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Deep freeze may save plants from global warming

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The planet’s temperature is rising and the environmental impacts are complex and catastrophic. 2016 was the hottest year on record and, in Australia, 7,000 hectares of mangroves stretching along the Gulf of Carpentaria died of thirst. A perfect storm of higher temperatures, prolonged drought and an El Nino-related reduction in sea levels meant it took just a month for the mangroves, which spanned 10,000 kilometres from Queensland to the Northern Territory, to be wiped out.

In 2016, 7,000 hectares of mangroves stretching along the Gulf of Carpentaria died of thirst (stock photo).

The rapidity of the mangroves’ demise shocked scientists, who described the destruction as the worst of its kind in the world. Professor Ricardo Mancera, School of Pharmacy and Biomedical Sciences, who is leading a research project aimed at preserving the seeds of threatened species, believes the environmental catastrophe serves as a warning.

“The recent large-scale demise of recalcitrant-seeded mangroves in northern Australia is an ominous reminder that localised extinction of important keystone species can occur rapidly, highlighting the plight of threatened rainforests,” Professor Mancera said.

“Eastern Australia alone is estimated to have more than 1500 rainforest plant species with desiccation sensitive seeds, the majority of which are found in remnant rainforest habitats. A high proportion of them are threatened by habitat loss and global warming.”

Rainforests house some of the most diverse ecosystems on earth, however they have been under threat for decades. Approximately half of the world’s rainforests have been destroyed by development, such as land clearing for agriculture, logging, mining and road construction. Global warming and climate change are an added and ongoing risk to the survival of existing rainforests, and their plant and animal populations.

Professor Mancera’s project, ‘Advanced cryobanking for recalcitrant-seeded Australian rainforest plants’ seeks to examine the impediments to using cryobanking to successfully preserve plants, like those found in Australia’s threatened rainforests. Cryobanking is the use of deep freeze storage at liquid nitrogen temperatures (-196°C) for the long-term preservation of plant, animal and human tissues.

Eastern Australia has more than 1500 rainforest plant species with desiccation sensitive seeds (stock photo).

“Plants with recalcitrant (unorthodox) seeds are difficult to preserve because they do not survive drying and freezing. If their seeds are stored for long periods they lose their viability because of free radical damage arising from their high rate of metabolic activity,” Professor Mancera said.

“Attempts to increase their storage longevity by reducing seed moisture content, and/or lowering temperature of storage, generally exacerbates the loss of viability. Consequently, it would be highly desirable to develop suitable cryobanking approaches for their long term storage.

“In this project we specifically want to obtain fundamental knowledge about these two major impediments by using a combination of biochemical, biophysical and molecular simulation approaches, such that we can optimise cryobanking of a wide range of endangered and commercially-important Australian rainforest species.

“This will ultimately enable conservation agencies to greatly enhance their ability to preserve the unique Australian rainforest flora, which is particularly important given current and future threats due to habitat loss and global warming.”

Plants in tissue culture following full survival and regeneration after cryopreservation.

Professor Mancera said the project outcomes would also benefit areas such as food science, reproductive medicine and the Australian macadamia industry, as many valuable cultivars and endangered wild species of macadamia do not have methods for their long term storage. Australia is the world’s largest producer of macadamias, and the industry is worth more than $200M annually.

Professor Mancera’s project is funded by a four-year grant from the Australian Research Council (ARC) under the Linkage program. The grant will be administered by Curtin University, and also involves senior researchers from the Royal Melbourne Institute of Technology (RMIT) University and the University of Western Australia (UWA).

“The project will cement ongoing and productive collaborations with the Biodiversity Conservation Centre at Kings Park and, importantly, it will also expand collaborations with the Australian Plant Bank at the Australian Botanic Garden-Mount Annan (NSW),” Professor Mancera said.

“It will also consolidate a new collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and the Australian Synchrotron. The project will also establish new collaborations with leading researchers in the USA in the field of cryopreservation from the US Department of Agriculture and the University of South Dakota.”

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