Freezing seeds: an insurance policy for the future

Seeds that don't respond well to traditional preservation techniques are called recalcitrant seeds. We're talking about seeds like acorns and conkers. Freezing them is not an option because ice forms in the seed tissue, and that will destroy them. So what can be done? 

Once we extract the seed embryos we dry them. This is crucial. Water from the embryo tissues could freeze into ice and damage the embryo. How do we do this? We use a self-made “flash dryer”. (Don't try this at home). 

Because the seed embryos are dry we can freeze them without worrying about the formation of ice. How do we do this? We use gases at very low temperatures. 

Surrounded by liquid nitrogen at about -180 °C, our seeds are frozen and safe.  They are stored inside so-called cryo-vessels, ready to be brought back to life one day. 

The seeds are stored at very cool temperatures. Think of the kitchen freezer, but 10 times colder. 

It's amazing to think that seeds can be brought back or recovered and germinated after freezing them. When they are grown in test tubes, our scientists glean new insights about bringing plants back from seeds, protecting them from disease and for agriculture.