Araucaria Bidwillii Research Articles

Not All Edible Nuts Are Eaten: Evidence for Continued Aboriginal Cultural Use and Dispersal of Bunya Pine (Araucaria bidwillii) in Southern But Not in Northern Queensland

Globally, there is increasing evidence that Indigenous peoples have manipulated plant and animal populations over millennia. The Bunya Pine ( Araucaria bidwillii Hook.) is a coniferous tree native to subtropical and tropical eastern Australia, which produces 30–100 large, edible seeds within a large cone weighing 5–10 kgs. Endemic Bunya populations occur as two disjunct populations: one in south-eastern Queensland/north-east New South Wales and the other in northern Queensland. We investigated possible pre- and postcolonial Bunya seed dispersal within and between the two separate populations by utilising multidisciplinary methods to examine Aboriginal cultural connections with Bunya. Analysis of historical sources and ethnographic interviews conducted with Aboriginal knowledge holders provided strong evidence for localised deliberate dispersal within the southern population but no solid evidence for dispersal in the north, suggesting two distinct modes of Aboriginal interaction with this species. Early European colonial records documented the Indigenous cultural significance of southern Bunya, evidenced by large feast gatherings, creation Stories, Aboriginal familial tree connections, seed carrying and planting, and storage in camps. The continued cultural attachment post-colonisation was evident from ethnographic interviews with Indigenous knowledge holders that revealed plantings of this species on Aboriginal missions and modern grave sites. The development of an overarching effective biocultural management plan to conserve the biological and cultural importance of this species is therefore particularly important for the southern population, especially in the face of new threats from pathogenic dieback. The individal tree connections of certain Aboriginal families also warrant deeper ethnographic study to target planting and restoration efforts that preserve these kin-based biocultural connections.

Araucaria bidwillii genomics suggest Indigenous Peoples broadened translocation practices in response to settler colonialism

Abstract Retracing past anthropogenic dispersal of culturally important taxa offers insights to the biogeographic history of species, as well as the history of the people who interacted with them. Bunya Pine (Araucaria bidwillii Hook.) is a culturally and spiritually significant conifer tree for several Indigenous groups in eastern Australia. Sharing the edible nuts and attending Bunya gatherings is an important way for these groups to maintain their cultural connections and it has been hypothesized that prior to European colonization, Indigenous Peoples facilitated the dispersal of Bunya Pine as part of these ancient traditions. We used ethnohistorical information on the use of Bunya Pine by Indigenous Peoples to interpret genomic patterns within and between disjunct distributions of Bunya Pine. We found signatures of long‐term isolation within the Australian Wet Tropics (AWT) and extensive gene flow within southeast Queensland (SEQ) that does not fit models of faunal or passive dispersal. Within SEQ, we found greater population structure amongst sites known to pre‐date European colonization, than when colonial‐era planted sites were included in our analyses, suggesting that pre‐colonial translocation was sporadic or localized rather than systematic and widespread. Increased Indigenous translocations in conjunction with plantings by European settlers appears to have erased the natural pre‐colonial population structure of SEQ Bunya Pine. Our stairway plot models suggest sharp population decline of SEQ Bunya Pine in the early and late Pleistocene, though we did not find evidence that anthropogenic dispersal facilitated effective population size growth of the species in the Holocene. We concluded that pre‐colonial translocation of SEQ Bunya Pine was likely restricted by kinship‐based custodial rights, and that when Indigenous Peoples were displaced by European settlers, translocation was intensified to maintain cultural connectivity. This study is an example of how Indigenous Australian groups adapt plant management strategies to meet socio‐cultural needs and demonstrates the potential for plant genomics to supplement Indigenous Biocultural Knowledge that has been impacted by colonial dispossession. Read the free Plain Language Summary for this article on the Journal blog.

Chemical composition of bunya nuts (Araucaria bidwillii) compared to Araucaria angustifolia and Araucaria araucana species

Three of nineteen Araucaria tree species from around the world produce large edible seeds. While composition is established for edible pinhão and piñones nuts from Brazil and Chile, respectively, the first detailed characterisation for the composition of edible Araucaria bidwillii (bunya nut) from Australia is provided. Almost half of the kernel weight is moisture and the main component in the dried kernel is starch. Whilst low in protein and fat, it contains all essential amino acids and half the fatty acids are polyunsaturated (Omega-3 and 6). Bunya nuts are a source of dietary fibre, folate and minerals (Cu, Mn, Fe, Mg), while the nut husks and inner coating are high in phenolics, mainly catechin. The composition supports the Traditional Knowledge of Aboriginal Australians that the bunya nut is an energy dense and nutrient rich food. Similarities in the composition among the three different edible varieties were found, which should assist in developing sustainable value chain propositions via shared knowledge on processing and utilisation.

The ecology, evolution and management of mast reproduction in Australian plants

Australia is home to a diverse assemblage of plant species that display marked population-level variation in inter-annual flower or seed output (i.e. masting). These include a semelparous bamboo with an estimated inter-crop period of 40–50 years, numerous iteroparous masting gymnosperms, angiosperms that include landscape-dominant eucalypts, arid-zone wattles and spinifex (Triodia spp.) grasses, and a rich selection of species that display disturbance-related forms of masting such as pyrogenic flowering and environmental prediction. Despite the prevalence of masting in the Australian flora, there has been a paucity of research on these plants. Nevertheless, from the literature available, it appears that, similar to other parts of the world, a continuum of inter-year reproductive variability exists, with a small number of species displaying extreme–high inter-annual seeding variability. From experimental studies and many anecdotal reports, most of the fitness benefits associated with masting evident overseas also operate in Australia (e.g. predator satiation, improved pollination efficiency, and environmental prediction). Additionally, some Australian masting species offer periodically important food resources for Aboriginal nations in the form of seed or fruit. These include the bunya pine (Araucaria bidwillii), members of the cycad genera Cycas and Macrozamia, spinifex (Triodia) grasses, and mulga shrubs (Acacia aneura). Key future research areas for effective conservation of Australian masting plants include (1) improved understanding of how management interventions such as burning and silvicultural thinning influence regeneration dynamics and higher-order trophic interactions, (2) further longitudinal monitoring across a range of habitats to identify other, as yet unknown, species that display reproductive intermittency, and (3) elucidation of how changes to temperature, precipitation and fire regimes under climate change will affect reproduction and regeneration dynamics of the Australian masting flora.

Metabolomic profiling of three Araucaria species, and their possible potential role against COVID-19

The COVID-19 pandemic in Egypt is a part of the worldwide global crisis of coronavirus 2 (SARS-CoV-2). The contagious life-threatening condition causes acute respiratory syndrome. The present study aimed to assess the compounds identified by LC-MS of the methanolic leaves extracts from three conifers trees cultivated in Egypt (Araucaria bidwillii, Araucaria. cunninghamii and Araucaria heterophylla) via docking technique as potential inhibitor of COVID-19 virus on multiple targets; viral main protease (Mpro, 6LU7), non-structural protein-16 which is a methyl transferase (nsp16, 6W4H) and RNA dependent RNA polymerase (nsp12, 7BV2). Among the three targets, nsp16 was the best target recognized by the tested compounds as can be deduced from docking studies. Moreover, the methanolic extract of A. cunninghamii showed the highest radical-scavenging activity using (DPPH test) with 53.7 µg/mL comparable to ascorbic acid with IC50 = 46 µg/mL The anti-inflammatory potential carried using enzyme linked immunoassay showed the highest activity for A. cunninghamii and A. bidwillii followed by A. heterophylla with IC50 = 23.20 ± 1.17 µg/mL, 82.83 ± 3.21 µg/mL and 221.13 ± 6.7 µg/mL, respectively (Celecoxib was used as a standard drug with IC50 = 141.92 ± 4.52 µg/mL). Moreover, a molecular docking study was carried for the LC-MS annotated metabolites to validate their anti-inflammatory inhibitory effect using Celecoxib as a reference compound and showed a high docking score (−7.7 kcal/mol) for Octadecyl (E) P-coumarate and (−7.3 kcal/mol) for secoisolariciresinol rhamnoside. Communicated by Ramaswamy H. Sarma

Artigo de dados de fragmentos de lenhos carbonizados de araucariaceae a partir de análise de infravermelho (FTIR)

Os dados fazem parte de uma tese de doutorado que objetivou desenvolver uma metodologia para avaliar por métodos físicos e químicos os lenhos carbonizados artificialmente de três espécimes da família Araucariaceae: Araucaria angustifolia, Araucaria bidwillii e Araucaria columnaris. O processo de carbonização dos fragmentos dos lenhos foi realizado em mufla. As temperaturas da queima dos lenhos in natura carbonizados foram de 200ºC a 600ºC, variando-se a temperatura de 50ºC em 50ºC e com taxa de aquecimento avaliada em 25°C min-1. Posteriormente ao processo de carbonização, os espectros foram adquiridos no espectrofotômetro de infravermelho, num intervalo entre 1900 a 650 cm-1, com resolução de 4 cm-1 e 64 varreduras.

The Long-Term Survival and Growth of Enrichment Plantings in Logged Tropical Rainforest in North Queensland, Australia

Enrichment planting is often suggested as a means of enhancing the productivity of logged rainforest. However, little is known about the long-term survival and growth of these trees. In this study, we used historical data from enrichment planting trials ranging from 15 to 32 years old to examine the survival and growth of 16 tree species across different sites in north Queensland, Australia. The results complement and extend current knowledge on the potential role of enrichment planting from a production perspective. A key finding was that the initial level of post-logging overwood did not appear to affect the immediate survival of enrichment plantings, but in the longer term (up to 30 years) survival decreased as post-logging overwood and regrowth increased. This suggests that removal of overwood should take place at the time of enrichment planting. A further key finding was that despite regular tending to remove vegetation adjacent to the plantings, competition from saplings and trees that were situated outside the tended area emerged as a major source of competition in some plots. By implication, the success of enrichment planting may depend on removal of competition from the entire logged area, not just adjacent to enrichment plantings. Results between individual species and trials varied widely. The best development of Flindersia brayleyana resulted in a mean tree diameter of 32.5 cm at age 22 for the 100 tallest trees per hectare. Although Eucalyptus grandis, Eucalyptus microcorys, and Eucalyptus pilularis all failed—as expected, because they do not normally grow in rainforest—Corymbia torelliana, Cardwellia sublimis, Araucaria bidwillii, Khaya senegalensis, Flindersia amboinensis, and Swietenia macrophylla also failed although they grow naturally in similar sites. In other trials, tree height and basal area growth were often poor. For example, Khaya ivorensis grew to a basal area of only 1.3 m2/ha and a mean height of 7.7 m at age 10, and Flindersia ifflaiana only grew to a basal area of 0.7 m2/ha and a height of 7.9 m, also at age 10. Overall, these results emphasise the necessity of site–species matching before enrichment planting begins and the necessity of post-planting monitoring and remedial tending.

Changes in bacterial community composition across natural grassland and pine forests in the Bunya Mountains in subtropical Australia

Tree and grass species coexist in many ecosystems worldwide and support multiple ecosystem functions and services. However, the distribution of bacterial communities and factors driving coexistence in tree–grass associations and their ecosystem functions remain poorly understood. In this study, the distribution of soil bacteria and their link to changes in abiotic factors were investigated in adjacent montane grassland (C4 plants) and pine forest (bunya pine and hoop pine; C3 plants) sites in the Bunya Mountains, subtropical Australia. Different vegetation (grassy balds and forest) had a substantial effect on terrestrial ecosystem properties, with higher levels of soil nutrients (e.g. total nitrogen (N), total phosphorus (P)) and electrical conductivity (EC), and lower δ13C values and pH under forests compared with grassland. Bacterial α-diversity (total species per operational taxonomic unit richness) did not differ between grassland and pine forest sites, whereas strong shifts in the bacterial community composition and structure were evident. Patterns in bacterial community structure were strongly associated with changes in soil pH, EC, total P and δ13C. Different bacterial groups associated with pine forest (Gammaproteobacteria and Alphaproteobacteria) and grassland (Acidobacteria and Verrucomicrobia) were identified as key groups contributing to the segregation of these two ecosystems in the Bunya Mountains. These findings suggest that heterogeneity in soil edaphic properties (e.g. key nutrients) likely contributed to variation in bacterial β-diversity of grassland and pine forest, which has potential implications for species coexistence and ecosystem function in montane eastern Australia.

Verification of the anti-inflammatory activity of the polyphenolic-rich fraction of Araucaria bidwillii Hook. using phytohaemagglutinin-stimulated human peripheral blood mononuclear cells and virtual screening

Ethnopharmacological relevanceAraucaria bidwillii Hook., the bunya pine, is an evergreen plant belonging to family Araucariaceae. Traditionally, its leaves and oleoresins have been used as herbal remedies to alleviate pain and inflammation. Based upon the frequent adverse effects accompanying synthetic anti-inflammatory drugs, this study will assess the anti-inflammatory activity of both the total methanol extract and the polyphenolic-rich fraction of A. bidwillii leaves. Materials and methodsThe anti-inflammatory activity was assessed in vitro using phytohaemagglutinin-stimulated human peripheral blood mononuclear cells (PBMCs). Isolation of the major compounds was conducted using various chromatographic techniques. Molecular modelling studies are performed on tumor necrosis factor-α (TNF-α), cyclooxygenase-II (COX-II) and 5-lipooxygenase (5-LOX). ResultsBoth the total methanol extract of Araucaria bidwillii leaves and its fraction revealed a dose-dependent manner in lowering the levels of IL-1β, IL-6 and TNF-α with an equivalent activity to that of indomethacin. In addition, the phytochemical investigation of the polyphenolic-rich fraction results in identification of agathisflavone-4′,7''-dimethyl ether (1), 7-O-methyl-6-hydroxyapigenin (2) and 4′,4′-di-O-methylamentoflavone (3) as the main components. In silico molecular modelling showed that agathisflavone-4′,7''-dimethyl ether (1) exhibited the fittest binding in TNF-α active sites, while 7-O-methyl-6-hydroxyapigenin (2) showed the highest inhibition in COX-II whereas 4′,4′-di-O-methylamentoflavone (3) is the most potent 5-LOX inhibitor. ConclusionThus, the leaves of Araucaria bidwillii could afford a potent anti-inflammatory agent that effectively ameliorates inflammation and its related hazards. This in turn consolidates the fact of using the leaves of Araucaria bidwillii to sooth inflammation in traditional medicine.

The use of a replanted riparian habitat by the Lumholtz's Tree‐kangaroo (Dendrolagus lumholtzi)

SummaryThis study describes the use of a section of a replanted riparian wildlife corridor by Lumholtz's Tree‐kangaroo (Dendrolagus lumholtzi) (referred to here as LTK) on the Atherton Tablelands in north‐east Queensland, Australia. Selection of plants for replanting had been adjusted to the seasonally inundated clay‐rich and acid soils of the site, and, in some cases, with the aim to establish wind breaks which resulted in a plant composition of this section that differs from known LTK habitats. Through semi‐regular daily observations of individual LTKs over eight years, it was found that LTKs were most commonly recorded on Tallowwood (Eucalyptus microcorys), Rose Gum (E. grandis), Caribbean Pine (Pinus caribaea) and Bunya Pine (Araucaria bidwillii) which were planted as wind breaks in the 1950s and 1980s. On a section planted in 1998, it was found that LTKs used certain tree species more frequently than would have been expected from the relative number in which these species had been planted. This may be associated with certain structural features of the used tree species. The presence of these structural habitat features may allow LTKs to establish home ranges within the restored habitat. Home ranges were calculated for four females, and it was found that they did not differ in size from those reported from other LTK habitats. However, home ranges showed extensive overlaps. The study reveals that LTK will colonise replanted habitat and may be adaptable in its spatial requirements in a restored landscape.

AIR POLLUTION TOLERANCE INDEX OF SOME SELECTED GYMNOSPERM SPECIES ALONG THE ROAD SIDE OF KATHMANDU VALLEY, NEPAL

Response of plants towards air pollution is assessed by air pollution tolerance index (APTI). Four species of Gymnosperms (Thuja orientiales, Cedrus deodara, Pinus roxburghii and Araucaria bidwillii) were evaluated for APTI. Leaves were collected during winter season from polluted sites (Airport, Dhumbarahi, Jawalakhel, Ratnapark, and Sankhapark) and less polluted site (Narayanthan) of Kathmandu valley. Of four gymnosperm species collected from road side, all species (Cedrus deodara, Araucaria bidwillii, Thuja orientiales and Pinus roxburghii) showed high value of APTI (i.e., more than 8), indicating their resistance to air pollution.ECOPRINT 24: 13-19, 2017

Unintentional path dependence: Australian guitar manufacturing, bunya pine and legacies of forestry decisions and resource stewardship

ABSTRACTAustralian guitar manufacturers are increasingly competitive globally, known for quality, design, and sustainability. Also distinguishing Australian guitar making is the use of native timbers—a result of unforeseen historical endowments of available trees from earlier eras of colonial appropriation and State-sponsored planting. We develop a critical-materialist, and historical, evolutionary economic geography to trace an example of unintentional path dependence. Present craft-based manufacturing is linked to past regimes of resource stewardship. We illustrate this through the example of the bunya pine (Araucaria bidwillii), an endemic tree with Indigenous significance now used industrially as a ‘tonewood’ in guitar making. With limited geographic range, bunya was planted by State forestry during the inter-war period, considered ‘useful’ in difficult locations where other industrial species failed. Reflecting prevailing stewardship norms, bunya trees were pruned and cared for, even though always considered marginal. Abandoned as an industrial forestry species, a half century later surviving cultivated bunya trees were rediscovered for guitar making. From this case, we argue that economic geographers remain attentive to material resource histories, as antecedent to contemporary configurations. Earlier decisions, ideologies and labour processes bestow present generations with available material resources, enabling new geographic concentrations of expertise. Acknowledging how historical materialities of resource stewardship reverberate unpredictably in the present, guitar makers and tonewood specialists are contemplating prospects for longer-term scarcities, and experimenting in anticipation of them now.

Substantial resource reallocation during germination of Araucaria bidwillii (bunya pine), an Australian rainforest conifer with large seeds and cryptogeal germination

Araucaria bidwillii has cryptogeal germination, with seedlings not starting photosynthesis for several months after imbibition. Our results indicate that this complex process is metabolically relatively efficient. Araucaria bidwillii (bunya pine, Araucariaceae), an Australian rainforest conifer, produces heavy (15–20 g fresh mass) recalcitrant seeds that feature an unusual cryptogeal germination sequence. Germination features a substantial reallocation of starch from the massive megagametophyte (12–14 g fresh mass) to the hypocotyl which progressively develops into a tuberous, belowground storage organ. While germination (radicle emergence) is very rapid after imbibition, seedlings do not commence photosynthesis for several months. We were interested in the metabolic efficiency of this lengthy and complex developmental process that depends solely on stored resources. On average, the seeds had a dry mass of 10.1 g (seed coat 29 %, megagametophyte 68 %, embryo 3 %). Over 47 days the megagametophyte lost 91 % of its mass (mainly through the almost complete export of its abundant starch reserves), while the embryo/seedling increased in mass by 19 times and the hypocotyl almost 200 times. In total, a 13–14 % loss of dry mass occurred in converting a large seed at soil level into an established seedling with substantial protected belowground reserves. If only considering the living components of the seed/seedling (i.e. excluding the substantial and woody seed coat) then an 18 % loss occurred. Comparison with its closest cryptocotylar relatives from South America (A. araucana and A. angustifolia) and a range of hypocotylar rainforest angiosperms indicates that the complicated germination sequence of A. bidwillii is relatively efficient. While A. bidwillii now has a highly disjunct and contracted distribution this would appear not to be directly related to the metabolic efficiency of its unusual germination sequence.

Encounters with Trees

Ten years ago, a colleague and I co-wrote an article about the Bunya pine tree in Queensland's literary history. In the course of our joint research, we made an interesting and surprising discovery: that there appeared to be two separate and distinct ways of seeing or imagining the Bunya in early Queensland literature – there were, in effect, two different Bunyas. One was the Romantic Bunya, a dark, gloomy, threatening tree, overwhelming in size, and sublime in its capacity to elicit awe and even terror from those nervous European explorers who found themselves surrounded by them. This is the Bunya described in Leichhardt's letters and in the novels of Rosa Praed, for whom it evoked anxieties about cannibalism among the Aboriginal tribes who gathered at the triennial feast.

Proteolytic enzymes in storage protein mobilization and cell death of the megagametophyte of Araucaria bidwillii Hook. post-germinated seeds

In the present manuscript, we report on the proteolytic enzymes acting in the Araucaria bidwillii megagametophyte throughout seed germination. At seed maturity the megagametophyte contains a bulk of reserves for the growing embryo, thus representing the major storage tissue of the bunya pine seed. Soon after seed germination the megagametophyte undergoes storage protein mobilization, degenerating as a no longer needed tissue by the late germinative stages. By using in-solution and in-gel assays, and mass spectrometric analyses we detected exopeptidases and proteinases differently active in this tissue at selected germinative stages, and obtained preliminary data on the nature of an endopeptidase active at the late stages. Early germination stages were characterized by aminopeptidase and aspartic, metallo and cysteine proteinase activities; carboxypeptidases and serine proteinases became highly active by the late stages. Partial sequencing of a protein responsible for late stage serine peptidase activity sensitive to the caspase-6 inhibitor, showed a set of amino acid sequences with various degrees of identity with various plant subtilisin-like serine proteinases. The participation of the early stage proteases in the storage protein mobilization and the involvement of the late stage proteases in the megagametophyte cell death are proposed and discussed.

Hypocotyl of seedlings of the large-seeded species Araucaria angustifolia: an important underground sink of the seed reserves

Araucaria angustifolia exhibits cryptogeal germination, where the root–hypocotyl axis emerges first and penetrates into the soil. In Araucaria bidwillii, the whole process of transferring reserves from the seed to the seedling takes place before shoot emergence, and there is a major storage of these reserves in the underground hypocotyl, which assumes a tuberous form. In A. angustifolia, the shoot emerges before seed reserves are depleted. Though it does not grow like a tuber, the hypocotyl of A. angustifolia grows thicker than the adjacent taproot during initial growth, and we hypothesize that it may act as a major sink for seed reserves during this stage. The study tests this hypothesis by evaluating changes in the mass of different plant parts during initial growth. Four harvests were conducted during a ~6-month period to compare the dry mass of different fractions (attached seed, seedling, its shoot and root and the hypocotyl) of seedlings growing under darkness and high light. While seed reserves were still being depleted, the hypocotyl mass showed an initial increase and then a reduction. This was more abrupt when light was available. After seed mass had stabilized, the mass of the hypocotyl continued to decrease in the dark-grown seedlings, but showed a second increase in the light-grown ones. Results confirm the hypothesis that the hypocotyl represents a major sink for the seed reserves of A. angustifolia, acting as an underground storage structure for the growing seedling. Its reserves seem to be important for sustaining initial shoot growth and might also act as a storage sink for photosynthates.

Diversity of soil and rhizosphere fungi under Araucaria bidwillii (Bunya pine) at an Australian tropical montane rainforest site

Samples of rhizosphere soil and bulk soil were collected from under Araucaria bidwillii in a tropical montane rainforest at Mount Lewis forest reserve, Queensland, Australia. DNA was extracted from soil and denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified partial rDNA internal transcribed spacer (ITS) regions of rhizosphere and bulk soil samples compared. Neither canonical analysis of the principal coordinates nor principal component analysis revealed clear separation of soil samples according to their origin in rhizosphere or bulk soil. Following amplification of rDNA ITS regions using the primers ITS1-F and ITS4, restriction fragment length polymorphism (RFLP) and sequence analyses were also used to identify fungal sequences that were present in clone assemblages from rhizosphere soil and bulk soil. A total of fifty-three RFLP types were thus identified, with the majority being ascomycetes and the remainder basidiomycetes or zygomycetes. Nine RFLP types had affinity with Mortierellaceae, and phylogenetic analysis indicated that these probably represent multiple Mortierella species in both rhizosphere and bulk soil samples. Similar evidence was obtained for the presence of multiple Trichosporon species. RFLP type 53 from a bulk soil sample was identified as a Soil Clone Group I ascomycete, confirming the widespread occurrence of this group.

Converting Australian tropical rainforest to native Araucariaceae plantations alters soil fungal communities

Native rainforest tree plantations are increasingly viewed as potentially important for high value timber production and provision of a range of ecological services in tropical and subtropical areas. In order to determine the extent to which conversion of rainforest to native Araucariaceae plantation influences soil fungi, we compared soil fungal communities under native rainforest and 73–74 year-old Araucaria bidwillii, Araucaria cunninghamii and Agathis robusta plantations at Gadgarra State Forest, Queensland, Australia. Following direct extraction of DNA from soil, terminal restriction fragment length polymorphism (T-RFLP) analysis of rDNA internal transcribed spacer (ITS) regions was conducted. Ordination analysis of the T-RFLP data revealed significant separation of the fungal communities according to forest type along the first canonical axis, with the native rainforest samples separating from the three Araucariaceae plantations along the second axis. Overall, the most abundant ITS sequences in clone assemblages from the four forest types were Ascomycota, followed by Basidiomycota, Zygomycota and Chitridomycota, however their relative importance varied in individual forest types. The results indicate that conversion of tropical rainforest to monoculture plantations of native trees can significantly alter soil fungal diversity.

Investigation on cell death in the megagametophyte of Araucaria bidwillii Hook. post-germinated seeds

The megagametophyte of the Araucaria bidwillii seed is a storage tissue that surrounds and feeds the embryo. When all its reserves are mobilized, the megagametophyte degenerates as a no longer needed tissue. In this work we present a biochemical and a cytological characterization of the megagametophyte cell death. The TUNEL assay showed progressive DNA fragmentation throughout the post-germinative stages, while DNA electrophoretic analysis highlighted a smear as the predominant pattern of DNA degradation and internucleosomal DNA cleavage only for a minority of cells at late post-germinative stages. Cytological investigations at these stages detected profound changes in the size and morphology of the megagametophyte nuclei. By using in vitro assays, we were able to show a substantial increase in proteolytic activities, including caspase-like protease activities during the megagametophyte degeneration. Among the caspase-like enzymes, caspase 6- and 1-like proteases appeared to be the most active in the megagametophyte with a preference for acidic pH. On the basis of our results, we propose that the major pathway of cell death in the Araucaria bidwillii megagametophyte is necrosis; however, we do not exclude that some cells undergo developmental programmed cell death.

Achievements in forest tree improvement in Australia and New Zealand 6: Genetic improvement and conservation of Araucaria cunninghamii in Queensland

Summary Araucaria cunninghamii (hoop pine) typically occurs as an emergent tree over subtropical and tropical rainforests, in a discontinuous distribution that extends from West Irian Jaya at about 0°30'S, through the highlands of Indonesian New Guinea and Papua New Guinea, along the east coast of Australia from 11°39'S in Queensland to 30°35'S in northern New South Wales. Plantations established in Queensland since the 1920s now total about 44 000 ha, and constitute the primary source for the continuing supply of hoop pine quality timber and pulpwood, with a sustainable harvest exceeding 440 000 m3 y−1. Establishment of these managed plantations allowed logging of all native forests of Araucaria species (hoop pine and bunya pine, A. bidwillii) on state-owned lands to cease in the late 1980s, and the preservation of large areas of araucarian forest types within a system of state-owned and managed reserves. The successful plantation program with this species has been strongly supported by genetic improvement activities since the late 1940s — through knowledge of provenance variation and reproductive biology, the provision of reliable sources of improved seed, and the capture of substantial genetic gains in traits of economic importance (for example growth, stem straightness, internode length and spiral grain). As such, hoop pine is one of the few tropical tree species that, for more than half a century, has been the subject of continuous genetic improvement. The history of commercialisation and genetic improvement of hoop pine provides an excellent example of the dual economic and conservation benefits that may be obtained in tropical tree species through the integration of gene conservation and genetic improvement with commercial plantation development. This paper outlines the natural distribution and reproductive biology of hoop pine, describes the major achievements of the genetic improvement program in Queensland over the past 50+ y, summarises current understanding of the genetic variation and control of key selection traits, and outlines the means by which genetic diversity in the species is being conserved.