|Title||Tarbush leaf surface terpene profile in relation to mammalian herbivory|
|Publication Type||Government Report|
|Year of Publication||1996|
|Authors||Estell R.E., Fredrickson E.L., Anderson D.M., Havstad K, Remmenga M.D.|
|Edition||Gen. Tech. Rep. INT-GTR|
|Publisher||US Forest Service|
|Keywords||diet selection, Epicuticular wax, Flourensia cernua, leaf surface chemistry, monoterpenes, sesquiterpenes|
Cattle, sheep and goats were densely stocked in pad docks containing tarbush (Flourensia cernua DC) for six to nine days and defoliation of 160 plants was recorded daily during two years. Plants were separated into high, moderate or low defoliation categories. Leaves were collected from plants during the same stage of maturity during the third year. Leaf surface compounds were extracted with ethanol and mono- and sesquiterpenes were analyzed using gas chromatography/ion trap mass spectrometry. A set of 11 variables was identified that appeared most closely related to plant defoliation categories: dry matter, ash, limonene, camphor, borneol, a copaene, B caryophyllene, a pinene, p-cymene, cis-jasmone and caryophyllene oxide concentrations. This group distinguished among all three defoliation categories (P < 0.03) when subjected to multivariate analysis. These data support the hypothesis that leaf surface chemistry is related to degree of defoliation of individual tarbush plants by livestock.