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Dive into the research topics where Shane R. Turner is active.

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Featured researches published by Shane R. Turner.


Australian Journal of Botany | 2007

Seed dormancy and germination stimulation syndromes for Australian temperate species

David J. Merritt; Shane R. Turner; Samantha Clarke; Kingsley W. Dixon

Understanding seed germination biology and the dynamics of seed dormancy is essential to developing reliable germination techniques. This paper presents some new data and reviews recent findings from germination studies on Australian species, with respect to the role of temperature and moisture in the control of dormancy and germination. A seed-burial experiment was conducted over a 1-year period (January–December) with seeds of Acanthocarpus preissii Lehm., Astroloma xerophyllum (DC.) Sond., Gahnia grandis (Labill.) S.T.Blake, Goodenia scaevolina F.Muell. and Tersonia cyathiflora (Fenzl) J.W.Green to determine the fluctuations in temperature and moisture seeds naturally experience in the buried environment. All seeds became hydrated during autumn (March) while soil temperatures were >15°C, suggestive of a period of warm stratification before the onset of cooler winter temperatures appropriate for germination. Evidence of rapid wetting and drying of seeds in the soil environment was also present. Laboratory experiments testing stratification as a means for dormancy loss showed that several weeks of warm stratification at 26/13°C or 33/18°C promoted germination of Lomandra preissii (Endl.) Ewart, Marianthus bicolor (Putt.) F.Muell. and Xyris lanata R.Br. seeds. X. lanata seeds also responded to several weeks of cold stratification at 5°C. By integrating this new data with other published data on germination of Australian species, diagrammatic models of germination timing, dormancy syndromes and propagation strategies for temperate Australian species are presented as working hypotheses to help direct future research.


Trends in Plant Science | 2011

Little evidence for fire-adapted plant traits in Mediterranean climate regions

S. Don Bradshaw; Kingsley W. Dixon; Stephen D. Hopper; Hans Lambers; Shane R. Turner

As climate change increases vegetation combustibility, humans are impacted by wildfires through loss of lives and property, leading to an increased emphasis on prescribed burning practices to reduce hazards. A key and pervading concept accepted by most environmental managers is that combustible ecosystems have traditionally burnt because plants are fire adapted. In this opinion article, we explore the concept of plant traits adapted to fire in Mediterranean climates. In the light of major threats to biodiversity conservation, we recommend caution in deliberately increasing fire frequencies if ecosystem degradation and plant extinctions are to be averted as a result of the practice.


Seed Science Research | 2006

Effects of a butenolide present in smoke on light-mediated germination of Australian Asteraceae

David J. Merritt; M. Kristiansen; Gavin R. Flematti; Shane R. Turner; Emilio L. Ghisalberti; Robert D. Trengove; Kingsley W. Dixon

This study investigated the effects of 3-methyl-2H-furo[2,3-c]pyran-2-one, a germination active butenolide present in plant-derived smoke, gibberellic acid and smoke water on seeds of Australian Asteraceae exposed to different light regimes. Seeds of all species required light, with maximum germination occurring under white light, or light dominated by 640 nm. Compared to untreated seeds, butenolide increased germination of Angianthus tomentosus, Gnephosis tenuissima, Myriocephalus guerinae, Podolepis canescens and Rhodanthe citrina at suboptimal light wavelengths and in the dark to a level equal to, or greater than, smoke water. Germination of Erymophyllum glossanthus and Gnephosis acicularis was not promoted by butenolide or smoke water under any light regime. The action of gibberellic acid was compared to that of butenolide for three species (Angianthus tomentosus, Myriocephalus guerinae and Podolepis canescens), and both compounds were found to stimulate germination. This study provides evidence that butenolide can act in a similar fashion as gibberellic acid in promoting seed germination of light-sensitive seeds. The ecological significance of these findings is discussed.


Seed Science Research | 2005

Physical dormancy in seeds of six genera of Australian Rhamnaceae

Shane R. Turner; David J. Merritt; Carol C. Baskin; Kingsley W. Dixon; Jerry M. Baskin

Physical dormancy (PY) was identified in six genera representative of Australian Rhamnaceae and subsequently was broken, based on identification of key seed dormancy characteristics: (1) isolation and classification of embryo features; (2) imbibition experiments to determine the rate and amount of water uptake in seeds; and (3) determination of optimum temperature regimes for germination. All six species had relatively large spatulate embryos. Imbibition studies showed all species possessed PY (i.e. a water-impervious seed coat) that was broken by a hot-water treatment. Alleviation of PY resulted in high germination (<70%) at 7/18°C, temperatures similar to winter in south-west Western Australia. Germination was suppressed at higher temperatures and in the presence of light. The study adds information to our knowledge of seed dormancy in Australian Rhamnaceae, and highlights the benefits of understanding dormancy states in seeds prior to evaluating dormancy-release mechanisms on wild species used in restoration ecology and horticulture.


Australian Journal of Botany | 2007

The contribution of in vitro technology and cryogenic storage to conservation of indigenous plants

Eric Bunn; Shane R. Turner; M. Panaia; Kingsley W. Dixon

In vitro culture has enabled a variety of recalcitrant and threatened plant taxa to be micropropagated in the absence of viable conventional propagation methods. Cryogenic storage research has provided alternative protocols for efficient long-term germplasm storage for many plant species. Recent advances in tissue-culture methods such as somatic embryogenesis have enabled the production of >20 000 somatic embryos of a recalcitrant native Australian rush in a few months, far higher than other in vitro methods for these types of plants. Cryogenic protocols are reported for >30 species of Australian vascular plants, seed and numerous mycorrhizal fungi (mainly orchid spp.), greatly extending the range and type of material that can be stored through the application of cryogenic methods. The role of in vitro and cryogenic research initiatives in botanic gardens for plant biodiversity conservation and restoration is discussed, using examples of successful ex situ conservation through tissue-culture and cryogenic-storage research.


In Vitro Cellular & Developmental Biology – Plant | 2011

Cryopreservation of threatened native Australian species—what have we learned and where to from here?

Anja Kaczmarczyk; Shane R. Turner; Eric Bunn; Ricardo L. Mancera; Kingsley W. Dixon

Cryogenic storage techniques have been developed and adopted for more than 100 (mainly agricultural) plant species worldwide, and within Australia, at least 30 critically endangered plants have been stored long term using cryogenic approaches. Nevertheless, there are many species that are very difficult to store using current procedures, and organizations involved in plant germplasm conservation (such as botanic gardens, agricultural institutions, etc.) that utilise cryogenic storage techniques are in some respects at a crossroads in their endeavours to cheaply and effectively store a wide selection of species and genotypes for conservation and agricultural/horticultural purposes. For taxa that are not amenable to current cryogenic approaches, new ways of developing cryogenic storage techniques need to be investigated, including research into the ways in which cell membranes interact and change when cooled to cryogenic temperatures (−196°C in liquid nitrogen) in the presence of various cryoprotective agents. This review highlights the current state of cryogenic research both within Australia and internationally, provides a case study on threatened plant species and also describes several new research initiatives that aim to provide answers to why some native species are quite amenable to widely utilised cryogenic approaches whilst others are currently non-responsive. New approaches aim to integrate laboratory and membrane modelling paradigms to provide guidelines for the development of new cryopreservation protocols and to assess the robustness of theoretical models in predicting optimum cryogenic conditions.


Annals of Botany | 2010

Prior hydration of Brassica tournefortii seeds reduces the stimulatory effect of karrikinolide on germination and increases seed sensitivity to abscisic acid

Rowena L. Long; Kimberlyn Williams; Erin M. Griffiths; Gavin R. Flematti; David J. Merritt; Jason Stevens; Shane R. Turner; Stephen B. Powles; Kingsley W. Dixon

BACKGROUND AND AIMS The smoke-derived compound karrikinolide (KAR(1)) shows significant potential as a trigger for the synchronous germination of seeds in a variety of plant-management contexts, from weed seeds in paddocks, to native seeds when restoring degraded lands. Understanding how KAR(1) interacts with seed physiology is a necessary precursor to the development of the compound as an efficient and effective management tool. This study tested the ability of KAR(1) to stimulate germination of seeds of the global agronomic weed Brassica tournefortii, at different hydration states, to gain insight into how the timing of KAR(1) applications in the field should be managed relative to rain events. METHODS Seeds of B. tournefortii were brought to five different hydration states [equilibrated at 15 % relative humidity (RH), 47 % RH, 96 % RH, fully imbibed, or re-dried to 15 % RH following maximum imbibition] then exposed to 1 nm or 1 microm KAR(1) for one of five durations (3 min, 1 h, 24 h, 14 d or no exposure). KEY RESULTS Dry seeds with no history of imbibition were the most sensitive to KAR(1); sensitivity was lower in seeds that were fully imbibed or fully imbibed then re-dried. In addition, reduced sensitivity to KAR(1) was associated with an increased sensitivity to exogenously applied abscisic acid (ABA). CONCLUSIONS Seed water content and history of imbibition were found to significantly influence whether seeds germinate in response to KAR(1). To optimize the germination response of seeds, KAR(1) should be applied to dry seeds, when sensitivity to ABA is minimized.


Annals of Botany | 2008

Occurrence of Physical Dormancy in Seeds of Australian Sapindaceae: A Survey of 14 Species in Nine Genera

A. Cook; Shane R. Turner; Jerry M. Baskin; Carol C. Baskin; Kathryn J. Steadman; Kingsley W. Dixon

BACKGROUND AND AIMS Sapindaceae is one of 16 angiosperm families whose seeds have physical dormancy (PY). However, the extent and nature of PY within this family is poorly known. The primary aims of this study were: (1) to evaluate seed characteristics and determine presence (or not) of PY within nine genera of Australian Sapindaceae; and (2) to compare the frequency of PY across the phylogenetic tree within Australian Sapindaceae. METHODS Viability, imbibition and seed characteristics were assessed for 14 taxa from nine genera of Sapindaceae. For five species of Dodonaea, optimal conditions for germination and dormancy break were evaluated. An in situ burial experiment was performed on D. hackettiana seeds to identify the factor(s) responsible for overcoming PY. Classes of dormancy and of non-dormancy for 26 genera of Sapindaceae were mapped onto a phylogenetic tree for the family. KEY RESULTS Mean seed viability across all taxa was 69.7 %. Embryos were fully developed and folded (seven genera) or bent (two genera); no endosperm was present. Seeds of all five Dodonaea spp. and of Distichostemon hispidulus had PY. Hot-water treatment released PY in these six species. Optimal germination temperature for seeds of the four Dodonaea spp. that germinated was 15-20 degrees C. Following 5 months burial in soil, 36.4 % of D. hackettiana seeds had lost PY and germinated by the beginning of the winter wet season (May). Laboratory and field data indicate that dormancy was broken by warm, moist temperatures (> or =50 degrees C) during summer. CONCLUSIONS PY occurs infrequently in genera of Sapindaceae native to Australia. Seeds of Dodonaea and Distichostemon had PY, whereas those of the other seven genera did not. Seeds of these two genera and of Diplopeltis (a previous study) are the only three of the 20 native Australian genera of Sapindaceae for which germination has been studied that have PY; all three belong to subfamily Dodonaeoideae.


Annals of Botany | 2009

Identification and characterization of the water gap in the physically dormant seeds of Dodonaea petiolaris: a first report for Sapindaceae

Shane R. Turner; A. Cook; Jerry M. Baskin; Carol C. Baskin; R. E. Tuckett; Kathryn J. Steadman; Kingsley W. Dixon

BACKGROUND AND AIMS The Sapindaceae is one of 17 plant families in which seed dormancy is caused by a water-impermeable seed or fruit coat (physical dormancy, PY). However, until now the water gap in Sapindaceae had not been identified. The primary aim of this study was to identify the water gap in Dodonaea petiolaris (Sapindaceae) seeds and to describe its basic morphology and anatomy. METHODS Seed fill, viability, water-uptake (imbibition) and other characteristics were assessed for D. petiolaris seeds. The location and structure of the water gap were investigated using a blocking experiment, time series photography, scanning electron microscopy and light microscopy. Dodonaea petiolaris seeds with PY also were assessed for loss of PY at four ecologically significant temperatures under moist and dry conditions. Seeds of three other species of Sapindaceae were examined for presence of a water gap. KEY RESULTS The water gap in D. petiolaris seeds was identified as a small plug in the seed coat adjacent to the hilum and opposite the area where the radicle emerges. The plug was dislodged (i.e. water gap opened = dormancy break) by dipping seeds in boiling water for 2.5 min or by incubating seeds on a moist substrate at 20/35 degrees C for 24 weeks. Layers of cells in the plug, including palisade and subpalisade, are similar to those in the rest of the seed coat. The same kind of water gap was found in three other species of Sapindaceae, Diplopeltis huegelii, Distichostemon hispidulus and Dodonaea aptera. CONCLUSIONS Following dormancy break (opening of water gap), initial uptake of water by the seed occurs only through the water gap. Thus, the plug must be dislodged before the otherwise intact seed can germinate. The anatomy of the plug is similar to water gaps in some of the other plant families with PY.


In Vitro Cellular & Developmental Biology – Plant | 2011

Biotechnology for saving rare and threatened flora in a biodiversity hotspot

Eric Bunn; Shane R. Turner; Kingsley W. Dixon

The Southwest Australian Floristic Region (SWAFR) is a plant biodiversity hotspot with a geographically isolated and predominantly endemic flora. Known threatening processes (i.e. excessive clearing of native vegetation, soil salinity, soil erosion and chronic weed infestation) combined with uncertain but potentially deleterious environmental (climate) changes pose great challenges for conservation and restoration efforts. With a paucity of nature reserves, in situ protection of species can be problematic. For many species, ex situ conservation becomes the only viable strategy for saving species from extinction via seed banking or living collections established through vegetative propagation, or tissue (in vitro) culture methods. Development of specific in vitro protocols is necessary to successfully initiate culture lines, with considerable development of nutrient media, plant growth regulator regimes and incubation conditions required to optimise shoot regeneration and multiplication, especially with woody species of the SWAFR. In addition, integration of root induction and acclimatization stages has allowed significant improvements in speed and success of plant production of both endangered and difficult-to-propagate woody species. We contend that there is also considerable potential for expansion of alternative in vitro technologies such as somatic embryogenesis for difficult taxa to complement existing ex situ conservation and restoration strategies in biodiversity hotspots such as SWAFR.

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David J. Merritt

University of Western Australia

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Eric Bunn

University of Western Australia

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Adam T. Cross

University of Western Australia

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Anja Kaczmarczyk

Botanic Gardens and Parks Authority

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Todd E. Erickson

University of Western Australia

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