Can plants protect themselves against increased UV-B?
Yes, partly. Plants already have reasonable UV shielding; for most plants only a small proportion of the UV-B radiation striking a leaf actually penetrates very far into the inner tissues. Also, when exposed to an enhanced UV-B level, many species of plants can increase the UV-absorbing pigments in their tissues. Other adaptations include increased thickness of leaves which reduces the proportion of inner tissues exposed to UV-B radiation. Several repair mechanisms also exist in plants, as is the case for other organisms. This includes repair systems for DNA damage or oxidant injury. The net damage a plant experiences is the result of the balance among damage, protection and repair processes. For many plants, the net damage is negligible.
