r Therefore the external radiation which was weived was predominatly beta radiation from the contaminated surface layer of p soil. After careful consideration of all possible causal agents it seems highly Brobable that radiation is the cause of the tumorous growths on Ipomoea. How- er, it must be pointed out that we have not attempted to experimentally induce ich tumors and that no radiation induced plant tumors have been previously ees : ported in the literature to our knowledge. be We feel justified, however, in con- uding that the tumorous tissue herein described most nearly resembles radiation maged tissue. “C knowledgment. We wish to acknowledge with gratitude the suggestions made by Dr. EB. Je sus, Department of Horticulture, Oregon State College, Corvallis, Oregon. This work has been supported in part by funds contributed by the AEC under : « UNIVERSITY ANCUTVES UNIV. OF WASH. LisARIES 1 CRRRE yet Be: beontract to W=28-09-eng 33, now AT(l5=1)540, Applied Fisheries Laboratory. t ' Be eReeS smceae oe ATTRANaemematany 5ema > bol ey aT eye! ha ARcae NT Re, @ies to other parts of the plant. S i roducts are absorbed onto roots but are not translocated in significant quenti- ERARe SESeeOE S From the work of Jacotsen and Overstreet (17), it is known that fission ay ere 1 alee ary RRROOTETS SSSReT bee EK RSREO TR Tae 3wat cies SB: GH. + aA at 4 ABMSMaltaA OtaNSiy,NIG LE sie jeSTETS1.0cibakonSA aR iat oteid EE. nas MERCTLCS I oh fi AECD-3446(App. )