For this question, let's first explore why plants have their colors. Plants use combine energy from the sun, along with water and carbon dioxide, to create sugar energy they can use; glucose. This process if called photosynthesis, and occurs in algae and some bacteria as well as in plants. To harness the energy of the particles of light (called photons), plants have specialized compartments (organelles) within cells called chloroplasts. Chloroplasts contain specialized molecules which, due to their atomic structure, can respond to single photons of light and start the chain of photosynthesis. These specialized, light-responsive molecules are also called pigments.

Pigments absorb light of different energies, and doing so, they also reflect light of different parts of the spectrum (rainbow). The main photosynthetic pigment is chlorophyll, which strongly absorbs blue and red light but not much green light, and this gives leaves their green color.

Chlorophyll is often supported by other pigments called carotenes, which give orange colors, and xanthophylls, which give yellow colors. The colors of these pigments are usually masked by the green of chlorophylls, but can show through when chlorophyll decreases in deciduous leaves preparing for winter. Some plants express anthocyanin pigments which give red color in new foliage to act as protection from damaging sunlight. Some plants, such as the European Beech, express more carotenes and xanthophylls, and these pigments can mask the green of chlorophyll, giving the leaves a year-round purple-red color.

In plants, these pigments are made by metabolic processes with in the plants cells. The proteins that produce the pigments are encoded in the DNA of the plants. If changes occur to the DNA code instructions for producing proteins, or for the regulation of the pigment-producing process, the balance of colors seen in a plant could be altered. If the change is too great (like getting rid of chlorophyll altogether) the plant may not be able to gather enough light energy to survive.

To address the rest of this question, let's briefly address radiation:

Some heavy atomic elements, such as uranium and plutonium, can split into unstable lighter forms and in the process energy is released as radioactivity. These energy-releasing elements can be found in nature, but are produced in large quantities from nuclear weapons and nuclear energy production. Normally, the radioactive elements from nuclear power production are disposed of in a controlled manner, but if anaccident occurs, the waste can be released into the environment.

Scientific researchers sometimes use radioactive energy to change the DNA of theorganisms they're studying. These DNA changes are called mutations. They can use the information about the effects of the mutations to understand the genetics of the system they are studying. Mutations in the genes for the proteins that manage or produce pigments in plants could potentially change the colors of the resulting plants.

If there was enough radioactive contamination in the environment to change the DNA of organisms, but not too much to kill them all, you might see slightly altered versions of organisms. For example, in the area surrounding the nuclear power plant that exploded in 1986 in Chernobyl, Ukraine, the plants and animals exposed to high radiation have been studied. Some birds show partial feather color change due to DNA changes, and some trees grow irregularly due to the contamination.

So, after a long explanation, it does seem possible that after exposure to radiation, plants could gain changes in their DNA that might lead to changes in their coloration. However, for a whole plant to change, the mutations would need to be present when the plant was very young, like a seed. The changes would also have to allow the plant to still survive and photosynthesize, so the color changes would have to be within the physically possible range of existing pigments. Also, over time, if the plants did not grow and reproduce as well as unaffected plants, the mutated plants would not persist over several generations.

It is possible but there are a lot of conditions which would need to be met. The mutation caused by the radiation would have to be early in the plants development, for example while it was still a seed, so that the entire plant would show the new colors.Also, the pigment which gives a plant its green color is chlorophyll. And the reason we see the green light is because that is the one color the plant doesn't use. So if the plant was reflecting red and purple light it would need to be in a light environment that had enough of the other colors of light coming in so that it could produce enough energy to survive. While there are a lot of conditions to be met it is certainly possible.

Answer #3Hi Lancelot,No and yes. Mutations don't do much of anything to the individual that gets exposed to the fallout; they affect its offspring. A mutation certainly could affect a plant embryo or a pollen grain or some such enough to cause it to change color. However, the green color in plants is due to their chlorophyll, the pigment that allows them to get energy from sunlight. Without that, the plant would die fairly quickly.