Climate change is not only disrupting our weather and eroding our coastlines, it's also threatening our native plants.
There is a back-up plan for our indigenous flora though - seed banks. Seeds tucked away in a freezer for protection, to be used if and when is needed.
It’s not uncommon though, seed banks are in place all over the world. One of the most well known seed banking initiatives is the Svalbard Global Seed Vault, northern Norway, with more than a million samples from around the world.
“It’s a very efficient way of storing the genetic diversity of plants that are held within seeds, so you can store a large number of seeds and that genetic diversity in a relatively small area,” says Craig McGill, research officer in Seed Science and Technology at Massey University.
Boxes with seeds from around the world are saved for posterity in the seed vault in Svalbard. Photo: AFP
And with DOC classifying 403 plant species as threatened in 2017, this could be the perfect solution.
“One advantage of seed banking is that we can take those seeds that are already under threat but we can also look to bank the entire flora population and for those threats in the future that may arise that we don’t know about,” McGill says.
The national gene-bank of seeds are stored in the Margot Forde Germplasm Centre, which houses 1800 of New Zealand’s grassland species and more than 65,000 seed samples. Meanwhile, McGill’s NZ Indigenous Flora Seed Bank initiative, which started running later in 2013, has 200 species and 892 samples.
However, he says there are challenges in storing some native seeds.
In order to process them, they have to dry it down to very low moisture - an equilibrium of relative humidity of 15 percent - then store it at -20 degrees. The trouble is that that level of moisture can be too dry for some native plants to survive for long periods.
“For Kauri, they can remove the moisture and store it but they don’t know for how long it’ll survive … because seeds will eventually die in storage and what we’re trying to do with seed banking is maximise that storage life and push it out as far as we can, and that ranges across the species.”
Kauri it has been stored with some survival for six years, but after about 12 years the viability starts to drop off, McGill says.
Another challenge is that New Zealand lacks data on how long seeds will survive in storage for, he says.
“For many of the species we don’t know whether we can take the water out of them or not without them losing viability.”
On the other hand, Cryopreservation is being looked at as a possible way to extend preservation and the storage life of seeds.
“That’s where we store the seed at -196 degrees in liquid nitrogen or above the liquid nitrogen at -160, that’s more complex than the standard seed banking but for some of our species, particularly the ones that can’t be dried, that’s an approach that’s been tried.”
Volunteers can also pitch in if they’re interested in helping prepare seeds for storage, McGill says.
