Why aren't plants damaged by UV light?

Thanks to Gareth Jenkins for the answer!

Gareth - The answer is that plants have evolved very effective ways of protecting themselves from the harmful ultraviolet radiation in sunlight that causes sunburn and melanoma in humans. Although we humans can shelter from bright sunlight, exposure to UV radiation is an unavoidable hazard for plants. They need to be exposed to sunlight for photosynthesis, which fuels their growth. Plants avoid damage by sunlight in three main ways. Firstly, they reflect it by having a waxy coating and hairs on the surface of leaves. But this reduces light exposure in general and doesn't prevent UV exposure specifically. Second, plants actually make their own sunscreen and deposit it in the outer tissues. These sunscreen molecules work in the same way as our sunscreen by selectively absorbing UV wavelengths.

James - Well, that's a whole lot more convenient than applying sunscreen out of a bottle and now for that other solution.

Gareth - Thirdly, plants have effective mechanisms to repair any damage to their cells caused by UV exposure. An important feature of all these protective mechanisms is that they're stimulated when plants are exposed to UV radiation. Even very low levels of UV, such as found on a dull winter's day in the UK, are sufficient to stimulate production of the sunscreen and UV repair mechanisms. This ensures that protection is already in place when plants are subsequently exposed to high levels of UV in bright sunlight. Remarkably, plants can detect the presence of UV using a photoreceptor protein, and this causes genes to be activated that enable production of the sunscreen and damage repair mechanisms. So plants are able to avoid damage in sunlight through genetic processes, stimulated by their ability to sense and respond to UV light.