Translator Disclaimer
1 January 2018 Spectrophotometry of Artemisia tridentata to Quantitatively Determine Subspecies
Bryce A. Richardson, Alicia A. Boyd, Tanner Tobiasson, Matthew J. Germino
Author Affiliations +

Ecological restoration is predicated on our abilities to discern plant taxa. Taxonomic identification is a first step in ensuring that plants are appropriately adapted to the site. An example of the need to identify taxonomic differences comes from big sagebrush (Artemisia tridentata). This species is composed of three predominant subspecies occupying distinct environmental niches, but overlap and hybridization are common in ecotones. Restoration of A. tridentata largely occurs using wildland collected seed, but there is uncertainty in the identification of subspecies or mix of subspecies fromseed collections. Laboratory techniques that can determine subspecies composition would be desirable to ensure that subspeciesmatch the restoration site environment. In this study, we use spectrophotometry to quantify chemical differences in the water-soluble compound, coumarin. Ultraviolet (UV) absorbance of A. tridentata subsp. vaseyana showed distinct differences among A.t. tridentata and wyomingensis. No UV absorbance differences were detected between A.t. tridentata and wyomingensis. Analyses of samples from > 600 plants growing in two common gardens showed that UV absorbance was unaffected by environment. Moreover, plant tissues (leaves and seed chaff) explained only a small amount of the variance. UV fluorescence of water-eluted plant tissue has been used for many years to indicate A.t. vaseyana; however, interpretation has been subjective. Use of spectrophotometry to acquire UV absorbance provides empirical results that can be used in seed testing laboratories using the seed chaff present with the seed to certify A. tridentata subspecies composition. On the basis of ourmethods, UV absorbance values < 2.7 would indicate A.t. vaseyana and values > 3.1 would indicate either A.t. tridentata or wyomingensis. UV absorbance values between 2.7 and 3.1 would indicate a mixture of A.t. vaseyana and the other two subspecies.

Published by Elsevier Inc. on behalf of The Society for Range Management.
Bryce A. Richardson, Alicia A. Boyd, Tanner Tobiasson, and Matthew J. Germino "Spectrophotometry of Artemisia tridentata to Quantitatively Determine Subspecies ," Rangeland Ecology and Management 71(1), 87-90, (1 January 2018).
Received: 27 March 2017; Accepted: 1 July 2017; Published: 1 January 2018

mixed-effect model
seed certification
ultraviolet fluorescence
Get copyright permission
Back to Top