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Ex situ conservation techniques for Genoplesiums and Prasophyllums

Improving ex situ techniques to support threatened orchid translocations (Genoplesium and Prasophyllum) species.

Project description

The Orchidaceae is well represented on state and federal threatened species lists. In NSW, 81 taxa are currently listed under NSW TSC Act, 25% of which are critically endangered. Threatening processes such as habitat loss, browsing by native and exotic herbivores, small population size and protracted drought have contributed to these declines. In addition to this, catastrophic climate change is likely to place additional pressures on populations in the future.
Ex-situ conservation techniques developed for several threatened orchid genera have significantly reduced their risk of extinction. Translocation has enabled threatened species practitioners to increase orchid population sizes, maximise genetic diversity and protect populations from deleterious stochastic events. Furthermore, ex-situ conservation techniques improve the adaptive capacity of orchid taxa to survive climate change by providing opportunities to establish new populations in more suitable climate envelopes.
Orchids have crucial relationships with mycorrhizal fungi which are essential for seed germination and plant survival. Consequently, raising plant stock for the purposes of translocation requires complex laboratory techniques to identify and isolate orchid mycorrhizae.
There are twelve threatened Prasophyllum and seven threatened Genoplesium species with conservation projects developed under the Saving Our Species program in NSW. To date, no techniques have been developed to effectively germinate and raise seedlings for the purposes of translocation. This project aims to answer the following research questions:
  1. What fungi are required to germinate Prasophyllum and Genoplesium seeds?
  2. What is the optimal medium required for fungal growth to germinate seeds for Prasophyllum and Genoplesium?
  3. What temperatures are optimal for the germination of Prasophyllum and Genoplesium as well as the survival of their mycorrhizal fungi?
  4. What are the optimal nursery conditions that enable mature ex-situ plants to survive?
Using their specialised laboratory facilities, the Australian Plant Bank would develop orchid propagation techniques for these two genera. The program would work closely with Saving our Species SPCs who are responsible for the recovery of selected Prasophyllum and Genoplesium taxa. Coordinators would provide in kind support for the project by conducting field trips to hand pollinate plants as well as collect soil, seed and plant material.

Expected outcomes

  • Development of orchid propagation techniques to enable the establishment of ex-situ Prasophyllum and Genoplesium populations.
  • Identification and isolation of mycorrhizal fungi that play a crucial role in the germination and survival of Prasophyllum and Genoplesium;
  • Symbiotic germination of target Prasophyllum and Genoplesium taxa
The four species that are the focus of this project are G. plumosum, G. rhyoliticum, P. affine and P. petilum.

This project has been supported by the New South Wales Government's Saving our Species program through its Department of Planning, Industry and Environment.