Plants in Peril Go Cold

Cara Santa Maria: The Huntington Botanical Gardens in San Marino, California. 120 acres. 15 thousand plant varieties. Some of which are critically imperiled. Here in this horticultural paradise, researchers are finding new ways to conserve our most treasured species. Tim Thibault is a curator who specializes in woody plants, like magnolias.

Tim Thibault: Magnolias are a wonderfully charismatic plant, huge flowers, a lot of things that people are really attracted to. But curiously, a lot of them are endangered. A recent survey by Botanic Gardens Conservation International found that 48 percent of all the world's 300 plus magnolia species are endangered.

Cara Santa Maria: Why do you think it is that magnolias specifically are endangered?

Tim Thibault: The two main threats that are listed are logging and conversion to agriculture. Those are both are population issues.

Cara Santa Maria: That’s why the Huntington’s Collection is so important. They’re preserving and protecting many endangered plant species. Oh wow.

Sean Lahmeyer: So this is one of the greenhouses where we keep our desert collection.

Cara Santa Maria: Sean Lahmeyer is a conservation specialist at the Gardens.

Sean Lahmeyer: We are in an age of an extinction--a man made extinction--and our collection is broad. And we have parts of our collection that are really valuable to the conservation process, because we can implement conservation protocols here that we would hope others would utilize out in the field.

Cara Santa Maria: Sean has his sights set on aloes and agaves, two types of succulents that are important to the Huntington’s core collections. Unfortunately, it’s not always possible to store seeds in a so-called bank or vault. So two years ago, the Gardens set out to find a way to conserve these plants. Their approach? Putting them into a deep freeze. It's called cryopreservation.

Raquel Folgado: To homogenize the samples. I want to have them all the same size.

Cara Santa Maria: Raquel Folgado is an expert in the process. She joined the team to develop a protocol, or step-by-step guide, for freezing plant tissue and bringing it back, unharmed, so it can be regrown.

Raquel Folgado: When I started I thought it was magic. And there are still parts that are kind of magic because we don't understand how they are doing what they do to recover.

Cara Santa Maria: I wanted to see first hand how the whole process works. First, they collect just the right part of the plant. That’s where Tim comes in.

Tim Thibault: This does have what for Raquel is absolute gold. It still has these viable lateral buds, and that's the material that we'll collect and she'll work with in the lab.

Cara Santa Maria: Within that bud lives a tiny cluster of cells, called a meristem, that’s actively growing. The next step? Raquel carefully removes it under the microscope.

Raquel Folgado: So now we see a small leaf there, and we know that behind is our meristem that we want to rescue.

Cara Santa Maria: She then moves the tiny piece of tissue through a series of cryoprotectant solutions--liquid baths meant to slowly prepare the cells for freezing by taking out the water and protecting them from stress. You see, freezing water can destroy the plant.

Raquel Folgado: This water with the low temperature will become ice and this cracks the cell wall or the membranes. This is the danger, actually. This is the main danger we need to avoid.

Cara Santa Maria: The water freezes and it expands and it actually damages the cells themselves.

Raquel Folgado: It cracks. Because, you have to think that the ice can be like glass. So they are crystals, and that's what we do with the cryoprotectants. We form a solid that solidifies at this low temperature. But it does not form crystals, so it will not crack the cell walls.

Cara Santa Maria: Finally, it’s time to go into deep freeze. The extreme cold of liquid nitrogen slows down the biological activity of the plant, allowing it to live in this suspended state, potentially indefinitely. Almost a cold that we can’t really imagine.

Raquel Folgado: Yeah there are, I think, there are no colder places on earth.

Cara Santa Maria: But even this unimaginable cold, more than 300 degrees below zero, can be reversed.

Sean Lahmeyer: So this is Aloe veseyi. It’s from Zambia...

Cara Santa Maria: Sean showed me a group of aloe plants that were once in deep freeze and have been successfully regrown. They seem to be trucking along, none the wiser that they were once part of this grand experiment--this frozen garden.

Sean Lahmeyer: What we are looking at here are plants out of cryopreservation and we are growing them out now continue to watch them, just making sure they look as the species should. We’re not -- we’re making sure that the cryopreservation process didn’t harm them in any way.

Cara Santa Maria: Back in the lab, hundreds more plants are waking up from their subzero slumber to find new life. It’s more than just a bank. It’s a way to preserve genetic material that’s critically imperiled. A process that could one day save the lives of thousands of plant species, species threatened by our own destructive behavior.

Raquel Folgado: It’s important because we are living in the Earth, and we need the Earth to live. The Earth does not need us. There are plants that keep treasures that might be used for the humanity to cure diseases that we have. So they can save us actually. For them to save us we should save them first.

Cara Santa Maria: And thanks to the science being done by Raquel and her team at the Huntington Gardens, we are one step closer to doing just that, preserving biological diversity and sharing crucial knowledge so these vital species can be enjoyed for generations to come. I’m Cara Santa Maria, for SoCal Connected.

Thousands of plants around the world are endangered or have gone extinct, victims of climate change, logging and habitat loss. At the Huntington Botanical Garden in San Marino, botanists are trying to save them through the science of “cryopreservation” or freezing. But succulents have a high water content that turns to destructive ice when frozen. Reporter Cara Santa Maria talks to cryopreservationist, Raquel Folgado, to see how she is working to overcome the icy challenge and if plants can be brought back to life after a deep freeze.

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