Great Basin Naturalist Memoirs


In April and May of 1973, 24 individual plants were exposed to 14CO2 with techniques used in our other studies in the field. Seven to 8 months later, part of the plants were excavated and counted by plant part for 14C. The remainder of the plants were excavated at 13 months. The results indicated that from 3 to 20 percent of the carbon for leaves in the next year came from stems and roots of Grayia spinosa (Hook) Moq., Ceratoides lanata(Pursh) J. T. Howell, Atriplex confertifolia (Torr. & Frem.) S. Wats., Lycium pallidum Miers, Ambrosia dumosa (A.Gray) Payne, and Acamptopappus shockleyi A. Gray. Nearly all of the root segments were labeled at sampling time; however, some of the roots were labeled at higher amounts than others. Some roots had very little 14C, and these are assumed to be very new roots rather than dead roots because of their small size. The roots with high levels of 14C are assumed to be formed near the time of labeling, and those with low levels to be formed after the time of labeling. From 17 to 65 percent of the 14C fixed was recovered after 7 to 13 months.