Establishment of an ex-situ collection and seed orchard for the endangered Grampians Globe-pea.
Dr Noushka Reiter Australian Network for Plant Conservation Inc. Canberra ACT
Sphaerolobium acanthos is an erect wiry shrub to 1 m tall with numerous spinescent, rigid, scabrous branchlets. The leaves are subulate, 2-3 mm long, initially scattered along stems, but soon falling so that the plant appears more or less leafless. One or two yellow, orange or reddish brown flowers are borne on a common peduncle; the stigma is subtended by a ring of hairs. The pod is obovate to ellipsoid. Flowers November- January (Walsh and Entwisle, 1996). The Grampians Globe-pea Sphaerolobium acanthos (Crisp, 1994) is endemic to the Grampians National Park in the state of Victoria in Australia. It was currently known from three small populations within the park and the population was believed to be 26 plants. This project has discovered an additional population of 6 plants and increased the number of known plants at Mt William to 50. Past herbarium records indicate that this species was once more widespread through the Park. Recent searches of previous localities suggest that the species no longer occurs at these sites. The plant has been tested and is susceptible and at risk from Phytophthora cinnamomi which is known to be at least near the three populations (Reiter et al, 2004). The plant has been listed under the Flora and Fauna Guarantee Act 1988. This species has recently been assessed as critically endangered under the IUCN criteria (David Cameron pers.com). Ex situ conservation methods for Fabaceae, using both seed germination techniques (Roche et al, 1997; Loyd et al, 2000 and Offord and Meagher, 2009) and micro propagation in Fabaceae and physiologically similar species (Rout, 2005; Cenkci et al, 2008; Toth et al, 2004 and Anthony et al, 2000) offer a sound basis for exploring methods for the ex-situ conservation of Sphaerolobium acanthos.
i) Seed collection.
Seed was collected from the remaining three populations in January 2015 and January 2016. The two populations that had seed collected from where the largest known population on Mt William and the new population discovered on Redmans track. Plants were bagged post natural pollination in December with stockings and seed was subsequently collected from pods that had naturally dehisced within the stockings.
A small proportion (less than 10%) of seed was collected from each of the remaining plants that produce seed in 2015 and 2016. Records of number of plants remaining in each population were recorded and add to the small existing knowledge of the species. Approximately 400 seeds were collected.
Collection of seed was not taken from Calactasia falls as cuttings of each individual, see below have struck. Seed was unable to be collected from the 4th population of 6 plants on the Northern side of the Park as these plants had been thoroughly eaten by goats.
(ii) Determination of optimum propagation methods using both seed and tissue.
The second largest population is at Calactasia Falls in the Grampians. Each plant had cutting material removed in August 2015. Each cutting was trimmed to have at least one growing node, a sliver was taken from the woody stem and the stem was then placed in both 3 g/L Indole-3 butyric Acid and 0.1% Indole-3 butyric Acid. The plants were then kept on a heat bed until cuttings struck. They were then transferred to pots and an open nursery area (Figure 1). Both concentrations worked well and over 90 % of cuttings struck.
Seed germination trials will commence in July 2015 with standard techniques for germination including scarification, hot water and smoked water (Roche et al, 1997; Loyd et al, 2000 and Offord and Meagher; 2009). Percentage seed viability will be recorded. Percentage successful germination for each method trialled will be recorded.
Figure 1: Ex-situ collection of plants propagated from cuttings from Calactasia Falls
(iii) Seed orcharding
The 60 established nursery plants will be used for seed orcharding when they mature. Any additional plants from seed germination trials will be added to this ex-situ collection.
(iv) Lodge seed with the Victorian Conservation Seedbank
Half the seed has been lodged with the Victorian Conservation Seed Bank.
If suitable collections are available after collection in summer of 2016/17 then a duplicate will be lodged with the Millennium Seed Bank at the Royal Botanic Gardens. The seed will be made available for conservation activities as required.
Aim: Seed collection from remaining plants.
Result: Completed though additional collections will be made this coming summer.
Aim: Micro propagation from tissue culture samples.
Result: Cuttings struck easily in the nursery, without the need for tissue culture. Micro-propagation trials with seed collected will commence in July 2016.
Aim: Seed testing and storage. Seed orcharding and maintenance of propagated plants at Royal Botanic Gardens Victoria.
Result: Seed stored from two populations, one population of plants grown and retained for seed orcharding, additional two populations to be added.
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Cenkci, S., Kargioglu, M., Dayan, S., & Konuk, M. (2008). In vitro propagation of an endangered plant species, Thermopsis turcica (Fabaceae). Biologia, 63(5), 652-657.
Crisp, M.D. (1994): Sphaerolobium acanthos (Fabaceae: Mirbeliae), a new species from the Grampians, Victoria. Muelleria, 8, 151-154.
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