Re: How many RAD's does it take to affect a patatoe to where it stops growing?

Michael:

You ask: How many RAD's does it take to affect a potato to where it stops growing?

I can't give you an exact answer, because I can't find anyone who has done that experiment. In general, however, plants are very resistant to ionizing radiation.

Back in the early 1950's a group at the Brookhaven National Laboratory exposed a variety of different kinds of growing plants to continuous irradiation. Potatoes (Solanum tuberosum) were "mildly affected" when exposed to 300 rads per day for 10 weeks, and "severely affected" when exposed to 600 rads per day for 10 weeks. in contrast, a human exposed to 50 rads per day would be dead in ten weeks.

Many scientists have looked at the dose of ionizing radiation required to keeps plants from germinating. This dose varies from one kind of plant to another, but it generally requires more than 50000 rad (in a single dose) to have much of an effect on germination. In contrast, a single dose of 1000 rad would be lethal to a human.

Sources:

• AH Sparrow and E Christensen: Tolerance of certain higher plants to chronic exposure to gamma rays from cobalt-60. Science 118:697-698, 1953
• DS Grosch and LE Hopwood: Biological Effects of Radiation. Academic Press, 1979.

John Moulder
Radiation Biologist
Medical College of Wisconsin