“Rooting is the process of forcing portions of plant material to form roots in order to create a genetic clone of the original plant,” Bryars said. “We expedite this process by using a synthetic auxin, the plant hormone responsible for root formation. Auxin acts by forming a callus of undifferentiated cells which then form roots.”
Bryars said that if 50% of the cuttings root and grow into trees, that would be a success. She said they are working with terminal buds from the top of the tree and it should take about two to three years for the new-growth trees to be transplantable.
The new Pratt ginkgoes will be planted alongside Alderman Library once it has been renovated, replacing ginkgoes that are being removed to accommodate the renovation work. When ginkgo trees were first planted alongside Alderman Library, the trees were female and people unwittingly tracked the malodorous fruit into the building on their shoes. Landscapers later removed the female ginkgoes and replaced them with males taken from an earlier rooting of Pratt ginkgo cuttings.
“The collaboration with Monticello came out of the Alderman Library construction project, which requires the removal of the only genetic matches to the Pratt ginkgo we have,” said Richard Hopkins, landscape superintendent at the University’s Division of Facilities Management. “We want to continue the tradition of having ginkgo trees along the side of the library, but we also want to be assured that they will all be male trees to avoid the same issue again with the fruit. The trees don’t fruit for many years after planting, so you don’t know if you have a male or female until the tree has reached a significant size. The Pratt is male, so rooted cuttings guarantee that the trees grown from the cuttings will also all be male.”