A "Stem Well" Method of Introducing Radioisotopes into Plants to Study Food Chains

To study the transfer to material through grazing food chains in herbaceous vegetation, a well surrounding the lower stem was used to introduce the radionuclides Fe59, Sr85, and Zn65 into the vascular tissue. In most cases after 1 week the radionuclides from the wells were distributed throughout the aboveground part of the plants. Iron—59 was uniformly distributed in the folige of Sorghum and Solidago. Strontium—85 was distributed uniformly in Sorghum but remained concentrated in the stem of Solidago and did not move into the leaves. Zinc—65 moved laterally into the leaves near the point of application but its distribution in the upper portions of the plants was spotty. In Rumex, however, zinc—65 moved to all portions of the plant above the well. The same radionuclides applied as spots to the leaves did not move throughout the plant but remained concentrated at the points of application. See full-text article at JSTOR