Rainforest Conservation Program
- Start date:
- 01 Jan 2013
- End date:
- 31 Dec 2018
- Dr Catherine A Offord,
Dr Karen D Sommerville,
- Project sponsors:
- The Arcadia Fund have provided 50% of the project funding over a five year period.
Supporters helping to match the Arcadia Fund include:
Tony Maxwell and Robyn Godlee,
Hon Justice Peter Garling and Jane Garling,
the Greatorex Foundation,
Dr Jan Roberts and Ken Roberts AM and
Principal Conservation Partner HSBC.
- Catherine A Offord
- Investigating germination requirements and seedbanking potential of individual species
- Banking seeds that can be conserved by seedbanking and developing alternative conservation measures for those that can’t
- Providing plants for display, interpretation and reintroduction
- Passing on lessons learned to the wider community.
Australian rainforest plants are under threat from habitat fragmentation, weeds, disease and climate change. Seedbanking is a cost effective way of conserving vulnerable plants, but not all species can survive the necessary drying and freezing.
This program focusses on assessing the storage potential of seeds from Australian rainforest species, storing those seeds suitable for seedbanking and looking for alternative conservation measures for those that are not.
Until this project commenced, little was known about how many of these species could be conserved using seedbanking techniques. The findings will be important to the restoration and management of Australia’s vulnerable rainforests.
Until this project commenced, little was known about how many of these species could be conserved using seedbanking techniques.
||Facts & Findings
||Rainforest species are often rare and seeds few, making collecting difficult
|Species germination tested
||Many species have very woody seeds; some take a long time to germinate
|Species tested for storage life in the seedbank
||While some species can tolerate drying, they may not last long in seedbank storage
|Species established as seedlings
||Seedlings are used for further research and for planting out
|Species established in tissue culture
||Tissue culture may be the only way to conserve extremely rare species
|Species tested for survival in cryostorage over liquid nitrogen (at -192°C)
||Material can be held indefinitely until needed
||Knowledge transfer is essential for landholders and restoration
|Peer-reviewed articles published
|General articles published
|Book chapters published
|Hours of training (no. students x no. hours)
||We contribute to programs in Australia and elsewhere e.g. Vietnam in 2015
Ex situ Conservation Techniques for Australian Rainforest Species
Seedbanking is an effective ex situ conservation technique for species with seeds that tolerate drying to 3-7% moisture content and long term storage at -20ºC. However, it has been estimated that as many as 50% of rainforest species may produce seeds that do not tolerate desiccation; the remainder may tolerate desiccation but may not tolerate freezing or may be comparatively short-lived in storage at -20ºC.
We investigated freezing tolerance and comparative longevity in storage for 5 Australian rainforest trees with desiccation-tolerant seeds. Seeds stored at -20ºC for 2 to 7 years were removed from storage, thawed and germinated on 0.7% agar at 20 or 25ºC with a 12 h photoperiod. Seeds that had retained their viability following freezing (germination ≥ 84%) were rehydrated for two weeks at 20ºC and 47% relative humidity then artificially aged at 43±2ºC and 60% relative humidity. Seeds were withdrawn from the aging environment at intervals of 1, 2, 5, 9, 20 and 30 days and tested for their ability to germinate. The number of days in the aging environment required to reduce germination by 50% was estimated by Probit analysis in GenStat v11. Species found to be comparatively short-lived were further tested for their ability to tolerate cryopreservation (storage in LN vapour at -192ºC) with no pre-treatment.
Of the five species tested, only Archirhodomyrtus beckleri failed to germinate following freezing. Abrophyllum ornans tolerated freezing but storage for 7 years at -20ºC reduced its germinability from 100% to 41%. The remaining three species – Caldcluvia paniculosa, Cuttsia viburnea and Quintinia verdonii – had retained viability following storage at -20ºC for 2-3 years but proved to be comparatively short-lived under artificial aging conditions (p50 < 5 days) and therefore also likely to be short-lived in storage at the standard seedbanking temperature of -20ºC. All three species tolerated storage for 1 week at -192ºC with no significant reduction in germination percentage.
Cryopreservation is likely to be the best option for long-term storage of both desiccation-sensitive and desiccation-tolerant seeds from rainforest regions.
It has been estimated that as many as 50% of rainforest species may produce seeds that do not tolerate desiccation.
Maximising the Value of Seed Collections for Horticulture and
Seed collection and processing can be a costly and time-consuming element of plant production and germplasm conservation. Understanding seed set, viability and germination, and responses to handling and storage conditions might provide information for decision-making relating to both horticultural plant production and long-term seed conservation.
In this study, two species, Backhousia citriodora and B. myrtifolia were used to model how seed characteristics should be assessed. Commonly used in horticulture and readily available from Australian seed suppliers, anecdotal industry information suggested seed viability was an issue for both species.
It was found that low seed set rather than seed viability was the reason for apparent low germination. Although seeds were found only in a small percentage of capsules, for B. citriodora 8-16.5% and for B. myrtifolia 20 & 35%, the extracted seed had relatively high germination rates; B. citriodora 74% and B. myrtifolia 94%.
This finding underlines the importance of implementing ongoing seed quality assessment to maximise effectiveness of seed collection. In addition, an examination of storage options and seed longevity indicated that an alternative seed storage method such as cryopreservation should be considered to ensure long-term conservation of germplasm of these two species.