Canadian Forest Service Publications
Anthocyanins of jack pine (Pinus banksiana) seedlings. 2002. Nozzolillo, C.; Isabelle, P.; Andersen, O.M.; Abou-Zaid, M.M. Canadian Journal of Botany 80: 796-801.
Available from: Great Lakes Forestry Centre
Catalog ID: 20593
Purpling of the needles of jack pine seedlings in forest tree nurseries in the autumn is a result of the production of at least five anthocyanin pigments: cyanidin 3-O-glucoside (80%), delphinidin 3-O-glucoside (8%), peonidin 3-O-glucoside (8%), petunidin 3-O-glucoside (3%) and malvidin 3-O-glucoside (trace). The twigs subtending the needles also produce a similar range of pigments. The entire spectrum of pigments is produced from the time of the first exposure to freezing temperatures. Proanthocyanidins are a prominent feature of the needle phenolics and the question of their possible involvement in the purpling phenomenon following exposure to sub-zero temperatures is raised. The red colour of the hypocotyl of the newly germinated seedling is also a result of a similar mixture of pigments.