@article {50895,
	title = {Distribution and concentration of total phenolics, condensed tannins, and nordihydroguaiaretic acid (NDGA) in creosotebush (<i>Larrea tridentata)</i>},
	journal = {Biochemical Systematics and Ecology},
	volume = {30},
	number = {10},
	year = {2002},
	month = {November 1, 2002},
	pages = {905-912},
	abstract = {Shrubs have been replacing arid grasslands over large parts of the American southwest for most of the last century.  Multiple mechanisms have been proposed to explain this vegetation shift.  One hypothesis invokes allelopathy as a mechanism for maintenance of shrub dominance in former arid grasslands.  This paper focuses on the presence and distribution of  compounds with allelopathic and/or phytotoxic potential found within creosotebush [Larrea tridentata (Sess. \& Moc. ex DC.) Cov.  Total phenolics, condensed tannins and nordihydroguaiaretic acid (NDGA) were measured in nine categories of tissue within creosotebush.  Total phenolic and condensed tannin concentrations were determined using colorimetric methods while NDGA content was determined with high performance liquid chromatography (HPLC).  Total phenolics were present throughout the plant with highest concentrations in leaves (36.2 mg/g), green stems (40.8 mg/g)  and roots (mean for all root categories = 28.6 mg/g).  Condensed tannins were found in all tissues except larger woody stems (5 to 12mm in diameter) with highest concentrations in flowers (1.7 mg/g), seeds (1.1 mg/g), and roots less than 5mm in diameter (1.1 mg/g).  Flowers, leaves, green stems and small woody stems (<5mm in diameter) all contained NDGA with highest concentrations in leaves (38.3 mg/g) and green stems (32.5 mg/g).  The distribution and nature of secondary compounds are variable among various locations within the plant.  Moreover, secondary compounds are present in locations and concentrations that suggest they could have a role in allelopathic and/or phytotoxic interactions with surrounding organisms.},
	url = {/files/bibliography/02-044.pdf},
	author = {P.W. Hyder and E.L. Fredrickson and Richard E. Estell and M.R. Tellez and Gibbens, Robert P.}
}
