bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the Colonization of Plant Roots by Verticillium dahliae Klebahn With Use of Immunofluorescent Staining
Authors: Fitzell R , Evans G , Fahy PC
Published: December 2005

The colonization of plant roots by Verticillium dahliae was studied with use of fluorescent antibodies to stain
the fungus in soil and on plant roots. Microsclerotia were observed germinating in rhizosphere soil and in soil
amended with nutrients. Germination occurred much earlier in soil amended with either a sugariamino acid
solution or a solution of wheat root extract than in soil amended with distilled water. Usually only a single
germ tube was observed, but some microsclerotia produced two, three or more initials. These grew into
hyphal strands up to 100 μm long, but most began to lyse when the length exceeded 30 μm.
Hyphae of V. dahliae were observed on the roots of both immune (wheat) and susceptible (common
thorn-apple, cotton and Noogoora burr) plants growing in field soils infested with microsclerotia. These
hyphae were sparse, up to 1500 μm in length and appeared to enter the cortex of the young roots directly,
without the aid of specialized penetrating structures such as appressoria. Sporulating hyphae were observed
on the rhizoplane of each of the four species examined. Conidial germination, however, was not observed on
the rhizoplane.
By cultural methods it was established that V . Dahliae colonized plant roots 2-3 cm back from the root
tip, suggesting that microsclerotia are stimulated to germinate by the advancing root. Examination of the
rhizosphere soil around the root cap and the zone prior to vascular differentiation failed to produce evidence
of conidia or other structures that may have functioned as an intermediate stage in the colonization of plant
roots by V. dahliae.
Evidence for the presence of an intercontinental genome in the Australian hexaploid alliance of Hibiscus Sect. Furcaria
Authors: Menzel MY , Martin DW
Published: December 2005

Genomes of the G group in Hibiscus sect. Furcaria have been found previously in one African diploid species and in various ailoploid combinations in Africa, India and Sri Lanka, North and South America and the Hawaiian Islands. Study of 11 interspecific hybrids between the Australian species H. heterophyllus and H. splendens and G-genome testers indicates that genomes somewhat related to the G group are present in the Australian allohexaploid alliance. These genomes are designated G′. Several of the intercontinental hybrids studied were weak, inviable or morphologically abnormal. The data support the interpretation that the genomes of the Australian alliance have diverged more from African and New World genomes than the latter two have from each other.
Aspects of the Mineral Nutrition of the Western Australian Christmas Tree (Nuytsia floribunda (Labill.) R. Br.), With Special Reference to the Main Root
Authors: Hocking PJ
Published: December 2005

A study was made of the shape, dimensions and possible nutritional significance of the main root of the hemi parasite Nuytsia floribunda. Levels of nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, sodium, iron, manganese, zinc and copper were determined in the main root: haustoria, xylem sap, mucilage, trunk and leaves. The main root was approximately turnip-shaped and there was no evidence of a tap-root. Haustoria were confined to the top 15-20 cm of the soil and were attached to a variety of woody and herbaceous host plants. Haustoria contained the highest levels of nitrogen and phosphorus, the trunk and main root the highest levels of calcium, magnesium and sodium. Potassium and sodium accounted for 75% of the minerals in xylem sap. calcium and magnesium for 60% of the minerals in mucilage which exuded from wounds in the main root. Concentration gradients of most minerals existed across the main root. Nitrogen, phosphorus, potassium, sulfur and sodium were more concentrated in the outer zone of the root, calcium, magnesium, manganese and copper in the central part. Nuytsia appears to draw on stored nutrients in some situations. Conservative estimates suggested that nutrient reserves in the main root could not provide the amounts required for flower and fruit production. It was concluded that reproductive and vegetative growth draws on reserves in organs other than the main root and the extensive lateral root system may be important in this respect.
Shoot Regeneration in vitro From Native Australian Fruit-Bearing Trees - Quandong and Plum Bush
Authors: Barlass M , Grant WJR , Skene KGM
Published: December 2005

Explants from quandong (Santalum acuminatum) and plum bush ( S. lanceolatum), native Australian trees,
regenerated shoots in aseptic culture. In the presence of cytokinin. shoots were produced in quantity from all
cultured aerial parts of quandong seedlings. Individually cultured nodes of I-yr-old plum bush and
quandong plants proliferated axillary shoots, while internodal pieces produced adventitious shoot growth.
Shoots were also regenerated from explants of a 5-yr-old mature quandong tree. Excised in vitro-grown
shoots produced roots in culture on a medium containing indolebutyric acid at pH 4 following shoot
etiolation. These results offer the promise of clonal propagation in species in which conventional vegetative
propagation by cuttings has not been reported, and will provide a useful adjunct to a quandong breeding
program to develop edible fruit and nuts in semiarid areas.
Interaction of Certain Isolates of Soil Fungi With Gaeumannomyces graminis var. Tritici on Agar Media
Authors: Sivasithamparam K , Parker CA
Published: December 2005

One hundred and thirty-two isolates of fungi from the rhizosphere of wheat were tested for interaction with the take-all fungus (Gaeumannomyces graminis var. tritici) on a nutrient-rich and a nutrient-poor agar medium. Ten different types of interaction were observed. A 'window' type of lysis of the pathogen, not previously described for any fungus, was observed only when it was paired with certain isolates on the nutrient-poor medium. The pathogen was able to inhibit the growth of certain soil fungi on a nutrient-poor medium.
Somatic Embryogenesis in the Leaf Explants of Chinese Celery
Authors: Zee S , Wu SC
Published: December 2005

The development of embryoids from leaf explants of Apium graveolens var. dulce cultured on Murashige and Skoog medium with 0.5 mg/l 2,4-D and 0.6 mg/l kinetin was followed. Four stages were recognized: (1) cell proliferation, (2) pro-embryoid formation, (3) torpedo embryoid formation and (4) plantlet formation. All embryoids were derived from the cortical tissues of leaf explants; no embryoids formed in the epidermal tissues.
Comparison of the Early Growth Characteristics of the Eucalyptus Subgenera Monocalyptus and Symphyomyrtus
Authors: Davidson NJ , Reid JB
Published: December 2005

The early growth characteristics of six Tasmanian species from each of the Eucalyptus subgenera Monocalyptus and Symphyomyrtus were examined. The species chosen from each subgenus came from a range of habitats extending from low altitude dry sclerophyll sites to subalpine sites. Marked differences in the rate of germination, percentage of viable seeds, total dry weight, and the root to shoot ratio were observed after 3 and 7 months' growth, as well as different responses to the level of nutrient provided. These subgeneric differences were generally larger than the differences observed between species chosen from one subgenus but from different ecological sites. The most striking differences were possibly the higher root to shoot ratio found in the subgenus Symphyomyrtus and the generally faster establishment of species from this subgenus. The results show that the two subgenera possess different early growth patterns. This may suggest that the subgenera exploit their environment in slightly different ways and may, at least partly, explain the frequent occurrence of mixed stands of eucalypts in south-eastern Australia. where stands frequently contain one species from each subgenus.
Regeneration of native plants on abandoned Mallee farmland in south-eastern Australia
Authors: Onans J , Parsons RF
Published: December 2005

The vegetation is described on 12 sites from which mallee vegetation has been cleared and which have since been left undisturbed for periods from 1 to 39 years. Comparisons are made with three virgin stands. Early regeneration in paddocks is dominated by annual herbs but shrubs, especially Acacia, Dodonaea and Cassia. usually become dominant. Wind-dispersed or soil-stored seed allows species to occur after severe site disturbance. Rabbit grazing effects on native plants appear not to bc catastrophic at present. The only site studied in detail where mallee eucalypt seedlings were seen was a!ong a firebreak recently cleared through virgin mallee. Minimal competition from older eucalypts is an important factor for eucalypt beedllng establishment. No eucalypt seedlings were found more than 10 m from a seed source. Such regeneration is facilitated by seed release following fire or felling. Competition from shrubs and lack of an adequate seed source may well mean that eucalypts will no longer dominate the climax vegetation in many areas. their place being taken by formerly seral species of Acacia and Dodonuea. The findings have features of both the tolerance and inhibition models of succession of Connell and Slatyer.
Note on Paper 'Optical Diffraction Analysis for Estimating Foliage Angle Distribution in Grassland Canopies', by J. A. Smith and J. K. Berry.
Authors: Lang ARG
Published: December 2005

It is shown that a technique previously described for analysing foliage angular distribution in grassland canopies is not well based theoretically because it does not give exact measures of the probability density of longitudinal leaf length with respect to inclination angle.
Water Potential and Stomatal Conductance of Three Eucalyptus Species in the Mount Lofty Ranges, South Australia: Responses to Summer Drought
Authors: Sinclair R
Published: December 2005

Water potential and stomatal conductance were measured for three eucalypt species: Eucalyptus obliqua L'Hérit., E. fasciculosa F. Muell. and E. leucoxylon F. Muell. Field sites were located in the Mt Lofty Ranges, S.A., near the lower altitudinal limits of the E. obliqua population, where this species begins to be replaced by one or other of the other two. Pairs of trees, one pair of each species, were selected at each site growing within a few metres of each other. Measurements were made in late winter 1977 and during the unusually dry summer of 1977-78. In late winter E. obliqua and E. fasciculosa results were similar. Both had dawn water potential maxima of approximately -0.4 MPa, and stomatal conductance was high throughout the day. By mid summer E. obliqua was suffering water stress. Dawn water potential maxima of -1.93 and -4.35 MPa were measured, and stomatal conductance was low, but not zero, throughout the day. Adjacent E. fasciculosa showed few signs of stress; dawn maximum water potential was -0.7 MPa, and stornatal conductances were high. By late summer both water potentials and stornatal conductances of E. obliqua were much lower than those of adjacent trees of either of the other two species. The significance of these differences is discussed in relation to factors affecting eucalypt distribution patterns.
Eucalyptus Physiology. II. Temperature Responses
Authors: Paton DM
Published: December 2005

Seedlings of 13 Eucalyptus species were grown at three temperature regimes. One species was exposed to
sublethal high temperatures. Another species was frost-hardened by low temperatures.
Maximum growth of species from hot low latitudes of Australia involved high-temperature optima.
These were higher than the medium optima of species from the cooler southern latitudes. Such relationships
between temperature optimum for growth and temperature of location of seed source were also observed
among latitudinal provenances of E. camaldulensis and among altitudinal provenances of E. paucifora and
E. viminalis. These examples of adaptive variation involved temperature optima, not maximum growth rate.
The absence of high optima in southern species and high-altitude provenances was often associated with
severe growth abnormalities and poor survival of plants grown at 33°C and above.
Frost resistance of E. viminalis depended on exposure to near freezing, hardening temperatures for about
2 days. Altitudinal ecotypes for level of resistance and for rate of hardening were sometimes detected in such
low-temperature responses.
These results support the concept that the distribution of Eucalyptus species is related to their tolerance of
extreme conditions rather than to their maximum growth rate under less severe conditions. The relative
insensitivity of the genus to day length suggests that this concept should emphasize the importance of
temperature but exclude day length and the combined effects of both.
Effect of heat treatment of forest soil on germination of buried seed
Authors: Warcup JH
Published: December 2005

Treatment of forest soils from south-eastern Australia with aerated steam within the range 5°C (5 min) to 71°(30 min) often increased the number and variety of buried seed which germinated compared with seed germination in untreated soil. At the lower temperature (55°) prominent germination occurred in species of Juncaceae and Cyperaceae, Poranthera microphylla, Oxalis corniculata and some grasses. At higher temperatures, legumes, some epacrids and species of genera such as Pomaderris, Spyridium, Dichondra, Geranium, Opevcularia and Poranthera germinated. Artificial exposure of surface open-forest soil to the sun in summer was sufficient to cause or increase germination of several species when the soil was subsequently moistened.
Western Australian Species-Rich Kwongan (Sclerophyllous Shrubland) Affected by Drought
Authors: Hnatiuk RJ , Hopkins AJM
Published: December 2005

Observations of responses to aseasonal water stress are reported for 238 above-ground perennial species of native vascular plants in a 20 km2 area of Western Australia surveyed during the second consecutive year of below average rainfall. Eighty-six species (36%) were found with dead individuals. Both vegetative regeneration and seedling regeneration appeared to be successful means of surviving drought stress in this region. The drought affected species of the families Proteaceae and Epacridaceae more than those of other major families. There are similarities in the response of the vegetation to the two main, irregularly occurring phenomena, aseasonal drought and fire: both can affect vegetation over large areas and yet leave considerable patches within the area that are little affected. Together these two factors contribute to the production of complex and dynamic mosaic-patterns in the vegetation.
Frost Resistance of Subalpine Eucalyptus Species. I. Experiments Using a Radiation Frost Room
Authors: Harwood CE
Published: December 2005

Frost resistance of seedlings of four subalpine Eucalyptus species was studied using a frost room that
simulated natural radiation frosts. Seedlings from populations at and above valley-bottom treelines were
examined.
With cooling rates similar to those of natural frosts, initial freezing was detected within the temperature
range – 2.1 to – 6.9 °C, with a mean initial freezing temperature of -4.5°C. Seedlings in an unhardened
state, produced by a temperature regime of 23°C day / l8°C night, had very little freezing resistance, with
complete leaf death being produced by exposure to - 6° for 4 h.
A hardening regime of 16/4°C, with 12-h-photo- and thermoperiod, enabled E. pauciflora seedlings to
harden in 3-4 weeks to the extent that the mean leaf damage produced by a frost of - 8.5 °C was about 50%.
Hardening for longer periods under this regime enabled seedlings to withstand frosts below - 10°C with
very little damage. A 9/4°C regime was much more effective than a 919 °C regime in promoting hardening.
E. pauciflora leaves sprayed with water before a frost were slightly more damaged than dry leaves. The
greater damage appeared to be the result of the slightly lower temperatures of the wetted leaves during the
frost. Two damaging frosts, occurring within 2-3 days, produced slightly more damage than that which
would be predicted by adding the damage that would have been produced by each frost acting separately.
E. stellulata and the 'pendula' form of E.pauciflora, the populations extending furthest down gradients of
increasing frost severity to the valley bottoms, had the greatest seedling frost resistance. Treeline populations
of E. rubida and the 'forest' form of E. pauciflora were intermediate in resistance, and E. dalryrnpleana, a
species that did not extend to the treeline, was least resistant. Examinations of variation in frost resistance of
E. pauciflora seedlings from parent trees sampled along two environmental gradients produced two different
results. Frost resistance increased markedly down a transect from forest form of E. pauclflora on a hillside to
pendula form of E. pauciflora near a valley bottom, but a corresponding increase did not occur down
another transect where the pendula form was absent.
Pathogens (Phycomycetes: Entomophthoraceae) of the blue-green aphid Acyrthosiphon kondoi Shinji and other aphids in Australia
Authors: Milner RJ , Teakle RE , Lutton GG , Dare FM
Published: December 2005

Aphid pathogens were collected in Australia, mainly from June 1977 until September 1979. A brief description is given of each of the six species of Entomophthora found; E. aphidis, E. exitialis, E. obscura. E. phalloides, E. planchoniana and E. virulenta. A key to these species is provided. The principal host aphids studied were two exotic legume aphids. Acyrthosiphon kondoi and Therioaphis trfolii f. maculata. In addition, pathogens were identified from Aphis craccivoua, Brevicoryne brassicae, Cliaetosiphon tetraihodum, Hyperoniyzus lactucae, Macrosiphum rosae, M. euplzorbiae, Myzus ornatus, M. persicae, Sitobion miscanthi, Rhopalosiphum rujabdorninalis, Acyrthosiphon pisum 'Broom-biotype' from Tasmania, Capitophorus elaeragni and three unidentified species. Three pathogens (E. exitialis, E. obscura and E. planchoniana) have been found causing epizootics in A. kondoi. Only one pathogen, E. obscura, occurs regularly in populations of T. trifolii f. maculata. The potential for introducing Entomophthora species for microbial control of aphids in Australia is discussed.
The Mineral Nutrition of Developing Fruits of Kennedia prostrata R. Br. Ex Ait., A Perennial Australian Legume
Authors: Hocking PJ
Published: December 2005

The nutrition of developing fruits of K. prostrata was studied in natural habitat near Perth, Western Australia. Changes in the contents of specific nutrients in pods and seeds are described. Seeds accumulated > 80% of the N and P of the fruit, 36-58% of its K, S, Ca, Mg, Fe and Zn but < 25% of its Na. Pods lost 77-87% of their N and P, 20-39% of their Mg, Zn, Mn and Cu, and 9-15% of their K, S, Ca and Fe during senescence. Na was not withdrawn from pods. Retranslocation from pods were considered to be capable of providing > 50% of the N and P accumulated by seeds, although the values for most nutrients and DM ranged from 16 to 35%. Fruit-tip exudate had some characteristics of phloem sap (e.g. alkaline pH, 15-2096 sucrose, a high
level of K-), but contained 2 . 5 mg/ml Mg2+ and appeared to be contaminated with mucilage. The testa
contained 75% of the seed's dry matter and the major part of its K, Ca, Mg, Mn and Ca; the embryo most of
the seed's N, P and S. Information for Kennedla is discussed in relation to data for cultivated legumes as there
is no comparable study on another native legume.
Chromosomal Differentiation Among Ecotypes of Phalaris aquatica L.
Authors: Putievsky E , Oram RN , Malafant K
Published: December 2005

Seventy-two hybrids of P. aquatica were made among 13 diverse Mediterranean ecotypes and cv. Australian,
and five indicators of hybrid abnormality were measured in the first two generations. The proportions of
stainable, apparently normal pollen grains formed by F, hybrids varied between 5 and 98% and their spikelet
fertility ranged from 19 to 77%. Of the 43 hybrids that were derived from pairs of self-incompatible parents,
13 were highly self-compatible. Crosses between lines from different groups of parents produced F2 progeny
containing up to 17% of lethal seedlings and up to 39% of male sterile plants. In the cross between cv.
Australian and the Moroccan ecotype, CPI 19331: the frequency ofzebra-striped lethal seedlings was as high
as 33% in F2 progenies, but only 0 or 1% in back-crosses to either parent. Hence the zebra-striped phenotype
was not caused by a mutation existing in the parents but rather by deletions or duplications generated during
meiosis in the F1 hybrids.
Many meiotic irregularities were observed in the pollen mother cells of the F1 and F2 hybrids between cv.
Australian and CPI 19331. These included small loops, acentric fragments, univalents and multivalents at
diakinesis, and bridges at anaphase I, indicating that the genomes of these two lines differed by several
inversions and interchanges. These structural differences would lead to a range of duplications and
deficiencies in the gametes. and hence could account for each of the five kinds of hybrid abnormality
observed in the F1 and F2 generations. One aneuploid F2 plant with 25 chromosomes was found.
A dihaploid plant in cv. Australian had an average of 4.3 bivalents per pollen mother cell, whereas
virtually all chromosomes in the tetraploid parental lines paired as bivalents. Thus, P. aquatica is a
segmental allotetraploid with a system which prevents homoeologous pairing in tetraploids but not in
dihaploids.
The partial barriers to hybridization between P. aquatica lines are not closely related to their geographic
origins or varietal classifications. These barriers may hinder but have not prevented the recombination of
parental traits during the development of improved cultivars.
A biosystematic study of the Kangaroo Paws, Anigozanthos and Macropidia (Haemodoraceae).
Authors: Hopper SD
Published: December 2005

Seed set, seed germlnatlon and hybrld pollen fertilltles following controlled pollinations of 4828 flowers were investigated in the 12 species of kangaroo paws to assess taxonomlc and evolutionary relationships, document breeding systems and explore the potential and limitations in syntheesizing horticulturally desirable hybrlds in the group.
All species except Anigozanthos flavidus set few seeds on selfing relative to numbers set on intrapopulational crossing, and thus were predominantly outbreeding. Interpopulational crossing barriers in A humilis were usually non-existent. In A. viridis they occurred between races in a geographical pattern consistent wtth the occurrence of the Wallace Effect (reproductive character displacement) In A. bicolor they were complex and generally uncorrelated wlth interpopulational distances or morphological (racial) divergence, while in A. manglesii they were associated consistently wlth racial differences. Interspecific crosses involving 79 species combinations and 215 population combinations invariably revealed crossing barriers more potent than those seen in intraspecific crosses.
The biosystematic data support the taxonomic conclusions that Anigozanthos and Macropidra are genetically isolated genera, that recognition of just two sections (Anigozanthos and Hapianthesis) represents the best subgeneric classification of Anlgozanthos and that members of the A. bicolor-A. gabrielae, A viridis, A humilis-A kalbarriensis and A rufus-A pulcherrimus groups each constitute distinct species rather than intraspecific taxa The majority of Interspecific F1 hybrids were found to succumb to fungal attack, snail predation and/or inappropriate watering within 2 or 3 years of cultivation Hybrids of A. flavidus appeared to be the most vigorous, long-lived and floriferous, and probably are the most suitable for large-scale horticultural development
Ginkgo Leaves from Paleogene Sediments in Tasmania
Authors: Carpenter Raymond J. , Hill Robert S.
Published: December 2005

A single nearly complete leaf and several fragments in Paleogene sediments
from southern Tasmania confirm the Cenozoic presence of
Ginkgo L. in Australia. The specimens, assigned to
G. australis McCoy, add to our knowledge of probable
deciduous forms in the southern Australian Paleogene, when winter darkness at
the prevailing high latitudes made this strategy competitive.
Leaf Anatomy of Wollemi Pine (Wollemia nobilis, Araucariaceae)
Authors: Burrows Geoffrey E. , Bullock Suzanne
Published: December 2005

Leaves of adult morphology from Wollemi pine(Wollemia nobilis W.G.Jones, K.D.Hill & J.M.Allen)possess a thick cuticle, sunken stomata, abundant hypodermal fibres, distinctpalisade and spongy mesophyll with most palisade development on the adaxialside, compartmented cells, resin canals, sclereids, and vascular bundles withtransfusion tissue and a fibre cap abaxial to the phloem. Stomata are presenton both leaf surfaces, although in greater density on the abaxial surface, andusually have an oblique orientation and four or five subsidiary cells. At thelight microscope level, Araucaria can be distinguishedfrom Agathis as it possesses unusual compartmented cellsin the mesophyll, while Agathis does not. In addition,most Agathis species are hypostomatic, while mostAraucaria species have stomata on both the abaxial andadaxial surfaces. Thus W. nobilis has a leaf anatomywhich has a greater similarity to Araucaria than toAgathis.
Molecular and morphological variation in the Senna artemisioides complex
Authors: Holman J. E. , Playford J.
Published: December 2005

The Senna artemisioides
species complex is characterised by extremely variable foliar morphology. This
paper presents the results of an integrative study on reproductive biology,
morphology and genetic variation to explore the evolutionary and systematic
relationships within this species complex at Idalia National Park in central
Queensland. Senna artemisioides showed discontinuous
variation at both genetic and phenotypic level. At three sites, foliar
morphology was discontinuous, being represented as discrete clusters. Analysis
of isozyme variation indicated that many of the discrete morphological groups
are distinguished by fixed genetic differences. Morphotypes were also
characterised by widespread monomorphism. Most of the genetic variation was
between morphotypes rather than within morphotypes. These fixed genetic
differences indicate a lack of gene flow between morphotypes and therefore an
absence of hybridisation. The two most distinct morphological groups
(pyllodinous, pinnate) had high genetic distances of 0.5, a value beyond the
usual distance between congeneric species. Forty-two percent of pairwise
comparisons between other morphotypes yielded genetic distance values that
were relatively high (0.21–0.42). Some phenotypically distinct
morphotypes, however, showed little or no isozyme divergence. The combined
evidence suggests that genetically distinct morphotypes are independent
lineages originating from an ancestral sexual reproductive event that is
perpetuated by apomictic reproduction.
Ascoma Development in Neophyllis melacarpa (Lecanorales, Ascomycota), with Notes on the Systematic Position of the Genus
Authors: Döring Heidi , Henssen Aino , Wedin Mats
Published: December 2005

The ascoma ontogeny of Neophyllis melacarpa (F.Wilson)F.Wilson is described and similarities toAustropeltum glareosum Henssen, Döring & Kantvilas are pointed out. Neophyllis is shown to formtrue podetia as well as pseudopodetia, and an unpigmented boundary tissue ofthin-walled, plasma-rich hyphae. Characteristic features include the formationof a boundary tissue separating a hypophysiate pseudopodetium from theascomatal tissue, a large subglobose hypothecium, and a cortical covering ofyounger developmental stages. Ascus structure and conidiophore anatomy aredescribed and similarities to Austropeltum arediscussed. The secondary product chemistry of Neophyllisis described in detail, and two chemical taxa, corresponding to the currentlyaccepted species N. melacarpa andN. pachyphylla (MÜll.Arg.) Schneider, aretentatively accepted. The systematic position ofNeophyllis is discussed, and the generic distinctnessfrom Gymnoderma is clarified. It is concluded thatNeophyllis is closely related toAustropeltum, and that there is no support for regardingNeophyllis as closely related toCladonia, the generic type of Cladoniaceae. The possibleaffinities of Neophyllis to Stereocaulaceae andSphaerophoraceae are discussed, but it is pointed out that the delimitation ofall three families needs further investigation.
Ecophysiological responses of Araucaria angustifolia
seedlings to different irradiance levels.
Authors: Duarte Leandro da S. , Dillenburg Lúcia R.
Published: December 2005

Brazilian pine (Araucaria angustifolia [Bert.]
O.Ktze.) is an indigenous conifer of the southern region of South America,
typically regarded as a sun-loving species. However, there is insufficient
information on the species’ behaviour under different irradiances to
characterise its plasticity to light. The purpose of this work was to measure
some ecophysiological responses of Brazilian pine seedlings to three
irradiance levels: 100, 45 and 10% full sunlight. Thirty seedlings were
grown under each of the irradiance treatments and, after 5 months, growth
parameters, leaf chlorophyll concentration and in vivo
nitrate reductase activity, in both leaves and roots, were analysed. There was
no increase in shoot biomass allocation in response to shading, in contrast to
results from other experiments. Only low-light seedlings showed significant
increase in specific leaf area, as well as in the ratio of height to shoot
biomass. Chlorophyll content and the ratio of chlorophyll
a to chlorophyll b did not vary
among treatments. Nitrate reductase activity was detected only in roots and
was reduced in the low-light treatment. An overall analysis of the results
points to a normal growth of Brazilian pine seedlings at both high- and
medium-light sites, at least in their initial stages of development.
Variation in frost tolerance and seedling morphology of the spotted gums Corymbia maculata, C. variegata, C. henryi and C. citriodora
Authors: Larmour J. S. , Whitfeld S. J. , Harwood C. E. , Owen J. V.
Published: December 2005

The frost tolerance of seedlings of spotted gums representing four closely
related species; Corymbia maculata (seven provenances),
C. variegata (six provenances),
C. henryi (one provenance) and
C. citriodora (two provenances) was examined. Each
provenance of C. maculata,
C. variegata and C. henryi was
represented by 10 seedlings from each of eight open-pollinated families, while
the two C. citriodora provenances were each represented
by 40 seedlings from a provenance bulk seedlot. Excised leaf discs from
seedlings hardened by exposure to the Canberra winter were subjected to test
temperatures of –4.2, –6.1 and –8.0˚C. Damage to the
discs was estimated by the electrical conductivity of leachate produced by
soaking the disks in water after exposure to freezing temperatures.
Exposure to –6.1˚C for 1 h produced leachate conductivities
corresponding to 37% of discs receiving lethal injury and gave good
discrimination between tolerant and susceptible material. There were
significant differences in frost tolerance between species, provenances within
species, and between open-pollinated families within provenances.
Corymbia variegata displayed significantly greater frost
tolerance than the other three species. Species rankings were consistent
across the three test temperatures. Inland, high altitude provenances of
C. variegata and C. maculata had
greater frost tolerance than those from lowland coastal locations, while there
were no consistent trends of frost tolerance with latitude in these species.
Analysis of seedling morphological characters effectively separated the
different species in a manner consistent with the taxonomic review by Hill and
Johnson (1995). Characters which separated C. maculata
and C. variegata included the leaf pair at which the
changeover from juvenile to intermediate leaf morphology occurred and the
degree of pubescence of the leaves and stem, leaf size and shape.
Corymbia variegata and the southern provenance of
C. citriodora were separated only by the citronella
scent of C. citriodora, the northern
C. citriodora provenance had distinctly different leaf
size and shape.Corymbia henryi seedlings had greater
stem and leaf pubescence than those of C. maculata as
well as distinctly shaped leaves, characterised by having the greatest length
from the widest point to the leaf base.
Southern Conifers in Time and Space
Authors: Hill Robert S. , Brodribb Tim J.
Published: December 2005

The three southern conifer families, Araucariaceae, Cupressaceae and
Podocarpaceae, have a long history and continue to be an important part of the
vegetation today. The Araucariaceae have the most extensive fossil record,
occurring in both hemispheres, and with Araucaria in
particular having an ancient origin. In the Southern Hemisphere
Araucaria and Agathis have
substantial macrofossil records, especially in Australasia, and
Wollemia probably also has an important macrofossil
record. At least one extinct genus of Araucariaceae is present as a
macrofossil during the Cenozoic. Cupressaceae macrofossils are difficult to
identify in older sediments, but the southern genera begin their record in the
Cretaceous (Athrotaxis) and become more diverse and
extensive during the Cenozoic. Several extinct genera of Cupressaceae also
occur in Cretaceous and Cenozoic sediments in Australasia. The Podocarpaceae
probably begin their macrofossil record in the Triassic, although the early
history is still uncertain. Occasional Podocarpaceae macrofossils have been
recorded in the Northern Hemisphere, but they are essentially a southern
family. The Cenozoic macrofossil record of the Podocarpaceae is extensive,
especially in south-eastern Australia, where the majority of the extant genera
have been recorded. Some extinct genera have also been reported from across
high southern latitudes, confirming an extremely diverse and widespread suite
of Podocarpaceae during the Cenozoic in the region.
In the Southern Hemisphere today conifers achieve greatest abundance in wet
forests. Those which compete successfully with broad-leaved angiosperms in
warmer forests produce broad, flat photosynthetic shoots. In the Araucariaceae
this is achieved by the planation of multiveined leaves into large compound
shoots. In the other two families leaves are now limited to a single vein
(except Nageia), and to overcome this limitation many
genera have resorted to re-orientation of leaves and two-dimensional
flattening of shoots. The Podocarpaceae show greatest development of this
strategy with 11 of 19 genera producing shoots analogous to compound leaves.
The concentration of conifers in wet forest left them vulnerable to the
climate change which occurred in the Cenozoic, and decreases in diversity have
occurred since the Paleogene in all regions where fossil records are
available. Information about the history of the dry forest conifers is
extremely limited because of a lack of fossilisation in such environments. The
southern conifers, past and present, demonstrate an ability to compete
effectively with angiosperms in many habitats and should not be viewed as
remnants which are ineffectual against angiosperm competitors.
Natural and culture-induced genetic variation in plantains (Musa spp. AAB group)
Authors: Newbury H. J. , Howell E. C. , Crouch Jonathan H. , Ford-Lloyd B. V.
Published: December 2005

Random amplified polymorphic DNA (RAPD) analysis of 15, mostly African,
plantain land races revealed a very low proportion of polymorphic bands (13 of
276). However, further examination of these 13 marker bands demonstrated that
they varied within land races and could not be used to distinguish between
land races. In many cases, this could be directly associated with tissue
culture treatment of the material. In order to investigate tissue culture
effects in more detail, a single meristem of the West African plantain Agbagba
was introduced into axenic culture and subjected to three cycles of
micropropagation. A total of 48 regenerated plants were established under
field conditions and subjected to RAPD analysis. By using 40 arbitrarily
selected primers, about 400 bands were scored across this population of
in vitro-derived plants. Sixteen of the bands were
polymorphic within the population of Agabgba plants, distinguishing 13
genotypes. The pattern of relationships of these genotypes was established by
cluster analysis; field characterisation of the plants supported the
relationships revealed by RAPD data. The high level of RAPD polymorphism
(4% of bands polymorphic), along with a clear correlation between the
genotypic classification of individual plants and their tissue culture
pedigree, suggests that a substantial amount of genetic variation existed
within the original cultured meristem. On this basis, a putative Agbagba
meristem representing an apparent sectoral chimera has been constructed. A
model is presented that takes account of the persistence and high rate of
somaclonal variation and proposes that the mother Agbagba plant comprised a
periclinal chimera.
Acetylene Reduction Rates by Selected Leguminous and Non-Leguminous Plants of Groote Eylandt, Northern Territory.
Authors: Langkamp PJ , Farnell GK , Dalling MJ
Published: December 2005

Acetylene (C2H2) reduction associated with the roots of various grasses and sedges and by nodules of selected legumes was investigated in a Eucalyptus tetrodonta open-forest and a Melaleuca leucadendron open-forest swamp complex. High rates of non-legume C2H2 reduction, as measured by the excised root assay, were associated only with plants found in the swamp complex: the sedge Fimbristylis dichotoma and the grasses Imperata cylindrica and Paspalum vaginatum (70 ± 30, 161 ± 69 and 23 ± 15 nmol C2H4 g dry wt -1h-1 respectively). An initial lag period of 8 h before C2H2 reduction was detected was not eliminated or reduced by the addition of sucrose. Nearly all the C2H2 reduction activity was associated with the roots with very little activity in topsoil or subsoil. The addition of inorganic nitrogen or aspartic or citric acids stopped the reduction of C2H2, but addition of sucrose stimulated it. Current potential photosynthesis appeared to be related to C2H2 reduction ability. Acetylene reduction activity by rooted nodules of various leguminous species was distinctly seasonal, being greatest in the wet season. Members of the Mimosaceae had twice the wet season activity of those of the Caesalpiniaceae and Fabaceae (20.4 ± 2.9 and 10.1 ± 4.0 nmol mg fresh wt-1h-1 respectively). The results indicate that the nitrogen accretion rate in the E. tetrodonta open-forest will be low (0.05-1 kg Nha-1yr-1) and that mineralization of soil organic matter could account for all the nitrogen utilized by the ecosystem over a wet season.
Association of Phytophthora cinnamomi With Pinus radiata in South Australia
Authors: Bumbieris M
Published: December 2005

In a pine forest plantation, P. cinnamomi was rarely isolated from the root zones, and never from the roots, of established P. radiata growing at P. cinnamomi sites. When a P. cinnamomi site was replanted with P. radiata, a third of the young pines died during the first 9 months, about 50% of them yielding P. cinnamomi from roots. Death of the trees followed an increase in the soil population density of P. cinnamomi which appeared to be correlated with increasing soil temp. and high soil moisture.
Reproductive Success of Two Eucalyptus Hybrid Populations. I. Generalized Seed Output Model and Comparison of Fruit Parameters
Authors: Drake DW
Published: December 2005

The dynamics of the reproductive success of two interspecific Eucalyptus hybrid populations are examined
here and in a subsequent paper in relation to a generalized model of seed output of a single plant. The model
describes a structural system of seed output per plant under both physiological and physical regulation. It
can readily be extended to a population model and to postdispersal reproductive stages.
Fruit loss, output and damage in the two populations are presented. The E. melanophloia × E. crebra
hybrids are considerably less fertile than their parent species. Significant loss of reproductive structures
during maturation and low reproductive effort, together with variable canopy size and proportion of canopy
bearing fruits, result in the fruit output per average hybrid tree being 10% of either of the average species
trees. Biotic damage to surviving hybrid fruits by an insect and a fungus is individually significantly greater
than levels suffered by the species and together account for an average of 56% of fruits compared with 16%
for either species. Damage and loss levels to these hybrids are more or less constant in space and time and
constitute a strong selective force against these hybrids.
In contrast, fruit loss parameters are low and differences between the taxa are non-significant throughout
the E.populnea × E. crebra hybrid system, resulting in hybrid fertility about equal to the fertilities of the
parents.
These contrasting results are discussed in relation to hybrid frequencies in the ecotone and levels of
hybrid population development.
Reproductive Success of Two Eucalyptus Hybrid Populations. II. Comparison of Predispersal Seed Parameters
Authors: Drake DW
Published: December 2005

The reproductive success of E. melanophloia × E. crebra and E. populnea × E. crebra hybrid populations is
examined in terms of seed output. Predispersal seed losses and outputs from fruits and trees of hybrids and
species in mixed- and single-species stands are presented. The contribution of the hybrid population to the
total eucalypt seed output is considered by including in the estimates the numbers of hybrid and species trees
per unit area of ecotone.
Losses of E. melanophloia × E. crebra hybrid seeds through abortion, insect predation and fungal
infection are significantly greater than losses of parent seeds and seeds of the other hybrid, and average 70%
overall compared with 22% for each parent. If losses through bud maturation failure are included, 93% of the
hybrid potential is lost. Hybrid outputs of 7 × 103 whole seeds per tree and 22 × 104 per ha of ecotone are
respectively 1.5%, and 0.3% of the total seed output of the three taxa.
Overall losses in the E. populnea × E. crebra hybrid system are much lower and less important to survival.
The effect on seed number is dependent upon seed potential per fruit. E. populnea is the least affected (9%
loss, very high potential), E. crebra the worst (21%, very low) and the hybrids are intermediate and in a
relatively strong competitive position (20%, intermediate). Hybrid outputs of 145 × 103 seeds per tree and
23 × 103 per ha are respectively 21% and 17% of the total output.
The significance of these results is discussed in relation to the reliance of eucalypts upon a high seed
output strategy for survival and to the hybridization success of the two systems.
Influence of weather on mouldiness and the mycoflora of legume pasture during the dry season in tropical Australia
Authors: Shipton WA , McCown RL , Williams WT
Published: December 2005

Spoilage of high quality dry legume herbage as a result of dew and/or small falls of rain during the dry season is a hazard associated with this type of development in the northern Australian beef industry. The most important effect of moisture is the reduction of palatability of forage as a result of mouldiness. This paper describes studies on the relationship between mouldiness and the mycoflora of dry leaf litter in swards of Caribbean stylo at Katherine, Darwin and Townsville from May to August 1978. Forty-three fungi were identified on 42 samples. Numerical methods were used to classify the samples of litter into nine affinity groups distinguished by the possession of different mycofloras. This grouping of the samples correlated well with other factors such as the degree of discoloration and the particular history of the litter from which they were drawn. From this information it was concluded that increase in discoloration, clearly related to degree of mouldiness, was also related to stages in a fungal succession. The stage of the succession attained depended on the time of sampling, weather, sward management and the level at which leaves were sampled from the litter.
Behaviour of Cochliobolus sativus during its infection of barley and wheat leaves
Authors: Yadav BS
Published: December 2005

Similar incidences of germination and appressoria formation, with or without added nutrients to the infection drops, suggested that the nutrients contained in C. sativus conidia were sufficient for germination and formation of appressoria. Appressoria developed poorly on glass slides compared with development on leaf surfaces. Sharp, fine infection pegs developed within 12-15 h and 14-18 h after inoculation onto cleared and uncleared leaves respectively. Percentages of penetration and colonization of cleared leaves were lower than those of uncleared leaves and increased significantly when various nutrients including leaf leachates were added to the infection drops. Carbohydrate and protein levels were much lower in cleared than in uncleared leaves. Leaf leachates contained sugars and amino acids which made up an adequate food supply for the pathogen. Sugar and amino acid contents of the infection drops decreased during the penetration phase on healthy leaves as well as on the glass surface. Within this period, however, the degree of change in sugar content was much greater on leaves than on the glass surface. These observations led to the conclusion that C. sativus conidia required an exogenous supply of nutrients to enable successful penetration. Nutrients leached from cells of healthy leaves were absorbed by the spores and utilized to provide the energy required for penetration. The parasite population on healthy leaves of barley and wheat was generally synchronous, suggesting that this host-pathogen combination is conducive to the early host-parasite interactions.
Morphometrics of the aerial roots of Kingia australis (Liliales)
Authors: Lamont B
Published: December 2005

Kingia australis, common in the heaths and forests of south-western Australia, is distinguished from all other grass trees in Australia by the presence of a mantle of concealed aerial roots. A ring of up to 50 root primordia is initiated in winter from the stem apex. In plants more than 1 m high, initiation and commencement of elongation of the primary roots are no longer annual but dependent on the fire history of the plant. These roots descend between the stem and persistent leaf bases at about 2 cm per growing month, sending many lateral branches among the leaf bases. Aerial roots gradually replace the space occupied by the leaf bases until they may account for 45% of the dry weight of the aerial caudex. The caudex of one 6-m-high specimen bore up to 27 roots per cm2 transection of the root mantle, with about 3000 primary roots entering the soil. All underground primary roots (except the initial contractile roots) have an aerial origin and are concentrated vertically under the canopy. After 300-400 years the stem starts to die back from the base, and the aerial roots attached to that portion disintegrate. By propping up the stem and bridging the dead zone of the stem, the living aerial roots greatly extend the potential height and longevity of the plant. In addition, the hairy laterals are ideally located to absorb water and nutrients directly from the leaf bases. Protective and aerating functions are also indicated.
Physiological Activity, in a Semiarid Environment, of Eucalyptus Camaldulensis Dehn. From Two Provenances
Authors: Moreshet S
Published: December 2005

Seedlings of provenances from Victoria and the Northern Territory were planted in S. Israel. Measurements of diam. growth, CO2 uptake and stomatal conductance at age 4-5 yr showed that the Victorian provenance was better adapted to the semiarid conditions of S. Israel than the Northern Territory provenance.