Labeled Oxygen: Increased Diffusion Rate through Soil Containing Growing Corn Roots

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Science  23 Aug 1963:
Vol. 141, Issue 3582, pp. 735-736
DOI: 10.1126/science.141.3582.735


The diffusion of oxygen labeled with oxygen-18 through cores of wet soil increased significantly when roots of growing corn seedlings penetrated the cores. The increase was small or absent when roots grew through a layer of soft wax or a layer of water-saturated 0.5-mm glass beads, indicating that the diffusion increase was a joint effect of the roots and airfilled pores in the soil. A possible mechanism is suggested.