Tannin Allocation in Blackbrush (Coleogyne ramosissima)
Biochemical Systematics and Ecology
Blackbrush (Coleogyne ramosissima) is a spinescent shrub occurring in nearly monospecific stands in the southwestern United States. Winter browsing by domestic goats stimulates spring twig production by blackbrush plants. Current season's twigs produced by older branches growing on the outer edges of the plant canopy (terminal branches) contained 2.37 times more tannins than did older twigs. Within blackbrush plants, current season's twigs on terminal branches contained 1.34 times more tannins than did current season's twigs on sprouts and younger branches (basal branches). When analysed separately, current season's terminal twigs contained 1.47 times more tannins than did leaves, while current season's basal twigs contained 1.10 times more tannins than did leaves. Phytochemicals, mainly phenolics, in blackbrush reduce its risk of being over-utilized by domestic herbivores, and the occurrence and distribution of tannins in blackbrush lend support to hypotheses dealing with secondary compounds as plant defenses.
Provenza, F. and Malechek, J. (1983). Tannin allocation in blackbrush (Coleogyne ramosissima). Biochemical Systematics and Ecology, 11(3): 233-238.