Australian Journal of Botany
Volume 65 Number 8 2017
RESEARCH FRONT: Seeds at the Forefront: the Contribution of Australian Seed Science to Restoration, Conservation and Crop Security
Rainforests in the South Pacific are under threat as a result of ongoing logging, clearing for agriculture or mining, introduced species and other anthropogenic sources. Ex situ conservation offers a means to prevent the extinction of rainforest plants and provide a source of material for ecosystem restoration. Preliminary research to determine which species are suitable for seed banking, and which require alternative conservation methods, is urgently required.
BT17036Seed dormancy and germination of three grassy woodland forbs required for diverse restoration
Restoration is vital for the re-establishment of degraded communities, but success is often hindered by issues related to seed biology. We examined dormancy-alleviation and germination-promotion techniques for three common grassy woodland forbs required for diverse restoration. Scarification of the seed produced the highest germination for Dianella longifolia and Stackhousia monogyna, whereas germination of Dianella revoluta requires further examination. This information can advance methods to propagate these species from seed and contribute to greater understorey diversity in grassy woodland restoration.
Contributions by Australia’s crop wild relatives to plant breeding are dependent upon their availability for research via genebanks, yet the comprehensiveness of genebank collections for these species has not been assessed. We determined the state of representation of Australia’s major food crop wild relatives in ex situ conservation, identifying the gaps needing to be filled and outlining the key activities required to more fully safeguard their diversity and to increase their use.
BT17154Benefits of adopting seed-based technologies for rehabilitation in the mining sector: a Pilbara perspective
Many aspects of seed biology are often overlooked in large-scale rehabilitation programs leading to the inefficient use of seed, and, consequently, limited plant establishment success. Through targeted research programs, a large body of empirical seed-use knowledge is now available to the mining and rehabilitation sector. In this paper we highlight how this knowledge has been used to improve direct seeding practices, through large-scale seed procurement, improved seed storage protocols, seed dormancy classification for over 100 species, effective pre-treatments to promote germination, and topsoil and growth media management research
BT17155Seed ecology informs restoration approaches for threatened species in water-limited environments: a case study on the short-range Banded Ironstone endemic Ricinocarpos brevis (Euphorbiaceae)
Translocation of threatened species is challenging, especially when using direct seeding for in-situ establishment. Within Australia, ~14% of threatened species translocations use directly sown seeds with unpredictable and highly variable results. Using laboratory and field experiments, we focussed on understanding the relative importance of temperature, moisture, light, germination stimulants and sowing depth to develop a detailed seed ecology profile of the threatened shrub, Ricinocarpos brevis. Moisture was identified as the primary factor regulating germination and in situ emergence. With this knowledge, strategies to deal with this limitation can now be developed and implemented for future translocation success.
BT17152Unassisted invasions: understanding and responding to Australia’s high-impact environmental grass weeds
Alien grass species are among the worst environmental weeds in Australia. We analysed the 339 currently naturalised species and found 17 to seriously impact diverse environments across Australia. Available evidence suggests their success was assisted by ecological novelty, high propagule pressure and an ability to respond to, and even alter, natural disturbance regimes. New management approaches will be needed to negate these natural advantages.
The peer-reviewed and edited version of record published online before inclusion in an issue
BT17174Autophagy is associated with male sterility in pistillate flowers of Maytenus obtusifolia (Celastraceae)
Programmed cell death (PCD) is an organised cellular degradation and may promote sterility during reproductive development. We investigated the cellular changes that lead to the absence of pollen in pistillate flowers of Maytenus obtusifolia and observed that PCD is promoted by autophagy. These results may contribute to a better understand of the cellular bases of plant fertility.
BT17164The influence of ethanol as a solvent on the gibberellic acid-induced germination of Brachyscome and Allittia (Asteraceae) seeds
Gibberellic acid (GA3) is a hormone often used in seed science research. Because of its low solubility in water, GA3 is commonly dissolved in a small quantity of ethanol before making up to volume with water. This low concentration of ethanol was found to affect seed germination in Brachyscome and Allittia species, so pure water is recommended for dissolving GA3 in seed trials with these species.
BT17104Does carbon storage confer waterlogging tolerance? Evidence from four evergreen species of a temperate rainforest
In evergreen rainforests, deep shade and waterlogging are two common stressors affecting seedling performance in the understorey. We tested the hypothesis that high levels of carbon storage confer shade- and waterlogging- tolerances by preventing carbon limitation under stress. Results showed that shade-tolerant species exhibited lower carbon storage and performed better under waterlogging conditions than shade-intolerant species, suggesting that carbon storage does not confer waterlogging tolerance. This information will help in understanding the dynamics of the forests where species with contrasting shade tolerance occur.
BT17151Breaking the rules: discovery of sexual deception in Caladenia abbreviata (Orchidaceae), a species with brightly coloured flowers and a non-insectiform labellum
Caladenia is unique among orchids in that it contains both species pollinated by food-foraging insects, and species pollinated by sexual deception, providing the opportunity to investigate the evolution of sexual mimicry. Here, we report a new case of pollination by sexual deception in the Caladenia filamentosa complex, a group with brightly coloured, scented flowers previously thought to be pollinated by food deception. Our findings demonstrated that sexual deception can be achieved without dull-coloured flowers and insectiform labella.
The study of the reproductive biology of promissory wild species is essential for their culture, conservation and plant breeding. We studied the breeding system, floral morphology and floral visitors of Gleditsia amorphoides. It is a tree endemic to the Chaquenean Forest of South America, with multiple uses, such as, for example, as a source of timber and products with industrial applications, such as galactomannans and saponins. Our results showed that G. amorphoides is a xenogamous species with functionally unisexual flowers that require pollinators (beetles, flies and bees) for the formation of seeds and fruits.
BT17086Floral nectaries of Heliocarpus popayanensis and Luehea divaricata (Malvaceae-Grewioideae): structure and ultrastructure
The position of floral nectaries is an important character. Nectar secretion and its relationship with floral visitors is an interesting aspect.
BT17116Genetic and environmental parameters show associations with essential oil composition in West Australian sandalwood (Santalum spicatum)
Santalum spicatum contains a valuable, terpene-rich essential oil in its heartwood. In this study we sought to improve understanding of genetic and environmental contributors to chemical variability. Results showing links of variability with genetics and the environment will be used to direct future studies which aim to improve breeding options for terpenes sought by industry. Further work should be directed at finding additional causes of terpene variation across species of Santalum, which can be used to improve commercial and conservation goals.
BT17128Population genetics of Melaleuca irbyana (Myrtaceae) the ‘swamp tea tree’ and implications for its conservation and restoration
The endangered tree Melaleuca irbyana (Myrtaceae) dominates the critically endangered, south-east Queensland swamp tea tree forest where there are active recovery programs. New populations were recently found in the Brigalow Belt outside its previously known range and were found to be genetically distinct. The species populations contain moderate genetic diversity and are not principally clonal. There is considerable differentiation among populations, particularly between the geographic regions it occupies, so care should be taken to consider local provenance in restoration plantings.
BT17175Wild seedlings of a tree endemic on granite outcrops show no evidence of inbreeding depression
Our understanding of how recruitment influences population genetic structure of plants endemic to granite outcrops is limited. I surveyed genetic diversity, growth rate and survival, and parentage of seedlings in a rare recruitment event of the granite-endemic tree Eucalyptus caesia. The seedlings were less heterozygous than adults, yet there were no trends in heterozygosity or fixation values of seedlings over 20 months to match those of adults, and no evidence for reduced growth rates or survivorship of relatively inbred offspring. E. caesia may have mechanisms in place to cope with low genetic variation and genetic insularity.
BT17091Comparison of biomass removal, nutrient manipulation and native seed addition to restore the ground layer of a degraded grassy woodland
Scalping (topsoil removal), grass canopy removal by burning or slashing, nutrient reduction by adding carbon to the soil and native plant recruitment improvement by adding seed were compared as tools for restoring Cumberland Plain Woodland ground cover. The greatest increases in native species numbers occurred when (i) the topsoil was scalped and native seed added, (ii) the grass canopy was burnt, and soil carbon and native seed added; or (iii) the grass canopy was slashed and native seed added.
Callitris glaucophylla is an iconic Australian conifer, but in much of the arid zone there has been little recent regeneration. We found that near Roxby Downs, at the arid extreme of its range, good rain in 2010/11 did not lead to seedling establishment, probably because the wet period was not long enough. Radiocarbon dating showed these trees have a maximum lifespan of ~270 years, which together with instrumental climate records suggests that here, trees of this species have only 2–8 climatic opportunities to reproduce.
These articles have been peer reviewed and accepted for publication. They are still in production and have not been edited, so may differ from the final published form.
Using bioregional variation in fire history, fire response and vital attributes as a basis for managing threatened flora in a fire-prone Mediterranean climate biodiversity hotspot
Occurrence of polyploidy in populations of Acacia dealbata Link in Southeast Tasmania and cytotypic variation in reproductive traits
Autophagy is associated to male sterility in pistillate flowers of Maytenus obtusifolia Mart. (Celastraceae)
The influence of ethanol as a solvent on the gibberellic acid-induced germination of Brachyscome and Allittia (Asteraceae) seeds
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Seed ecology informs restoration approaches for threatened species in water-limited environments: a case study on the short-range Banded Ironstone endemic Ricinocarpos brevis (Euphorbiaceae)Australian Journal of Botany 65 (8)Shane R. Turner, Wolfgang Lewandrowski, Carole P. Elliott, Luis Merino-Martín, Ben P. Miller, Jason C. Stevens, Todd E. Erickson, David J. Merritt
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Germination ecology of the endangered species Asterolasia buxifolia (Rutaceae): smoke response depends on season and lightAustralian Journal of Botany 65 (3)Justin C. Collette, Mark K. J. Ooi
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Genetic and environmental parameters show associations with essential oil composition in West Australian sandalwood (Santalum spicatum)Australian Journal of Botany (Online Early)Jessie Moniodis, Michael Renton, Christopher G. Jones, E. Liz Barbour, Margaret Byrne
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