic attributes is similar and any differences in climatic profile for all species in each category
are considered biologically insignificant. Both life forms in section Abietinae are well represented in
the climatically distinct southern and northern sandplains indicating no climatic preferences within the
lineage. There are no consistent trends in environmental attributes from fire-killed to resprouting
ecotypes of B. ashbyi E.G.Baker and B. violacea C.A. Gardner. Multiple-partitioning classification of
the floristic data produced 10 groups varying greatly in geography, species richness, and proportion and
endemism of each life form. The Lesueur (northern) district has four endemic seeders, six endemic
resprouters and a mean of 10 resprouters per cell. The East Eyre (southern) district has five endemic
seeders, no endemic resprouters and one resprouter per cell. Both groups have a mean growing season
of 5 months. The relative aridities and fluctuations of present and past (Quaternary and late Tertiary)
climates are invoked to explain the much higher proportion of resprouters in the northern than southern
sandplains and the absence of seeders in the most marginal cells. The absence of endemic species yet
high proportion of resprouters (73%) in the extreme south-western corner of the region might be
explained by elimination of seeders through frequent burning by Aborigines in the late Quaternary. The
increase in the proportion of fire-killed species along the south coast from 23% to 100% at the edge of
the Nullarbor Plain also requires an explanation.
Vegetative Attributes, Taxonomy, and Character Syndromes in Grasses Around a Sheep Camp on the Northern Tablelands of New South Wales
Authors: Rogers RW
Published: December 2005

Thirty common grasses from unfertilised sheep pastures of the Northern Tablelands of New South Wales were grouped according to their distribution about a sheep camp. The frequency and relative frequency of 16 of these grasses related to their distribution. It is argued that the distribution patterns detected can be attributed to stocking by sheep. The relationship between distribution, origin of the species, life cycle, life form and growing season were examined, and all were found to show statistically significant relationships. When the species were clustered using vegetative attributes which were significantly related to distribution, groups were formed which related more to taxonomy at tribal level than to distribution. Contingency analysis, relating the presence of the same attributes to species groups based on distribution pattern, showed that only photosynthetic mechanism and origin were related to that pattern, whereas all attributes, except origin, were related to tribe. Although individual characters are related to distribution and hence presumably to stocking, there is no single syndrome of characters related to distribution.
The Ecophysiology of Allosyncarpia ternata (Myrtaceae) in Northern Australia: Tree Physiognomy, Leaf Characteristics and Assimilation at Contrasting Sites
Authors: Fordyce IR , Duff GA , Eamus D
Published: December 2005

Allosyncarpia ternata S.T.Blake, a large, evergreen tree endemic to the northern part of the Northern Territory, Australia, dominates the canopy in a wide variety of habitats, including monsoon rainforest on ravine floors, open forest and woodland on cliffs, screes and sandsheets, and open woodland on ridges and hilltops. This study examines tree physiognomy, leaf characteristics and leaf assimilation rates of A. ternata growing at sites with strongly contrasting micro-climates near Baroalba Springs, Kakadu National Park. By comparison with trees growing on the ravine floor, cliff and hilltop trees are generally shorter, they branch lower, are more frequently multi stemmed and have higher ratios of canopy width to height, while their leaves are generally smaller and thicker and contain less chlorophyll a and chlorophyll b per unit dry weight. They have lower mean specific leaf areas and higher mean stomatal densities. Assimilation measurements on leaves at a cliff site showed significantly higher rates of light-saturated assimilation during the morning than in the afternoon. On the ravine floor, by contrast, assimilation responses to changes in light flux density did not vary significantly through the day. Leaves of trees growing on the ravine floor had lower values oi light-saturated assimilation and light compensation point, and higher values of apparent quantum yield than cliffside leaves.
Lichen Succession on Leaves of the Rainforest Shrub, Capparis arborea (Capparaceae)
Authors: Rogers RW
Published: December 2005

The lichen flora on leaves of Capparis arborea (F. Muell.) Maiden growing in undisturbed rainforest at
Mt Glorious, Queensland, Australia was examined. The sequence of colonisation on leaves of
increasing age on twigs (a chronosequence) was determined, and, although involving the same lichen
species, was found not to be the same as that reported on Wilkiea macrophylla in the same forest.
Analysis of variance demonstrated that total lichen cover and the cover of the common species Porina
epiphylla on the leaves was significantly related to both leaf position in a chronosequence and to leaf
area, with a significant interaction between the two. The relationship between the cover of lichen
species on a leaf and the size and age of the leaf is apparently complex. Frequency of four species was
related to position in the chronosequence, and of six species to size of the leaf. Lichen succession is not
a simple time-dependent sequence on this host plant species.
The Rediscovery and Distribution of Rumex drummondii (Polygonaceae) in South-Western Australia
Authors: Scott JK , Yeoh PB
Published: December 2005

Rumex drummondii Meisn., a south-western Australian endemic vascular plant species recorded from widely separated localities, had not been collected for 46 years and was considered possibly extinct. The methods developed from search theory, which has been used for finding lost people or objects, were applied to finding R. drummondii, starting from previous records. Eleven populations of the species were discovered within a 50 km radius in the Kalgan River and Manypeaks region. A disjunct population of six plants was found in 1992 in a parking area at a crossing of the Moore River, 480 km north north west of the others, but had disappeared by 1994. Surveys in the Gingin Brook and Moore River region and between Kalannie and Kulja, another disjunct record, failed to find further plants. The species occupies temporarily wet depressions, lake edges and roadside excavations and dam edges protected from grazing by sheep; habitats also occupied by congeneric weedy species. The species occurs on road verges and farmland and is known from one nature reserve. The rediscovery of R. drummondii enables it to be included in the assessment of potential biological control agents for related weed species in the genera Emex and Rumex.
Extrafloral Nectaries in Chamelaucium uncinatum: a First Record in the Myrtaceae
Authors: Obrien SP
Published: December 2005

The morphology and anatomy of cryptic extrafloral nectaries are described in Chamelaucium uncinatum Schauer. This is the first time these nectaries have been recorded in the Myrtaceae. Extrafloral nectaries occur in all leaf axils and secrete nectar continuously until the stem to which the leaf is attached becomes woody. Bees and flies visit the nectaries and collect nectar. Possible reasons for the evolution of extrafloral nectaries in C. uncinatum are discussed.
Morphology and Anatomy of Leaves of Eucalyptus camaldulensis Clones: Variation Between Geographically Separated Locations
Authors: James SA , Bell DT
Published: December 2005

Leaves of six clonal individuals of Eucalyptus camaldulensis Dehnh. from five Australian locations were compared. Two clones were from Wooramel, WA while single clonal lines were from Dongara, WA, Erudina, SA, Murray Bridge, SA and Silverton, NSW. Principal component analysis of climatic factors for the five locations, derived by BIOCLIM, provided patterns of temperature, radiation and atmospheric moisture, which might be expected to influence the morphological and anatomical features of the leaves. Isozyme analysis indicated that the two Wooramel clones were closely related, but comparable similarity in isozyme pattern was also found between a Wooramel clone and the representative from Murray Bridge. Leaf morphological and anatomical features showed patterns related to the habitat climate of the parent plants, but considerable genetic variation was observable even within a single location. Leaf thickness was generally greatest for clones from the more arid locations and least for clones from the most mesic of locations, but leaf length and width were not associated with any of the climatic factors considered. Thin leaf cuticles were associated with thin leaves. Leaf thickness was determined by the thickness of the internal cell layers, as all clones contained an epidermal and three palisade parenchyma cell layers on both adaxial and abaxial sides. Adaxial palisade layers were thicker than abaxial palisade layers. Stomatal density was not related to leaf dimensions, but clones with the greatest stomatal density tended to have the smallest stomatal pore dimensions. Oil gland density was greatest for leaves of Western Australian clones. Clones from the more arid locations displayed larger chloroplasts. In general, there was a lack of correlation between leaf characteristics and climatic data. Ground water availability, root structure and internal transport of water may have a greater influence on leaf structure than atmospheric demand.
Short Secondary Vessel Members in Branching Regions in Branching Regions in Roots of Arabidopsis thaliana
Authors: Lev-Yadun S
Published: December 2005

Vessel members of the secondary xylem in roots of Arabidopsis thaliana (L.) Heynh. are shorter than
normal vessel members at branching points, where side roots develop. The vessel members in the axis
are formed after branching occurs, suggesting that the signal for shorter vessel members is transmitted
only after the initiation of root branching. This phenomenon represents an additional structural change
to other known modifications at branching points in plants.
Protogyny, Self-Incompatibility and Pollination in Anthocercis gracilis (Solanaceae)
Authors: Stace HM
Published: December 2005

The pollination biology of A. gracilis was examined in glasshouse plants and natural populations. The species is both protogynous and pre-zygotically self-sterile (self-incompatible). Protogyny prevents autopollination (autogamous self-pollination), and self-incompatibility avoids geitonogamous self-fertilisation. This sequence is essential because prior selfing blocks the style with pollen tubes and prevents subsequent outcrossing. Flowers have no discernible daytime odour, the pollen is clumped and not easily shaken from opened anthers, and daytime insect visitors are rarely observed in the field. However in long-established populations, mast plants carry one or a few capsules during winter-spring and seeds per capsule are generally high. Reproduction of natural populations involves reliable pollinators of unknown identity, possibly small flies, bees or moths lured by a tiny amount of sucrose-rich nectar secreted by the hypogynous disc. It is not anomalous that A. gracilis has two devices for preventing self-fertilisation, protogyny and strong self-incompatibility, as both are functional aspects of the same outcrossing system. This is the first report of self-incompatibility in the Anthocercideae which is an old and apparently basal lineage in the Solanaceae.
Abnormal and Unusual Inflorescences of Taro, Colocasia esculenta (Araceae)
Authors: Ivancic A
Published: December 2005

Taro (Colocasia esculenta (L.) Schott) breeding success depends strongly on hybridisation. The main
problem in artificial hybridisation of taro is the irregularity of flowering and the occurrence of abnormal
floral structures. Abnormal inflorescences appear continually in cultivated and wild taro populations in
Papua New Guinea and the Solomon Islands. Their frequency and phenotypic expression are strongly
influenced by the environment and cannot always be distinguished from unusual types which are
influenced less or not at all by the environment. The frequency of abnormal inflorescences increases
with the application of flower-inducing hormones which are frequently used in breeding programs.
Abnormal and unusual inflorescences are classified into 16 groups. Several types can be efficiently used
in hybridisation. Some of the genotypes characterised by unusual or abnormal floral traits represent a
potential genetic source for future improvement of taro. They may be used as genetic markers, as the
source of the genetic variation for ornamental characteristics or for the improvement of flowering
ability.
Optimisation of Tissue Culture Conditions for Transformation Studies Using Immature Embryos of Australian Barley Cultivars
Authors: Walmsley AM , Henry RJ , Birch RG
Published: December 2005

Eight Australian barley cultivars were tested for efficiency of embryonic callus initiation and plant regeneration, from immature embryo explants in tissue culture. Optimisation of tissue culture conditions was performed for cultivars Bandulla, Clipper, Schooner and Tallon in an attempt to increase regeneration frequencies to levels suitable for genetic engineering of barley. Variables tested were 2,4-D concentration, salt composition, carbon source and immature embryo explant. Optimal culture medium composition varied between cultivars. Shoot regeneration rates from culture of isolated scutellar tissues were low for all four cultivars. Halved, immature embryos produced most shoots for cultivars Clipper, Schooner and Tallon, whereas Bandulla performed best with entire immature embryo explants. Clipper (a malting barley) and Bandulla (a feed barley) are suggested as model Australian cultivars for transformation studies. Immature embryos of Bandulla produced an average of 5.3 shoots and Clipper 10.1 shoots per embryo under optimal conditions. Our results show that rates of somatic embryo and plant regeneration sufficient for use in transformation studies can be achieved for diverse Australian Barley cultivars, through systematic testing of a range of key variables including explant type and medium composition.