Agronomy and Horticulture, Department of


Document Type


Date of this Version

July 1978


Published in JOURNAL OF RANGE MANAGEMENT 31 (4), July 1978. Copyright 1978. Used by permission.


Radioactive carbon dioxide was utilized to trace carbohydrate translocation in blue grama, sideoats grama, and switchgrass. Tagged tillers retained 77% of their fixed carbon following a 24-hour translocation period. The roots were the strongest sink of assimilate, receiving 76.2% of the total 14C translocated. The pre-elongated and elongated tiller fractions received 16.3% and 7.5% of the 14C translocated, respectively. Major differences among the grasses became evident upon examination of relative total activity (RTA) ratios in elongated/pre-elongated tillers and root/shoot fractions. Switchgrass produced many more elongated tillers and had the highest elongated/pre-elongated RTA ratio. Blue grama had the greatest weight of pre-elongated tillers, a strong above-ground sink, and therefore had the lowest root/ shoot RTA ratio. Sideoats grama had RTA ratios similar to those of blue grama.