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Botanists collaborate to secure future of rare Tasmanian plant

19/08/2009

The Royal Tasmanian Botanical Gardens is working towards securing the future of a rare and ancient Tasmanian native plant discovered by legendary tin miner and naturalist Deny King.

The project involves a collaborative effort by botanists and staff from the RTBG, DPIPWE's Threatened Species Section and the Plant Science Department of the University of Tasmania.

Lomatia tasmanica, commonly known as King's Lomatia, is critically endangered with less than 500 plants growing in the wild in a tiny pocket of Tasmania's isolated south west.

The RTBG has been propagating the plant from cuttings since 1994 and efforts over the past four years have introduced the species into tissue culture at the UTAS Department of Plant Science.

Lomatia tasmanica has proven to be a difficult customer to grow away from its wild home but the RTBG has nearly reached its goal to produce a conservation collection of 50 plants.

RTBG horticulturist botanist Natalie Tapson said that unlike many plants which reproduce from seed, King's Lomatia is a sterile clone which reproduces new plants by suckering in the wild.

"Fossil leaves of the plant found in the south west were dated at 43,600 years old and given that the species is a clone, it is possibly the oldest living plant in the world," Natalie said.

While Deny King first found the species growing in 1934, it was only formally described by renowned Tasmanian Herbarium botanist the late Dr Winifred Curtis in 1967, two years after the King family collected a flower from the wild.

Natalie said King's Lomatia grows as a shrub or small tree up to eight metres in height.

"It has broad leathery divided leaves and after about seven years produces clusters of waxy burgundy flowers at the ends of the branches," she said.

"There are 46 examples of the shrub in the RTBG's conservation collection of 130 threatened species. They are multi-branched due to repeated cutting for propagation material and usually flower in December."

The challenge to propagate the plant and secure an ex-situ conservation collection has created huge interest in botanical circles.

It is believed climate change already has led to the decline of King's Lomatia in the wild and humidity and moisture variants in a controlled environment have affected propagation.

It is susceptible to repeated wildfire and Phytophthora (root rot) and it resents root disturbance. Major losses have occurred when potting up and transferring from pot to garden bed.

Only specimens that have been grafted on to the rootstock of another Tasmanian species, Lomatia tinctoria, have survived in the ground.

"It is a difficult plant to propagate and we have had many losses," Natalie said.

"As the species is a clone, it is an ideal candidate for proliferation in tissue culture propagation. One advantage is that large numbers of plants can be produced from small amounts of material once a species has been successfully established in vitro."

Natalie said more work needs to be done on the high incidence of "blackening" and mortality after stems are cut for tissue culture.

This work will continue but shortage of material is a problem and trials can only be carried out once a year. This has generally been done in August when the stems on the RTBG plants are relatively soft and before flowering occurs.

"The survival of explants in vitro has been increased from a few days to over eight months and research will continue with this difficult clone in the hope of mass producing it to help secure its survival into the future," Natalie said.

Botanists collaborate to secure future of rare Tasmanian plant

The rare King's Lomatia produces burgundy flowers

Botanists collaborate to secure future of rare Tasmanian plant

The RTBG has nearly reached its goal to produce a conservation collection of 50 King's Lomatia plants

Botanists collaborate to secure future of rare Tasmanian plant

King's Lomatia is an ideal candidate for proliferation in tissue culture propagation "in vitro".