Juglans cinerea is the butternut or white walnut. You’d typically find it in the eastern United States, but it’s getting harder to find. That’s thanks to Ophiognomonia clavigignenti-juglandacearum, a fungus that causes butternut canker, a fatal disease for the tree. Now butternut is endangered. Botanists are gathering seeds to help preserve the plant, but this hasn’t been a huge success because the seeds are difficult to conserve with the usual methods. Now Martin Williams and colleagues have published a new method with a 76% survival rate after seven years. The seeds are cryopreserved.
Cryopreservation means storing the seeds in liquid nitrogen, which boils at -196 ℃. The team used seeds from trees in an ex-situ conservation project in New Brunswick, Canada. The team pulled seeds that had been stored for zero, two and seven years to see how well they germinated.
They found a remarkable number of the seeds germinated, around three-quarters. Also, they discovered there was no obvious decline in the seeds after storage in liquid nitrogen, but the authors point out there are limits to this study. They write: “[W]e did not find any significant viability loss due to cryostorage after 7 years, but we do acknowledge that this is only based on one seed lot. However, the high viability of all the seed lots after 7 years post-LN is encouraging and points to minimal loss due to cryostorage conditions.”
“Although seven years is not considered very long when compared to orthodox seed sources that can be kept for 20+ years, it is better than the current storage duration for the species and validates the efforts done in safeguarding butternut through cryopreservation.”
READ THE ARTICLE
Williams, M., Brophy, M. and van der Meer, B.M. (2023) “Cryogenic storage increases the longevity of butternut (Juglans cinerea, L.) seed embryogenic axes,” Cryobiology. Available at: https://doi.org/10.1016/j.cryobiol.2023.01.002.
What is “WMP Medium” (Picture A) ?
A good question. It’s Woody Plant Medium, a medium created to help grow woody plants. For more information there’s this page: https://www.diagnocine.com/Product/Woody-Plant-Medium-w-CaCl2-and-Vitamins-wo-Sucrose-and-Agar/71568#:~:text=Woody%20Plant%20Medium%20was%20originally,salts%2C%20vitamins%20and%20amino%20acid.